WATERBIRDS AS BIOINDICATORS OP WETLAND QUALITY: 
CASE STUDY OF THE MUNI-POMADZE RAMSAR SITE.
GHANA
By
ABDOURAHAMANE L SALAMATOU 
(10173906)
DEPARTMENT OF ANIMAL BIOLOGY AND CONSERVATION
of Ghana, Legon 
In partial fulfilment of the requirement for the award of 
Mphil Biodiversity Studies 
Degree
June, 2010
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(^397905
blhc
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DECLARATION
I hereby declare that this thesis is entirely the result of research work undertaken under 
the supervision of Prof. Yaa Ntiamoa-Baidu, Prof. Chris Gordon, and Dr. E.H. Owusu 
of the Department of Animal Biology and Conservation Science, University of Ghana. 
It has neither been submitted wholly nor partially to any other University for a degree. 
With the exception of reference to other people's work that I have duly acknowledged, 
all other experimental work described in this thesis was carried out by me. All forms of 
assistance received while working on this thesis have also been duly acknowledged.
Abdourahamane I. Salamatou
(Student)
Date.
Signed
Prof. Yaa Ntiamoa-Baidu
(Principal Supervisor)
Date. \ L f -  -  V ) 6 X .  -  X J > r t
Prof. Chris Gordon
(Supervisor)
Date.
Dr. E. H. Owusu
(Supervisor)
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DEDICATION
This work is dedicated to my parents, Mr Abdourahamane llliassou and Ms 
Abdourahaniane Amina Moussa for their unlimited support throughout my studies. I 
cannot thank them enough, then just to say “JAZAK ALLAHU KHAYRAN”.
I also dedicate this work to Mrs Diakite Halima for her encouragement and advice 
during my studies in Ghana
May the Almighty ALLAH bless all of you and reward you with Jannat
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ACKNOWLEDGEMENT
Allahumdullillah. I thank the Almighty Allah for helping and giving me strength to 
finish up this work.
I am forever grateful to Prof. Yaa Ntiamoa-Baidu for her support, understanding, and 
patience throughout the supervision of my thesis. I am equally grateful to Prof. Gordon 
and Dr. Owusu for serving as my supervisors and providing helpful criticism. I thank 
all of them for contributing their time and thoughts towards the completion of my 
work.
I also thank my family for their patience, love, and continued support as I worked to 
reach my goal. My appreciation goes to my friends enrolled in the Biodiversity 
(Abigail, Garshong, and Japheth) and Environmental Science programme (Nana 
Abeyie and Stephen), Mr Nassir Dabo, Safian, Atto, Kenan, Julliet, and Daniel, Peace 
among others.
I am also thankful to all members of the Zoology Department, especially Prof. 
Attuquayefio, Dr Holbech, Dr Daaparh, Mr Gbogbo, Dr Adomako of the Botany 
Department, Prof. Awaiss, Mr Amankwa of the Wildlife Division and all staff of the 
Centre for African Wetlands. My special thanks go to Prof Ofori, Dr Mensah, and Mr 
Lamptey for their assistance with the analysis o f data.
My sincere gratitude goes to Mr Ali, Mr Ankrah, Mr Ansah, and Mr KJuby who helped 
me with the field work at the Muni-Pomadze Ramsar Site, without forgetting Edem 
and Richard, both fishermen at Akosua village (MPRS)
I also appreciate the services provided by the Ecological Laboratory Centre of the 
University of Ghana.
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TABLE OF CONTENTS
DECLARATION.......................................................................................... i
DEDICATION.............................................................................................ii
ACKNOWLEDGEMENT.........................................................................iii
TABLE OF CONTENTS.......................................................... iv
LIST OF FIGURES....................................................................  ix
LIST OF TABLES......................................................................  xiii
APPENDICES................................................................................. iv
ABSTRACT...........................................................................   xvi
CHAPTER I .................................................................................... 1
INTRODUCTION.................................................................. 1
1.1 Background............................................................................................................ I
1.2 Justification.................................................................................................................7
1.3 Hypotheses............................................................................................................ g
1.4 Objectives..............................................................................................................9
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CHAPTER TWO 10
LITERATURE REVIEW......................................................................... 10
2.1 Waterbirds and Wetlands................................................................................... 10
2.2 Importance of Waterbirds................................................................................... 10
2.3 Wetland Quality.................................................................................................. 13
2.4 Factors Affecting Habitat Use by Waterbirds................................................... 15
2.4.1 Waterbird abundance and diversity....................................................................15
2.4.2 Waterbird distribution in wetlands....................................................................16
2.4.3 Foraging birds.....................................................................................................17
2.4.3.1. Morphological adaptations andfeeding strategies........................................... 18
2.4.3.2. Prey distribution and availability..................................................................... 20
2.4.4 Roosting waterbirds............................................................................................22
2.5 Migration in Waterbirds.....................................................................................23
2.6 Waterbirds in Coastal Wetlands of Ghana........................................................25
2.7 Threats to Ghanaian Coastal Wetlands............................................................. 27
CHAPTER III................................................................................ 28
MATERIALS AND METHODS______________________________ 28
3.1 Study Area.......................................................................................................... 28
3.1.1 Location and size................................................................................................ 28
3.1.2 Climate and vegetation...................................................................................... 30
3.1.3 Geomorphology and soils..................................................................................31
3.1.4 Demography and socio-economics.................................................................... 32
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3.2 Methods.............................................................................................................33
3.2.1 Selection of study sites..................................................................................... 33
3.2.1.1.. Site A (Mudflat I)...............................................................................................35
3.2.1.2 Site B (Inland Water)........................................................................................35
3.2.1.3 Site C (Lagoon Mid-Section)........................................................................... 35
3.2.1.4 Site D (Mudflat II).............................................................................................35
3.2.1.5.. Site E (Seaward Site)........................................................................................ 36
32.1.6... Site SP (Salt Pond)........................................................................................... 36
3.2.2 Sampling design................................................................................................38
3.2.3 Avifaunal survey..............................................................................................40
3.2.4 Habitat use by waterbirds.................................................................................40
3.2.5 Benthic macroinvertebrate sampling...............................................................40
3.2.6 Measurement of environmental parameters....................................................41
3.3 Analysis of Data............................................................................................... 42
CHAPTER IV ...........................................................................  45
RESULTS.....................................................................................  45
4.1 Water Quality at the Muni-Pomadze Ramsar Site.......................................... 45
4.1.1 Characteristics of the Muni Lagoon.................................................................45
4.1.2 Spatio-temporal variations in physico-chemical parameters of the Muni
Lagoon.............................................................................................................................. 47
4.2 The Macrobenthic Community at the Muni-Pomadze Ramsar Site.............. 51
4.2.1 Spatio-temporal variation in the distribution and abundance of Macrobenthic
invertebrates at the Muni Lagoon.................................................................................. 5 1
4.2.2 Macrobenthic species diversity and community structure...............................62
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4.2.3 Macrobenthic invertebrate community structure.............................................. 67
4.3 Waterbirds at the Muni-Pomadze Ramsar Site.................................................69
4.3. 1......Diversity and abundance of waterbirds recorded at the Muni-Pomadze
Ramsar Site......................................................................................................................69
4.3.2 Tidal influence on waterbird abundance at the Muni-Pomadze Ramsar
Site.....................................................................................................................................72
4.3.3 Seasonal patterns in waterbird occurrence at the Muni-Pomadze Ramsar
Site.....................................................................................................................................75
4.3.4 Habitat selection by waterbirds at the Muni-Pomadze Ramsar Site...............79
4.3.4.1 Long-term changes in the habitat available for waterbirds............................ 79
4.3.4.2 Spatio-temporal variations in the abundance and distribution o f  waterbirds at 
the Muni-Pomadze Ramsar............................................................................................. 81
4.3.4.2.1 Waterbird diversity........................................................................................... 81
4.3.4.2.2 Spatio-temporal variations in the abundance and distribution of the major
waterbird groups at Muni Lagoon....................................................................................84
4.3.5 Spatio-temporal variations in habitat use by waterbirds at the MPRS............91
4.3.5.1 Roosting and feeding Birds............................................................................... 91
4.3.5.2 Spatio-temporal variations in the feeding activity o f  waterbirds....................92
4.4 Biota-Environment Interaction at the MPRS...................................................96
4.5 Muni-Pomadze Habitat Condition.................................................................. 104
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4.2.3 Macrobenthic invertebrate community structure............................................. 67
4.3 Waterbirds at the Muni-Pomadze Ramsar Site................................................ 69
4.3. 1 Diversity and abundance of waterbirds recorded at the Muni-Pomadze
Ramsar Site......................................................................................................................69
4.3.2 Tidal influence on waterbird abundance at the Muni-Pomadze Ramsar 
Site.....................................................................................................................................72
4.3.3 Seasonal patterns in waterbird occurrence at the Muni-Pomadze Ramsar 
Site.....................................................................................................................................75
4.3.4 Habitat selection by waterbirds at the Muni-Pomadze Ramsar She..............79
4.3.4.1 Long-term changes in the habitat available for waterbirds............................ 79
4.3.4.2 Spatio-temporal variations in the abundance and distribution o f  waterbirds at
the Muni-Pomadze Ramsar............................................................................................. 81
4.3.4.2.1 Waterbird diversity........................................................................................... 81
4.3.4.2.2 Spatio-temporal variations in the abundance and distribution of the major
waterbird groups at Muni Lagoon....................................................................................84
4.3.5 Spatio-temporal variations in habitat use by waterbirds at the MPRS 91
4.3.5.1 Roosting andfeeding Birds...............................................................................91
4.3.5.2 Spatio-temporal variations in the feeding activity o f waterbirds................... 92
4.4 Biota-Environment Interaction at the MPRS.................................................. 96
4.5 Muni-Pomadze Habitat Condition..................................................................104
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5.1 Muni-Pomadze Wetland Quality.....................................................................106
5.2 Waterbirds at the Muni-Pomadze Ramsar Site............................................... 116
5.2.1 Changes in waterbird populations...................................................................116
5.2.2 Seasonal patterns in the occurrence of waterbirds at the MPRS....................126
5.2.3 Tidal differences in waterbird abundance.......................................................128
5.3 Habitat Selection by Waterbirds......................................................................130
5.4 Waterbird Activities at the Muni-Pomadze Ramsar Site............................... 133
5.4.1 Comfort activities of waterbirds at MPRS......................................................134
5.4.2 Roosting activity of waterbirds....................................................................... 134
5.5 Feeding Activity of Waterbirds at MPRS.......................................................136
5.6 Waterbirds as Bioindicators of Wetland Quality............................................139
CHAPTER SIX................................................................................ 142
CONCLUSIONS AND RECOMMENDATIONS..................  142
6.1 Conclusions..................................................................................................... 142
62  Recommendations............................................................................................144
REFERENCES ........................................................................... 146
APPENDICES............................................................................................................. 174
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LIST OF FIGURES
Figure 3.1: Muni-Pomadze Ramsar Site.................................................................. -29
Figure 3.2: Rainfall Patterns, Tidal Level and Water Depth at the Muni Lagoon during
the Study Period (Sept-09 to Apr-10).....................................................................-3 2
Figure 3.3: Sampling Sites in the Muni Lagoon......................................................34
Fig*re 3.4: Spatial Variations in the Mean Water Depth at the Muni Lagoon over the
Study Period (Sept 09-Apr 10)...................................................................................37
Fig are 3.5: Sampling Points in the Muni Lagoon (Source CERGIS)__________ 39
Ffgare 4.1: Spatio-temporal Variations in Mean Turbidity (NTU) at the Muni lagoon
over the Study Period (Sept 09- Apr 10.........................................................49
Flgare 42: Spatio-temporal Variations in the Mean Temperature (°C) at the Muni
Lagoon over the Study Period (Sept 09- Apr 10).....................................................49
Flgare 43: Spatio-temporal Variations in the Mean pH at the Muni Lagoon over the
Study Period (Sept 09- Apr 10 ) .................................................................................49
Figure 4.4: Spatio-temporal Variations in the Mean Salinity (%•) at the
Muni Lagoon over the Study Period (Sept 09- Apr 10 ) .........................................50
Figure 4.5: Spatio-temporal Variations in the Mean Dissolved Oxygen (mg/L) at the
Muni Lagoon over the Study Period (Sept 09- Apr 10)...........................................50
Flgare 4.6: Spatio-temporal Variations in the Mean Conductivity (mS/cm) at the Muni
Lagoon over the Study Period (Sept 09- Apr 10).................................................... JO
Figure 4.7: Spatio-temporal Variations in the Density of Noiomasius spp. at the Muni
Lagoon over the Study Period (Sept.09- Apr. 10 ) .....................................................53
Figure 4.8: Spatio-temporal Variations in the Density of Capitella spp. at the Muni
Lagoon over the Study Period (Sept. 09-Apr. 10)...................................................... 54
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Figure 4.9: Spatio-temporal Variations in the Density and Distribution of Leiochrides
africanus at Muni Lagoon over the Study Period (Sept.09- Apr. 10).................—55
Figure 4.10: Spatio-temporal Variations in the Distribution and Density of Nephlys
spp. at the Muni Lagoon over the Study Period (Sept.09-Apr. 10)......................... 56
F ig ir t  4.11: Spatio-temporal Variations in the Distribution and Density of Neiris spp
at the Muni Lagoon over the Study Period (Sept.09- Apr. 10)................................57
Figure 4.12: Spatio-temporal Variations in the Distribution and Density of Anadara
senilis at the Muni lagoon over the study period (Sept.09- Apr. 10 ) ....................... 59
Figure 4.13: Spatio-temporal Variations in the Distribution and Density of Tellina 
spp. and other Bivalves (last figure on the right) at the Muni Lagoon over the Study
Period (Sept09- Apr. 10)...............................................................................   60
Figare 4.14: Spatio-temporal Variations in the Distribution and Density of
Amphipods at the Muni Lagoon over the Study Period (Sept09- Apr. 10).............61
Figure 4.15: Spatio-temporal Variation in the Distribution and Density of Uca sp at
the Muni Lagoon over the Study Period (Sept.09- Apr. 10)......................................61
Figare 4.16: Spatio-temporal Variations in the Density of Macroinvertebrates at
MPRS over the Study Period (Sept.09- Apr. 10)....................................................... 66
Figare 4.17: Group Average Agglomerative Dendograms of Bray-Curtis Similarity 
of Macrobenthic Faunal Abundance Data for the Six Sampling Sites over the Eight 
Months Study Period. (A) indicates Dendogram Based on Sampling Sites whereas (B) 
indicates the one based on Monthly Variations. SIMPROF test P < 0.05.
 -  68
Figure 4.18: Correlation between High and Low Tide Counts of Watertoirds found at 
MPRS belonging to Guilds 2. 3 and 4 .......................................................................74
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Figure 4.19: Monthly Variations in Waterbirds Abundance at the MPRS at Low Tide
......................................................................................................................................75
Figure 4.20: Seasonal Variations in the Abundance of the Commonest Waders (a).
Terns (b). and Herons (c).............................................................................................77
Flgare 4.21: Long-term Changes in the Muni-Pomadze Ramsar Site...................... 80
Figure 4.22: Group Average Agglomerative Dendogram of Bray-Curtis Similarity of 
Waterbird Species Abundance Data from Six Different Sites in the Muni Lagoon over
a Period of Eight Months....................................................................... .....................83
Flgare 4.23: Distribution of Waders in Muni Lagoon over the Study Period (Sept
09/Apr 10)...................................................................................................................... 84
Flgare 4.24: Spatio-temporal Variations in the Abundance and Distribution of
Waders at Different Sites of the Muni Lagoon..........................................  „...85
Flgare 4.25: Spatio-temporal Variations in the Abundance and Distribution of the
three Most Abundant Waders....................................................................................... 86
Flgare 4.26: Distribution of Terns in the Muni Lagoon over the Study Period
(Sept09/ Apr 10)........................................................................................................... 87
Flgare 4.27: Spatio-temporal Variations in the Abundance and Distribution o f Terns
at the Muni Lagoon......................................................................................................88
Figare 4.28: Distribution of Herons/egrets at the Different Sites of the Muni Lagoon
over the Study Period................................................................................................... 89
Figare 4.29: Spatio-temporal Variations in the Abundance and Distribution of
Herons and Egrets at the Muni Lagoon........................................................................90
Figure 4 JO: Group Average Agglomerative Dendogram of Bray-Curtis Similarity of 
WateTbird Feeding Activity over a Period of Eight Months.......................................96
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Figure 4.31: CCA Ordination Diagrams for the Abundance (left) and Activity (right)
of Waterbird in Relation to Environmental Variables.................................................102
Figure 432: CCA Ordination Diagrams for the Abundance of Macrobenthic Species 
(left) and Macrobenthic Major Taxa (right) in Relation to Environmental 
Variables..........................................................................................    103
Flgare 4.33: ABC plots over the Eight Months Sampling Period (Sept 09- Apr 10) in 
the Different Sections of the Muni lagoon................................................................. 105
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LIST OF TABLES
Table 3.1: Soil Percentage Composition at the Muni Lagoon................................36
Table 4.1: Summary of Statistics of Physico-chemical Characteristics o f Water
Samples....................................................................................................................... 44
Table 4.2: Interrelationships among Water Variables............................................. 46
Table 4.3: Distribution and Density of Macrobenthic Fauna at MPRS................... 62
Table 4.4: Diversity Indices of Macrobenthic Invertebrates found at the Muni
Lagoon. ........................................................................................................ ...........63
Table 4.5: Temporal Variations in Macrobenthic Community Structure.............. 64
Table 4.6: Waterbird Species and Relative Abundance at the Muni Lagoon
(September 2009/ April 2010)...................................................................................69
Table 4.7: Tidal Influence on the Relative Abundance of Waterbirds at the Muni
Lagoon (December 2009/ April 2010)......................................................................71
Table 4.8: Seasonal Variations in the Number of Bird Days Spent by Waterbirds on
MPRS........................................................................................................................ 76
Table 4.9: Waterbird Diversity Indices for Different Sites of the Muni
Lagoon........................................................................................................................80
Table 4.10: The Use of Different Sites by Waterbirds in the Muni Lagoon.........89
Table 4.11: Seasonal Changes in the Use of site A by Waterbirds........................ 91
Table 4.12: Seasonal Changes in the Use of Site B by Waterbirds.......................91
Table 4.13: Seasonal Changes in the Use of Site C by waterbirds  .........92
Table 4.14: Seasonal Changes in the Use of Site D by waterbirds....................... 92
Table 4.15: Seasonal Changes in the Use of Site E by waterbirds........................93
Table 4.16: Seasonal Changes in the Use of Site SP by waterbirds ......................93
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Table 4.17: Biota-environment Interactions in Sites BCESP from December to April 
........................................................................................................................................95
Table 4.18: Influence of Habitat Types on the Interaction between Environment and
Fauna Abundance and Activity.................................................................................... 98
Table 5.1: Waterbird Population Status at the MPRS................................................117
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APPENDICES
APPENDICES.................................................................................................... 174
Appendix I .................................. ......................................................................... 174
Appendix II: Water Quality Analysis of the Muni Lagoon................................175
Appendix III: Spatio-temporal variation in major feeding groups at MPRS.....177
Appendix IV : Biota environment interration........................................................178
Appendix V : Habitat Use by Waterbirds.............................................................. 179
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ABSTRACT
The Muni-Pomadze Ramsar Site is the fifth most important coastal wetland in Ghana. 
It was designated as a Ramsar Site in 1992, based on its internationally important tem 
populations and the total population of waterbirds supported by the site. An assessment 
of the ecological character of the MPRS, habitat use by waterbirds, and the value of 
waterbirds as indicators of wetland health was carried out from September 2009 to 
April 2010. This involved the use of satellite imageries in order to assess changes in 
the habitat, monthly water quality assessment, benthic macroinvertebrates sampling, 
and waterbird monitoring. The habitat analysis showed that the size of the Muni 
Lagoon decreased by 50% from 1990 to 2007; the extent of herbaceous shrubs 
decreased by 99%; and the infrastructural development in the area quadrupled. The 
water quality analysis showed that Muni remains a shallow, hypersaline lagoon even 
though the salinity ranges recorded were lower compared to previous years as a result 
of the opening of the connection between the lagoon and the sea. A total of 1,723 
individuals belonging to 10 groups of macrobenthic invertebrates were recorded. Of 
these, polychaetes- Annelida constituted 90.71%, bivalves- Mollusca 7.84% and the 
crustaceans-Arthropoda 1.45%. Muni Lagoon is clearly a stressed environment as its 
benthic population was dominated by a single taxon (Capitellid worms) and influenced 
by the fluctuating high temperature and salinity. Thirty-three waterbird species 
belonging to eight families were recorded, with a cumulative total sighting of 14.342 
individual birds, of which waders represented 67% terns 28% and herons 5%. The 
results show decreases in the species as well as populations of waterbirds when 
compared to the counts recorded in 1986-1998. Changes have occurred also in the 
waterbird community structure of the MPRS, with the Ringed Plover Charidrius 
hialicula now being the most abundant wader species instead of the Curlew Sandpiper
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Calidris ferruginea which was the most abundant in the 1986-1998 counts. The site 
however still supports nationally important populations of five wader species. 
Waterbird distribution and activity in the Muni lagoon varied not only according to 
feeding groups and guilds but also according to time and site. Using the Bray-Curtis 
similarity index, the Muni Lagoon can be categorised into three sections based on the 
waterbird distribution. The MPRS remains an important roosting site for the tem, 
which use mostly Sites C (Mid-Lagoon portion) and E (Seaward section), and foraging 
ground (mudflat areas A and D) for the non-breeding waders. Waders roosted mostly 
at Site SP (Salt Ponds). Water depth was the key factor influencing prey accessibility 
and availability for waterbirds and biomass of polychaetes was the only factor 
determining the distribution of feeding waders. The highest benthic diversity was 
recorded at Site E due to recruitment from the sea, while that of waterbird was 
recorded at Site B due to the heterogeneity of the habitat of that site. Despite the 
habitat losses and the general deterioration of the health of the MPRS, the site 
continues to support significant numbers of waterbirds, although the populations have 
gone down. Thus, based on the finding of this research, it may be concluded that 
waterbirds are not early indicators of wetland quality. Depending on what has been lost 
or gained, a change in the environmental health of a wetland may not result in changes 
in the waterbird community, such that by the time the birds stop using the altered site, 
the site may be degraded beyond redemption. It is suggested therefore that bird 
monitoring at the MPRS continues over a longer period to enable the re-assessment of 
its international importance. The management of the site should be reinforced and 
accompanied with a habitat restoration program. Changes in the waterbird community 
structure should also be further investigated.
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CHAPTER I
INTRODUCTION
1.1 Background
Waterbirds are a key biodiversity group that depend ecologically on wetlands for 
feeding, roosting, and nesting. The success of waterbirds in relation to these activities, 
and hence their survival, is determined by the quality of wetlands they encounter on 
their migratory routes.
The key factors that influence habitat selection of migratory waterbirds during the non­
breeding season are availability of food, safe roosting sites and the extent of 
disturbance (Piersma, 1994; Ntiamoa-Baidu el a!., 1998). With regard to foraging 
areas, the spatio-temporal distribution of waterbirds is largely determined by prey 
distribution and accessibility. These in turn, are strongly influenced by sediment type 
and exposition time in the case of probing waders, as well as water depth within the 
wetland (Moreira, 199S). The distribution and abundance in space and time of aquatic 
invertebrates, the primary food sources for many shorebirds, are affected by a wide 
range of biological, physico-chemical and hydrological variables such as water 
temperature variation, water quality, contaminants, and habitat alteration (Skagen and 
Oman, 1996; Pothoven et at., 2001).
The survival of any waterbird species is highly dependent upon the quality of the
wetland it inhabits during its lifetime, or at least during its annual migration cycle. The
breeding success of some waterbird spccies is positively correlated with the abundance
of resources available at the staging or stopover sites during the non-breeding period.
Of the numerous threats confronting waterbirds and wetlands, studies have shown that
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the greatest are habitat and biodiversity loss (Hill el al., 1997; International Wader 
Study Group, 2003; ZOckler el al., 2003).
Wetlands have been defined as “areas of marsh, fen, peatland or water, whether natural 
or artificial, permanent or temporary, with water that is static or flowing, fresh, 
brackish or salt, including areas of marine water, the depth of which at low tide does 
not exceed six metres"( www.ramsar.org). Globally, wetlands cover an area of 12 
million Km3 (Millennium Ecosystem Assessment, 2005), and can be classified into 
three main groups: (i) coastal/marine, (ii) inland and (iii) man-made. They may also be 
classified as (i) coral reefs, (ii) rocky marine shores, (iii) estuarine waters, (iv) 
intertidal mudflats, (v) intertidal marshes, (vi) intertidal forested wetlands, (vii) coastal 
lagoons, (viii) permanent inland deltas, (ix) freshwater lakes, (x) alpine, (xi) tundra, 
(xii) swamp forest wetlands, (xiii) oases, (xiv) aquaculture- farm pond, (xv) dams, 
(xvi) salt exploitation site, (xvii) waste water treatment areas, etc. (www .wetland.org).
Although wetlands occupy only 4% of the earth’s ice-free land surface (Prigent, 200IX 
they are among the most valuable ecosystems for human beings as well as flora and 
fauna (Millennium Ecosystem Assessment, 2005). Their importance is thus not limited 
to direct socio-economic benefit to people through resource utilisation such as fishing 
and ecotourism, but also include vital ecosystem functions such as facilitating ground 
water recharge, nutrient retention, flood and erosion control, and sediment filtration 
(Simonit el al., 2005; Ministry of Land, Forestry and Mines, 2007). Wetlands also 
represent biodiversity conservation hotspots and provide habitat not only for species 
that inhabit them permanently, but also for long-distance migrant birds, critical habitats 
during their non-breeding seasons (Ntiamoa-Baidu. 1991; Piersma and Ntiamoa-Baidu. 
1995; Thompson and Polet, 2000; van dc Kam el al., 2004; Gbogbo. 2007a).
