Biodiversity Change: Preliminary Monitoring of Anura Species in Selected Vegetation Sites in Southwestern Nigeria

Abstract

Four study sites with different vegetation structures in southwest Nigeria were selected and monitored for anuran species between 2007–2009 applying the transect sampling method. These study sites were located at Ijede (06º 34’ 072’’ N 003º 35’ 030’’ E), Ijebu Oru (06º 56’ 493’’N 003º 56’ 792’’E), Onidundun (07º 37’ 313’’ N 003º 55’ 258’’ E) and Ibapon Oyewole (08º 05’ 129’’ N 004º 11’ 132’’ E), all in southwest Nigeria. The study sites of Ijebu Oru (forests/abandoned farmlands) and Ibapon Oyewole (savanna) had a mean number of species and individuals of 21 and 14, and 236 ± 5 and 108 ± 7.9, respectively. However, at Ijede (swamps/forests), there was 18% reduction (6% in 2008; 12% in 2009) of the initial number of species recorded in 2007 due to shifting agricultural practices. Hylarana albolabris, Aubria subsigillata and Ptychadena aequiplicata were no longer accounted for in 2009 surveys. At Onidundun (derived savanna/forests), there was a 17% reduction of anuran species (Ptychadena mascareniensis, Hyperolius f. burtoni and Arthroleptis sp.) in 2008, but 12% of these species (Hyperolius f. burtoni and Ptychadena mascareniensis) were again seen in 2009 after substantial amount of vegetation growth had occurred. The mean number of species and individuals at the study sites of Ijede and Onidundun were 16.67 ± 1.5 and 16.67 ± 1.5; and 203.67 ± 6.7 and 169.67 ± 8.3, respectively. In general, fewer number of amphibian species were observed during the dry season at the four study sites. Habitat destruction and modification are key causes of habitat loss of anuran species observed in this study. Biomonitoring procedures should be applied regularly to detect changes (increase/decrease) in the diversity and abundance of anuran species within a specified study area of interest over time.