Spatial distribution modelling reveals climatically suitable areas for bumblebees in undersampled parts of the Iberian Peninsula

The Iberian Peninsula supports a high diversity of bumblebees, with 38 species all of which are at or near the south-western edge of their range. We might expect them to be threatened by climate change, but their distributions within Iberia are poorly documented. In this study, we examine the climatic conditions that explain the distribution of Iberian bumblebees. Species distribution models (SDMs) were built using a presence-only technique (Maxent), incorporating presence data of Iberian bumblebees (initially 5795 records for 38 species) with seven climatic variables. We observed that: (i) mountain regions were highlighted as rich in species (bumblebee hot spots); (ii) rare species are climatic specialist species that mainly inhabit mountain regions; (iii) common species are more tolerant of a broader range of climates, notably of higher temperatures; (iv) some areas of Iberia are largely undersampled, including areas predicted to support high bumblebee diversity. We identify areas where targeted searches may reveal undiscovered populations of rare bumblebee species. Obtaining a good knowledge of the current distribution of species is a vital first step towards devising approaches for their conservation.