Aspects of community ecology of reptiles in the swamp forests of the Upper Orashi Forest Reserve (Niger Delta, Nigeria)

Abstract

The study of community composition shifts due to increased habitat modifications and deforestation is a primary issue in contemporary tropical community ecology theory. As the forest habitat conversion process has been very short in Africa relative to the evolutionary temporal scale, it is likely that animal communities are not at an equilibrium. The Upper OrashiForest Reserve(NigerDelta regionofSouthern Nigeria) is a valuable case study as it is one of the few remnant deltaic swamp forest patches inside a highly developed and deforested region. In this paper, we investigated some aspects of the community ecology of reptiles of thisforestareabasedonstandardizedfieldsurveysacross26 study plots. Overall, we recorded 34 species, with the detected number of both species (34 versus 27) and individuals (562 versus 381) being higher during the wet season. Diversity/dominance diagrams showed similar trends in both seasons, but diversity measures showed that evenness was remarkably higher by wet season. Analysis of similarities (ANOSIM) confirmed that the species-richness estimate generated by Chao’s index was significantly higher for the wet season. However, the profiles of the diversity curves were comparable in the two seasons. The proportion of forest-specialist species decreased compared to that observed at the same study area 15+ years ago, with a gradual process of biotic homogenization being apparent.