Using physiology and performance to predict climate driven distribution range shifts in three temperate African anurans species: a hybrid modelling approach

Dr Mohlamatsane Mokhatla^1,2, Dr  John Measey², Dr Dennis Rödder³

¹South African National Parks, Sedgefield, South Africa, ²Centre for Invasion Biology (CIB), Department of Botany and Zoology, Stellenbosch University, Stellenbosch, South Africa, ³Zoologische Forschungsmuseum Alexander Koenig (ZFMK), Bonn, Germany

Changes in climate have had an overriding influence on species distribution throughout time. The manner in which climate is currently changing is likely to be one of the leading threats to anuran diversity by the end of this century. Here we used physiological information to build performance surfaces, which were later used as spatial predictors in species distribution modelling. These Maxent models predict the impacts of climatic fluctuations on the species range shifts of three African anurans with different ecological properties: i) the principally aquatic African clawed frog (Xenopus laevis), ii) partially-aquatic common river frog (Amietia delalandii) and iii) semi-terrestrial raucous toad (Sclerophrys capensis). Projection time frames comprise the Last Glacial Maximum (LGM ≈ 21 000 YA), current conditions, and expected future conditions in 2080. We find that ecophysiology modelling techniques accurately predict the distribution of these widely distributed African anurans. Potential distributions suggest that anuran species lost thermally suitable space since the LGM, and that the rate of loss between the current conditions and 2080, far exceeds the rate of loss experienced between the LGM and current climate conditions. Of interest is that the models suggest that A. delalandii will gain climatically suitable space by the year 2080, while S. capensis is expected to lose suitable climate space in the same period. Our results suggest that species may respond to changes in climate individually, which will largely be driven by how species adapt to climatic changes at the species-process levels, informed by differences in physiolological properties translated in performance.

Biography:

Mohlamatsane Mokhatla has recently completed his PhD (Zoology) which aimed at comparing methods that estimated the impact of climate change on the distribution ranges of temperate African anurans. The project specifically compared simple correlative models to more complex ecophysiology models that incorporated physiology and performance into species distribution models. He is currently employed as a scientist (socio-ecological system) by the South African National Parks (SANParks), based at the Garden Route National Park and his responsibilities include understanding how decisions implemented by SANParks affect the nearby communities and how the communities affect SANParks. He is also interested in developing his PhD ideas further and looking into more cost-effective methods of monitoring frog species and populations in the Garden Route.