Fig. 2 Conceptual differences among proposed niche overlap analyses. Imagine a in A novel method to calculate climatic niche similarity among species with restricted ranges-the case of terrestrial Lycian salamanders

Fig. 2 Conceptual differences among proposed niche overlap analyses. Imagine a set of three species with different preferences along an environmental gradient. Using SDM projections, it is possible to derive for each species a probability distribution across the gradient. Comparing two species as proposed by Warren et al. (2008), the overlap (grey area in the middle panel) of their respective probability distributions in geographic space is computed (pair-wise niche overlap). In our jackknife approach, a probability distribution derived from all species records is compared to a probability distribution derived from all minus one species. The 1−the resulting overlap value reflects the relative contribution of the omitted species to the entire probability distribution (grey area in the lower panel) and can be used as measure to rank all species when omitting them iteratively. Note that these specific indices are comparable only across each method but not among the different approaches