Stone and white-clawed crayfish distribution modelling in relation to environmental parameters: past, present and future

European indigenous freshwater crayfish species (ICS), once widespread and abundant, suffer reduction in their distribution and numbers throughout Europe. Three out of five ICS are listed in the IUCN Red List of Threatened Species and are protected by European and national legislations. The ICS are mainly threatened by habitat deterioration, water quality decline, the presence of non-indigenous American and Australian crayfish species and climate change. In order to protect endangered ICS diversity, it is necessary to prepare efficient management plans, and to develop them, a thorough knowledge on ICS is needed. In addition to data on their biology, ecological needs and their diversity, it is necessary to know their distribution patterns. Today, Species distribution models (SDMs), based on the relationship between the species occurrence records and the environmental variables predict the potential distribution of species, have found an extensive application in conservation biology, ecology and biogeography. Here, we aim to predict the potential current, future and past distribution for stone crayfish (Austropotamobius torrentium) and white-clawed crayfish (Austropotamobius pallipes) to get insights into their range dynamics across time. Models were developed using presence only records of the two species and a set of bioclimatic predictors selected based on their ecological relevance and availability for the selected time periods, excluding highly correlated ones. Resulting SDMs enabled us to evaluate the potential contemporary range of the two indigenous species as well as to predict the impact of ongoing climate change on their future distribution. Moreover, projection of the current model onto the Last glacial maximum and Last Interglacial allowed us to identify putative LGM refugia and areas of long-term persistence for both species.