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Wetlands are among the most threatened ecosystems in the world, being subjected to 
unsustainable resource utilisation, vegetation disturbance, habitat degradation, 
sedimentation, drainage and pollution (Millennium Ecosystem Assessment, 2005). 
These, mostly anthropogenic habitat disturbance factors have negative implications for 
the livelihood of local communities in particular (Turner el al., 1990).
In Ghana, there is increasing evidence that the rate of environmental degradation has 
increased in recent years (Gyasi el al., 1995; Ryan and Ntiamoa-Baidu, 1998) leading 
to habitat alteration and its associated effects, such as loss of biodiversity and change 
in the ecological character of wetlands, among others. Historically, wetlands have been 
considered as “wastelands” and therefore have been subjected to extensive degradation 
from (i) draining for agricultural and irrigation purposes, (ii) livestock ranching, (iii) 
solid waste disposal and (iv) dumping grounds for sewage and other pollutants 
emanating from households and industries (Ryan and Ntiamoa-Baidu, 2000). For 
example, in Ghana, increasing salt-winning has had a great impact on wetlands by 
reducing the available feeding areas for birds and limiting the abundance and diversity 
of macroinvertebrates that form the bulk of the prey for waterbirds (Gbogbo, 2007a).
Ghana's 550-km coastline includes over 90 lagoons (Mensah, 1979; Gordon. 1987; 
Gordon el al., 1998; Koranteng el al., 2000; Gbogbo. 2007b), many of which 
constitute key habitats for diverse and rare avifauna including globally important 
concentrations of migrants and restricted range species such as the Roseate Tem 
(Sterna dougalii). On the basis of the internationally important waterbird populations 
they support, and other ecological, socio-cultural and economic values that these 
coastal wetlands represent, the Government of Ghana as a contracting party' to the 
Ramsar Convention, has designated six wetlands as “Ramsar sites” (i.e.. wetlands of
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international importance, especially for waterfowls). These include one inland wetland, 
Owabi Wildlife Sanctuary, in the Ashanti region, and five coastal wetlands, namely, 
Muni-Pomadze in the Central Region, Densu Delta, Sakumo and Songor in the 
Greater-Accra Region, and Keta in the Volta Region fNtiamoa-Baidu and Gordon, 
1991; Gordon, 1996; Armah el al., 2005; Ministry of Lands, Forestry and Mines, 
2007).
Since the designation of these Ramsar Sites, Ghana has invested substantial efforts and 
resources into wetland conservation. The Ghana Coastal Wetlands Management 
Strategy document (Ntiamoa-Baidu and Gordon, 1991) essentially outlines the 
importance of, and threats to Ghana's coastal wetlands, and provides recommendations 
on strategies to maintain the ecological integrity of these vulnerable biotopes. In 1994, 
the Coastal Wetlands Management Project (CWMP) was commissioned with the 
objective of restoring and maintaining the ecological integrity of Ghana's five coastal 
wetlands. This was followed by the National Wetlands Conservation Strategy and 
Action Plan in 1999 (revised in 2007), initiated with the ultimate goal of conservation 
and sustainable use of Ghana's wetland resources through documenting strategies for 
incorporating wetland management into activities of government, communities and 
individuals within the broader context of environmental management (Ministry of 
Land, Forestry and Mines, 1999; 2007).
In order to achieve any conservation and sustainable utilisation goal, and to understand 
the functioning of wetland ecosystems, there is a need for ecological monitoring and 
surveillance programmes which often involve the use of bioindicators or biomonitors 
to complement physical monitoring. Different zoological taxa. either single or 
combined, can be used to monitor environmental alterations, and can also be classified
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as positive and negative indicators based on the information they provide. Waterbirds 
have been used as bioindicators in assessing the environmental status of wetlands with 
regard to pollution, habitat degradation, vegetation disturbance, water quality and 
resource productivity (BirdLife International, 2004). For example, changes in the 
ranges of migratory waterbirds may result from changes in habitat quality and 
mortality rates (Ogden el at., 1987). Newton (2004) also stated that a decline in 
Redshank (Tringa tot anus) populations may give indications of nesting she destruction 
through land drainage. Hence, for a biomonitor to be useful, it must be sensitive to 
changes in the variable for which it is a proxy measure, and must be predictable and 
easy to measure (Furness and Greenwood, 1993). Continuous long-term monitoring of 
the populations of bird species can therefore provide useful data in describing the 
implications of anthropogenic activities for habitat condition and biodiversity (Owusu 
et al., 2002).
Waterbirds are of interest also to scientists and/or conservationists as indicators of 
wetland status and as parameters of restoration success and regional biodiversity. 
Although waterbird populations may not provide ideal early warning signals of 
environmental deterioration, changes in their diversity and composition in a given area 
over a period of time, may be indicative of the state of the habitat (Temple and Wiens, 
1989). This is because generally the impact of habitat alteration on birdlife depends on 
what has been lost and what has been substituted in the area involved, and on the 
spatial relationships that exist in the new landscape, including the extent of 
connectivity and fragmentation. Pollutants for example, can affect birds directly 
through lethal and sub-lethal stress, or indirectly through habitat alteration (Furness 
and Greenwood, 1993). Birds accumulate heavy metals through continuous preening 
of contaminated materials off their feathers and by taking in food or water containing
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industrial effluents, polluted agricultural run-off, as well as untreated domestic and 
industrial waste. When present in high concentrations, these contaminants in addition 
to organochlorines, can affect the breeding success of waterbirds, particularly those at 
higher trophic levels (i.e., piscivores. raptors, etc.) (Furness and Greenwood, 1993).
Wetland quality, from the perspective of waterbirds, can be described inler-aJia, as the 
water quality, food availability, as well as roosting and nesting sites, which determine 
the welfare of a bird or bird community assemblages. Wetland quality is the most 
holistic factor that influences waterbird communities. It is determined by the 
ecological character of the wetland in question which is a combination of the 
ecosystem components, processes and benefits that characterise the wetland at a given 
point in time. Wetland quality in terms of its fauna, flora and hydrology also 
determines its socio-economic and cultural importance to humans directly and 
indirectly, while human activities and utilisation of the wetland could also alter the 
ecological character of the wetland (www.ramsar.org).
The ecological character of a wetland could be defined as “the sum of biological, 
physical, and chemical parametric components and their interactions which maintain 
the wetland and its products, functions and attributes” (www.ramsar.org). Any 
alteration of these attributes can either enhance or diminish the value of a site and 
therefore affect not only the habitat, and hence its value for humans, but also the 
survival of the fauna, especially the waterbirds that depend on the wetland. Changes in 
faunal diversity and use of the wetland by waterbirds could therefore provide an 
insight into the conditions of the wetland.
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1.2 Justification
The Muni-Pomadze Ramsar Site (MPRS) is an important wintering and staging area 
for migratory and resident waterbirds with total population estimated at 20,000 
(Ntiamoa-Baidu el al., 2001). The site has been classified as a “Globally Important 
Bird Area" (Ntiamoa-Baidu el al., 2000a). A total of 48 species of waterbirds (out of 
88 species found on the Ghanaian coast) have been recorded on the site, comprising 29 
species of waders, eight species of terns, two species of gulls, seven species of herons 
and egrets (ardeids), and one species each of duck and cormorant (Grimes, 1987; 
Ntiamoa-Baidu el al., 2000a). The MPRS also supports at least 21 species of mammals 
(Ryan and Attuquayefio, 2000), 31 species of herpetofauna (13 amphibians and 19 
reptiles) (Raxworthy and Attuquayefio, 2000) and 114 species of terrestrial birds 
(Ntiamoa-Baidu el al., 2000b).
The MPRS faces a number of threats, particularly unsustainable resource exploitation 
including fishing, hunting, and fuel wood harvesting, overgrazing by cattle, and 
improper farming practices such as indiscriminate slash bum agriculture that lead to 
devastating bushfires and erosion. Sanitation and waste disposal facilities of 
surrounding local communities are relatively poor, resulting in high levels of pollutants 
in the lagoon. The degradation of the wetland has largely been attributed to 
unsustainable human activities and expanding dry land coverage (Amatekpor. 1994; 
Ryan and Ntiamoa-Baidu, 1998). However, the use of the site by waterbirds was found 
to have increased by 400% between 1986 and 1998 (Ntiamoa-Baidu el al., 2000a). 
This increase was attributed to an increase in prey availability induced by inflow of sea 
water to the lagoon in 1994, and possible degradation of other coastal wetlands making 
the Muni lagoon more suitable for birds although there was no data to suggest same or
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otherwise in the other coastal wetlands (Ntiamoa- Baidu, et a l 2000a). It is therefore 
necessary to understand the extent of bird-habitat interactions and the consequences of 
habitat changes on waterbird populations. The need for such ecological study becomes 
more urgent when considered against the background of general global declines in the 
populations of Palaearctic-African migratory shorebirds (International Wader Study 
Group. 2003).
This research was intended as a continuation of 1986-1998 baseline study and the 
monitoring of the use of the MPRS by waterbirds and to test whether or not waterbirds 
provide a good indicator of the health of the Muni-Pomadze wetland ecosystem.
U  Hypotheses
• Waterbird populations and their use of the wetland habitat provide good 
indication of the quality of the Muni Pomadze Ramsar Site.
• The ecological character of the Muni Pomadze Ramsar Site has not altered in 
the past 15 years (1992-2007) since its designation as a Ramsar site.
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The main objective of the study was to assess the current ecological status of the Muni 
Pomadze wetland, the role of waterbird communities in the wetland ecosystem and the 
value of waterbirds as bioindicators of wetland ecosystem health. The specific 
objectives were to:
•  determine the ecological status of the Muni Pomadze wetland with focus on 
physical water parameters, macroinvertebrates and waterbirds.
•  compare the species diversity of waterbirds and benthic macroinvertebrates 
within different sections of the Muni lagoon.
•  determine the spatio-temporal patterns of wetland use by individual waterbird 
groups for roosting and feeding.
•  investigate the relationships between physicochemical water quality parameters 
(temperature, salinity, dissolved oxygen, conductivity, turbidity, and water 
depth) and benthos assemblages (abundance/density and diversity), and their 
influence on waterbird distribution.
•  compare present habitat conditions and bird communities to past situations.
• evaluate the potential use of waterbird species as bioindicators of wetland 
ecosystem health.
1.4 Objectives
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CHAPTER TWO
LITERATURE REVIEW
2.1 Waterbirds and Wetlands
Waterbirds belong to the orders Anseriformes, Charadriiformes, Ciconiiformes, 
Gaviiformes. Graiformes, Pelecaniformes, Podicipediformes and Procelariformes, 
(Bolduc and Afton, 2008). They are further categorised into three main groups: (i) 
Seabirds (e.g. gulls and terns), (ii) Shorebirds/Waders (e.g. plovers, sandpipers, stilts) 
and (iii) Waterfowl (e.g. ducks). Waterbirds are ecologically dependent on the 
interconnected networks of wetlands, which serve as staging or stopover sites along 
their migratory flyways. They use these habitats for foraging, nesting, roosting, 
moulting and comfort activities.
Even though wetlands are essential, dynamic biotopes that support and maintain a 
diverse community of birds through their seasonally-available resources during both 
migration and breeding periods, wetlands are limited (patchy) in their distribution on 
the terrestrial landscape (Duncan el al., 1999; Liang el al., 2002).
12  Importance of Waterbirds
Waterbirds have high aesthetic and cultural values. They are used as symbols by both
traditional communities and environmental organisations, where they serve as flagship
species, helping in the conservation of other biodiversity' components. Aside their
biological, cultural, and aesthetic values, waterbirds and terrestrial birds are also the
focus of an ever-expanding bird watchers’ community all over the world, hence
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contributing to a country's economy in general and that of the local communities in 
particular through ecotourism. Large waterbirds, such as ducks, provide good food 
sources for local communities.
In order to achieve sustainable utilisation and conservation of natural resources at the 
local national and international levels, there is the need to assess ecosystem conditions 
and changes, and to determine the necessity for active management However, in 
assessing these changes, it is practically difficult and costly to assess changes within 
the function, properties, and values of an ecosystem. Selected components can 
therefore be used as proxy measures of wider conditions. The quality of these 
indicators depends on their inter-relationship with the others. Biological components 
serving these functions are called biological indicators and may be derived from any 
level of biological organisation.
As a key biodiversity group in wetlands, waterbirds are widely used in monitoring and 
surveillance programmes as indicators of wetland value and status, as well as 
parameters of restoration success of regional biodiversity (Scott and Rose, 1996). They 
represent good ecological/environmental indicators of habitats in which they occur and 
contribute greatly to secondary productivity (Ahulu el a l 2006). The occurrence of 
waterbirds at the top of the food chain makes them sensitive to changes in their 
habitats and factors affecting those below them. Waterbirds such as seabirds are hence 
vulnerable to bioaccumulation of toxic chemicals and have been used as good 
indicators of marine pollution (Furness and Greenwood, 1993). The sensitivity of 
waterbirds to environmental changes and their high species turnover also provide a 
means to assess the ecological status of a site (Morrison. 1986; Furness and 
Greenwood, 1993).
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Colonial waterbirds are used as bioindicators of habitat quality and condition as well as 
parameters of restoration success (Scott and Rose, 1996). The bioindicators derived 
from colonial waterbirds include contaminant burden and population numbers (egg 
shell quality, growth, behaviour, mortality, presence/absence, distribution, and 
population indices, etc.). and certain suborganismal bioindicators (genotoxicity, tissue 
concentration of contaminants) (Furness and Greenwood, 1993).
Waterbird abundance is indicative of abundance of prey such as fishes and 
macroinvertebrates they feed upon. For example, a study conducted at Densu 
floodplains suggested that Common Tems for example were indicators of rich fish 
stock in the sea and in lagoons (Ahulu et al., 2006). Changes in the ranges of migratory 
waterbirds may result from changes in habitat quality and mortality rates (Ogden el al., 
1987). Increasing numbers of nesting migratory waterbirds could be as a result of the 
abundant food available at the foraging sites. Moreover, Norris el al. (2004) and 
Newton (2004) observed declines in the populations of Redshank as a result of nesting 
site destruction in summer by land drainage. Population sizes of migratory waterbird 
species are therefore influenced by conditions in more than one part of the world. 
Everything depends on what has been lost and substituted, as well as the degree of 
disturbance (Norris el al., 2004).
As compared to other taxa used as bioindicators of wetland quality, waterbirds which 
are highly conspicuous and have longer life-spans, enable scientists to carry out long­
term researches. This character is most important in conservation and environmental 
impact assessment since long-term changes in diversity, population and species 
assemblages of waterbirds are indicative of changes in the ecological character of their 
habitat. The availability of large data-bases of both survey protocols and trends in
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population size and distribution of waterbirds make them better indicators of wetland 
condition/health. Waterbirds therefore represent an important tool in biodiversity 
conservation, due to their conspicuousness, abundance, high species turnover, and 
sensitiveness to changes occurring in their habitat. They are useful in determining the 
quality of the wetland in which they live (Temple and Wiens, 1989).
2_3 Wetland Quality
“Habitat”, defined as “the resources and conditions present in an area that produce 
occupancy, including survival and reproduction by a given organism”, is of great 
importance in animal ecology and conservation science. Its quality is a determinant of 
the type and health of the organisms living in it (Johson, 2007).
According to Hall el al. (1997) habitat quality is the ability of an environment to 
provide conditions appropriate for individual and population persistence and can be 
identified at three operational levels; individual, species and population. While 
individual-specific habitat quality tends to improve the fitness of an organism in that 
environment, population-specific habitat quality tends to support the largest population 
(Franklin el al., 2000). Nonetheless, the former has a higher intrinsic rate of population 
growth and the latter, a higher carrying capacity. Individual birds will get access to 
quality food, hence maximising their chances of survival and reproduction.
An assessment of habitat quality can therefore be carried out directly by measuring 
attributes of habitat itself, or indirectly by measuring variables for individual birds 
and/or populations in different habitats to reveal variations in habitat quality or both 
(Johson, 2007). Nevertheless, habitat quality is not limited to only the immediate
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surroundings of the birds or the resources necessary for its survival and reproduction, 
but also the conditions that constrain their use (Morrison el al., 2006). It is thus 
necessary to consider the response of the birds to all factors in its environment in order 
to make conclusive deductions and understand the functioning of the birds’ ecosystem.
Financial and time constraints coupled with the feasibility and limited staff available, 
contribute to the limited knowledge available on habitat use by individual waterbird 
species and factors affecting i t  Hence, it is difficult to successfully and directly assess 
the quality of the habitat of that particular bird species or the whole population in the 
particular area. Barnes el al. (1995), for example, evaluated habitat quality for 
Northern Bobwhites (Colinus virginicmus) by quantifying grass forage quality, food 
(insect) abundance and availability o f cover.
Furthermore, Johson (2007) classified bird-based indicators of habitat quality into 
broad groups; demographic, distributional and individual condition measures to which 
behavioural observations could be added. He however noticed that most demographic 
studies were limited to abundance and reproduction, leaving the life-history of birds. 
Though not complete, such studies have yielded essential information on habitat 
quality. Some of the limitations are the fact that they did not take into consideration 
human disturbance, and also the fact that demographic data are difficult to obtain. 
They reveal only a portion of a habitat's value.
Other measures that can be used to indicate habitat quality include habitat selection 
when well described protocols are available. Changes in waterbird demographics or 
performance over a period of time or in sites displaying a gradient of a variable of 
interest may reveal variations in habitat quality. However, in some cases, birds may 
choose poor and avoid rich habitats and can further exhibit site fidelity (Rapport. 1991;
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Railsback et al., 2003). It is thus important to know and understand the ideal 
distribution of an animal and its habitat selection before using its distribution to reveal 
variations in habitat quality.
Individual condition measures (weight, growth, etc.) represent the third means of 
habitat quality assessment. However, for successful habitat quality evaluation, there 
should be a combination of demographic, distribution and individual condition 
measures. It is also important to know how spatio-temporal variations are linked and/or 
determined by habitat quality.
2.4 Factors Affecting Habitat Use by Waterbirds
2.4.1 Waterbird abundance and diversity
As a response of waterbird communities to the type, size and heterogeneity of the 
various components of wetlands, as well as migration, there is a spatio-temporal 
variability on the species-habitat relationship. The temporal variability is mainly driven 
by the influx of waterbird species during their migratory period (Page et al., 1979; 
Shuford el al., 1998; Mungula el al., 2005). The presence of different habitat types in a 
wetland increases species richness, which varies also with seasonal changes in these 
habitats. In wetlands of Central-South Chile, for example, Gonzalez-Gajardo et al. 
(2009) observed spatiotemporal fluctuations in the composition of waterbird 
assemblages as a response to the structural heterogeneity. According to Zou et al. 
(2006), of all the wetland types, the intertidal mudflats are the richest habitats both in 
terms of species richness and abundance of waterbirds.
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Furthermore, Paszkowski and Tonn (2000) suggested that the bigger a wetland is, the 
higher the number of microhabitats it may provide, hence the greater the number of 
species. In an urbanised area of the Targus Estuary, in Portugal, for example, Rosa et 
al. (2003) observed that species richness was positively influenced by wider mudflats 
and margins covered by salt marsh. Even though van de Kam et al. (2004) reported 
that migratory waterbirds are more attracted to large expanses of wetlands than the 
small ones, Hudson (1983) and Garay el al. (1991) showed that smaller wetlands could 
also maintain equally important waterbird densities and diversities. In Ghana, G bog bo 
(2007b) found that unmanaged wetlands which are smaller than the managed ones 
support higher densities of ducks and cormorants, stalking herons and fishing terns, 
and therefore the importance and conservation of which cannot be neglected.
2.4.2 Waterbird distribution in wetlands
Waterbird distribution may be categorised as large-scale and local. Large scale patterns 
in shorebird distribution are mainly altered in several ways by the natural patchy 
occurrence of wetlands (Brown and Dinsmore, 1986; Knutson el al., 1999), whereas 
local distribution is mainly influenced by the patchy food distribution within these 
wetlands (Piersma el al., 1993). Furthermore, as a result of this irregular distribution of 
prey items in the patches within wetlands, there are variations in the distribution 
patterns of shorebirds, which could be also associated with the variability of the coastal 
landscape at a regional scale (Myers el al., 1987; van Gils el al., 2003). The presence 
of safe roosting sites within a lagoon or a wetland also determines the distribution of 
roosting birds in such ecosystems (van de Kam el al., 1999; Blanc el al., 2006).
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2.43 Foraging birds
Waterbirds feed on a large variety of food ranging from macroinvertebrates (e.g. 
plovers), small fishes (Black-Winged Stilt and herons) to seeds and plants (herbivorous 
ducks). They consequently have different foraging habitats ranging from grasses 
around water bodies, shallow waters, mudflats, salt marshes, mangroves, etc. The 
benthic invertebrates, the primary food of waterbirds, strongly influence the feeding 
behaviour and distribution. Waterbird communities are therefore influenced by types, 
sizes and quantities of food available within wetlands (Murkin and Kadlec, 1986; 
Colwell and Landrum, 1993; Skagen and Oman, 1996)
According to Piersma and Ntiamoa-Baidu (1995) and Battley et al. (2003) waterbirds 
concentrate in areas with high food density. There is a strong correlation between 
densities of shorebirds and their prey (Meire, 1993; Kalejta and Hockey, 1994). 
Individual birds choose their foraging habitats based on their expected food intake rate 
rather than food density, though there is a strong correlation between bird distribution 
and food (Piersma, et al., 1993). However, in the case of visual foraging birds such as 
Grey plovers (Pluvialis squataroia), Kalejta and Hockey (1994) found that their 
densities are better predicted by prey biomass rather than abundance.
On their feeding grounds, waterbird distribution is determined by their diet and factors 
likely to influence the availability/accessibility of their food, safe roosting sites and the 
extent of disturbance, which form the basis for habitat selection during the non­
breeding period (Piersma, 1994). Furthermore, food availability of waterbirds is driven 
by their feeding adaptations and strategies, hydrology, and physiochemical 
environment of the wetland in question. Nevertheless, due to the burgeoning human
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population and its impact on waterbird habitat, human disturbance is a critical factor 
that is likely to influence their activities.
2.4.3.1 Morphological adaptations and feeding strategies
Birds have evolved several mechanisms to adapt to their niches, like specialised 
feeding methods, as well as bill and toe modifications. These morphological 
adaptations, in combination with the type of food they eat define their feeding habitat, 
the range of food they could prey upon and their feeding styles. For instance, habitat 
selection by non-diving waterbirds in terms of water depth selection depends on 
characteristic bill lengths, shapes, neck length, leg lengths and body sizes that allow 
them to feed at specific water depths. In order to facilitate the study of the feeding 
ecology of waterbirds, feeding guilds have been formed based on these character 
combinations and the way waterbirds obtained their food (Zwarts and Wannink, 1984).
Waterbirds are therefore more-or-less specialised for feeding on certain prey types, and 
whenever two species or sub-species were found to depend on the same resources, they 
both developed their restricted foraging range in order to reduce competition and 
maximise their food intake (Beukema el al., 1993). For example, even though Waders 
such as oystercatcher (Haemantopus spp.) and knots (Calidris canutus) have both 
specialised in bivalves, they have restricted range of prey sizes and feed on prey 
burrowed at a limited depth in sediment. They also select habitat with higher densities 
of benthic invertebrates (Safran el al.. 1997). In situations where there is short supply 
of food resources due to temporal or local changcs in the distribution, abundance and 
availability of their primary food resource, bird species can be induced to either change 
their feeding area or switch to their alternative preys. This switching behaviour can
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therefore be considered as an optimal foraging behaviour in that it helps maximise 
energy intake (Beukema el a l, 1993).
When displaying an optimal foraging behaviour, many waterbird species select preys 
that give the maximum energy return for the energy invested in capture (Zwarts and 
Drcnt, 1981; Ens et al., 1994). Zwarts and Drent (1981) observed oystercatchers 
switching from mussels to cockles when the banks of mussels had disappeared. During 
severe scarcity, especially after a severe winter, they either switch back to other areas 
with mussels or other areas with non-mussel prey (Zwarts and Wanink, 1993). Desprez 
et al. (1992) observed them to switch to other prey than cockles.
Ens (1982) however, observed that waterbirds do not always select prey that generate 
more energy but those whose profitability exceeds the average intake rate. He also 
found that oystercatchers hammering mussels did not select large mussels as a result of 
selectivity but profitability. They feed only on a given class of mussels and they may 
spend more time trying to feed on thick mussels. The ability of a bird to cope in a 
profitable way determines its ability to switch to its alternative prey. The success of 
switch further depends on the availability and density of the alternative prey (Zwarts et 
al., 1992) and thus on the stability and fluctuation patterns of the alternative prey. If 
unstable as well, then for a successful switch, the alternate species should show 
synchronisation in their fluctuation patterns.
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I.4.3.2 Prey distribution and availability
The physico-chemical environment of wetland directly or indirectly affects waterbird 
feeding ecology. It is direct in the sense that morphological constraints of waterbirds 
determine where they feed in different water depths and columns (Safran et al., 1997) 
and indirect through its effect on the distribution of their food.
Wetland use by waterbirds is highly dependent on the fluctuating hydrology 
(Kingsford et al., 2004) caused by unpredictable events and water chemistry (Liang et 
al., 2002) and the species-specific depth requirement (Bolduc and Afton, 2004). 
Hydrological diversity within and among wetlands, often dictates where and when 
waterbird species can access their food. Young and Chan (1997) stated that large 
wading birds such as herons and egrets, for example, choose feeding sites in drained 
fish ponds where water is shallow and fish are more concentrated. Ntiamoa-Baidu et 
al. (1998) found that small Waders feed in habitat ranging from dry mudflats to wet 
mud, and shallow water of not more than 20 cm. In coastal wetlands, foraging birds 
are more abundant at low tide when the intertidal macroinvertebrates are more 
exposed. Hence the role played by the tide in the feeding ecology of waterbirds.
