A landscape‐level analysis of bird taxonomic, functional and phylogenetic β‐diversity in habitat island systems

Abstract Aim How β‐diversity patterns are shaped by landscape‐level processes remains unclear across habitat island systems. Here we assessed landscape‐level bird β‐diversity in habitat island systems and aimed to (1) evaluate the relative contribution of turnover (β SIM ) and nestedness‐resultant (β SNE ) components to multisite β‐diversity (β SOR ) from taxonomic, functional and phylogenetic dimensions; (2) examine the influence of climate factors and system characteristics in shaping landscape‐level patterns of β‐diversity measures; and (3) study how β‐diversity patterns of bird communities vary with the spatial extents of island systems. Location Global. Taxon Birds. Methods We compiled bird data in 22 habitat island systems from literature and classified these island systems into small and large spatial scales. We partitioned β SOR into β SIM and β SNE from three dimensions for each system and calculated standardized functional and phylogenetic β‐diversity measures. We assessed the effects of climate factors and system characteristics on observed and standardized β‐diversity measures by multiple linear models for both small and large systems. Results We found that the dominant role of β SIM to β SOR in habitat island systems was pervasive. However, the best explanatory variables were not consistent across systems, which depended on the β‐diversity components, diversity dimensions and spatial extent of habitat island systems. In general, climate factors acted as the main drivers of bird communities across small and large systems, whereas system characteristics played minor roles. Main conclusions Spatial turnover dominated overall bird β‐diversity in most habitat island systems. Our results imply the roles of niche‐based assembly processes through the interplay among differential functional traits and phylogenetic distances of species, climate factors and system characteristics as well as spatial extent in driving bird communities across multiple habitat island systems at a landscape level. This study offers a better understanding of the processes underlying macroecological patterns of isolated biological communities across habitat island systems.