Fig. 2From: Species richness, phylogenetic diversity and phylogenetic structure patterns of exotic and native plants along an elevational gradient in the HimalayaVariation of (A) Species richness (SR) and (B) Phylogenetic diversity (PD) of exotic and native plant species along the elevational gradient in Sikkim Himalaya. Both exotic and native plant species showed unimodal hump-shaped curves for PD and SR along the elevational gradient. The primary Y-axis in both the plots represents SR and PD of native species, while secondary Y-axis represents SR and PD of exotic species. The fitted lines in both the plots were generated using Friedman’s super smoother function and do not imply any cause–effect relationshipBack to article page