Niche expansion and unfilling
Schoener’s D on species occupancy disentangles climate availability and the extent of niche divergence of clade pairs, but does not take into account the difference between partial filling and expansion (Petitpierre et al. 2012). However, expansions measured can characterize true niche shifts, when native and invaded ranges overlapped in climatic space, We followed Petitpierre et al. (2012), three categories were considered in: (1) stable environments where species occurs in both ranges, (2) unfilled environments where species occur only in the native range, and (3) expansion environments where the species occur only in the invaded range.