SEASONAL ANURAN SPECIES COMPOSITION AND DISTRIBUTION PATTERNS ON A DELTA LANDSCAPE, OKPARA TOWN INLAND, DELTA STATE, NIGERIA
Abstract
The effect of seasonal difference and land use types on the composition and distribution of anuran
assemblages were investigated in the Delta region of Nigeria. Overall, 27 anuran species and a
mean total of 43.39 12.21, 32.53 20.3, 40.07 1 and 26.56 9.7 individuals were recorded In
96 hours of combined VES (visual encounter survey) and AES (acoustical encounter survey)
sampling in Sites A, B, C and D respectively, that were. representatives of the mosaic habitats in
the area. The highest (20.5) and lowest (14) number of species were recorded in Site 11, (primary
forest) and B (fallowed farmland and agricultural plots) respectively. Species richness was not
significantly different across the study sites during the wet season (F3,67= 2.389, P> 0.05) and
also during the dry season (F3,56 = 2.255, P> 0.05). From the results of Sites A, Band D,
calculated t-test was at 2.933,4.085 and 3.204 respectively and showed that there was significant
difference (P< 0.05) between the abundance of anurans in the wet and dry seasons while Site C
showed no significant difference (P< 0.05) in both wet and dry seasons. Anthropogenic activities
had an effect on the species richness and evenness of anurans. Site D that was characterized by
the primary forest showed the highest species richness (1.19) and evenness (1.1) among the study
sites. It is evident that the conversion of the native habitats of the anurans for agricultural
purposes no doubt has a negative effect on its diversity. In every community, it is inevitable that
agricultural land uses are necessary (0 provide the basic food for survival, but efforts should be
made towards the conservation of some pristine forest land which will serve as an ecological pool
of original animal species of that region.