Gbogbo et al. (2009) found that waterbird species belonging to Guilds 1. 3, 4 and 5 
responded significantly to decreasing water level, while those belonging to the Guild 2 
responded significantly in a second order polynomial function. Their numbers were 
hence optimum when water levels were neither too high nor too low. Some studies 
have shown that waterbird density is highest at low water depth, thus the assumption 
cannot be generalised (Kingsford et al., 2004; Holm and Clausen. 2006). Bolduc and 
Afton (2004) explained that there should be an optimum water depth at which
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waterbirds are expected to maximise their resource utilisation, otherwise it will mean 
that waterbird numbers are highest when water depth is virtually zero.
Factors such as salinity, dissolved oxygen, temperature, turbidity, sediment hardness, 
oxygen penetrability and particle size, affect waterbird distribution through their effect 
on benthic macroinvertebrates. According to Leland and Fend (1998) and Me Rae et 
al. (1998), salinity significantly affects benthic invertebrate communities as they 
exhibit differences in salinity tolerance levels (Euliss et al., 1999). During the rainy 
season, the reduction in salinity changes the benthic community structure and 
composition (Seapy, 1981; Wilcox, 1986), while Liang et al. (2002) observed a 
decrease in small benthic invertebrates with increasing salinity.
Dissolved oxygen is one of the physical parameters that determined the health of a 
water body. It gives an indication on the capability of a given water body to support 
biological processes. The optimum range for dissolved oxygen is 5-10mg/L; when it is 
below 2mg/L it becomes unfavourable to fishes and other fauna. High temperature 
values and salinity lead to environmental stress in benthic communities, whereas high 
water turbidity inhibits waterbird vision when feeding. High water temperature also 
limits light penetration that is necessary for photosynthesis of algae and phytoplankton 
that serve as primary producers in aquatic ecosystems and also represent food sources 
for benthic organisms.
Another factor such as sediment exposition time also influences bird distribution 
patterns through food availability (Kalejta and Hockey. 1994). There is high positive 
correlation between the number of Dunlin (Calidris alpina). Common Redshank 
(Tringa totanus) and Grey Plovers (Pluvialix squatarola), among others, and the width 
of the intertidal area in wash estuary. Physiognomy probably influences food
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availability in that wider sectors will have consequently longer exposition time and 
consequently allow longer feeding periods (Goss-Custard and Yates, 1992; Yates et 
al.. 1996).
Several studies have shown the importance of habitat physiognomy and preference in 
wetlands. Blanco et al. (2006) found that shorebird distribution was heterogeneous in 
the Buenos Aires (Argentina) coastal zone with estuarine saltmarsh landscape having 
higher use and providing better foraging condition. Sanderlings (Calidris alba) prefer 
sandy beaches where they occur in patches in areas where the waves have just receded 
(Morrison and Ross, 1989; Petracci, 2002). This is known to increase penetrability of 
their beak. Shorebird distribution and abundance in the Central Valley of California, 
for instance is simultaneously influenced by species habitat preferences, seasonal and 
geographic variation in habitat availability and north to south variations in climatic 
conditions (Suford et al., 1998). They also found that in some cases, habitat and 
physical variables could be used as predictors of feeding conditions.
2.4.4 Roosting waterbirds
Roosting behaviour in waterbirds is a complex phenomenon (KofTijberg et al., 2003). 
They gather in large and dense flocks, mostly in mixed species, in order to minimise 
the risk of predation for individuals, but also save energy when staying close together 
at roost. In intertidal areas, this phenomenon is mostly observed at high tide. However, 
the attendance of high tide roosts depends on actual water tables, distance to the 
nearest feeding areas, the degree of human disturbance and species specific behaviour.
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2.5 Migration in Waterbirds
Waterbird species can be classified as sedentary, nomadic or migratory. The migratory 
species experience seasonal, daily or irregular movements that may cover short 
distances (microgeographic migration) or thousands of kilometres (macrogeographic 
migration) (Linzey, 2001). Black-Crowned Cranes (BaJearica pavonina) migrating 
from southern Senegal to wetlands in Guinea-Bissau, and the Aitic Tem (Sterna 
paradisea) which travels a distance of 50,000 km between Antarctica and northern 
Scandinavia, are examples of short and long-distance migrants respectively. The Artie 
Tem has a record of covering a distance of 50,000 km in a single year (Jourdain et al., 
2007).
These periodic movements or migration of a population or part of a population of 
animals away from a region and their subsequent return to that same region is caused 
by the local depletion of harvestable prey and high cost of maintenance during 
unfavourable conditions (Ens el al., 1994). In some species with two distinct 
populations (discrete migratory and sedentary) such as the Eurasian Spoonbill 
(Platalea leucorodia) which occurs in Africa, only part of the population migrates 
during winter (Dodman and Diagana, 2007). It is also known that the cost of travelling 
by medium-sized to small waders such as Knots (Calidris spp.) from temperate regions 
to the tropics is much lower than the cost of living in the temperate regions during 
winter (Piersma el al., 1991). Knots travelling to Mauritania. Banc d'Arguin in West 
Africa save relatively about 45% of an average maintenance energy requirement spent 
if they had stayed in Europe during the northern winter.
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2.6 Waterbirds in Coastal Wetlands of Ghana
Coastal wetlands in Ghana are located in three habitat types; (i) estuaries with sandy 
shores (e.g. Esiama), (ii) brackish water lagoons/ salt pan complexes (Elmina, 
Pambros), (iii) brackish lagoons with shallow margins and mudflats (Muni, Sakumo, 
Songor and Keta). Moreover, Ghana's coastal wetlands are effectively not tidal 
systems but rather lagoons with surrounding flood plains (van de Kam et al., 2004). Of 
these lagoons, two types can be distinguished: (i) open lagoons associated with large 
rivers which have a permanent connection to the sea, and (ii) closed lagoons with sand 
dunes that can break intermittently depending on the water levels caused by heavy 
rains (Mensah, 1979; Gordon, 1987). The open system is ecologically more stable than 
the unpredictable closed ones (Finlayson et al., 2000).
Coastal wetlands are important areas for resident and wintering Palaearctic migrant 
waterbirds that use the East Atlantic and Mediterranean flyways (Smit and Piersma, 
1989; Van de Kam et al., 2004). They receive significant numbers of waterbirds from 
different breeding ranges than most wetlands in West Africa, more specifically other 
countries along the Gulf of Guinea (Altenburg et al., 1983; Tye and Tye, 1987). The 
value of the coastal lagoons of Ghana as staging and wintering grounds for migratory 
waterbirds has been documented in several publications based on data that has been 
gathered since 1986.
Out of approximately 100 wetlands found along the coastline of Ghana, eight namely 
Esiama Beach, Elmina Beach, Dcnsu Delta, and Muni, Sakumo. Keta and Songor 
Lagoons, have been recognised to be of importance in terms of total populations and 
bird species. Data gathered from these sites informed the process of designating five of
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Migration is a complex phenomenon (Bairlein et al., 2002; Rees el al., 2005) affected 
by series of factors ranging from general, seasonal environmental, ecological to 
species-specific biological and physiological factors. Thus the migration strategies 
vary according to physiological/biological characteristics of the birds and unfavourable 
climatic/environmental conditions affecting them through limitations of food 
availability. The rainy season in Africa, winter in the northern hemisphere, wind speed 
and direction arc major environmental variables that trigger migration. The effect of 
climate change on timing changes migratory behaviour at the scale of populations. As 
a result of a combination of factors, waterbirds use different migration strategies, the 
extents of which are related to their differential evolutionary fitness (Ens et al.. 1994).
There are different migration strategies by waterbirds. some of which have been 
observed in waders moving from coastal West Africa to sub-Arctic breeding grounds. 
Birds that require local or regional interspersed habitats after every short distance 
flight, like Turnstone (Arenaria inlerpres), usually hop from closely interspersed 
habitats. Others such as Dunlin (Calidris alpina) and Redshank (Tringa tot anus) skip, 
or fly long distances without stopping, whereas Red Knot (Calidris canutus) and Bar­
tailed Godwit (Limosa lapponica) jump from one part of the hemisphere to another.
Despite all this complexity of factors attributed to migration, many species of 
waterbird prefer to migrate than to stay in the northern hemisphere during winter and 
further exhibit site fidelity behaviour which can be expressed as a result of various 
selective pressures that favour individuals which have an intimate knowledge of their 
environment. Detailed knowledge of migration and its routes and stopover sites was 
derived from years of bird ringing (using metal rings and individual colour-marks) and 
recently from satellite tracking (some species) (Davidson et al., 1999).
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2.6 Waterbirds in Coastal Wetlands of Ghana
Coastal wetlands in Ghana are located in three habitat types; (i) estuaries with sandy 
shores (e.g. Esiama), (ii) brackish water lagoons/ salt pan complexes (Elmina, 
Pambros), (iii) brackish lagoons with shallow margins and mudflats (Muni, Sakumo. 
Songor and Keta). Moreover. Ghana's coastal wetlands are effectively not tidal 
systems but rather lagoons with surrounding flood plains (van de Kam et al., 2004). Of 
these lagoons, two types can be distinguished: (i) open lagoons associated with large 
rivers which have a permanent connection to the sea, and (ii) closed lagoons with sand 
dunes that can break intermittently depending on the water levels caused by heavy 
rains (Mensah, 1979; Gordon. 1987). The open system is ecologically more stable than 
the unpredictable closed ones (Finlayson et al., 2000).
Coastal wetlands are important areas for resident and wintering Palaearctic migrant 
waterbirds that use the East Atlantic and Mediterranean flyways (Smit and Piersma, 
1989; Van de Kam el al., 2004). They receive significant numbers of waterbirds from 
different breeding ranges than most wetlands in West Africa, more specifically other 
countries along the Gulf of Guinea (Altenburg et al., 1983; Tye and Tye. 1987). The 
value of the coastal lagoons of Ghana as staging and wintering grounds for migratory 
waterbirds has been documented in several publications based on data that has been 
gathered since 1986.
Out of approximately 100 wetlands found along the coastline of Ghana, eight, namely 
Esiama Beach, Elmina Beach. Dcnsu Delta, and Muni, Sakumo, Keta and Songor 
Lagoons, have been recognised to be of importance in terms of total populations and 
bird species. Data gathered from these sites informed the process of designating five of
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them (Muni, Densu, Sakumo, Songor and Keta) as Ramsar Site (Ntiamoa-Baidu, 1991; 
Ntiamoa-Baidu and Gordon 1991).
Migrant waterbirds begin to arrive on the Ghanaian coast from the end of August to 
early September and remain until April. The peak numbers however usually occur 
from September to December. Waterbirds are thus most abundant during the dry 
season when water levels in lagoons are Ailing and the shallow waters and exposed 
mudflats offer favourable condition for foraging. More than 50 species of waterbirds 
occur in coastal lagoons (Piersma and Ntiamoa-Baidu, 1995; Gbogbo, 2007a,b; 
Gbogbo el al., 2009).
Migrant waders arrive in coastal Ghana in August and reach a peak in 
November/December and most (50%) of them leave in January leaving a small portion 
which remain until final departure in April. They are observed to use more than one 
wetland during their stay on the coast of Ghana; hence the evidence of local 
movements within sites and between habitat zones (e.g. Sanderlings ringed in Essiama 
were found in Muni lagoon). Furthermore, there is a site preference character exhibited 
by some waders; Sanderlings and Oystercatchers prefer sandy beaches whereas curlew 
sandpiper, spotted redshank and avocet prefer mudflats. They are consequently found 
to be more abundant in one habitat zone than the other.
The importance of these coastal wetlands is not restricted to only their international 
important populations of birds but also the socio-cultural and economic values they 
provide to local communities. They are used for fishing, fanning and ecotourism.
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2.7 Threats to Ghanaian Coastal Wetlands
The Ghana coast is not an exception to the globally increasing urbanisation and 
industrial development that affect coastal regions worldwide. Attuquayeflo and 
Gbogbo (2001) stated that of the threats affecting coastal wetlands, land ownership, 
fishing, hunting of waterbirds, sewage disposal and pollution, cutting of mangroves, 
farming and habitat reclamation and commercial salt production greatly contribute to 
the degradation of wetlands and loss of biodiversity in Ghana. According to Gordon et 
al. (1998), wetlands such as Korle, Teshie and Kpeshie, Fosu and Benya lagoons are 
so polluted that they can no longer support life. Another prominent threat to coastal 
wetlands and therefore waterbirds in Ghana is sea level rise, which may reduce the 
intertidal mudflats areas used by waders. Habitat could be loss through erosion, 
fragmentation, pollution and even inundation, and consequently waders belonging to 
Guilds 2, 3, and 4 are most at risk, more especially against the background of the 
globally decreasing number of waterbird species.
Most studies on waterbirds and wetlands in Ghana were carried out in the Keta-Songor 
complex, the largest wetland, and few others on Sakumo. Densu. Laiwi and Mukwe 
lagoons (Gbogbo, 2007a, b; Gbogbo et al., 2009) in the Greater Accra region. Muni- 
Pomadze Ramsar site is the smallest of all the five coastal wetlands in Ghana.
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CHAPTER III
MATERIALS AND METHODS
3.1 Study Area
3.1.1 Location and size
The Muni-Pomadze Ramsar Site (5°19'-5°27’ N, 0°37-0°4r E) is located south-west 
of the coastal town of Winneba in the Central Region of Ghana (Gordon et al., 2000; 
Koranteng et al., 2000) approximately SS km west of Accra. This site was designated 
as a Ramsar Site in August 1992. It covers an area of 95 km2, which is the entire 
catchment area of three seasonal streams, the Pratu, Goaku and Muni which drain into 
the Muni Lagoon. The area of the shallow, saline lagoon is estimated at 3 km2 
(Ntiamoa- Baidu and Hollis, 1988) but may expand across the surrounding floodplain 
to 6 km2 during the rainy season. The lagoon is separated from the sea by a sand bar 
during the dry season which gets breached intermittently during the rainy season. This 
Ramsar Site also encompasses two forest reserves (Yenku A and B, and salt pans) 
(Figure 3.1).
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\ 0* 40’vt M P R S
H H > .V • • •’
!
-  M M M  Mtt K X * 0 « .
rtK*u HOC* 1  
00*fS1 i tM lv l
\ *4 \  ’ v\ \  \ v t M \ P
5*24'N a  
| >
*    4 ••
fo * " * d «V  - -  /
n £ T  	     . .  '  V
 
 V  \ ^  Ivwodi* R S • • ! - K
X « .M•
Mankwodx*
9 » 3 3 
KilOMCTftt
MUNI-POMADZE RAMSAR SITE
Figure 3.1: Muui-Pomadze Ramsar Site
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3.1.2 Climate and vegetation
The MPRS experiences a bimodal rainfall pattern with two distinct peaks and troughs 
occurring in March/April-July and September-November and December-February 
respectively. Annual precipitation is about 850 mm (Gordon el al., 2000). The mean 
annual temperature of MPRS is around 27°C with the relative humidity as measured at 
15:00 hours GMT averaging 70-80% for most part of the year and dropping to below 
65% in the dry season (Gordon et al., 2000). These climatic conditions show that the 
MPRS falls within the coastal savanna zone (Wuver and Attuquayefio, 2006).
Two meteorological stations are found at the MPRS. The first is located at Winneba to 
the east and the second at Apam to the west. The mean rainfall was highest in January 
2010 in all the stations (Figure 3.2) and the tide level was highest in October 2009. The 
highest mean water depth was however observed in February 2010 as compared to the 
mean rainfall values. There was a drop in mean rainfall values in December and a 
gradual decrease from October to December 2009 and February to April 2010 (Figure 
3.2). The open Muni Lagoon is thus influenced by both rainfall and tidal level in the 
area.
Fifty-three percent of the Ramsar Site is classified as natural vegetation. 32.5% as 
agricultural land, and the remainder as built-up areas (Gordon el al., 2000). The natural 
flora of the site is divided into four main types (Oteng-Yeboah, 1994): (i) flood plain 
vegetation (mangrove and wetland vegetation), (ii) dune vegetation, (iii) riverine 
vegetation, and (iv) terrestrial vegetation on elevated ground (combination of 
grasslands, thickets, and eucalyptus plantations) (Gordon el al.. 2000). The floodplain 
vegetation surrounding the Muni lagoon is consistent with the vegetation found at the
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shoreline of other coastal lagoons in Ghana (e.g. Sesuvium portulacastrum, Paspalum 
virginicum and Sporolohus virginicus).
3.1.3 Geomorphology and soils
The geomorphology of the MPRS can be categorised into four sections (Gordon el al., 
2000):
• Yenku Hills with a maximum height of 290 m and the Egyasimanku Hills
(max. Height = 205 m) spread from the north to the north-east and the south­
west portion of the Ramsar Site.
• A complex of estrusive and hyperbyssal rocks (greenstones) from the upper 
Brimian that serves as a basement to the western part of the catchment area.
• Lagoonal deposits of sand located in the central portion of the catchment.
• Outcrops of Tarkwaian quartzschists and biotite-homblends, with grey and 
pink phenocrysts in the eastern part of the MPRS. The sand bar separating the
lagoon from the sea is formed by the strong long shore littoral drift of sand
from the west to east direction.
Amatekpor (1994) stated that “soils of the MPRS vary with the elevated and 
undulating areas, as well as the lagoon; with higher ground on the slopes being 
occupied by the Adzintam-Mankoadzi complex (37% of the catchment), and the 
summits and steep slopes of the hills in the area, occupied by a shallow clay/ loam soil 
the Yenku-Adzimtan (12%). The fourth type of soil, the Oyibi-Muni association (11%) 
is also a poorly-drained soil with clear stratification in the sands and clays. It is the 
typical soil found in coastal lagoons in Ghana. The last types of soils, the Osibi-Bumbi 
association (39%) are low land soils with poorer drainage".
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shoreline of other coastal lagoons in Ghana (e.g. Sesuvium poriulacastrum, Paspalum 
virginicum and Sporolohus virginicus).
3 .1J Geomorphology and soils
The geomorphology of the MPRS can be categorised into four sections (Gordon el al., 
2000):
•  Yenku Hills with a maximum height of 290 m and the Egyasimanku Hills 
(max. Height = 205 m) spread from the north to the north-east and the south­
west portion of the Ramsar Site.
• A complex of estrusive and hyperbyssal rocks (greenstones) from the upper 
Brimian that serves as a basement to the western part of the catchment area.
• Lagoonal deposits of sand located in the central portion of the catchment.
• Outcrops of Tarkwaian quartzschists and biotite-homblends, with grey and 
pink phenocrysts in the eastern part of the MPRS. The sand bar separating the 
lagoon from the sea is formed by the strong long shore littoral drift of sand 
from the west to east direction.
Amatekpor (1994) stated that "soils of the MPRS vary with the elevated and 
undulating areas, as well as the lagoon; with higher ground on the slopes being 
occupied by the Adzintam-Mankoadzi complex (37% of the catchment), and the 
summits and steep slopes of the hills in the area, occupied by a shallow clay/ loam soil, 
the Yenku-Adzimtan (12%). The fourth type of soil, the Ovibi-Muni association (11%) 
is also a poorly-drained soil with clear stratification in the sands and clays. It is the 
typical soil found in coastal lagoons in Ghana. The last types of soils, the Osibi-Bumbi 
association (39%) are low land soils with poorer drainage”.
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The topography of the Muni-Pomadze Ramsar Site has a slope of not more than 5-20% 
grades. If left bare, the moderately to highly erodible soils on slopes of 2-25% could 
yield up to 16 tons per hectare per year of sediment which would eventually end up in 
the lagoon.
' 70
E 60
y. so
X 40
i 30
t  20 
3  10
s- 0
>  u  z  cc cr trilv 6 8x )) :8  6EO <.A  , A  ,C  % °  z  Q '  “■ 5  <
—♦—Mean rainfall apam tidal level
—• —Mean rainfall Winneba I   ♦  Mean vsater depth
Figure 3.2: Rainfall Patterns, Tidal Level and Water Depth at the Mnni Lagoon 
daring the Study Period (Sept-09 to Apr-10).
3.1.4 Demography and socio-economics
The nine major settlements within the MPRS constituted a population of 32,000 people 
in 1984. This went up to about 47,327 by the year 2000 (Ghana Statistical Service, 
2005). The population growth rate is less than 1% annually (Gordon el al., 2000). The 
dominant ethnic groups are the Fanti, Ewe and migrant Fulani herdsmen. The 
management of the site is vested jointly in two local or traditional authorities. The 
Effutu have responsibility for issues concerning the Muni Lagoon, while the Gomoa 
manage the wetlands. Chief Fishermen arc responsible for fishing-related issues in 
their respective traditional communities.
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The primary occupations of the local inhabitants are fishing and farming (e.g. maize 
and cassava), but there are other minor activities like hunting (Effutu people), cattle 
grazing, sand, clay and gravel mining, salt winning and charcoal production. The 
MPRS is home to the annual “Aboakyir" festival, during which “Asafo” companies 
compete to capture a live bushbuck (Wuver and Attuquayefio, 2006).
3 i  Methods
3.2.1 Selection of study sites
The Muni lagoon was stratified into six sampling sites: (i) Site A (Mudflal I), (ii) Site 
B (Inland Water), (iii) Site C (Lagoon Mid-Section), (iv) Site D (Mudflat II), (v) Site E 
(Seaward Site), and (vi) Site SP (Salt Pond) (Figure 3.3). The extents of these sampling 
sites were defined using physical references of the landscape. Sites A, C; and D are 
located in the eastern part centre of the lagoon. Site E in the southern part, and Sites B 
and F in the northern part of the lagoon.
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LEGEND
Y M A
B
C
I)
E
SP
Figure 3 J : Sampling Sites in the Muni Lagoon
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3.11.1 Site A (Mudflat I)
This site is close to Akosua village, with portions of it serving as a waste dump site for 
the local population. There is flooding at high tide and water depth is the lowest 
compared to the other sites (Figure 3.4). The site is also linked to a small stream which 
becomes prominent during heavy rains. The vegetation is dominated by Sesuvium 
portulacastrum and other grasses. This site has the highest soil clay percentage 
(17.54%) of all the sites (Table 3.1).
3.11.2 Site B (Inland Water)
This site receives freshwater inflows from the Pratu, Boaku and Muni rivers. During 
the dry season, there is high salinity due to high evaporation and low freshwater 
inflow. The soil composition is sand (84.8%), clay (13.6%) and silts (1.6%) (Table 
3.1).
3.2.1.3 Site C (Lagoon Mid-Section)
This site represents the mid-section of the Muni lagoon, where fishing activities are 
more prominent than at the other sites except Site E. Dead seashells are also most 
abundant at this site. Sandy soil dominates (84.9%) in the area.
3.11.4 Site D (Mudflat II)
This is also a mudflat bordered by mangroves to the west. Water depth is affected by
the tide levels of the sea, resulting in flooding of the site during high tides.
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3.2.1.5 Site E (Seaward Site)
This site connects the lagoon to the sea, and is thus the deepest portion of the lagoon 
(Figure 3.4). There is fishing at the site, which had the highest soil silt composition 
(2.6%) of all the sites.
3.2.1.6 Site SP (Salt Pond)
This site is the most hypersaline of all the sites due to salt production using water 
pumped occasionally from the sea. There is no direct influence of increasing or 
decreasing water levels in the lagoon, but rather by the frequency of sea water 
pumping into the salt ponds. Wind force and direction influence the mixing of the 
water column in the salt ponds because of the enclosed nature of the site.
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50
E 45o 40
JZ 35
- 30
•o 25
lm 20
15
* 10
eSJ 5a* 0
f  *
I
B C D E SP 
Sites
Figure 3.4: Spatial Variations in the Mean Water Depth at the Mnni Lagoon over 
the Study Period (Sept 09-Apr 10).
Table 3.1: Soil and Sediment Percentage Composition at the Mnni Lagoon
SILT SAND CLAY TOTAL
A 1.54 80.92 17.54 100
B 1.60 84.8 13.60 100
C 2.22 84.87 12.91 100
E 2.59 80.90 16.51 100
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3.2.2 Sampling design
At each site, monthly waterbird counts, benthic macroinvertebrate sampling and water 
quality assessments were undertaken for a period of eight months (September 2009 to 
April 2010). The water and benthos sampling points at each site are shown in Figure
3.5 and the GPS coordinates of the sampling locations are in Appendix I.
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TOPOGRAPHIC MAP OF MUNI LAGOON
Figure 3.5: Sampling Points in the Muni Lagoon (Source CERSGIS)
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Multiple waterbird counts were carried out every month at each site over the study 
period (eight months) during both high and low tides. This was to determine the 
spatio-temporal variations in the distribution and abundance of waterbirds within the 
Muni lagoon across seasons (Bibby el al., 1993). The total counts were done on foot, 
from fixed points in the landscape with good visibility along transects using a 20 x 60 
telescope and 10 x 40 binoculars. The surveys always began from the eastern bank of 
the lagoon, moving towards the inlets of the two rivers, and then returning to cover 
the southern banks (Ntiamoa-Baidu el al., 2000a). Bird species identification followed 
Borrow and Demey (2004). All species seen were counted and the total for each 
species at the six sites were pooled at the end of the count.
3 J .4  Habitat use by waterbirds
The number of birds feeding, roosting (sleeping, standing) and undergoing comfort 
(preening, bathing, stretching) activities were estimated during low tide counts every 
month at each site using the scan method. Waterbirds were categorised into Waders. 
Terns and Herons, and further put into guilds according to Piersma and Ntiamoa- 
Baidu (1995), and Ntiamoa-Baidu et al. (1998).
3 i i  Benthic macroinvertebrate sampling
At each of the sampling sites, five sediment cores were taken using a hand held soil 
PVC corer, with a core area of 0.177m3 in order to examine the benthos. The core 
depths ranged from 5-15 cm. The benthos was then carefully removed from each 
corer separately and extracted by wet sieving using a sieve of 300 microns mesh size. 
Drops of Rose Bengal were added to the collccted substrate to improve identification
3.2 3  Avifauna! survey
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of the specimens which were then fixed in 4% formalin and sent to the laboratory. 
Benthic species identification by means of a microscope followed Day (1967a, b). 
Species richness and numbers of individual benthic macroinvertebrate prey were 
estimated as well as the biomass at each section. After identification, the 
macroinvertebrates were dried at 60°C in an oven for two days, and the dry weight 
recorded. The benthos was grouped into polychaetes, bivalves and crustaceans.
