Diversity and Habitat Preferences of Anurans in the Atewa Range Forest Reserve, Eastern Region, Ghana

Abstract

This study investigated anuran diversity and habitat preferences in the Atewa Range Forest Reserve, Eastern Region, Ghana. The study analysed the effect of habitat variables (leaf cover, leaf litter depth, canopy cover and altitude) on anuran species richness and abundance. Sampling was carried out in four habitats (farmland, Cedrela plantation, riparian forest and swamp forest). A total of 16 plots (200m x100m) established along an altitudinal gradient from 300 - 800 meters above sea level were sampled . Visual and acoustic encounter techniques were used in surveying anurans. Leaf litter depth, leaf cover, canopy cover and altitude were measured or approximated in the plots and analysed to determine their effects on species richness and abundance of frogs. The results indicated a record of 762 anurans belonging to 20 species and eight families over the entire study period. The most abundant species was the West African screeching frog (Arthroleptis spp.) which is associated with degraded habitats. Species composition was most similar between the Cedrela plantation and riparian forest habitats. Species richness increased with elevation and diversity peaked at upland elevations. The swamp forest (H'=1.947) was the most diverse habitat followed in that order by farmland (H'=1.468), riparian forest (1.076) and the Cedrela plantation(0.505) . Species richness was highest in the swamp forest, indicating that swamp forest habitats may be more favourable habitats for anurans. Significant differences were found between farmland and swamp forest habitats (R=0.292, P<0.009), suggesting that altitude affected anuran species composition and distribution. Leaf cover, canopy cover, altitude and leaf-litter depth were correlated with species richness and abundance of the anurans, however, only altitude (r= -0.534, P<0.05) and leaf cover (R= 0.585, P<0.05) were significant in predicting abundance and richness. The Atewa Range Forest Reserve is an important site for rare and endangered species (Conraua derooi and Amietophrynus togoensis). It is therefore recommended that the boundary and mid-altitudinal habitat sites at Atewa should be protected against further disturbance. To enable more reliable conclusions on the effect of habitat variables on anuran diversity, future research should include other habitat factors like disturbance, soil moisture, humidity and type of leaf cover.