Splitting hares: Current and future ecological niches predicted as distinctly different for two congeneric lagomorphs

The congeneric lagomorphs Lepus timidus and L. europaeus share allopatric distributions in many areas of Europe characterised by competitive exclusion and hybridisation. We investigated prospects for these species under climate change in northern England uplands. We created ensemble models predicting niche realisation for these species, influenced by abiotic and biotic factors, estimating niche overlap in geo-environmental space. The two species occupy distinctly different niches, influenced more by vegetation preferences than climatic differences. The current climate niche for L. timidus featured higher elevations with cooler temperatures and 168 km2 range extent. Its current habitat niche scale was larger at 269 km2, comprised entirely of upland dwarf shrubs: heather, cotton grass, moorland grasses. By contrast, the current climate niche predicted L. europaeus occupying lowland areas with a milder climate and range extent of 252 km2. Its current habitat niche was also greater, 401 km2, being mostly improved grassland. Competition was presently limited. The current niche predictions showed very little geographic overlap between the species. Niche overlap measured by Schoener Index was low: current climate niche 0.16; current habitat niche 0.07. The future climate niches for 2050 (IPCC RCP2.6), predicted L. timidus range contracting to 19 km2, on hilltops and L. europaeus range expanding to 765 km2. Consequently L. timidus range would be wholly within the L. europaeus range. In many contact zones throughout Europe, L. europaeus outcompetes L. timidus; however, in the Peak District their distributions are largely distinct. Future replacement of L. timidus by L. europaeus may be engendered by dietary convergence, should a warmer climate cause a transition of upland dwarf shrub vegetation to grasses. [Display omitted] •In England mountain hares do not compete with European brown hares because of different climate and habitat preferences.•The mountain hare range is predicted to severely diminish under climate change.•The range for European brown hares is predicted to greatly expand under climate change.•Future replacement of mountain hares by European brown hares may be engendered by dietary convergence, should a warmer climate cause a transition of upland dwarf shrub vegetation to grasses.