3.2.6 Measurement of environmental parameters
Environmental factors such as salinity, temperature, dissolved gases, turbidity and 
water depth, are key factors determining the activity, abundance and distribution of 
waterbirds as well as the macrobenthic community. These environmental parameters 
of the Muni lagoon were measured in-situ over the study period.
•  Mean Water Depth
Mean lagoon water depth measurements were taken by measuring the depth of the 
lagoon at three different points in each site every month, using a fixed graduated pole.
•  Water Quality
Water temperature, salinity, turbidity, dissolved oxygen (D.O.), pH and conductivity 
were measured monthly at each site. Salinity, water temperature and D.O. were 
measured by means of a D.O. meter, Hanna oxy-Check HI9147. Turbidity was 
measured using a HaCH 21 OOP Turbidimeter 46500-00. Conductivity was evaluated 
with a HaCH conductivity meter.
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•  Habitat Change
Satellite images of the MPRS were obtained from the Centre for Remote Censing and 
Geographic Information Services (CERSGIS), University of Ghana for the years 
1997. 2000. 2007.
3 J  Analysis of Data
Waterbird and benthic macroinvertebrate diversity were estimated using Primer v6 
software. Shannon-Wiener, Simpson reciprocal (1-D), Pielou's evenness and Magarlef 
richness indices were used to assess species diversity for each site (Clarke and 
Warwick. 1994; Clarke and Gorley, 2006).
Feeding activity of each waterbird group (waders, terns, and herons) was defined as 
the number of feeding birds divided by the total number of birds observed in at that 
site (Liang et a/., 2002).
Similarity among sites based on the feeding activities and abundance of waterbirds, 
was assessed using Cluster Analysis based on the group average agglomerative 
dendogram of Bray-Curtis similarity index in Primer software.
Primer software was also used to analyse benthic community assemblages by means 
of the Bray- Curtis similarity index. A fourth root transformation was applied to all 
biological data to minimise the effects of the dominant species prior to the similarity 
test. When dealing with spatial data, the samples were standardised by dividing them 
by the total. This was done because the sites were of different sizes. All hydrological 
data were log (x+|)-transformed to normalise them. The SIMPROF test at p <0.05
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was carried out to determine the presence or absence of structure, that gives statistical 
meaning to the groupings in the dendogram. Based on the abundance and biomass of 
polychaetes found at each site (A, B. C and E) during the study period, a comparison 
was carried out using Abundance Biomass Comparison curves in Primer v6 (Clarke 
and Warwick, 1994; Clarke and Gorley, 2006).
Non-parametric tests were used when the data were proven not to be normally 
distributed. Here, only hydrological variables were log(x+l)-transformed. Spearman’s 
correlation in SPSS 16.0 was used to determine bivariate correlations among 
hydrological variables; waterbirds (wader, heron, and tem) abundance and activities 
(roosting, feeding and comforting activities) and macrobenthic communities. The first 
part of the bivariate analysis took into consideration all sites apart from Sites A and D 
which were the only sites that were not sampled during the period December 2009 to 
April 2010. In order to analyse the difference in the impact of each factor at the 
different sites, data from Sites A, B, C, E and SP were used separately.
Another non-parametric test Kruskal-Wallis, was used to determine the existence of 
any significant differences in the number of species of waterbirds among the sampling 
sites using PracticStat Software (Ashcroft and Pereira, 2003). Whenever significant a 
post-hoc test the Fisher Least Significant Difference (LSD) test was carried out to 
determine the sites that were significantly different from each other in terms of 
waterbird species.
Chi-square analysis (Payne el al., 2006) (using GENSTAT 9°' edition) was used to 
determine whether there was any association between sites and time with regards to 
bird abundance and their activity (roosting and feeding).
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Multivariate analysis using Canonical Correspondence Analysis (CCA) CANOCO v 
4.45 (Ter Braak and Smilauer, 2002) was carried out to test for any interrelationship 
between hydrological and benthic assemblages; and hydrological variables and 
waterbirds abundance and activity. Sites that had been sampled during the whole 
study period (Sites B. C, E) were selected for the CCA. Sites A, D and SP were 
therefore excluded, as well as variables like conductivity and D.O. since they were not 
sampled for all the eight months.
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CHAPTER IV
RESULTS
4.1 Water Quality at the Muni-Pomadze Ramsar Site
4.1.1 Characteristics of the Muni Lagoon
Water samples were collected from the Muni lagoon over a period of eight months 
and analysed for the following parameters; water temperature, pH, turbidity, 
conductivity, salinity, and dissolved oxygen; the spatio-temporal variations of which 
are represented by the graphs below (Figure 4 .1 to 4.6).
Table 4.1 presents a summary of the physico-chemical characteristics of the Muni 
lagoon, and also indicates the number of times (N) the water samples were analysed 
for the various parameters.
Table 4.1: Summary of Statistics of Physico-chemical Characteristics of Water 
Samples
WATER VARIABLES MEAN VALUE (± S.D.) MIN MAX N
Water temperature ( °C) 32.12 ±3.67 25.20 39.50 35
Salinity (%o) 40.82 ± 2.95 20.20 106.00 35
Conductivity (mS/cm) 58.43 ± 0.73 38.60 74.80 30
Dissolved Oxygen (mg/L) 7.06 ± 1.40 5.50 10.60 26
pH 8.21 ±0.28 7.43 8.70 35
Turbidity (NTU) 27.49±20.06 5.04 89.30 35
N = number of samples analysed; S.D. = Standard Deviation
45
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The mean temperature of the Muni lagoon recorded during the sampling period was 
32.12°C (S.D. 3.67°C) with the minimum value recorded at Site E (25.2°C) in 
September 2009 and the maximum at Site B (39.5°C) in March 2010 (Table 4.1). The 
temperature was always above 25°C. A fall in temperature was however observed in 
November at all the sampled sites. Sites E and SP on one hand and site C and B on the 
other, had similar patterns in temperature variations from December to January 
(Appendix II).
The values of pH varied between 7.43 (SP in April) and 8.7 (B in November and E in 
December) and the calculated mean value was 8.21 (Table 4.1). A fall in pH was 
observed in Sites B, C, E and SP in January 2010. There was a similarity in the spatio- 
temporal variation pattern of pH in the Sites C, SP and B, between December 2009 
and April 2010. A positive correlation (r = 0.0489, P <0.05) was found between pH 
and temperature (Table 4.16). In Sites B and C, temperature was found to be highest 
when water depth was lowest in March and vice-versa in November in B (Appendix
Turbidity ranged from 5.02 NTU (in Site C in March 2010) to 89.3 NTU (in Site A in 
December 2009) with a mean value of 27.49 NTU. There was an increase in turbidity 
in November 2009 in all the sampled sites and a decrease in March 2010.
Mean salinity values of the Muni lagoon were high, with the highest salinity recorded 
as 106%o in SP and the lowest, 20.20%o in Site A (November). The mean salinity 
values were very high at Site SP. A drop in salinity was also observed in November in 
all sites sampled.
46
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Conductivity of the Muni lagoon ranged from 38.6 mS/cm in Site E in December to 
74.8 mS/cm in Site SP (December); with a mean value of 58.43 mS/cm. Conductivity 
values were high in Sites SP and B. There was a positive correlation between salinity 
and conductivity (r = 0.524, P< 0.05) (Table 4.2).
The mean dissolved oxygen was 7.6 mg/L. A peak was recorded in March at all sites 
sampled except site B whose D.O. rather increased in April. Site E and SP showed 
similar patterns in temporal variations of D.O. from December to April. The lowest 
D.O. values were recorded at Sites A and SP in December and the highest was 
recorded in Site B in April. Salinity and D.O. exhibited a negative relationship (r = - 
0.448. P< 0.05; Table 4.2).
Table 4.2: Interrelationships among Water Variables
Interacting variables r P
Salinity * D.O. -0.448 0.048
Salinity * Conductivity 0.524 0.018
pH* Temperature 0.489 0.028
4.1.2 Spatio-temporal variations in physico-chemical parameters of the Mnni 
Lagoon
The mean turbidity varied significantly among sites, with minimum mean value 
recorded at Site C (18.32 NTU) and the maximum at Site A (61.88 NTU). The 
temporal mean turbidity also varied among months, and ranged from 9.27 in March 
2010 to 54.52 NTU in November 2009 (Figure 4.1).
The spatial variation in the mean temperature (Figure 4.2) was very little and ranged
from 30.55°C (Site A) to 33.34°C (Site C). The temporal mean temperature values
47
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varied among months with the maximum (36.12°C) in March 2010 and minimum 
(27.16°C) in September 2010 (Figure 4.2). A drop was observed in mean temperature 
in November 2009.
The spatio-temporal variations in the mean pH were very small, although a drop was 
seen in January 2010 (Figure 4.3).
The spatio-temporal variation in mean salinity showed that the lagoon is hypersaline. 
The lowest mean salinity values (34.88%o) were recorded in Site A and the highest 
values, 60.IV  in Site SP. The mean temporal salinity values ranged from 30.55%o in 
November 2009 to 53.25%o in April 2010 (Figure 4.4).
Little variation was observed in the spatio-temporal mean values of dissolved oxygen 
at the Muni lagoon. Nevertheless, the spatial mean values ranged from 6 mg/L in D to 
7.83 mg/L in C, and the temporal mean values ranged from 5.9 in September 2009 to 
8.375 mg/L in April 2010 (Figure 4.5).
Like the mean salinity values, the mean conductivity was highest in Site SP. The 
month of January 2010 scored the highest temporal mean conductivity values during 
the sampling period (Figure 4.6).
48
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£■2
-e
100
80
60
40
20
0
1 * , . 1U 1 * ♦_* j:
A A
•r &
Months
Figure 4.1: Spatio-temporal Variations in Mean Turbidity (NTU) at the Mnni 
Lagoon over the Study Period (Sept 09-Apr 10)
/  < v
Months
Figure 4.2: Spatio-temporal Variations in the Mean Temperature (°C) at the 
Muni Lagoon over the Study Period (Sept 09- Apr 10)
c
Sites
SP
Months
Figure 4.3: Spatio-temporal Variations in the Mean pH at the Muni Lagoon over
the Study Period (Sept 09- Apr 10)
49
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120
Q. 100Q. 80
£ 60c 40a 20
4> 0
c
Sites
SP
120
*->Q. 100
•S 80
£c 60
3 40
c 20(fl<u 0
O 6
a
Months
< -  u.
f d c c . c c  Q- <
Figure 4.4: Spatio-temporal Variations in the Mean Salinity (%•) at the Mnni 
Lagoon over the study Period (Sept 09- Apr 10)
<r^  ^  <!*> .S' O^  4 ?  C T  ^  V *  ^  £
Months
Figure 4.5: Spatio-temporal Variations in the Mean Dissolved Oxygen (mg/L) at 
the Muni Lagoon over the Study Period (Sept 09- Apr 10)
in 
co
nd
uc
tiv
ity
 
(m
S/
cm
)
3 
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SS 
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—
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Sites
SP
£■ 80 
> 70 1 1  1
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“ Sio
2 an
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<£~ ^  < £
Months
Figure 4.6: Spatio-temporal Variations in the Mean Conductivity (mS/cm) at the
Muni Lagoon over the Study Period (Sept 09-Apr 10)
50
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4.2 The Macrobenthic Community at the Muni-Pomadze Ramsar Site
4.2.1 Spatio-temporal variation in the distribution and abundance of 
Macrobenthic invertebrates at the Muni Lagoon
The mean density of Notomastus spp. was relatively low, ranging from 0 to 5381 
individuals/m1 during the study period; however, a peak was observed in most Sites 
(B, C, and E) in January 2010 (Figure 4.7). A peak in density was recorded earlier in 
November 2009 at the Site B. Apart from Site A, the density o f Notomastus spp. in all 
other sites decreased in the month of October 2009. Furthermore, Notomastus spp. 
displayed preferences for Sites B and C in that they occurred in B in all the months 
and in C in all but the month of February 2010. An increase in their abundance was 
also recorded in Site A in December (3171 individuals/m2) and March (1219 
individuals/m2) (Figure 4.7).
Capitella spp. occurred most in Sites A, B and C, but were most abundant in Site C 
(25,928.71 individuals/m3). A significant increase in density of Capitella spp. was 
observed in sites A (10,580 individuals/m2) and C (12,043 individuals/m2) in March 
and in site B in April (4817 individuals/m2). Like the Notomastus spp., a decrease was 
observed in October (Figure 4.8).
Leiochrides africartus in the Muni lagoon occurred at all sites in September except in 
Site A. This species in addition to all the remaining species found at Muni lagoon 
except the opportunistic Capitella spp. were not found at site SP. L. africartus was 
most abundant in Site B (2499.26 individuals/m2) where it also occurred most (six out 
of eight) (Figure 4.9).
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Nephtys spp. were not encountered in October and March in all sites. Though very 
few at all sites, they were still most abundant in Sites A (534 individuals/m2) and B 
(727 individuals/m2) (Figure 4.10).
The spatio-temporal variation in the abundance and distribution of the Neiris spp. at 
the Muni lagoon was characterised by a shift in abundance from Site D (76 
individuals/m2) in September to Site A (76 individuals/m2) in December 2009, E (125) 
in January 2010 and Site B (76) in March 2010. They were however very low in 
abundance (Figure 4.11).
University of Ghana          http://ugspace.ug.edu.gh
Muni A
%
H
I
I
I I L  1 1
Months
Muni B
2>H 15
E io  !
sc03
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s; o  S  o  S  u. s
2  I S  IX  ( 3^ 9
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MuniC
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i  «
Months
*  15 
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Muni D
SEPT NOV JAN 
Moths
MAR
oH
15X«•
.E
1
10
C• 5
*0
C
3
3
0
Muni E
JL JL
Months
Figure 4.7: Spatio-temporal Variations in the Density of Notomastus spp. at the
Mnni Lagoon over the Study Period (Sept.09-Apr.10)
AP
R
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Ab
un
da
nc
e/
m
1* 
10
* 
I 
Ab
un
da
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s 
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Muni A Muni B
4 0
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20
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Months
a>
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Months
4 0
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Months
4 0
- * 3 0
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Muni D
SEPT NOV JAN 
Months
MAR
MuniE
4 0
a ,  4 0
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0   ^ t  ^ # 0 0 0
c
3
. o  n
<  0
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O  z  CD CC CC.
ru  uj <  a.O 2; u_ ^  <
Months
Figure 4.8: Spatio-temporal Variations in the Density of Capilella spp. at the
Muni Lagoon over the Study Period (Sept. 09-Apr.l0).
M
AR
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Muni A
5
a  4
J* 3
£  2
2 iro 0 _________ I  a  I5
i  /  o6  ^  ^  /
Months
bH
0*
cn
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Muni B
l l w
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UJ << UJO  5 u.
Months
MuniC
.r
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 I L _
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Months
Muni E
I i  i ____________
~  4K
E  3
I*" 1 T3 1
Muni D
SEPT NOV JAN 
Months
MAR
4
I
i
4
*•»
Months
Figure 4.9: Spatio-temporal Variations in the Density and Distribution of 
Ltiochrides africanus at Muni Lagoon over the Study Period (Sept.09-Apr.10)
55
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fO
iX
jW
/aauepunqv 
,01 
*riu/a3uepunqv 
,01 
x,u
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n
qv
Muni A
4
3
2
1
0 -
Months
Muni B
il
!>
I" 1 I i  *SEPT OCT NOV DEC JAN FEB MAR APR 
Months
Muni C
^  <*?^ <8> o'*-\* <v ^  £
Months
4b
*  3
E>2
Muni D
SEPT NOV JAN 
Months
MAR
*
i
41
4
«
MuniE
4
3
2
1
o L*_
Months
Figare 4.10: Spatio-temporal Variations in the Distribution and Density of 
Nephtys spp. at the Mnni Lagoon over the Study Period (Sept.09- Apr.10)
56
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& 0.
f o 0.
0.
3
i
Muni A
Months
J*
E
I fcre
■g
i
Muni B
1
0.8
0.6
0.4
0.2
0 - • — •— #•
t  b  gSi o  i
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o
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s q  J
Months
Muni D
1000
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* 800
- I  6000>
1 400 T
i  200
X>
«  0 _ f _ * ________________
f H > O z e o o c o cC 1 qj ^ ^ ^ ^
x5 0 5 4 5 u- 5 <
Months
Muni E
& 1 
;  o.8
- I  0.6
U
c  0.4re■o
5  0.2
JQ 1
H f - > o z c o a : ( r
i 3 2 5 4 1 5 1 )
Months
Figure 4.11: Spatio-temporal Variations in the Distribution and Density of Neiris 
spp. at the Muni Lagoon over the Study Period (Sept.09-Apr. 10)
57
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Bivalves were by far less abundant in the Muni lagoon than the polychaetes. They 
mostly occurred at Site C. Their spatio-temporal variations showed that:
a. Anadara senilis was the dominant bivalve and most abundant in Site C 
(1401.89 individuals/m1). They were found most in September 2009 in Site C 
(445 individuals/m2). October 2009 in D (378 individuals/m2). December 2009 
in B (399 individuals/m3), January 2010 in C (497 individuals/m2), February 
2010 in E (281 individuals/m2) and March, April 2010 in C (194 
individuals/m2 for both) (Figure 4.12).
b. Tellina spp. also occurred most in C and a January 2010 peak in abundance 
was recorded in sites E, C, B and A. They were found to move from one place 
to another according to the months. In September 2009 they occurred in D 
(220 individuals/m2), moved to B (125 individuals/m2) in October 2009, to C 
in November 2009 (76 individuals/m2), December 2009 in A (220 
individuals/m2), January 2010 in E (744 individuals/m2), then back to C (194- 
220-163) from February to April 2010 (Figure 4.13). Other bivalves were also 
encountered in B in January and February 2010 (Figure 4.14).
c. The Amphipods were recorded only a few times in the Muni Lagoon, 
especially at Sites A and B. They were most abundant in Site A (263) in 
February and B (243) in March 2010 (Figure 4.14). Other crustaceans such as 
the Uca spp. were sampled from February to April 2010 in Sites A (twice) and 
C (once) (Figure 4.15).
58
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Bivalves were by far less abundant in the Muni lagoon than the polychaetes. They 
mostly occurred at Site C. Their spatio-temporal variations showed that:
a. Anadara senilis was the dominant bivalve and most abundant in Site C 
(1401.89 individuals/m2). They were found most in September 2009 in Site C 
(445 individuals/m3), October 2009 in D (378 individuals/m2), December 2009 
in B (399 individuals/m2), January 2010 in C (497 individuals/m2), February 
2010 in E (281 individuals/m3) and March, April 2010 in C (194 
individuals/m2 for both) (Figure 4.12).
b. Tellina spp. also occurred most in C and a January 2010 peak in abundance 
was recorded in sites E, C, B and A. They were found to move from one place 
to another according to the months. In September 2009 they occurred in D 
(220 individuals/m2), moved to B (125 individuals/m2) in October 2009, to C 
in November 2009 (76 individuals/m2), December 2009 in A (220 
individuals/m2), January 2010 in E (744 individuals/m2), then back to C (194- 
220-163) from February to April 2010 (Figure 4.13). Other bivalves were also 
encountered in B in January and February 2010 (Figure 4.14).
c. The Amphipods were recorded only a few times in the Muni Lagoon, 
especially at Sites A and B. They were most abundant in Site A (263) in 
February and B (243) in March 2010 (Figure 4.14). Other crustaceans such as 
the Uca spp. were sampled from February to April 2010 in Sites A (twice) and 
C (once) (Figure 4.15).
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Muni A
§ I U  2  CD Ijl uQ 5 u.
Months
5
S  4
X  3
E  2
8 I
Muni B
1 1 1 \ _
Months
Muni C
-O<
i _ L
Go
Z  CD< *** u.
Months
Muni D
Months
1 1
! ;us 1•o n
MuniE
_____________ I , Lc  u3A< j:  h  >  u  z  co ce acQ - O Q a j <J- a j < Q .
S  o  2  a  5  ^  5  <  
Months
Figare 4.12: Spatio-temporal Variations in the Distribution and Density of
Anadara senilis at the Muni Lagoon over the Study Period (Sept.09-Apr.10)
59
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Muni A
3  2.5 ,
i  *
1.5
3 1
»  0.5
§ 0 —
3 t f i g a j a s s( 7 7 0 7 ^5 I 9
i l
Months
Muni B
b
3 2.5
2
1 1.5 <
C 1  T
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3
u
H  H  >  U  Z  CO cc ac
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U i S  §  o  5  u . <5
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<
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2.5 Muni C
& 2
"e 15 T T
s  1
S 0.5■D
5 n I I  ua  u A  <
SE
PT
 
I 
OC
T 
NO
V 
DE
C 
JA
N 
FE
B 
M
AR
 
AP
R
Months
bH
K 2.5
E 2.0
1.5
ere 1.0
c 0.5
i 0.0
Muni D
Months
Muni E
2.5
2
13
1
0.5
0 I I I
t-. > <->U o  “Jo  z  a u - <  CL5  <
Months
Muni B
0.4
0.3
0.2
0.1
0 -
■o< >  U Z CO ccU  ^  <r ^  <m o  5 Q 5  5
Months
Figure 4.13: Spatio-temporal Variations in the Distribution and Density of
Tellina spp. and other Bivalves (last figure on the right) at the Muni Lagoon over
the Study Period (Sept.09-Apr. 10).
60
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Muni A
1
0.5
2
1.5
t  d
UJ  O
CD OC QC
M U N  I-
U .  ^  <
Months
TJ
c3
5
Muni B
1.5
0.5
o  a* o z  o
Z  CD CC< ^  <2; u-
Months
Figure 4.14: Spatio-temporal Variations in the Distribution and Density of 
Amphipods at the Muni Lagoon over the Study Period (Sept.09-Apr.10).
Muni A Muni C
i
0.8
0.6
0.4
0.2
0 ii
s i
z
U J  <<Q 5 
Months
P O  c r
U J  <
I
h
b
H 0.8
X
E 0.6
a
c
(TJ 0.4
T3
3
3
0.2
0
Months
Figure 4.15: Spatio-temporal Variation in the Distribution and Density o f Uca
spp. at the Muni Lagoon over the Study Period (Sept.09-Apr.10).
61
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4.2.2 Macrobenthic species diversity and community structure
The macrobenthic invertebrate fauna found at the MPRS during the study period can 
be categorised into 10 groups (Table 4.3). A total of 1,723 individuals belonging to 
the above mentioned groups were recorded, of which polychaetes constituted 90.71%, 
bivalves 7.84% and crustaceans 1.45%.
Of the polychaetes, capitellid worms were by far the most abundant and dominant 
species occurring in all sites, even in conditions that would be normally unfavourable 
for macrobenthos. Capitella spp. was the only species found at Site SP where the 
mean salinity was 50.6%o and could reach up to 106%o. Some species were absent in 
specific areas. For example, Nephtys spp. were not found in Site A, and Neiris spp. 
were not found in the C. Polychaetes of the Muni lagoon were seen to decrease in 
October at all sampled sites except in Site A. The pattern of the spatiotemporal 
variations changed from site to site and was time-specific. At Sites A and C, the 
highest density of polychaetes was recorded in March 2010. Anadara senilis was the 
most abundant bivalve, occurring most often at the banks of the lagoon.
Few crustaceans were collected during sampling, amphipods being the most abundant 
All Tympanotonus shells sampled were inhabited by hermit crabs. Bivalves were 
found to be most abundant at Sites C and B but absent at Site SP (Table 4.3). Crabs 
(e.g. Callinecles spp, etc.) were observed at the Muni Lagoon except Uca spp. 
Crustaceans were only sampled in Sites A, B and C.
62
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Family diversity, richness and evenness were estimated using Shannon (H ) and 
Simpson (1-D), Magarlef (d’), and Pielou’s evenness (J’) respectively. Spatially, these 
indices (Table 4.4) showed that Sites A (0.78) and B (0.79) were the richest in terms 
of family (d’). Sites E 0 ’ = 0.75) had the most evenly-distributed benthic community 
and A (j’=0.47) the least. Shannon and Simpson diversity indices showed that Site E 
(H'= 1.45, l-D= 0.71) was the most diverse, followed by Site B. Only Capilella spp. 
were recorded in Site SP (H’= 0.0) making it the least diverse site.
Table 4.4: Diversity Indices of Macrobenthic Invertebrates at the Muni Lagoon
Sampling Sites
Diversity indices
A B C D E SP
Number of species (S) 9 9 7 7 7 1
Abundance 29119.4 26226 40230.5 12266 9349.22 250.65
(Mean/m1)
Magarlef richness (d) 0.78 0.79 0.57 0.64 0.66 0
Pielou's evenness (j1) 0.47 0.62 0.51 0.69 0.75 0
Shannon- wiener (H') 1.04 1.37 0.99 1.34 1.45 0
Simpson (1-D) 0.5 0.67 0.51 0.68 0.71 0
64
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Table 4.5 indicates the temporal variations in macroinvertebrate faunal assemblages 
of the Muni lagoon. Family richness was higher in February (d’ = 0.9) and lowest in 
October (d’= 0.38). Benthic invertebrates were most evenly distributed in October 
(J’= 0.8) and the least in March (J’ = 0.26). Shannon diversity index showed that 
macrobenthic community was the most diverse (H’= 1.45) in February whereas 
Simpson index showed that macrobenthic community was rather more diverse in 
September (1-D =0.68). The lowest diversity was recorded in March (H'=0.55; 1- D = 
0 .22).
Table 4.5: Temporal Variations in Macrobenthic Community Structure
Sampling
periods
(2009-2010)
Diversity Indices
Number
of
species
(S)
Abundance 
(mean /m1)
Magarlef
richness
(d)
Pielou's
evenness
O’)
Shannon-
wiener
(H1)
Simpson
(1-D)
SEPT 7 22063.1 0.6 0.67 1.31 0.68
OCT 4 2509.52 0.38 0.8 1.11 0.6
NOV 7 7528.31 0.67 0.67 1.3 0.64
DEC 7 11145.7 0.64 0.65 1.26 0.65
JAN 8 18052.5 0.71 0.57 1.19 0.58
FEB 9 7233.13 0.9 0.66 1.45 0.63
MAR 8 27010.8 0.69 0.26 0.55 0.22
APR 8 21898.9 0.7 0.31 0.65 0.29
65
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Macrobenthic invertebrates were abundant at the Muni lagoon (Figure 4.16). The 
highest density was recorded at Site C and the lowest at Site SP. The density varied 
greatly with time. It decreased drastically in October and February, and increased in 
January and March (when it reached its highest peak. Figure 4.16).
