Potential effects of climate change on high- and low-abundance populations of the Gaboon viper (Bitis gabonica) and the nose-horned viper (B. nasicornis) in southern Nigeria

During the last 15 years, intensive field research has been conducted on the ecology and population abundance of the Gaboon viper (Bitis gabonica) and the nose-horned viper (Bins nasicornis) in southern Nigeria. During these studies, we determined the occurrence of several high-abundance and low-abundance populations for these two species. In the present study, we analysed the potential effects of climate change by modelling the current dataset on viper abundance (both high and low) using generalized additive models. We used climatic surfaces of current conditions as spatially explicit predictors, and projected viper abundance into a future climatic scenario. The future climatic conditions seemed appropriate for a wide extension of the climatic niche for high-abundance Gaboon viper populations across our study area. On the contrary, the future climatic niche for high-abundance nose-horned viper populations is predicted to become narrower than at present. In future scenarios, the two species are predicted to have a larger overlap in their climatic niche, which is likely to increase interspecific competition.