A review of the palaeoclimatic inference potential of Iberian Quaternary fossil batrachians

Abstract

Ecological suitability analysis aims to model the potential or probable distribution of species using environmental variables and available species occurrence information as predictors. Most of the European fossil Quaternary amphibians belong to extant species, and being physiologically ectothermic animals, their current ecological niches could become a reliable inference tool to infer past environmental conditions. However, this expectation has never been properly verified. The validity and accuracy of palaeoclimatic inferences based on batrachian species ranges is tested on the Iberian Peninsula, using both palaeofaunistic and Recent distribution data, and an updated database of georeferenced species occurrences is provided. The difficulties of using current geographic information to represent the full spectrum of environmental conditions at which a species occurs are critically examined. A palaeofaunistic review of the role played by historical factors as dispersal limitations for present amphibian species ranges is presented using the available phylogeographical scenarios. Virtual hypothetical taxa can be devised by considering the distributions of several species together and relating their known joint presences with the environmental conditions in these locations. Species distribution models based on these virtual taxa provide the best advisable inferential procedure. For direct raw inferences of the mutual climatic range method, contrary to expectations, the combined taxa sets do not increase their accuracy with the number of species included. This preliminary review shows that Iberian amphibian palaeoclimatic inferences are both valid and reliable enough, a sufficient approximation to complement other techniques. The precision, however, is quite variable among taxa, reflecting the effect of non-climatic