Figure 4.16: Spatio-temporal Variations in the Density of Macroinvertebrates at
MPRS over the Study Period (Sept.09-Apr.10).
66
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4.23 Macrobenthic invertebrate community structure
The agglomerative dendogram based on the spatial density of macroinvertebrates 
found at the Muni lagoon over the study period indicated that at a similarity index 
greater than 20% the different sections of the Muni lagoon can be categorised into two 
groups. Site SP and Sites B. A. C, E. and D. The second group can further be divided 
into two (BAC) and (ED) (Figure 4.17.A). Furthermore The SIMPROF (PRIMER v6) 
test based on the spatial density showed that at 16.25% there was evidence of 
structure, though the same was not observed for the split at 80.62%.
At a similarity index greater than 70% two groups were identified in terms of the 
seasonality of macrobenthic density, October 2009 on one hand and (September 2009. 
November 2009, and April 2010) on the other (Figure 4.17.B). Nevertheless, the 
SIMPROF test (p <0.05) showed that at 62.3% similarity, n > p, indicating that there 
was evidence of structure. It however failed to show any evidence for the apparent 
division based on the macrobenthic faunal density at 74.02% Bray- Curtis similarity 
between months.
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Figure 4.17: Group Average Agglomerative Dendograms of Bray-Curtis 
Similarity of Macrobenthic Faunal Abundance Data for the Six Sampling Sites 
over the Eight Months Study Period. (A) indicates dendogram based on sampling 
sites whereas (B) indicates the one based on monthly variations. SIMPROF test, 
p < 0.05.
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4.3 Waterbirds at the Muni-Pomadze Ramsar Site
43.1 Diversity and abundance of waterbirds recorded at the Muni-Pomadze 
Ramsar Site
Table 4.6 presents the species of waterbirds recorded at the Muni-Pomadze Ramsar 
Site (MPRS) during the eight-month study (Sept-09 to Apr.-10), and the total 
sightings of individuals during the study as well as the maximum count recorded at 
any one time for each species. Thirty-three waterbird species belonging to eight 
families were recorded, with a cumulative total sighting of 14,342 individual birds, of 
which waders represented 67%, terns 28% and herons 5%.
Of the waders recorded during the study period, the Ringed Plover (Charadrius 
hiaticula) was by far the most abundant (2, 517). Together with the Sanderling 
(Calidris alba) and Greenshank (Tringa nebularia), the three species accounted for 
60% of total wader sightings. The least common species (encountered less than five 
times throughout the study period) were the Senegal Thick-Knee (Burhinus 
senegalensis). Dunlin (Calidris alpina), Spotted Redshank (Tringa erythropus), 
Kittlitz’s Plover (Charadirius pecuarius) and Collared Pratincole (Glareola 
pratincola).
The commonest terns were the Sandwich (Sterna sandvicensis) and Royal (Sterna 
maxima) Terns, representing 70.86% of the tem sightings. Although the Roseate Tern 
(S. dougalii') was not recorded during the regular survey periods, seven individuals 
were sighted at a high tide roost on the site on one occasion.
Other waterbirds commonly present on the site were Little Egrets (Egretta garzetta) 
and Reef Herons (Egretta gularis). The maximum numbers of the different groups of
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waterbirds recorded at any one time on the site were 1,070 waders (January 2010 at 
low tide and February 2010 at high tide), 881 terns (October 2009) and 145 herons 
(September 2009). The maximum numbers of Ringed Plover, Sanderling and 
Greenshank individuals recorded at any one time were 413, 308 and 187 respectively. 
Of the terns and herons, those with the highest counts at any one time were the 
Common Tem (Sterna hirundo) (676) and Little Egret (51).
Based on the maximum counts recorded at any one time, none of the waterbird 
species occurred in international ly-significant numbers. Nonetheless, five of the 
commonly-sighted species at Muni occurred in nationally significant numbers: Spur- 
Winged Plover (Vanellus spinosus), Whimbrel (Numenius phaeopus). Wood 
Sandpiper (Tringa glareola), Common Sandpiper (Actitis hypoleucos), and the 
Sanderling. These species represent 5% or more of the peak total Ghana coastal count 
(Ntiamoa-Baidu et al., 2000a).
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Table 4.6: Waterbird Species and Relative Abundance at the Muni Lagoon
(September 2009/April 2010).
Common name Scientific name
Total
sightings
Maximum 
recorded at any 
one time at Mnni
Waders
Senegal Thick-Knee Burhinus senegalensis 4 2
Collared Pratincole Glareola pralincola 66 52
Spur-Winged Plover Vane Hus splnosus* 159 36
Ruddy Turnstone Arenaria inlerpres 57 14
Kittlitz*s Plover Charadirius pecuarius 8 3
Common Ringed Plover Charadrius hiaticula 2517 413
While-Fronted Plover Charadrius marginatus 63 13
Grey Plover Pluvialis squatarola 255 39
Whimbrel Sumenius phaeopus* 262 34
Wood Sandpiper Tringa glareola • 116 56
Common Sandpiper Actilis hypoleucos * 280 57
Common Redshank Tringa tetanus 44 5
Dunlin Calidris alpine 1 1
Bar- Tailed Godv.il Limosa lapponica 36 7
Little Stint Calidris minuta 612 113
Sanderling Calidris alba • 1748 308
Curlew Sandpiper Calidris ferruginea 934 212
Black-Winged Stilt Himaruopus himanlopus 933 103
Spoiled Redshank Tringa erythropus 11 5
Common Greens hank Tringa nebularia 1478 187
Marsh Sandpiper Tringa slagnalilis 39 10
Herons, Egrets, & others
Grey Heron Ardea cine re a 51 12
Squacco Heron Ardeola ratio ides 1 1
Western Reef Egret Egretta gularis 208 32
Little Egret Egretta garzella 383 51
Great Egret Egretta alba 6 2
Green-Backed Heron Butorides striata 3 1
Long-Tailed Cormorant Phalacrocarax africanus 72 68
Terns
Common Tern Sterna hirundo 1000 676
Sandwich 1 cm Sterna sandvicensis 1376 386
Royal Tern Sterna maxima 1455 270
Little Tern Sterna alhi/rons 72 62
Black Tern Chlldonias niger 92 50
* Nationally significant numbers
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4.3.2 Tidal influence on waterbird abundance at the Muni-Pomadze Ramsar 
Site
Between December 2009 and April 2010, two counts were undertaken on each day of 
the survey at low and high tide to assess the best time for carrying out waterbird 
counts at the MPRS. Table 4.7 shows the total sightings of each individual species of 
waterbirds recorded during the low and high tide counts. The total sightings of 
waterbirds were higher at high tide from December 2009 to February 2010 then lower 
in March and April 2010.
Some species like the Common Tem and Kittlitz’s Plover were recorded only at low 
tide. Others such as the Sanderling, Curlew Sandpiper (Calidris ferruginea). Royal 
Tern. Spotted Redshank and Grey Heron (Ardea cinerea) were most abundant at high 
tide, while the Ringed-Plover and Little Stint (C. minuta) were more abundant at low 
tide.
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Table 4.7: Tidal Influence on the Relative Abundance of Waterbirds at the Muni
Lagoon (December 2009/April 2010).
Common name Scientific name
Total 
sightings at 
low tide
Total 
sightings 
at high 
tide
Waders
Senegal Thick-Knee Burhinus senegalensis 2 2
Collared Pratincole Glareola pratincola 55 11
Spur-Winged Plover Vanellus spinosus 77 38
Ruddy Turnstone Arenaria interpres 31 8
Kittlitz's Plover Charadirius pecuarius 6 0
Common Ringed Plover Charadrius hialicula 1431 736
White-Fronted Plover Charadrius marginatus 36 14
Grey Plover Pluvialis squaiarola 73 111
Whimbrel Numenius phaeopus 95 117
Wood Sandpiper Tringa glareola 72 39
Common Sandpiper Actilis hypoleucos 123 71
Common Redshank Tringa tetanus 20 12
Bar- Tailed Godwit Limosa lapponica 17 10
Little Stint Calidris minuta 370 158
Sanderling Calidris alba 592 926
Curlew Sandpiper Calidris ferruginea 254 633
Black-Winged Stilt Himantopus himantopus 396 315
Spotted Redshank Tringa erythropus 1 10
Common Greenshank Tringa nebularia 572 599
Marsh Sandpiper Tringa stagnatilis 14 9
Herons, Egrets, etc.
Grey Heron Ardea cinerea 15 36
Western Reef Egret Egretta gularis 82 78
Little Egret Egretta garzetta 161 154
Great Egret Egretta alba 2 2
Green-Backed Heron Butorides striata 1 2
Terns
Common Tern Sterna hirundo 36 0
Sandwich Tern Sterna sandvicensis 502 459
Royal Tem Sterna maxima 468 729
Little Tem Sterna alhifrons 4 3
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Figure 4.18 shows the relationship between high and low tide wader counts, with 
significant linear correlations for Guild 3 ( r= 0.53, P <0.05; df = 17) and Guild 4 (r = 
0.84; P < 0.05, df = 15), and an insignificant correlation for Guild 2 (r = 0.706. P> 
0.05. df = 47). It therefore means that waterbird species belonging to Guild 2 
displayed significant tidal preferences at the MPRS, as their numbers increase at low 
tide.
Figure 4.18: Correlation between High and Low Tide Counts of Waterbirds 
found at MPRS belonging to Guilds 2,3 and 4
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4.3.3 Seasonal patterns in waterbird occurrence at the Muni-Pomadze Ramsar 
Site
Figure 4.19 shows the monthly counts of waterbirds at the Muni Pomadze Ramsar 
Site. Waterbird numbers increased from September 2009, reaching a peak in October 
2009; dropping in November 2009 and rising again in December 2009 to reach a 
second peak in January 2010.
1800 
1600 
£  1400
g  1200
_  1000 m
j j  800 
600 
400
Sept-09 0ct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 
Months
Figure 4.19: Monthly Variations in Waterbirds Abundance at the MPRS at Low 
Tide
The waders and terns showed similar patterns in their occurrence; two peaks (October 
2009 and January 2010) and a fall in numbers in November. It was however observed 
that the January peak in numbers of waders was higher than the October peak, while 
that of terns was higher in October 2009 (Figure 4.20a). By March, over 30% of the 
peak population of waders had departed from the site with less than 20% of the tem 
population left at that period. The population of herons remained fairly stable
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throughout the study period; the highest numbers counted were always less than 100, 
and there was no clear pattern in their occurrence (Figure 4.20c).
Similar seasonal patterns were shown by the most abundant waders (Ringed Plover, 
Sanderling and Greenshank) and terns (Sandwich and the Common Terns) at the 
MPRS. Ringed Plover and Sanderling numbers peaked in October and January 
(Figure 4.20a). The population of Greenshanks peaked in January from a decrease in 
December, and fell in numbers in March 2010.
The pattern of abundance of the two most abundant terns (Common and Sandwich) 
showed one peak in October for the Common Tem and two peaks in November 2009 
and January 2010 for the Sandwich Tem (Figure 4.19b).
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1000
800
600
400
200
0
1200
Sept-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10
-O - Grccnshank —O — R.plover Sanderling —O— All waders 3
1000
Sept-09 0ct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 
—O -  Sandwich tern - O -  Common Tern -O -  All terns
Apr-10
b
Sept-09 0ct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 
—O -  Reef Heron - Q -  Little Egret -O -  All Egrets/Herons
Figare 4.20: Seasonal Variations in the Abundance of the Commonest Waders 
(a), Terns (b), and Herons (c).
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Table 4.8 presents the seasonal variations in the number of bird days spent by waders 
and tems during the non-breeding season at the MPRS. The non-breeding season was 
split according to the northern seasons and known trends of bird movements and 
activity at the site: (i) September to November (the northern autumn migration), (ii) 
December to February (the northern winter) and (iii) March to April (the northern 
spring migration period). Waders spend more days at the MPRS during northern 
winter and tems during northern autumn. Tems use the MPRS less than waders in all 
seasons but the period September-November 2009 (northern autumn).
Table 4.8: Seasonal Variations in the Number of Bird Days Spent by Waterbirds 
on MPRS
Survey periods
Total bird days 
spent by all 
waterbirds
Total bird days 
spent by 
waders
Total bird 
days spent 
by terns
September 09-November 
2009 155900 71880 72610
December 09-February 
2010 152206 107508 38594
March 10-April 2010 31664 26558 2720
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4.3.4 Habitat selection by waterbirds at the Muni-Pomadze Ramsar Site
4.3.4.I Long-term changes in the habitat available for waterbirds
There are five main habitat types: (i) forest habitat, (ii) sand dunes and beach, (iii) 
constructed salt ponds, (iv) riverine, and (v) shallow lagoon and mudflats, found at the 
Muni-Pomadze Ramsar Site. Of these, the shallow lagoon and its exposed mudflats, 
shrubs (mangroves), and salt-pans are the most important for waterbirds. They are 
used as feeding grounds, as well as roosting and nesting sites by waterbirds. Figure 
4.21 shows the satellite imageries of the site at three points in time over the last 17 
years, 1990,2000 and 2007. The imageries show that drastic alterations have occurred 
in the MPRS since 1990. There was an increase in the extent of bare surfaces and 
build-up areas while the Muni lagoon, the forest vegetation and herbaceous shrubs 
show decreases in extent of coverage. The size of the Muni lagoon reduced by about 
45% over a 10-year period (1990-2000) and more than 50% over the 17-year period. 
The extent of the built-up areas and bare surfaces quadrupled over the same period. 
Only 1% of the extent of herbaceous shrub coverage was left at the site as at 2007.
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C I . A 9 S I P I H D  S A TK I . I . I T K  I M A O R  M A P  O P  T i l  R P R O J E C T  A BRA
Legend
* * 
F . b . 2000
Figure 4.21: Long-term Changes in the Muni-Pomadze Ramsar Site
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4.3.4.2 Spatio-temporal variations in the abundance and distribution o f waterbirds at 
the Muni-Pomadze Ramsar Site
4J.4.2.1 Waterbird diversity
Table 4.9 shows the importance of the different sections of the Muni Lagoon in terms of 
species diversity indices. The number of all waterbird species recorded during the low 
tide counts at the MPRS over the study period, ranged from 18 to 26 species in the 
different sites. The highest numbers of species were recorded in Site C, the mid-portion 
of the lagoon (26), A (mudflat I) (25) and SP, the salt ponds (23) and the lowest in E, 
the portion closest to the sea (18). The numbers of waterbird species varied significantly 
among some of the sites (Kxuskal-Wallis test H= 12.67, P<0.05). Nonetheless, the LSD 
Fisher test showed significant variations (P< 0.05) between Sites A and D (mudflat II), 
A and E, C and E, and E and SP. Site A represented the most important site in terms of 
abundance, as it accounted for 27% of waterbirds found at the MPRS at low tide. It was 
followed by Site C (23. 5%), and Site SP (18.7%), with Site B (5.8%) being the least 
important.
Shannon and Simpson species diversity indices were greater in Site B (H'=2.24 and 1- 
D= 0.86). It was also found that waterbird species were most evenly-distributed in Site 
B as compared to other sites (Table 4.18). The mudflat area. Site A (H' = 224, 1-D = 
0.82) had greater species diversity than the second mudflat. Site D (H' = 2.03 and 1- D 
= 0.79). Site E had the least diversity of all sites (H= 1.44 and 1- D = 0.65). Site SP was 
also an important site with Shannon diversity H' = 2.21 and Simpson 1-D= 0.85.
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Table 4.9: Waterbird Diversity Indices for Different Sites of the Muni Lagoon.
Diversity indices
Sampling Sites
A B C D E SP
Number of species (S) 
Abundance
25 22 26 21 18 23
(Mean/m1) 2411 526 2131 1168 1129 1695
Magarlef richness (d) 3.08 3.35 3.26 2.83 2.42 2.96
Pielou's evenness (j') 0.7 0.75 0.65 0.67 0.50 0.70
Shannon- wiener (H') 2.24 2.30 2.10 2.03 1.44 2.21
Simpson (1-D) 0.82 0.86 0.78 0.79 0.65 0.85
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The spatial agglomerative dendogram based on waterbird abundance at MPRS revealed 
that waterbirds can be grouped into three significant station groups distinguished at a 
Bray-Curtis similarity level of 77%. The SIMPROF test based on the spatial variation in 
waterbird community composition showed no apparent reason for the split at 72.4 and 
77.6% similarity (re = 0.19, P< 99.1% and n =0 at P < 100%). However, an evidence of 
structure was found at P < 0.05, at both 61.35 and 67.41% (n = 2.6 and 2.4 and P < 0.6 
for both) (Figure 4.22). Thus, sites A, C and D can be combined as one group; sites SP 
and B as another group and site E as the third.
Trvabr* ‘wt-aniiwrt sr iwty ----------------------------------------------------- OC
-----------------------------------------------------  OA
  00 ^
fc=----------------------------------------------------- 0Sp-
---------------------------------------------------  OB
I—  F= t   1 I OE
80  70 80 90 100
Sinilarto
Figure 4.22: Group Average Agglomerative Dendogram of Bray-Curtis Similarity 
of Waterbird Species Abundance Data from Six Different Sites in the Muni 
Lagoon over a Period of Eight Months.
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4.3.4.2.2 Spatio-temporal variations in the abundance and distribution of the
major waterbird groups at Muni Lagoon
• Waders
Waders were more abundant at Sites A (total sightings of 1,854), SP (1,346) and D 
(1,089) of the Muni Lagoon. The lowest count was recorded at site E (128) (Figure 
4.23). Sites A and SP maintained relatively high numbers of waders throughout the 
study period. Sites C, D and B showed clear increases in numbers during the period 
December 2009 to January 2010, while Site E maintained very low numbers throughout 
(Figure 4.24). A linear correlation was found between the abundance of waders in sites 
ACD and that of BSP (r = 0.976; P<0.01).
2000
1 8 0 0  M
S> 1 6 0 0  ■
=  1 4 0 0  ■  B
■§, 1200 ■  ■
1000 ■  ■■  ■
1 . 1 1  _ I
A B C D E SP
Sites
Figure 4.23: Distribution of waders in Muni lagoon over the study period (Sept 
09/Aprl0).
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To
ta
l 
co
un
ts 
of 
wa
de
rs
 
To
ta
l c
ou
nt
 o
f 
w
ad
er
s
Muni A
600
Z  ®
<  UJ 
u.
cc cc3 ^5 <
Months
Muni C
600
500
400
300
200
100
0
Muni D
600
Months Months
Muni E
600
500
400
300
200
100
0
Months
600
cD•D 500(D
5 400
o 300
t3 200Ou 100
so 0
MuniSP
u  ^  MU <  a.O z  Q 3 u. |  <
Months
Figure 4.24: Spatio-temporal Variations in the Abundance and Distribution of
Waders at Different Sites of the Muni Lagoon.
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To
ta
l 
sig
ht
in
gs
 
To
ta
, ,
ig
h
t,
n
g
J
For the three most abundant waders at the Muni Pomadze Ramsar Sites, A, C and D, 
were the most important for Ringed Plovers, Sanderlings used Sites D, SP, A and C, 
whiles the Greenshanks were concentrated at Sites SP, A and B (Figure 4.25).
x Sanderlings
200
”  I  I  I  I  -  I
A B C D E SP 
Months
so° Greenshank
4 0 0
3 0 0  
200
100 I  
0 1 1 1  I  -
A B C D E SP 
Months
Figure 4.25: Spatio-temporal Variations in the Abundance and Distribution of the 
Three Most Abundant Waders.
Ringed-Plover
8 0 0
j j 1 600
*3
f 1 4 0 0  
"ra
o 200t-
0 l l
A B C D E SP 
Months
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•  Terns
The spatial distribution of tems at MPRS as demonstrated in Figure 4.26, shows that 
Sites A, C and E were the most important roosting sites for tems. The distribution of 
tems at the three sites showed clear seasonal patterns, with tems using Sites A and C in 
the period September 2009 to November 2009 and moving in Site E from November 
2009 to February 2010. Very low numbers of tems were observed in Sites B, D and SP 
throughout the study period (Figure 4. 27).
1400
1200
&c 1000
JZ 800 ■
in 600«ao 400►- i.
200 !
1  1 —  m _________
A B C D E SP
sites
Figure 4.26: Distribution of Terns in the Muni Lagoon over the Stady Period 
(Sept09/Aprl0).
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To
ta
l c
ou
nt
s 
of 
te
m
s 
to
ta
l c
ou
nt
 o
f 
te
m
s 
j 
To
ta
l 
co
un
ts 
of 
te
m
s
Muni A
800
600
400
200
0
t -  >  <_> z  <o ce
§ 2  Q 5  “  I
ccCL<
Months
Muni B
800
|
a  6oo
•5
“j 400
§  200 
3  no 0 K Q - l - > j J  Z  o  5  SfUJ s j O  Ui UJ Q »
' « O z ° ^ u" 5 <
Months
Muni C
Months
Muni D
Months
800 Muni E
600
400
200
0 ♦—
S; G «/> o
Months
Figure 4.27: Spatio-temporal Variations in the Abundance and Distribution of
Terns at the Muni Lagoon
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•  Herons/Egrets
The highest total sighting of herons and egrets was recorded at site SP (Figure 4.28). 
However, with the exception of the September count of 107 at Site SP and January 
count of 47 at Site B, the numbers of herons and egrets at all sites remained low 
throughout the study period (Figure 4.29).
Figure 4.28: Distribution of Herons/Egrets at the Different Sites of the Maai 
Lagoon over the Study Period.
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To
ta
l 
co
un
t 
of 
he
ro
ns
 
To
ta
l 
sig
ht
in
gs
 o
f 
he
ro
ns
 
To
ta
l 
sig
ht
in
gs
 
of 
he
ro
ns
Muni A Muni B
120
100
80
60
40
20
0
Months
120
1002c 80
8 60
§ 40>- 20
0
g I
2 <n< ^5 LI_
Months
Muni C
120 
100 
80 
60 
40 
20 
0
o'- ^  <3> &4? c r o ' ^  < r /  ^
Months
Muni D
120
100
80
60
40
20
0
Muni E
120
100
80
60
40
20
0 V
Months
Muni SP
Months
Figure 4 .29: Spatio-temporal variations in the abundance and distribution of
Herons and Egrets at the Mnni lagoon
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> 
MA
R 
♦ 
M
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4.3.5.1 Roosting and feeding Birds
Waterbird activities recorded during the study period fell into three groups; roosting 
(sleeping standing), feeding and comfort (preening, bathing, and stretching) activities. 
Table 4.10 shows how waterbirds used the six different sites of the lagoon and its 
environs during the study period. Sites C and SP were used more for roosting, while 
Sites A and D were used most by feeding birds. A chi-square association test between 
sites and months showed significant interaction in terms of number o f feeding 
(x*= 1951.27, P<0.00l, 35 df) and roosting birds (x*=5624.66, P<0.001, 35 df)- This 
showed that the sites displayed different characteristics depending on the time of the 
year.
The number of birds engaged in comfort activities was relatively smaller, even though it 
was higher in Sites A, C and E (Table 4.10).
Table 4.10: Use of Different Sites by Waterbirds in the Mnni Lagoon
4 3 .5  Spatio-temporal variations in habitat use by waterbirds at the MPRS
Sites Total sightings
Proportion feeding
Proportion
roosting
Proportion engaged 
in comfort activities
No.
•/.
No.
%
No.
%
A 2411 1641 68.1 713 29.57 57 2.33
B 526 271 51.5 252 47.91 3 0.59
C 2127 601 28.26 1506 70.80 20 0.94
D 1168 915 78.34 250 21.40 3 0.26
E 1129 125 11.07 976 86.45 28 2.48
SP 1693 466 27.53 1227 72.47 0 0
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43.5.2 Spatio-temporal variations in the feeding activity o f waterbirds
Tables 4.11 - 4.16 present the seasonal patterns in the use of the six sites of the MPRS 
by feeding and roosting waterbirds. The feeding activity of waterbirds found at MPRS 
varied among sites and months. The highest feeding activity at any one time was 
recorded at Sites D (78%) and A (68%) and remained high throughout the study period, 
except in November 2009 at A and November 2009 and March 2010 at D. The least 
used site in terms of feeding activity was Site E (11%), while the remaining two (B, SP) 
were equally used. While most sites had relatively high feeding activity in September 
and October, Sites C and SP did not. Nevertheless, Sites E and B had high feeding 
activity from September to November. The Kruskal-Wallis test showed that, feeding 
activity differed significantly among sites (H= 17.889, X2 (5, 0.05) = 11.070, P<0.05) 
and the LSD test showed further that the waterbird feeding activity in the following 
sites were significantly different from each other A and C, A and E, A and SP, B and E, 
B and SP, D and E, and D and SP. Feeding activity of waterbirds at Site A was found to 
be significantly correlated with biomass of polychaetes in that habitat (r = 0.75 and P< 
0.05).
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Table 4.11: Seasonal Changes in the Use of Site A by Waterbirds
Months
Total
sightings %. Feeding
%.
