Land Use and Landscape Structural Changes in the Ecoregions of Ghana
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Date
2014
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Disaster Research
Abstract
In recent years, land use (LU) and landscape structure
in ecoregions around the world have been faced with
enormous pressures, from rapid population growth to
urban sprawl. A preliminary account of changes in
land cover (LC) and landscape structure in the ecoregions
of Ghana is missing from the academic and research
literature. The study therefore provides a preliminary
assessment of the changing LU and landscape
structure in the ecoregions of Ghana, identifying the
causes and assessing their impact on land-based resources,
and on urban and agricultural development.
LU/LC maps produced from 30 m resolution Landsat
TM5 in 1990 and ETM+ in 2000 were classified into
dominant land cover types (LCTs) and used to survey
the changing landscape of Ghana. LC-changemap
preparation was done with change detection extension
“Ver¨anderung” (v3) in an ArcGIS 10.1 environment.
At the class level, Patch Analyst version 5.1 was used to
calculate land use (LU) statistics and to provide landscape
metrics for LU maps extracted from the satellite
imagery. The results showed that commonly observed
LCCs in the ecoregions of Ghana include conversion
of natural forest land to various forms of cultivated
lands, settlements, and open land, particularly
in closed and open forest and savannah woodland. The
dominant LU types in the ecoregions of Ghana are
arable lands, which increased by 6168.98 km2. Forest
and plantation LCTs decreased in area and were
replaced by agricultural land, forest garden, and open
land. Afforestation rarely occurred except in the rainforests.
The mean patch size (MPS), ameasure of fragmentation,
was generally reduced consistently from
1990 to 2000 in all the ecoregions. Similar results that
indicated increased fragmentation were an increased
number of patches (NumP) and the Shannon diversity
index (SDI). Habitat shape complexity inferred ecoregions
except for rainforest and wet evergreen. The SDI
and Shannon evenness index (SEI) showed that habitat
diversity was highest in the coastal savannah and
the deciduous forest ecoregions. The main drivers of
changes in the LUs and landscape structure are demand
for land and land-based natural resources to
support competing livelihoods and developmental activities
in the different ecoregions.
Description
Keywords
landscape metrics,, land change,, landscape planning,, urban sprawl,, fragmentation