Roosting
%. engaged in 
comfort activities
Sept-09 146 70.55 27.40 2.05
0ct-09 376 69.41 30.59 0
Nov-09 548 18.98 81.02 0
Dec-09 165 92.73 7.27 0
Jan-10 67 77.61 19.40 2.99
Feb- 10 295 86.78 13.22 0
Mars-10 327 90.52 9.48 0
Apr-10 487 85.42 3.90 10.68
TaMe 4.12: Seasonal Changes in the Use of Site B by Waterbirds
Total %. engaged in
Months sightings %. Feeding %. roosting comfort activities
Sept-09 20 70 25 5
0ct-09 42 73.81 26.19 0
Nov-09 15 100 0 0
Dec-09 91 45.05 52.75 22
Jan-10 197 23.86 76.14 0
Feb-10 34 70.59 29.41 0
Mars-10 68 70.59 29.41 0
Apr-10 59 86.44 13.56 0
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Table 4.13: Seasonal Changes in the Use of Site C by Waterbirds
Months
Total
sightings %. Feeding %. Roosting
%. engaged in 
comfort 
activities
Sept-09 618 21.2 75.57 3.23
0ct-09 821 6.58 93.42 0
Nov-09 77 80.52 19.48 0
Dec-09 179 69.27 30.73 0
Jan-10 200 66 34 0
Feb-10 93 75.27 24.73 0
Mars-10 41 26.83 73.17 0
Apr-10 98 17.35 82.65 0
Table 4.14: Seasonal Changes in the Use of Site D by Waterbirds
%. engaged in
Months Total sightings %. Feeding %. roosting comfort activities
Sept-09 106 86.79 13.21 0
0ct-09 129 58.14 41.86 0
Nov-09 0 0 0 0
Dec-09 119 67.23 32.77 0
Jan-10 544 83.09 16.36 0.55
Feb-10 173 84.97 15.03 0
Mars-10 25 40 60 0
Apr-10 72 81.94 18.06 0
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Table 4.15: Seasonal Changes in the Use of Site E by Waterbirds
Months
Total
sightings %. Feeding %. roosting
%. engaged in 
comfort activities
Sept-09 53 69.81 30.19 0
0ct-09 21 66.67 33.33 0
Nov-09 8 62.5 37.5 0
Dec-09 283 4.95 95.05 0
Jan-10 533 3.94 93.05 3
Feb-10 147 18.37 81.63 0
Mars-10 77 7.79 76.6 15.58
Apr-10 7 14.29 85.71 0
Table 4.16: Seasonal Changes in the Use of Site SP by Waterbirds
Months
Total
sightings %. Feeding
%.
Roosting
%. engaged in 
comfort activities
Sept-09 311 5.15 94.86 0
Oct-09 243 17.28 82.72 0
Nov-09 16 68.75 31.25 0
Dec-09 193 23.32 76.68 0
Jan-10 108 0.93 99.07 0
Feb- 10 323 26.32 73.68 0
Mars-10 341 61 39 0
Apr-10 158 36.71 63.29 0
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The agglomerative dendogram (Figure 4.30) based on temporal feeding activity of 
waterbirds at the MPRS over the study period showed that the feeding activities can be 
categorised into five, although they all showed more than 50% Bray-Curtis similarity. 
They aJso showed low inter-seasonal variability in waterbird activity at the MPRS. The 
SIMPROF test (P< 0.05) showed evidence of structure among the sampling periods.
[T— itom LOQpui) 
L- n « ~ f n c »  B Bsatmarna
StniUmv
Figure 4 JO: Group Average Agglomerative Dendogram of Bray-Curtis Similarity 
of Waterbird Feeding Activity over a Period of Eight Months.
4.4 Biota-Environment Interaction at the MPRS
Changes in the environmental characteristics of the Muni lagoon were seen to some 
extent to have an impact on the macrobenthic assemblages, waterbird communities, 
distribution and activity. A combination of the environmental variables with biota data 
obtained from Sites B, C, E, SP sampled from December 2009 to April 2010 showed 
that there could be significant interactions among environmental variables, between
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environment and benthic macro-invertebrate community, environment and waterbird 
community and between benthos and birds (Table 4.17).
Table 4.17: Biota-environment Interactions in Sites BCESP from December to 
April
INTERACTING VARIABLES
Salinity * D.O. -0.448 0.048*
Salinity * Conductivity 0.524 0.018*
pH* Temperature 0.489 0.028*
Water depth * Crustaceans -0.461 0.041*
D.O. * Polychaetes 0.512 0.021*
pH* Notomastus sp 0.575 0.008**
D.O. * Capitella spp 0.484 0.03*
Salinity * Nephtys sp -0.459 0.042*
Tellina sp * Conductivity -0.511 0.021*
Roosting Heron * Salinity 0.711 O * *
Roosting Heron * Conductivity 0.465 0.039*
Roosting Waders * Salinity 0.648 0.002**
Roosting waders * Conductivity 0.598 0.005**
Heron * Water depth -0.453 0.045*
Heron * Salinity 0.569 0.009**
Heron * Conductivity 0.504 0.023*
Roosting waders * Roosting tems -0.501 0.024*
Roosting waders* Roosting Herons 0.517 0.02*
Roosting tems * waders -0.536 0.007**
Feeding Herons* Crustaceans 0.536 0.015*
Tellina sp * Feeding Heron -0.473 0.035*
Polychaetes* Bivalve 0.612 0.004**
Environmental variables were found to affect benthic community in the Muni lagoon. 
Dissolved Oxygen was found to positively affect polychaetes (P<0.05). specifically the 
Capitella spp. (P<0.05). Salinity, as one of the major environmental parameters that 
plays a significant role in the benthic community composition and structure in coastal 
lagoons, was found to be negatively correlated (P<0.042) to the density/abundance of 
the Nephtys spp. in the Muni lagoon, whereas conductivity was negatively correlated to
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the density of Tellina spp. (P<0.021). Another environmental variable, the pH of the 
water was found to be strongly and positively correlated (P<0.0l) to the Nolomaslus 
spp. of Muni lagoon (Table 4.17).
Waterbird abundance and activity were found to depend to some extent on the 
environmental condition of the lagoon. Salinity and conductivity were seen to determine 
the roosting activity of both herons and waders (Table 4.17). The higher these 
environmental variables were, the higher the number of roosting waders and herons 
(P<0.0l). Water depth was found to negatively affect the number of herons found at 
Muni. A positive correlation was displayed between feeding herons and crustaceans and 
between them and Tellina spp. a bivalve found at Muni lagoon, although herons have 
not been observed to feed on them. The abundance of herons at the Muni lagoon 
seemed to increase with increasing salinity (P<0.01) and therefore conductivity 
(P<0.05).
Nevertheless, interactions were found within the waterbird community and activities. 
The number of roosting terns on one hand, waders and roosting waders in the other, 
were negatively correlated as shown in Table 4.17. Furthermore, an opposite interaction 
was found between the number of roosting waders and that of roosting herons.
However, based on the data collected over the study period in ail sections of the Muni 
lagoon (A,B, C, E, SP) except D, it was found that environmental variables and biota, 
could interact differently based on the area or the types of wetland in consideration as 
well as the dominant species that occur there (Table 4.18). The fact that Spearman's 
correlation failed to show any significance does not necessarily imply that there is no 
interaction between the tested variables.
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Water depth was found to affect feeding waders differently depending on habitat In 
Site B for instance, water depth and turbidity were negatively correlated to feeding 
waders, although the later was found to react positively to increasing wader depth in C 
(Table 4.26).
Roosting tems were affected by different environmental factors based on where they 
were located within the Muni lagoon; in that, when located in A they were negatively 
influenced by salinity while positively correlated to temperature when roosting in E. 
Roosting tems were recorded at Site A only once at low tide. The Site E represented a 
high tide roost for the tems.
Like, the roosting tems, roosting herons were found to be correlated with different 
environmental factors as the habitat in which they were found also differed, in Site E, 
they were negatively correlated with pH, but negatively correlated with water depth and 
turbidity in Site E. As temperature increased, the number of roosting waders was seen to 
increase (Table 4.18).
Feeding herons were negatively correlated with benthic organism (polychaetes (P<0.01) 
and bivalves (P< 0.05). Whiles the density of polychaetes was negatively influenced by 
salinity, that of crustaceans was influenced by water depth and turbidity negatively and 
that of bivalves by pH (C) and temperature (E) (Table 4.18).
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Table 4.18: Influence of Habitat Types on the Interaction between Environment 
and Fauna Abundance and Activity.
A
Interacting variables
Salinity * Tern
R
-1
P
0**
B
Interacting variables R P
Temperature* Roosting waders 0.81 0.015*
Water depth* pH 0.881 0.004**
Roosting Heron* Water depth -0.724 0.042*
Water depth * Feeding Waders -0.762 0.028*
Water depth * Crustaceans -0.733 0.039*
Turbidity ‘Water depth 0.833 0.01**
Turbidity* Waders -0.786 0.021*
Turbidity * Feeding waders -0.929 0.001**
Turbidity * roosting Heron -0.0896 0.003**
Salinity * Polychaetes -0.743 0.035*
Turbidity ‘Crustaceans -0.733 0.039*
Feeding Herons * Polychaetes -0.845 0.008**
C
Interacting variables R P
Water depth* Turbidity 0.708 0.05*
Water depth* Feeding Waders 0.878 0.004**
Water depth * Waders 0.805 0.016*
pH * Bivalves -0.826 0.011*
E
Interacting variables R P
Temperature* Roosting terns 0.778 0.023*
Temperature* Bivalves 0.726 0.041*
Roosting heron *pH -0.847 0.008**
Feeding Herons * Bivalves -0.752 0.031*
SP
Interacting variables R P
Temperature * Water depth 0.9 0.037*
Temperature* Turbidity -0.9 0.037*
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The Canonical Correspondence Analysis (CCA) model also indicated that there could 
be correlation between environmental and biological variables. The horizontal and 
vertical axes represent the most important environmental gradient along which 
waterbirds and benthic organisms were distributed. The direction of each environmental 
vector represents the maximum rate of change for that particular environmental variable 
and its length indicates the relative importance to the ordination (Lamptey and Armah, 
2008). The figure 4.31 below showed that there were correlation patterns between total 
abundance of birds and their activity with hydrological variables although the CCA 
failed to show any significant correlation between them as shown by table 4.17 and 
4.18, when using Spearman’s correlation coefficient.
Water depth was found to be the only environmental variable to have had a significant 
correlation with the abundance of macrobenthic invertebrates (P<0.05) (Appendix). The 
CCA indicated that water depth was the variable that best differentiated habitat of the 
studied macrobenthic fauna (Figure 4.32).
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- 1.0 1.0
Figure 4J1: CCA Ordination Diagrams for the Abundance (left) and Activity 
(right) of Waterbird in Relation to Environmental Variables
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The Abundance Biomass Comparison (ABC) curves below are plots of both abundance 
and biomass K-dominance lines based on the density and biomass of polychaetes 
sampled at the Muni lagoon. The extent to which the biomass curve lies above the 
dominance curve was measured as W (Warwick and Clarke, 1991). A positive or 
negative W indicated the extent of disturbance as the undisturbed condition or disturbed 
ones respectively. The ABC curves (Figure 4.33) below showed that Sites E and B of 
the Muni lagoon were undisturbed (w = 0.262 and w = 0.133) whiles Site A was 
moderately disturbed (w = -0.079) and site C highly disturbed (w = -0.211).
4.5 Muni-Pomadze Habitat Condition
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POLYCHAETES
i  AJauidane^  
v  B m r n t  1
1 so
I
J «°-
W -  -0 079
POLYCHAETES
POLYCHAETES
S
POLYCHAETES£
I
Figare 4.33: ABC Plots over the Eight Months Sampling Period (Sept 09-Apr 10) 
in the Different Sections of the Muni Lagoon.
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CHAPTER FIVE
DISCUSSION
5.1 Muni-Pomadze Wetland Quality
The Muni lagoon is separated from the sea by a sand bar, and consequently in addition 
to its physiochemical characteristics, it qualifies as a coastal lagoon (Bird, 1994). The 
water quality assessment carried out on the Muni lagoon from September 2009 to April 
2010 showed that the Muni system is a slightly alkaline, shallow, and hypersaline 
lagoon with relatively high mean water temperature. It also showed that the lagoon can 
support life based on its mean dissolved oxygen value, which falls within the 
recommended D.O. values, 5 to 8 mg/L that can support biological activities (FinJayson 
et al., 2000).
Water temperature is a key environmental parameter that plays a fundamental role in the 
solubility of salts and gases, as well as the dissociation of dissolved salts, and hence 
electric conductivity (Carr and Neary, 2006). Water temperature also positively 
influences the respiration rate of living organisms in water and enhances decomposition 
rate, thereby decreasing dissolved oxygen (Chapman, 1992; Anthony et al., 2009). The 
relatively high mean temperature of the waters of Muni Lagoon recorded during this 
study could be as a result of the shallow nature of the lagoon as compared to other 
studies. Several studies (Biney, 1990; Finlayson et al., 2000; Gordon et al., 2000; 
Armah et al., 2005; Lamptey and Armah, 2008; Tay et al.. 2009) carried out in Ghana 
on the Keta and Songor Lagoons, as well as the Muni Lagoon have attributed the high 
temperature of Ghanaian coastal lagoons to their shallow nature. Furthermore, this study 
showed that in Sites B (freshwater inflow) and C (mid lagoon), temperature was highest
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when water depth was lowest in March 2010, and vice-versa in November 2009, 
although no significant correlation was found between the two variables.
In November, low temperatures were recorded for all sites sampled, and this could be 
attributed to the time (8:15 am) of the measurements, as ambient temperature (which 
varies according to the time of the day) affects the temperature of the water. According 
to Turner (2003), changes in air temperature significantly influence that of the waters of 
coastal lagoons.
Results from this study also showed that water depths of the Muni lagoon were 
regulated by several factors. These include the amount and regularity of rainfall on one 
hand and the rate of evaporation on the other. Moreover, because Muni Lagoon 
remained open to the sea during the sampling period, sea tides and wave direction might 
have also had a role to play. Allen et al. (1981) indicated that water quantity and quality 
in a lagoon are affected by its water gain (rainfall, tide, runoff, etc.) and loss 
(evaporation). Tumbulto and Bannerman (1995) reported that seepage from the sea and 
discharges of water from the rivers represent minor water input to the Muni Lagoon. 
These must have also contributed to the variations in water depth.
The salinity and conductivity values of the Muni lagoon were characteristic of 
hypersaline coastal lagoons found in Ghana (Finlayson et al.. 2000: Gordon et al.. 2000; 
Lamptey and Armah, 2008; Tay et al., 2009). Limnological surveys carried out in 1994 
and 1999 (Gordon, 1994; Gordon and Ankrah. 1999; Gordon et al.. 2000) compared 
with the present values, showed that the mean salinity of the Muni lagoon had reduced 
by about 30%. The mean values varied from 56.88%o in 1994 (Gordon et al.. 2000) to 
40.28%o in 2009/2010. This comparison also showed that the highest values recorded at 
the Muni lagoon varied from l65%o in 1994 to 106%o as shown in this study. The low
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salinity values recorded during this study could be due to the fact that sea water must 
have diluted the waters of the lagoon, since the lagoon remained opened to the sea 
throughout the sampling period. Furthermore, the difference in the highest salinity 
values could be greater since the highest salinity recorded during this study was from 
the salt ponds while that from the previous studies was from the lagoon itself. Thus the 
lowering of salinity in the Muni lagoon is not without any consequences, as it favours 
macrobenthic organisms which can hardly survive in hypersaline conditions (Ntiamoa- 
Baidu et al., 2000a).
The values of salinity ranged from 20.296o in A (mudflat I) to 106 %o in SP (Salt Pan) 
and that of conductivity from 38.6 in E to 74.8 %o in SP. Even though salinity of the 
coastal lagoon was expected to be higher in the dry season, that of the site A (Mudflat I) 
was the lowest compared to the other sites. This is probably due to its proximity to the 
sea and its connection to a nearby stream. The inflow of the sea water might have 
contributed in lowering the salinity of the Site A through dilution. Furthermore during 
the short rainy season, the low salinity values of Site A might have been as a result of 
freshwater inflow from a nearby stream in Site A which becomes prominent during this 
period. Though Site E (sea water inflow) was the closest to the sea. it had higher mean 
salinity, due to the presence of a freshwater stream in Site A.
It has been well established that conductivity increases with increasing salinity 
(Sutherland, 1996). As expected, salinity of the Muni Lagoon was also positively 
correlated with conductivity. The reduction in salinity in November in some of the sites 
could be as a result of rainfall. Site SP had both the highest salinity and conductivity 
values, due to commercial salt winning. Sea water was pumped into the salt pans and 
allowed to evaporate, leaving behind salt that will be harvested.
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The values of the dissolved oxygen and pH recorded during this study showed little 
variability. This is common in most of the Ghanaian coastal lagoons, such as Songor 
and Keta (Piersma and Ntiamoa- Baidu, 1995; Finlayson el al.. 2000; and Lamptey and 
Armah. 2008). Muni lagoon (Biney. 1995; Gordon el al.. 2000), and other coastal 
lagoons located along the Gulf of Guinea (Kouame et al, 2009) in lagoons of Cote 
d’Ivoire.
Dissolved oxygen (D.O.) is one of the most important parameters in aquatic ecosystems 
that are used by aerobic organisms for their metabolism. The overall mean value of the 
dissolved oxygen at Muni lagoon was 7.06 (S.D. 1.4mg/L), within the recommended 
D.O. values of water that can support biological processes (World Resource Institute, 
2003). These values could be attributed to the shallowness of the lagoon that, under the 
effect of the wind, favours oxygen penetration through wind action. During this study, 
algal mats were often observed on the sediments, and through photosynthesis they 
contribute to the increase in D.O. The level of dissolved oxygen in water is known to 
depend not only on the physical characteristics o f the water such as temperature, the rate 
of aeration from atmosphere, temperature, salinity and air pressure but also the 
combination of these factors with the fauna present in the water.
Even though D.O. is expected to increase with reducing temperature (Joos el al„ 2003; 
Anthony et al., 2009), in Site C of the Muni lagoon the highest D. O mean values were 
recorded against the highest spatial mean temperature values. This is reasonable since 
large algal mats were often observed on the sediment at Site C. With increasing 
temperatures, these algae through photosynthesis, increase the level of oxygen in the 
surface water during the day. The Site D (mudflat II) had the lowest mean values, 
probably due to the fact that the site was surrounded by the remnant mangroves that
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provide shade, thus lowering temperature which is known to increase the rate of oxygen 
absorption by water. Decomposition of these plants absorbs oxygen, thereby reducing 
its concentration in the water. Nevertheless, little temporal mean variation in DO was 
observed at Muni, probably due to the presence of significant algal mats on the 
sediments.
The mean pH values of the Muni waters were fairly alkaline with low variability, 
typical of coastal lagoon waters (Finlayson et al., 2000; Lamptey and Armah, 2008). It 
is partly due to the influence of sea water which has a pH range of 7.5- 8.4 (Riley and 
Chester, 1971), as the lagoon was opened. The hydrogen ion concentration (pH) was 
low, probably because wind induced mixing would lead to very homogeneous water 
mass and the biological processes could have resulted in buffering the change in pH 
(Finlayson et al., 2000).
The mean turbidity values (27.49 NTU S.D. 20.06) o f the Muni lagoon showed that it is 
a turbid system that has a great variability. The minimum turbidity values recorded at 
Site C were probably due to the low disturbance as compared to the she with the highest 
turbidity values (Site A, mudflat I). The consolidated nature of the soils of Site C 
probably has also played a role; the ground was mostly covered with dead shells. Hence 
even when people cross the site or cany out activities, there was no much of sediment 
re-suspension.
Site A had the highest clay percentage and the lowest mean water depth; hence through 
wind mixing, the water could easily become turbid. Besides, trampling by people 
crossing the lagoon occurred a lot especially at site A, which is the shallowest thereby 
leaving behind a “soup like” solution of clay.
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There was an increase in turbidity in November 2009 in all the sampled sites and a 
decrease in March 2010. In November, turbidity was very high even though water levels 
were low, it could be as a result of wind mixing of the water. Rainfall occurred in 
March, thereby contributing to the decrease in turbidity recorded during that period.
These physiochemical parameters of the waters of the Muni Lagoon contribute 
enormously to the abundance and quality of biological resources found in it 
Nevertheless, the high values of temperature, salinity and turbidity recorded during this 
study are likely to affect waterbird communities both directly and indirectly through 
their effect on the macrobenthic organisms and fish, that are the primary food of the 
waterbirds. These macrobenthic and waterbird species should have either a limited 
tolerance range or level, above or below which they may be affected, or eliminated from 
the Muni system.
Temperature, as the governing factor in aquatic life processes is very important to 
macrobenthic and waterbird communities. Against the background of the narrow 
temperature tolerances of aquatic organisms, the high temperatures of Muni Lagoon 
could jeopardise their lives. The optimal temperature for aquatic life range from 5-25°C, 
and an increase in water temperature up to 34-37°C could decrease the density of 
benthic fauna. According to Anbuchezhian et al. (2009), a study conducted in the 
Coastal Belt of Thondi, Southeast Coast of India, high temperature of about 29.5°C 
recorded in the pre-monsoon season had an impact on the distribution of macrobenthic 
community and low temperature recorded in December 2009 and January 2010 months 
influence higher faunal density.
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Similarly, salinity is a limiting factor in the distribution of benthic organisms. Like 
temperature, the level of salinity in aquatic systems is important to aquatic plants and 
animals as species can survive only within certain salinity ranges (Friedl et al., 2004).
A key element contributing to stress is the frequent fluctuations in environmental 
parameters that may hinder the growth and reproductive processes of organisms in 
question, even though some species may be well-adapted to surviving in saline 
environments (Koranteng et al., 2000; Carr and Neary, 2006). This can cause changes in 
the structure and distribution pattern of organisms. According to Barnes (1980), coastal 
lagoons are naturally stressed environments due to the frequent variability in their 
waters. Muni Lagoon is therefore not an exception of a stressed environment based on 
the wide fluctuations in its physiochemical (mainly salinity and temperature) 
environment, the dominance of its benthic fauna by a single opportunistic species 
sampled during this survey. Even though salinity of the Muni lagoon has reduced (from 
2000 to 2009/2010), the environment has not improved. Its macrobenthic diversity is 
still being mainly contributed by just one taxon.
Based on the Abundance/Biomass Comparisons, Site A (Mudflat I) was found to be 
moderately disturbed while Site C (mid Lagoon) is highly disturbed. Site A receives 
household solid wastes and sewage which are washed into the lagoon during high tide 
and rains. This act by local people confirms the statement by Ryan and Ntiamoa-Baidu 
(2000) that wetlands are considered “wastelands” in Ghana and other countries of the 
world. The high turbidity values could also account for the disturbance in the area, since 
it inhibits light penetration and therefore have an effect on the chemistry of the water 
and photosynthesis. According to Addo Oduro (Pers. Comm.), the Biological Oxygen 
Demand (BOD) values obtained during his research on the impacts of human activities
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on the Muni Lagoon during the same period, were above the permissible levels. 
Furthermore, Gordon et al. (2000) recorded the highest biological oxygen demand 
(BOD) values in the southern sector of the lagoon, which correspond to Sites A and C in 
this study. The use of fertilizers by farmers in areas around the lagoon could have also 
played a role in the high BOD values recorded at Site C.
The ability of aquatic organisms to cope or survive in such stressed environment further 
determines their survival, community structure and composition. The macrobenthic 
community in Muni lagoon can be characterised as typical of a stressed hypersaline 
ecosystem. Of the macroinvertebrates sampled during this study, the Capitellid worms 
were the most abundant. These species are opportunistic species that are capable of 
tolerating very low oxygen and high salinity concentration (Day, 1967a; Ahulu et al-, 
2006).
Based on the macrobenthic community pattern obtained by multivariate analysis, two 
main zones can be distinguished. A group of Sites, A, B, C, D, and E located within the 
lagoon and the Salt Ponds (SP). The lagoon is influenced by the sea water and 
freshwater inflow from the three seasonal rivers that drain into the lagoon. 
Macrobenthic organisms are therefore recruited into the lagoon from these two sources, 
thus explaining the great species diversity at Sites E and B and abundance of the 
polychaetes and bivalves in the lagoon.
The high diversity of families recorded in the month of February 2010, could be 
attributed to the high tide level and rainfall that ensured recruitment from the sea and 
water inflow from the rivers (through immigration and an increase in reproduction) of 
certain faunistic species.
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Sites E (seaward section) and B (river inlet) were the most diverse and had the highest 
species richness. This is probably due to the inflow of river waters from Site B, and that 
of sea waters from Site E. into the lagoon, through which new species are recruited into 
the lagoon. This study is in accordance with da Silva el a/.(2005), a study carried out in 
a hypersaline coastal lagoon, Lagona de Araruama, in Brazil, the site closest to the sea 
scored the highest species richness, which also gradually reduced to the inner lagoon.
The Salt Ponds constructed for commercial salt wining are enclosed and only receive 
sea water pumped into them. The water is then allowed to evaporate in order to harvest 
salt, thus making the habitat very hypersaline (106 ppt). The hypersaline character of 
the Site SP is detrimental to the macrobenthic communities. It is therefore not surprising 
to record the lowest abundance and richness of macrobenthic species when salinity is so 
high (Liang el al., 2002) in created wetlands such as Salt Ponds. Nevertheless, Rossiter 
and Crawford (1981), and Nelson el al. (2000) also found higher species richness, 
abundance/density and diversity in natural wetlands.
At the Muni Pomadze Ramsar Site, the macrobenthic community is dominated by the 
opportunistic Capitella spp. which is known to proliferate in such stressful environmenL 
The macrobenthic fauna of the Muni lagoon experienced variations as a response to the 
fluctuating hydrology and water quality during the study period. The two peaks in 
macroinvertebrates at Muni lagoon recorded in January and March 2010 showed that 
the temporal variation in the density of benthic organisms could be linked to increasing 
rainfall in the area. Rain water through dilution of the concentrated salty water of the 
lagoon favours re-colonisation by benthic organisms. The Muni site recorded its highest 
amount of rain in January 2010. This is in agreement with several studies (Lamptey and 
Armah, 2008; Gordon, 2000) that recorded the highest abundance and diversity of
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macrobenthic species during the rainy season in Keta and Muni Lagoon in Ghana, 
respectively.
Furthermore, polychaetes of Muni lagoon were positively correlated with the dissolved 
oxygen and negatively correlated with salinity; therefore the reduction in salinity and 
the relatively high mean dissolved oxygen recorded in the she in March 2010 have 
contributed to the high abundance of macroinvertebrates recorded during the same 
period.
Site C, located in the middle of the Muni lagoon had the highest density of polychaetes 
and bivalves. This agrees with findings by Lamptey and Armah (2008) in another 
hypersaline lagoon, the Keta Lagoon. Site SP, which is the most hypersaline of all, had 
the least density and diversity. It is therefore obvious that high salinity affects the 
diversity and abundance of living aquatic organisms, as recorded by Garcia de Lomas el 
al. (2005) and Gordon (2000) in hypersaline ecosystems. Another stressor endured by 
benthic fauna in hypersaline environments is the wide variability in salinity that may 
inhibit the physiological responses of the organism.
From this study, the macrobenthic fauna displayed wide spatio-temporal patterns and 
are characterised by high inconsistency and dominance patterns within the sampling 
period as shown by Mistri et al. (2001).
Polychaetes were more abundant than bivalves at Muni Lagoon, probably due to the 
fact that bivalves cannot tolerate high salinity, as well as polychaetes (Delauge. 1994). 
Polychaetes of Muni Lagoon were dominated by the capitellid worms. Benthic species 
belonging to the family Capitellidea are known to survive in hypersaline ecosystem, 
more especially the opportunistic Capilella capitata Bivalves were dominated by
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Anctdara senilis, which were distributed along the banks, especially at low water levels. 
(Gordon. 2000; Ahulu el al., 2006)
The highest macrobenthic density was recorded in the middle portion of the Muni 
Lagoon. The macrobenthic community of the Site C increased under unfavourable 
condition, because it is dominated by Capitella spp., which could take advantage of 
such conditions.
5J Waterbirds i t  the Mnni-Pom*dze Ramsar Site
5.2.1 Chaages in waterbird populations
The Muni Pomadze Ramsar Site is the fifth most important wetland in Ghana (Wuver 
and Attuquayefio, 2006; Ministry of Lands, Forestry and Mines, 2007). It was 
designated as a Ramsar Site, in 1992, on the basis of its internationally important Tem 
(Royal, Sandwich, Black and Common) populations and its total waterbird population, 
estimated at 23,000 (Ntiamoa-Baidu et al., 2000a). The MPRS is also known to support 
48 out of the 88 species of waterbird known to occur on the coast of Ghana (Ntiamoa- 
Baidu et al., 2000a).
During this study, the maximum numbers of the four tem species (Royal, Sandwich, 
Black and Common) recorded at the MPRS were below the maximum counts recorded 
in the 1986-1998 survey (Table 5.1), and also below the 1% of the total East Atlantic 
Flyway population, thus failing to qualify as internationally important. Possible 
explanations for this would be that there has been a decrease in the size of the
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populations of the three tem species using the Muni Pomadze Ramsar Site or an 
increase in the global population estimates of the species.
The fact that most tems usually feed at sea during the day (Grimes, 1979; Ntiamoa- 
Baidu et al.. 2000a), instead of on the coastal lagoons, could be the reason why the 
numbers were low since counts were carried out only during the day. Tems arc most 
abundant at the lagoon roosting sites either at dawn before they go feeding or after dusk 
when they come back to the night roosting grounds (Ntiamoa-Baidu el al., 1992; 
2000a).
This study shows however that the MPRS is still important in terms of the number of 
waterbird species it supports, with 33 species being recorded during the eight-month 
study period compared to the 48 species recorded over a period of 12 years (Ntiamoa- 
Baidu et al., 2000a). The maximum counts of 1,070 waders, 145 herons and 881 tems 
recorded during this study were far below the 3,530 waders, 345 herons and 16,925 
tems recorded during the 1986-1998 survey (Ntiamoa-Baidu et al., 2000a). Natural and 
anthropogenic causes like habitat degradation, which lead to the loss in feeding and 
roosting habitats, reduction in the quality of wetlands could account for this reduction.
Five of the waterbird species recorded at Muni, the Spur-winged Plover, WhimbreL. 
Wood Sandpiper, Common Sandpiper, and the Sanderling occurred commonly on the 
coast of Ghana, in nationally important numbers. Compared with the 1986-1998 counts, 
the maximum count of five species recorded in this study was higher. 26 species were 
recorded in lower numbers and 16 species recorded in 1986-1998 were not seen at all in 
this study. One species, the Squacco heron (Ardeola ralloides) recorded once in this 
study, was not reported in the 1986-1998 survey. Of the six least common species 
recorded at the MPRS, the Senegal Thick-Knce (a local resident) and Dunlin (a
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Palaearctic migrant) are uncommon on the coastal wetlands of Ghana, thus their few 
numbers. The Collared Pratincole was recorded a few times, since as a local breeder its 
numbers only increased as its breeding period was approaching. Some species have 
restricted habitat or display habitat preferences (Oystercatcher, Sanderling, Jacana 
(Actophilornis Africana) and may therefore be more abundant at some sites than others 
(Ntiamoa-Baidu et al., 2000a).
There have also been some changes in the relative abundance of the different wader 
species. The Common Ringed Plover has now become the most abundant species, 
replacing the Curlew Sandpiper which was the most abundant at MPRS and at all other 
wetland sites on the coast of Ghana (Ntiamoa-Baidu, 1991). Although the population of 
Ringed Plovers at Muni was higher than that of the Curlew Sandpiper, it is clear that 
this change was not caused by an increase in the population of Ringed Plovers at 
MPRS. The populations of both species have decreased, and the maximum counts of the 
Ringed Plover and the Curlew Sandpiper were 35.5% and 87.5% respectively lower 
than the numbers recorded in the 1986-1998 study.
Though few species (e.g. Wood sandpiper, Spur-Winged Plover, Common Sandpiper) 
have increased in numbers, majority of waterbird species have decreased in abundance. 
The Common Sandpiper is one of the species that are known to use mangroves 
frequently. Even though mangroves are being destroyed at MPRS (Entsua-Mensah. 
1997), the number of Common Sandpipers recorded was higher than in the eartier study. 
The abundance of small fiddler crabs (Uca spp.), which the Common Sandpiper could 
easily prey upon (van de Kam el al., 2004), made the MPRS their suitable alternative 
habitat.
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The maximum number of Whimbrels recorded at the site has not changed, as the 
population of the species is known to be stable in West Africa (Rose and Scott, 1997). 
Whimbrels use tidal areas in Africa and are also specialised feeders on the most 
numerous species of fiddler crab (van de Kam el at., 2004). which they were observed 
feeding on at the MPRS.
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Table 5.1: Waterbird Population Status at the MPRS
Maximum recorded
at any onetime at
Common name Scientific name Mnni Status
1986-
1998
2009-
2010
Waders
Senegal thick-Knee Burhinus senegalensis 1 2 Increase
Senegal Wattled <*
Plover Vanellus senegalensis -
Collared Pratincole Glareola pralincola 65 52 Decrease
Spur-Winged Plover Vanellus spinosus 2 36* Increase
Ruddy Turnstone Arenaria inlerpres 30* 14 Decrease
Kittlitz's Plover Charadirius pecuarius 60 3 Decrease
Common Ringed 640 413Plover Charadrius hialicula Decrease
White-Fronted 35* 13Plover Charadrius marginalus Decrease
Grey Plover Pluvialis squatarola 210* 39 Decrease
Whimbrel Numenius phaeopus 35* 34* Stable
Wood Sandpiper Tringa glareola 15 56* Increase
Common Sandpiper Actitis hypoleucos 25 57* Increase
Common Redshank Tringa tetanus 15 5 Decrease
Dunlin Calidris alpine 2 1 Decrease
Bar- Tailed Godwit Limosa lapponica 30* 7 Decrease
Little Stint Calidris minuta 425 113 Decrease
Sanderling Calidris alba 485* 308* Decrease
Curlew Sandpiper Calidris ferruginea 1700 212 Decrease
Black-Winged Stilt
Himantopus
himantopus 475 103 Decrease
Spotted Red Shank Tringa erythropus 180 5 Decrease
Common Green 870* 187Shank Tringa nebularia Decrease
Marsh Sandpiper Tringa stagnatilis 150 10 Decrease
Eurasian
Oystercatcher Haemalopus ostralegus 2 -
Avocet Recurvirostra avosetta 50 - -
Knot Calidris canutus 35 -
Black-tailed Godwit Limosa limosa 50 _
Curlew Numenius arquata 10 - _
Broad billed
1Sandpiper Limicola falcinellus ~ _
Jacana Actophilomis Africana 1 - -
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Table 5.1: Waterbird Population Status at the MPRS (contlnned)
Maximum recorded
at any onetime at
Common name Scientific name Muni Status
1986-
1998
2009-
2010
Terns & Gulls
Common Tem Sterna hirundo 8210** 676 Decrease
Sandwich Tem Sterna sandvicensis 2230** 386 Decrease
Royal Tem Sterna maxima 3200** 270 Decrease
Little Tem Sterna albifrons 940 62 Decrease
Black Tem Chlidonias niger 6570** 50 Decrease
Roseate Ten Sterna dougalii 80* - -
Caspian Tem Sterna caspia 1 - -
Scooty Tems Sterna fuscata 1 - -
Black -headed Gull Larus ridibundus 3 - -
Lesser Black backed 20Gull Larus fuscus -
Herons, egrets & others
Yellow Billed Egret Egretta intermedia 6* - -
Black Heron Egretta ardesiaca 12* - -
Grey Heron Ardea cine re a 16 12 Decrease
Squacco Heron Ardeola ralloides - 1 -
Western Reef Egret Egretta gularis 78 32 Decrease
Little Egret Egretta garzetta 269 51 Decrease
Great Egret Egretta alba 16 2 Decrease
Green-Backed Heron Butorides striata 2 1 Decrease
Long-Tailed Phalacrocarax 16 68Cormorant africanus Increase
White face Tree 45Duck Dendrocygna viduata -
'Nationally significant numbers. •*Internationally significant numbers 
1986/1998 data from Ntiamoa-Baidu et al.(2000)__________________
The changes in waterbird numbers could probably be attributed to (i) habitat alteration 
that had occurred at MPRS (e.g. Increasing siltation/sedimentation of the lagoon, which 
could probably reduce the feeding efficiency of the Curlew Sandpiper, as the sediment 
might become harder), (ii) the probable existence of more favourable or better wetlands 
along their migratory pathway, which they migrate to, neglecting the degrading coastal 
wetlands, (iii) the Ringed Plover having a greater ability to adapt to changing/
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threatened environments than the Curlew Sandpiper. According to Gbogbo et al. 
(2009), Ringed Plovers were also the dominant wader species in the wetlands of Greater 
Accra Region. It is therefore important to pay critical attention to these changes in 
population composition of waterbirds as they could be indicative of serious wetland loss 
and alteration.
Coastal wetlands, such as the MPRS, and other wetlands around the world are subject to 
pressures from growing human populations, industrial and infrastructural development; 
leading to increasing rates of habitat change and pollution (Madsen, 1998; Willoughby 
et aL, 2001; White et al., 2007). This study found that from January 1990 to April 2007, 
there had been serious alterations to the habitats used by waterbirds at the MPRS. More 
than 50% of the Muni lagoon and its exposed mudflats that serve as roosting sites for 
terns and other waterbirds, and represent an important feeding area for waders, had been 
lost in 17 years, as shown by the satellite imageries. Over the same period, the built-up 
(infrastructure) and bare surfaces have quadrupled and 99% of the herbaceous shrubs, 
which provide roosting sites for waterbirds such as herons, have been lost. The changes 
in the terrestrial parts of the Ramsar site could be the direct result of population growth, 
and its associated demands for farm lands as well as unsustainable activities such as 
fishing, sand winning, charcoal production and hunting. The reduction in the wetland 
areas could result from the loss of forest and degradation of the catchment areas. The 
human population of the MPRS increased from 32,000 in 1984 to about 50,000 in 2000 
(Ghana Statistical Service, 1984; 2005). Human population growth exerts pressure on 
coastal wetlands but also leads to increasing infrastructural development and change in 
vegetation cover (Ntiamoa-Baidu and Gordon, 1991; Ryan and Ntiamoa-Baidu, 1998; 
Attuquayeflo and Gbogbo, 2001).
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Moreover, as population increases, more wetland habitat is encroached upon for 
residential and agricultural purposes. For example, since the main activities of the 
inhabitants of MPRS are fishing and fanning, the increasing population would result in 
increasing demand for natural resources. Fuelwood harvesting, cattle grazing, sand and 
gravel mining which can deteriorate the texture of the soil are common activities carried 
out at the MPRS. As a result of tree cutting, most of the forest blocks (Yenku A and B) 
in the Ramsar site have been destroyed.
The study area has also been affected by the reduction in rainfall as a result of the 
increase in temperature prevailing in coastal areas of Ghana (Environmental Protection 
Agency (EPA), 2000). These factors, coupled with the vulnerability of the soil to 
erosion, as well as bushfires would account for the habitat degradation at the Muni 
wetland (Amatekpor, 1994; Gordon el al., 2000; Wuver and Attuquayefio, 2006). When 
left bare, the soils of the MPRS, especially those with moderate to high erodibility, 
located on the upper ground on slopes (2-20%) and summits of the hills, ultimately end 
up being carried into the lagoon (Gordon el al.. 2000). Consequently, this would lead to 
siltation and/or sedimentation, thereby reducing the size of the lagoon, and probably 
leading to its pollution depending on the type of soil/rock from which the sediments are 
derived. This supports the findings that the moderately to highly erodible soils on slopes 
ranging from 2-25%, when left bare could yield up to 16 tonnes per year of sediment, 
which could eventually end up in the lagoon (Gordon el al.. 2000).
The loss of waterbird habitats and associated losses in suitable feeding and roosting 
sites would result in reduction in the use of the site by waterbirds. For instance, 
mangroves provide good high tide roosts for Whimbrels, herons, and Turnstones, apart 
from their role in ecosystem maintenance (Van de kam el al., 2004). It is known that
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waders belonging to Guilds 2, 3, and 4 would be most at risk (Gbogbo, 2007b) from 
habitat loss/fragmentation and pollution, in Ghana, due to their large numbers as 
decreasing trends have been reported in other areas such as the Banc d’Arguin in 
(Zwarts el a l, 1998), and other wetlands in South Africa and Senegal.
Of the populations of waders with known trends, 48% are known to be declining, 
compared with the 16% that are increasing (International Wader Study Group, 2003). 
Several researchers have attributed the world-wide decline in wader populations to 
human related unsustainable activities (International Wader Study Group, 2003; Stroud 
el al., 2006) such as burgeoning coastal human populations, habitat changes resulting 
from land-claim, dredging, urbanisation and encroachment upon protected areas, water 
abstraction, loss of wetlands (Dolman and Sutherland, 199S; Goss-Custard et al.. I99S; 
Zockler et al. 2003), shell-fisheries (Atkinson et al-, 2003), human disturbance (Liley, 
2000, Burton el al., 2002), and climate change (increasing temperature, decreasing 
rainfall resulting in the reduction of the numbers of temporal wetlands) (Dodman and 
Diagana, 2007). These factors in one way or the other affect the birds at their breeding, 
staging or wintering grounds during their migration.
According to Norris el al. (2004), bird numbers often change in response to habitat 
losses and additions through human actions, although it is also acknowledged that not 
all changes in waterbird numbers are the result of habitat changes. Thus, the reduction 
in the numbers of waterbirds recorded at the MPRS would be understandable, 
considering the habitat alterations that have occurred since its designation as a Ramsar 
Site.
It is known also that waterbirds either migrate to other wetlands along their flyway or 
relocate to neighbouring wetlands when conditions are unfavourable (Dodman and
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Diagana, 2007; Newton, 2008). Although there is no evidence of a shift in waterbird 
abundance from one wetland to another, there is evidence of local movements among 
the coastal wetlands in Ghana (Ntiamoa-Baidu, 1991; Gbogbo, 2007b). For example 
Sanderlings ringed in Esiama in Western Ghana, have been recorded at other wetlands 
including MPRS.
Habitat alterations are known to affect birds in several ways. Birds are however affected 
not only by wetlands in which they breed or live, but also wetlands they use during their 
migration cycle; thus the slightest alteration could have a great impact on the diversity, 
abundance, habitat use and reproduction by the birds and future generations. Above all, 
waterbird species, or individuals have their preferred habitats. When conditions are 
altered, depending on the ability of the bird to adapt to the new environment or switch 
to another, they either stay or move away from the place (Zwarts et al., 1992).
Although the MPRS no longer supports internationally important numbers of waterbird 
species, it still provides roosting sites for the rare Roseate Tem (Sterna dougalii). Some 
species (e.g. Redshank, Bar-tailed Godwit) were seen to change to the breeding 
plumage prior to migration to their breeding grounds, hence the importance of the she 
as a moulting ground. Tems use the site mainly for roosting, although a few Black and 
Little Tems have been recorded feeding in the lagoon and salt pans respectively during 
this study. The MPRS therefore still serves as important roosting, feeding, breeding and 
moulting grounds for waterbirds (Ntiamoa-Baidu et al., 2000a). This could be attributed 
to the prevailing favourable conditions at the Muni lagoon such as (i) food availability 
and accessibility, (ii) limited competition and predation, and (iii) safe roosting sites 
among others.
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Waterbird species display different patterns in their distribution during their non­
breeding period (Ntiamoa-Baidu, 1991), and this varies according to time (season, time 
of the day, etc.), sites (intertidal wetlands, lakes, etc) and species (Ntiamoa- Baidu el al., 
2000a; van de Kam el al., 2004; Bolduc and Afton, 2008).
At the Muni-Pomadze Ramsar Site, variations in avian distribution and abundance were 
observed during the study period. The observed patterns can be categorised into three 
time periods with peak numbers in October and January, and decreasing numbers in 
November. The fluctuations in the number/ abundance of waterbirds at the MPRS are 
explained by the seasonal migration patterns of waterbirds. Palaearctic migrants arrive 
on the coasts of Ghana at the end of August/early September and maintain relatively 
high numbers till April (Ntiamoa-Baidu, 1991).
From this study, it can be concluded that there were two peaks of migratory waterbirds 
abundance at the MPRS as was observed in some years between 1986 to 1998 
(Ntiamoa-Baidu el al., 2000a). The peak month of wader abundance recorded varied 
from December (4 out of the 12 years 1986-1998 survey), January (2), February (2), 
September, October, November and March (recorded once for each, during migration) 
(Ntiamoa- Baidu el al., 2000a). In other coastal wetlands of Ghana, Gbogbo (2007b) 
recorded the highest count in September 2005 at the managed wetlands (Densu Delta 
and Sakumo), and in March 2006 at the unmanaged ones (Laiwi and Mukwe Lagoons). 
The highest peak in wader counts recorded during this survey was therefore similar to 
those recorded in January 1988 and 1997.
5.2.2 Seasonal patterns in the occurrence of waterbirds at the MPRS
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The first influx of birds to the Muni site, which was dominated by tems, reached its 
peak in October, and by November, only a very small portion of the population was left 
at the site. It is well known that the peak period for tems occurring on the Ghana coast, 
is October (Grimes, 1979; Ntiamoa-Baidu, 1992; van der Winden el a 2002), thus 
explaining the October peak recorded at Muni during the survey. Furthermore, tem 
abundance on the Ghana coast during that period has been attributed to the increased 
availability and location of food sources in the coastal waters of Ghana (Grimes, 1979).
According to Grimes (1979), the seasonal upwelling offshore Ghana usually lasts for 
only a few months after it begins in August. During that period, shoals of Sardinella and 
anchovies, a good food source for tems, move from deeper waters to the surface. Tems 
therefore feed on these sardines and use the closest roosting sites available, such as 
exposed mudflats in coastal lagoons, and sand dunes, etc.
In late November, few of the sardines remain at the surface, forcing tems to move 
further offshore in search of new sources of food. There is evidence however that tems 
use the coasts of Namibia from February to March. From the time they leave Ghana to 
the period they appear in Namibia, there is a gap in knowledge concerning their 
locations (van der Winden et al., 1996).
The second influx of migratory waterbirds occurred in January 2010. During this 
period, the most abundant birds at the site were waders which were dominated by 
Ringed Plovers. Waders stayed longer at the site, as, more than half of the January peak 
remained at the site in March. Even in the month of April that coincides with the 
northern spring migration when waterbirds move back to their breeding grounds, the 
numbers of waterbirds recorded were relatively high. This may be explained by the 
usual congregation of waterbirds at staging sites to refuel before final migration
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(Summers et al.. 1995). The conditions at the staging sites may have severe 
consequences for the migration of waterbirds, and their breeding success. Based on the 
macrobenthic survey carried out during the study, it is clear that the high numbers of 
waders coincided with the peak in the density of polychaetes, their primary food source.
According to Ens et al. (1994), juvenile birds are late migrants due to the conspecific 
interactions that prevent them from getting enough food when feeding in the presence of 
adult birds; hence they may need more feeding time after the departure of the adult 
birds. This study did not establish whether or not the birds remaining on the site in April 
were juveniles. There is evidence that shorebirds use several coastal wetlands in Ghana 
(Macdonald, 1977; Ntiamoa-Baidu, 1991; Gbogbo 2007b), by moving from one 
wetland to another. Furthermore, Macdonald (1977) suggested that in Ghana, migrant 
waders use different wetlands at different times before final departure. There is also 
evidence that depending on their life-stages, some species of waterbirds may use the 
sites only as a stopover site for refuelling or as a non-breeding ground. Thus, throughout 
the northern winter, the MPRS remains important as a staging site by Palaearctic and 
inter African migrants.
5J.3 Tidal differences in waterbird abundance
Multiple counts carried out on each sampling day from December 2009 to April 2010 
showed that there are tidal influences on the occurrence and abundance of some 
waterbird species at the MPRS. Common Tems and Kittlitz's Plover occurred only at 
low tide. Sanderlings, Curlew Sandpipers, Royal Tems, Spotted Redshanks, and Grey 
Herons (Ardea cinerea), were most abundant at high tide, while Ringed Plovers and 
Little Stints were most abundant at low tide. Intertidal wetlands are affected by the level 
of tides, with increasing levels of tide resulting in water level increases, reduction of the
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salinity in case of hypersaline ecosystems and increase in salinity with freshwater 
ecosystems. Tidal level also brings changes in food availability and affects preferences 
by feeding waders.
In terms of open lagoons, the tide brings new nutrients from the sea and also improves 
accessibility to food for species like Sanderling and increases in food intake as a result 
of the softening of the sediment Low tide also helps to expose food items for small 
waders.
It is well known that the numbers of waterbirds using a site may vary seasonally and 
across the tidal cycle. Burton et al. (2004) explained this variation in numbers as a result 
of the varying availability of food through the tidal cycle, as well as the distance of sites 
from high tide roosts and their isolation from alternative habitats. These variations 
depend however on the sites and tend to be species-specific (species’ energetic 
requirements, food preferences and feeding strategy, etc.). Burton et al. (2004) observed 
that numbers of Oystercatchers, Dunlins and Curlew Sandpipers decreased towards low 
tide.
Significant differences were observed in the counts of waterbird species belonging to 
Guild 2. This difference is expected since birds belonging to Guild 2 mostly feed on 
exposed mudflats. It therefore means that at low tide, larger areas are exposed, 
favouring the accessibility and availability of the macrobenthic prey they feed upon.
From the observations, it may be concluded that it is better to count tems during high 
tide as their numbers better represent the size of their population. For Waders, some 
species such as the Ringed Plover and Little Stint are better counted at low tide when
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their numbers tend to be high, while others such as the Whimbrel and Grey Plover are 
best counted at high tide.
S3  Habitat Selection by Waterbird#
Based on the use of the site by waterbirds, the Muni Lagoon was categorised into three 
main sections. Site E (sea water inflow); Site A, C, and D (mid-lagoon and its 
surrounding mudflats), and Site B and SP (freshwater inflow and Salt Ponds). She E 
was located at the opening of the lagoon to the sea, and site SP and B were located al 
the northern section of the lagoon. The Sites A, C, and D were located at the middle part 
of the lagoon. The site varied in terms of salinity concentration and the distance from 
the shoreline.
During the dry season. Site E had lower salinity due to its closeness to the sea as sea 
water diluted the hypersaline waters at Site E; however during the rainy season, Shes B 
and SP had the lowest salinity. The middle portion of the lagoon had average salinity 
values that ranged between those recorded for the other two sections. This salinity 
gradient would result in variations in macroinvertebrate fauna distribution (Leland and 
Fend, 1998; Liang el al.. 2002), which in turn, would determine the distribution and 
abundance of waterbirds that depend on them. Several studies have also shown that prey 
distribution is the most important factor affecting the spatial distribution of waterbirds 
at intertidal areas (Colwell and Landrum, 1993; Moreira, 1995). In this study, the 
distribution pattern of the birds followed the same pattern as the macrobenthic species 
richness.
Colwell and Sundeen (2000) however reported that the main factors accounting for 
shorebird distribution on coastal beaches of Northern California were the proximity to
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the main feeding areas and the variation in habitat features which were thought to 
influence food availability and foraging activity. This would imply that waterbird 
distribution could be determined by the morphological adaptations and activities of the 
individual species.
During migration, waterbirds select their habitat based on three main factors; (i) 
availability of food, (ii) safe roosting sites, and (iii) the extent of disturbance (Piersma, 
1994). Food availability, the major factor, is determined by the morphology of the bird 
or species in question, its feeding requirements, and the wetland type and hydrology in 
which it finds itself. Thus wetlands with bigger habitat areas would be expected to 
attract greater number of species, due to the higher number of microhabitats they may 
provide (Paszkowski and Tonn, 2000; van de Kam et al., 2004). This was however not 
the case at the Muni Lagoon, as sites C (mid-lagoon section), A (mudflat I) and SP 
(constructed Salt Ponds) scored the highest number of species and abundance, while the 
largest site, E, had the least species diversity. It is possible therefore that smaller 
wetlands could hold equally important numbers of waterbird species (Hudson, 1983; 
Garay et al., 1991; Gbogbo, 2007b). It is therefore important to realise that the size of 
an area on its own does not account for the higher diversity recorded but rather its 
combination with other factors such as vegetation cover and structural heterogeneity of 
habitats within the wetland (Fairbaim and Dinsmore. 2001).
Habitat selection by waterbirds can be influenced also by the activity and requirement 
of the birds, since during migration, migratory birds are more likely to be found where 
they can maximise their food intake. Migratory waders, for instance, are observed to 
prefer intertidal mudflats during their non-breeding period (Rosa et al., 2003).
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Piersma and Ntiamoa-Baidu (1995) and Ntiamoa-Baidu et al. (1998) characterised 
waterbirds into seven guilds based on their functional responses to food (feeding style, 
mechanisms or identification of the food) as follows:
•  herbivorous ducks,
•  visual surface foragers waders (Plovers, Common Sandpiper, Turnstone, 
Redshank, etc.),
•  tactile surface foragers waders (Godwits, Sanderling, Little Stints, Curlew 
Sandpiper, etc.),
•  pelagic foragers waders (Greenshank, Black-winged Stilt, Avocet),
•  stalking herons (Little Egret and Reef Heron),
•  fishing pelicans and fishing terns (Black Tern, Royal Terns, etc.).
Hence at the MPRS, based on the distribution of the three most abundant species, it was 
observed that birds belonging to different guilds may display different habitat 
preferences. This might have resulted from the various morphological differences as 
well as the type of food they feed on.
Ringed Plovers, belonging to the Guild 2, are visual surface foraging species. They 
were recorded most at Site A during the sampling period, where they were found 
feeding continuously on worms from the soft mud. Sanderlings which belong to Guild 3 
used the site D most. They were seen feeding mostly at the edges of the water and also 
from the mud in mixed flocks with Ringed Plover, Little Stint, and Curlew Sandpiper. 
They usually follow the water movement caused by the wind or tide. The second 
favourite habitat, Site SP was most used for roosting. Sanderlings were found usually 
roosting in flocks on the sand or the exposed mudflats found within some of the unused 
ponds. Greenshanks were recorded mostly at site SP. This species belonging to Guild 4.
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exploited the areas with relatively high water levels. They displayed different feeding 
strategies varying from pecking, sweeping to ploughing in an organised sequential 
manner. They were seen roosting with the Little Egrets and Curlew Sandpiper.
During this study, the distribution of tems was influenced by the tidal cycle and the 
availability of small islands within the lagoons. These islands were located in Sites E 
and C. Water depth at Site A was relatively stable and low, therefore exposing the mud 
that served as roosting sites for the tems, which used the Muni Lagoon mainly as 
roosting sites.
During the day, tems were seen to use more than one roosting site depending on the tide 
level. At high tide, they are located at Site E, and at ebbing or low tide, or even when 
the tide is rising they could be found roosting in Site C.
S.4 Waterbird Activities at the Muni-Pomadze Ramsar Site
The main activities of waterbirds recorded during this study were roosting, feeding, and 
comfort activity. These activities varied according to site and time based on the spatio- 
temporal changes in the importance of the different sites at the MPRS. Variations in the 
number of waterbirds roosting and feeding were observed for the different sites and 
months sampled. A chi-square association test between sites and months showed 
significant interaction in terms of number of feeding birds (x2=1951.27, P <0.001. 35df) 
and that of roosting birds (x*=5624.66, PO.OOl, 35 df). This showed that the sites 
displayed different characteristics depending on the time of the year.
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5.4.1 Comfort activities of waterbirds at MPRS
The proportions of waterbirds engaged in comfort activities showed that they spent 
more time either feeding or roosting than preening or bathing. A similar study of 
waterbird activities at Songor and Keta (Ntiamoa-Baidu el al., 1998) showed that 
comfort activity was the behavioural activity recorded least often. For the 33 species 
recorded at Muni lagoon, the proportion of the birds observed during daytime that were 
engaged in comfort activity ranged from 0 to 2.48%, as compared to 2-31% of the 25 
birds species observed by Ntiamoa-Baidu et al. (1998) at other coastal lagoons in 
Ghana. The proportions recorded during this study are also lower than the 0.3-25% for 
the over 62 bird species recorded by Cotgreave and Clayton (1994).
5.4.2 Roosting activity of waterbirds
From this study, it can be concluded that Sites SP, E, and C were used most by roosting 
birds. The two Sites, E and C, are natural habitats of the Muni lagoon within which 
small islands are located. The population of waterbirds using the Sites E and C as 
roosting sites was dominated by tems, as a result of their preference for small islands 
surrounded by open waters (Ntiamoa- Baidu, 1992; van de Kam et al., 2004).
Site SP (constructed Salt Ponds), was used mainly by roosting waders and herons. They 
used both the banks and the ponds themselves depending on the water levels for this 
purpose, especially during high tide and depending on the time of the day. When 
temperatures are high or at dusk, the numbers of roosting birds increased at the SP. The 
distribution at the roosting site of wader is as follows: Spur-winged Plovers on drier 
places, Sanderlings and Curlew Sandpiper, Little Stint together on the shallowest parts
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of the salt ponds, and Greenshanks and Herons in the deeper parts of the Sait pans. 
Herons were also observed on the banks of the ponds.
Artificial habitats located closed to natural foraging habitats (Brusati et al., 2001) are 
alternative habitats for waterbirds that move from their preferred habitats such as 
beaches and mudflats during high or low tides (Erwin et a l 1994, Burger et al., 1997) 
to the constructed ponds. Salt ponds not only provide good roosting sites for waterbirds, 
but also serve as foraging habitat for large numbers of migratory waterbirds (Takekawa 
et aL, 2001; Wamock et al., 2002). Young (1998) recorded more herons feeding and 
roosting on coastal fish ponds.
The use of high tide roosts often varies among species and largely depends on the 
distance to the nearest favourable feeding areas and the potential risk of disturbance 
(van de Kam et al., 1999). Human activities impose a potential threat, especially, with 
high tide roosts (Blanc et al., 2006). Activities such as fishing that occur at MPRS 
affected the behaviour of roosting and feeding waterbirds. According to Blanc et al. 
(2006) birds perceive human beings as potential predators. At Songor lagoon, roosting 
terns, for instance were observed to fly out whenever people crossing the lagoon 
approach the roost (Ntiamoa-Baidu et al., 1998).
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The feeding activity of waterbirds at the MPRS is essentially determined by that of 
waders and herons, since tems used the site mainly for roosting. In order to maximise 
their prey intake during migration, waterbirds, especially waders, were observed to feed 
not only in areas of high prey density but more in areas of easy accessibility of suitable 
prey (Kushlan 2000; Gawlik, 2002). They therefore select profitable prey or profitable 
feeding areas. At the MPRS, foraging waterbirds were most abundant at Sites A and D, 
the two sites with mudflats of the Muni Lagoon. This observation confirms the 
importance of intertidal mudflats as feeding sites for migratory waders (van de Kam et 
al., 2004; Zou et al., 2006). The selection of these feeding sites is not haphazard, but a 
strategy by migrant waders that need to meet physiological demands during their non­
breeding and/or refuelling periods that will ensure timely return to their breeding 
grounds.
Even though Site A did not record the highest density of macrobenthic prey upon which 
waders depend it had the lowest water depth and therefore the highest food 
accessibility. It has been well-established that hydrological fluctuations within and 
among wetlands often dictate where and when waterbird species can access their food 
(Kingsford et al., 2004).
In coastal wetlands, waders are more abundant when their foraging areas are exposed, 
and their prey items become exposed. Low water depth is therefore critical for foraging 
birds, and hence the importance of low tide for feeding waders (Burton et al., 2004). 
Young and Chan (1997) pointed out that large wading birds such as herons and egrets 
choose feeding sites in drained fish ponds where water is shallow and fish are more 
concentrated. However, this cannot be generalised, since different waterbird species
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5.5 Feeding Activity of Waterbird* at MPRS
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have different water depth requirements (Bolduc and Afton, 2004; 2008). Even among 
waders, species belonging to different guilds may have different water depth range 
requirements. Ntiamoa-Baidu et al. ( 1998) found that the feeding habitat of waders in 
the Keta Lagoon ranged from dry mudflats to wet mud, and shallow water of not more 
than 20 cm. Ringed Plovers, for instance, fed on dry mud; Curlew Sandpipers on wet 
and water depth below 5 cm and Stilts and Greenshanks in deeper shallow waters 
(Piersma and Ntiamoa-Baidu, 1995), whereas diving birds, such as fishing tems and 
cormorants are probably not as limited by water depth. Several studies have found that 
waterbird density is highest at low water depth. It has been explained that there should 
be an optimum water depth at which waterbirds are expected to maximise their resource 
utilisation, otherwise it will mean that waterbird numbers are highest when water depth 
is virtually zero (e.g. Kingsford et at., 2004; Holm and Clausen, 2006; Bolduc and 
Afton, 2004).
The key role played by water depth in the selection of feeding habitat by waders is 
recognised (Ntiamoa-Baidu et al., 1998; Liang et at., 2002). It could thus be assumed 
that waterbird communities differ among areas showing different hydrobiological 
regimes at a given time, since different species have different depth requirements 
(Bolduc and Afton, 2004; 2008). Water depth was found to affect feeding waders 
differently depending on the habitat in which they were and morphological constraints 
(Safran et al., 1997).
The second probable reason for the abundance of feeding birds in Site A, is that Site C 
is highly disturbed/polluted as compared to A as shown by the Abundance/Biomass 
Comparison curves. In highly disturbed habitat as in the case of Site C, the biomass of 
macrobenthic invertebrates is lower than that of a site with lower disturbance. Since
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migratory birds always try to maximise their food intake or energy, they most often opt 
for prey items with high biomass and that are easily accessible.
Furthermore, sediment type and hardness are also factors that could limit food 
accessibility by feeding waterbirds. Hence the lower number of feeding waterbirds 
recorded at site C could also be attributed to the abundant shells on the ground that 
could probably limit the feeding activity of the birds. Most waders prefer soft mud or 
sand, where they can easily probe.
No correlation was found between density of shorebird and/of their prey as suggested 
by Goss-Custard et al. (1977), Bryant (1979), Meire (1993), and Kalejta and Hockey 
(1994). There was however, a correlation between the abundance of feeding birds and 
the biomass of polychaetes sampled at Site A (mudflat I). This is probably due to the 
dominance of birds that feed by visual foraging method (Guild 2), such as ringed 
plovers. This is in agreement with Kalejta and Hockey (1994) who stated that visual 
foraging birds are better predicted by prey biomass rather than density.
The periodic movements or migration of a population or part of a population of an 
animal species away from a region and their subsequent return to that same region is 
caused by the local depletion of harvestable prey and high cost of maintenance during 
unfavourable conditions (Ens et al., 1994). The refuelling periods involve the use of 
stopover or staging sites for feeding and resting which helps in the accumulation of 
energy, and is followed by alternate flight periods during which energy is consumed. 
Migratory waterbirds generally are bound to fixed time-schedules (Piersma. 1994); 
hence their heavy dependence on the resources found at their stop-over sites.
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The peak wader period that occurred in January 2010 corresponded to a peak in the 
density of macrobenthic invertebrates at the Muni lagoon. Even though no definite 
conclusion can be made concerning a causality effect between the two, it is necessary to 
highlight the high density of invertebrates at the site at a time when bird numbers were 
also high.
The findings of this study show that several factors influence waterbird use of Muni- 
Pomadze Ramsar Site. At the landscape scale, individual sites varied in waterbird use as 
a response to seasonal changes in the ecological characteristics of the sites (Mungula el 
al.. 2005).
Variations were recorded in the hydrological regime, the macrobenthic invertebrate 
community, as well as changes in waterbird species diversity, abundance and 
distribution. The fluctuations in water depth and quality, coupled with the 
spatiotemporal variations in the density of macroinvertebrates at the Muni lagoon 
determined the use of the different sites as feeding habitats over the study period.
5.6 Waterbirds as Bioindicators of Wetland Quality
Waterbird species and populations are sensitive to changes in their ecosystem; hence 
their importance as bioindicators in wetland monitoring programmes (Furness and 
Greenwood, 1993). Continuous long-term monitoring of the populations of bird species 
can provide useful data in describing the implications of anthropogenic activities for 
habitat condition and biodiversity (Owusu el al., 2002). Waterbird species and 
populations are used as bioindicators of environmental health with regards to pollution.
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habitat degradation, vegetation disturbance, water quality and resource productivity as 
well as food abundance (BirdLife International, 2004; Ahulu et al., 2006).
The habitat alterations that had occurred at the MPRS in the past 15 years would 
consequently affect its fauna. This study recorded decreases in the maximum counts of 
26 waterbird populations recorded at the MPRS. Studies by Norris el al. (2004) and 
Newton (2004) have shown that Redshank populations, for example, declined as a result 
of nesting sites destruction due to land drainage in summer. Wetland quality, from the 
perspective of waterbirds can be described inter-alia, as the water quality, food 
availability, as well as roosting and nesting sites, which determine the welfare of a bird 
or bird community assemblages. Wetland quality is the most holistic factor that 
influences waterbird communities.
The results of this study showed that Site C (Mid-Lagoon portion) had a higher density 
of macroinvertebrates than Site A (Mudflat I); however. Site A recorded the highest 
proportion of foraging birds. This would suggest that foraging waterbirds would prefer a 
poorer site in terms of prey density with good food accessibility than one with high 
density but poorer accessibility (Rapport, 1991; Railsback et al., 2003). Since the 
quality of a habitat or an environment is its ability to provide conditions appropriate for 
individual and population persistence of birds (Hall et al., 1997), it is obvious that it 
goes beyond the scope of the birds immediate surroundings and the resources necessary 
for their survival and reproduction, but also the conditions that constrain their use 
(Morrison et al., 2006).
The macrobenthic fauna of the Muni Lagoon is dominated by capitellid worms, and 
couples with the high mean salinity and temperature and their fluctuations indicate that 
conditions at the Muni Lagoon arc typical of a stressed environment. It would therefore
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be reasonable to suggest that in this case waterbirds are not good indicators of wetland 
quality, health or status, since the site still supports appreciable numbers of waterbirds. 
Further behavioural studies would be important therefore to complement the use of 
waterbirds as bioindicators of wetland quality. Temple and Wiens (1989) found that 
waterbirds are not early indicators of habitat degradation and proposed that birds may 
use a site till they exhaust all its natural resources before moving completely away.
Considering whether or not waterbirds are early indicators of wetland degradation, 
Johson (2007) stressed the need for complementary studies and classified bird-based 
indicators of habitat quality into broad groups, demographic, distributional and 
individual condition measures, to which behavioural observations could be added and 
the life history of the waterbird population also taken into consideration. It follows, 
therefore, that it is necessary to consider the response of birds to all factors in their 
environment in order to make conclusive deductions on the role of the birds in the 
wedand ecosystem and their value as bioindicators of wedand quality.
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CHAPTER SIX
CONCLUSIONS AND RECOMMENDATIONS 
6.1 Conclusions
The populations of waterbirds recorded at the MPRS suggest that the importance of the 
site for waterbirds currently is lower than what it was at the time of its designation as a 
Ramsar Site. The populations of the four tem species (RoyaL, Sandwich, Black and 
Common) which occurred in internationally important numbers at the time of 
designation were all far below the 1% threshold required to qualify for international 
importance. However, the MPRS still supports some nationally important populations 
of Spur-Winged Plover, Whimbrel, Wood Sandpiper, Common Sandpiper and 
Sanderlings. MPRS also provides valuable roosting sites for tems as well as feeding 
grounds for the non-breeding waders.
Habitat use varied among waterbird groups, with tems using the lagoon mainly for 
roosting, more specifically Site E (seaward section) and C (mid-Lagoon portion), and 
waders feeding more at Site A and D, the two mudflats surrounding the lagoon, roosting 
at Site SP, the constructed salt ponds. Herons were the least abundant at the MPRS and 
used Site B (freshwater inflow) and SP (Salt Ponds) most. Nevertheless spatiotemporal 
variations in the ecological character of the sites resulted in temporal variations in the 
activities of the birds and the macrobenthic density.
The influence of water quality on waterbird activities varied according to the sites. Of 
the water parameters measured, only salinity, conductivity and temperature significantly 
influenced roosting activity of waterbirds. The feeding activity of waterbirds in the
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Muni Lagoon was influenced by hydrological fluctuations that affected the accessibility 
and availability of food. In Site A, the number of feeding birds was correlated to the 
macrobenthic biomass instead of density.
The Muni- Pomadze wetland ecosystem is degrading due to natural (vulnerability of 
soils to erosion, and large expanse of shrubs sensitive to bush fire) and anthropogenic 
activities (urbanisation, agriculture, population growth, etc.). As such 99% of the 
herbaceous shrub is lost, built-up areas have quadrupled and the Muni Lagoon has 
reduced to about 50% of its original size.
At the Muni Pomadze Ramsar Site, the macrobenthic community is dominated by the 
opportunistic Capitella spp. which is known to proliferate in such stressful 
environments. The macrobenthic fauna of the Muni lagoon experienced variations in 
response to the fluctuating hydrology and water quality during the study period. The 
two peaks in macroinvertebrate abundance at Muni lagoon recorded in January and 
March 2010 showed that temporal variation in the density of benthic organisms could 
be linked to increasing rainfall in the area. It was also observed that the highest counts 
of waders were recorded in January when the highest density of benthic organisms was 
recorded. The macrobenthic community structure of the Muni Lagoon has not changed 
much since it is still dominated by only one taxon.
Even though salinity of the Muni Lagoon has reduced, its fluctuations make the lagoon 
it a very stressful environment. Both waterbird and benthic species are likely to be 
affected by temperature and salinity stress in the Muni ecosystem. Turbidity of the 
Muni waters was also recorded to be high probably due to the shallowness of the 
lagoon. Low variability was recorded in pH and D.O.
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Despite the habitat losses and the general deterioration of the health of the MPRS, the 
site continues to support significant numbers of waterbirds, although the populations 
have gone down. The findings of this study thus support that waterbirds arc not early 
indicators of wetland quality. Depending on what has been lost or gained, a change in 
the environmental health of a wetland may not necessarily result in immediate changes 
in the waterbird community. Thus by the time the birds stop using the altered site, the 
site may be degraded beyond redemption.
6J  Recommendations
As a result of this study, the following recommendations can be made:
• Habitat alterations that have occurred at the Muni-Pomadze Ramsar Site 
have led to the deterioration of its ecological character. The numbers of most 
waterbird species using the site have decreased and based on the current study, none of 
the waterbird species occurred in internationally important numbers. It is 
recommended therefore that the bird monitoring at the MPRS continue over a longer 
period to enable the re-assessment of the international importance of the site.
• The changes in the populations of the most abundant species of waders, 
the Curlew Sandpipers, should be investigated further. Curlew Sandpiper population is 
reducing in coastal wetlands of Ghana even though there is an increase in the global 
population.
• The use of waterbirds as bioindicators should be thoroughly understood 
and investigated before implementation. It should also be complemented with
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measures of other biological and ecological parameters in other to provide adequate 
information on the habitat.
• The Muni-Pomadze Ramsar Site can be zoned further into southern, 
eastern and northern sections for management purposes, and the degree of protection 
to be provided.
• The management of the site should also be reinforced and accompanied 
by a habitat restoration program. The Muni lagoon needs to be restored, especially 
with the prevailing climatic instability, to prevent it fiom drying up completely in the 
very near future.
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APPENDICES
Appendix I: GPS coordinates for the sampling points
SITE N w
A 00°38'3r 05°19'33”
B 00o38’4r' 05°20'05”
C 00°38’39" 05° 19*42"
D 00°389" 05°19,51"
E 00°39'03 05°19’24"
SP oo^s'is" 00°20'14"
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Appendix II: Water Quality Analysis of the Muni Lagoon
Water quality
Mont
h
Temperatur
e
Water
depth
turbidit
y
Salinit
y
D.O Conductivit
y PH
A
8.1
SEPT 28.2 12.5 63.7 38 5.8 58.08 1
OCT 32.5 12.5 21 36 8.3
NOV 27.9 12 73.5 20.2 68.98 8.5
DEC 33.6 13.67 89.3 45.3 8.3 44.2 8.5
B
8.1
SEPT 29.8 22 33.7 35 5.9 62.24 1
OCT 32 32 21 40 8.6
NOV 28.2 35.5 48.2 38.4 67.04 8.7
DEC 33.3 26 19.4 45.67 5.5 68.4 8.5
8.1
JAN 33.9 21 15 40 7.9 74.15 2
8.4
FEB 36.9 30 29.5 36 7.6 59.36 3 
8 2
MAR 39.5 18.7 7.95 39 6.9 62.44 1
APR 30 14 7.58 29 10.6 45.56 8.1
C
8.0
SEPT 25.3 32 14.8 37 6 58 8
OCT 32.9 21.7 13 40 8.4
NOV 28.2 32 50.4 38.6 55.4 8.4
8.4
DEC 36 30 7.21 41 6.2 48.2 5 
8 2
JAN 37.2 35 20 39 8.2 58 3
8.3
FEB 37.6 32 16.6 38 7.8 41.96 8
MAR 38.6 20.7 5.04 40 9.9 54.32 8.1
APR 30.9 25 19.54 40 8.9 73.64 7.8
D
SEPT 27.3 31 29.6 38 6 61.56
8.1
4
OCT 34 31 35 39 8.3
E
SEPT 25.2 40 29.6 39 5.8 63.28
8.0
6
OCT 31.2 45 9.6 37 8.4
NOV 27.9 17 46 25 46.28
8.3
3
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DEC 35 22 46.2 40 5.6 38.6 8.7
7.8
JAN 33.8 36 29 38 6.2 56.55 8
7.6
FEB 34.7 39 8.4 40 6.4 42.88 5
MAR 33.5 39 5.71 38 8.6 55.64 8
APR 31 39.7 13.85 38 7.3 44 8.1
Water quality
SP
Mont Water turbidit Salinit D.O Conductivit
h temperature depth y y . y pH
DEC 32 II 21.7 55 5.5 74.8 8.2
8.0
JAN 33.6 35.5 12 51.5 6 67 1
8.1
FEB 32.2 30 36.2 38 6.2 57.28 4
7.9
MAR 32.9 34 18.4 50 7.8 72.28 8
7.4
APR 27.5 21 44.53 106 6.7 72.8 3
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Appendix 111: Spatio-temporal Variation in Major Feeding Groups at MPRS
Spatio temporal variation in major feeding groups at MPRS
WADER
SEPT OCT NOV DEC JAN FEB MAR APR
A 137 284 135 162 66 292 299 479
B 18 38 12 89 150 33 59 48
C 138 74 77 170 191 92 22 39
D 96 85 0 118 532 167 24 67
E IS 15 6 16 29 35 6 6
SP 203 229 5 173 102 321 313 137
TOTAL 607 725 235 728 1070 940 723 776
HERON
SEPT OCT NOV DEC JAN FEB MAR APR
A 6 5 2 3 1 3 28 8
B 1 2 3 2 47 1 9 11
C 2 0 0 13 3 1 2 8
D 1 2 0 1 12 6 1 5
E 28 5 2 6 4 5 3 1
SP 107 14 11 20 6 2 28 21
TOTAL 145 28 18 45 73 18 71 54
TERN
SEP OCT NOV DEC JAN FEB MAR APR
A 3 87 411 0 0 0 0 0
B 1 2 0 0 0 0 0 0
C 478 747 0 0 6 0 17 51
D 9 42 0 0 0 0 0 0
E 10 1 0 261 500 107 68 0
SP 1 2 0 0 0 0 0 0
TOTAL 502 881 411 261 506 107 85 51
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APPENDIX IV: Biota-Environment Interrations
Effect of environmental parameters on Benthic species
Variable
Marginal Effects 
Var.N Lambda 1
Conditional Effects 
LambdaA P F
Water depth 2 0.16 0.16 0.025 3.27
turbidity 3 0.16 0.04 0.62 0.76
pH 5 0.11 0.09 0.14 1.87
Temperature 1 0.03 0.02 0.77 0.5
Salinity 4 0.03 0.02 0.855 0.38
Effect of environmental parameters on Benthic major taxa
Marginal Effects Conditional Effects
Variable Var.N Lambda! LambdaA P F
Water depth 2 0.03 0.03 0.07 2.36
Salinity 4 0.01 0.01 0.775 0.27
turbidity 3 0 0 0.99 0.01
pH 5 0 0 0.485 0.68
temperature 1 0 0 0.85 0.16
Effect of environmental parameters on waterbird abundance
Marginal Effects Conditional Effects
Variable Var.N Lambdal LambdaA P F
temperature 1 0.04 0.04 0.2 1.24
pH 5 0.02 0.02 0.595 0.38
turbidity 3 0.01 0.01 0.655 0.35
Salinity 4 0 0.01 0.745 0.28
Water depth 2 0 0.02 0.5 0.63
Effect of environmental parameters on waterbird activity
Marginal Effects Conditional Effects
Variable Var.N Lambdal LambdaA P F
temperature 1 0.06 0.06 0.24 1.24
Salinity 4 0.04 0.03 0.53 0.62
Water depth 2 0.03 0.06 0.21 1.4
turbidity 3 0.02 0.04 0.435 0.78
.RH ...... 5 0.02 0.03 0.58 0.49
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Appendix V: Habitat Use by Waterbirds
Survey
periods
Total
sightings
No. Days 
spent
Total days 
spent by birds
Northern Autumn
Survey
periods
Total
sightings
No. Days 
spent
Total days 
spent by birds waders terns
5 Sept 1254 70 87780 607 42490 502 35140
9 Oct 1634 36 58824 725 26100 881 31716
14 Nov 664 14 9296 235 3290 411 5754
Total days spent during Northern 
Autumn 155900 71880 72610
Northern Winter
Survey Total No. Days Total days 
periods sightings spent spent by birds
16 Dec 1034 66 68244 728 48048 261 17226
13jan 1649 38 62662 1070 40660 506 19228
20 feb 1065 20 21300 940 18800 107 2140
Total days spent during Northern
Winter 152206 107508 38594
Northern Spring 
Survey Total No. Days Total days 
periods sightings spent spent by birds
15 Mar 879 26 22854 723 18798 85 2210
10 Apr 881 10 8810 776 7760 51 510
Total days spent during Northern
Spring 31664 265S8 2720
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