Untangling the contributions of species and site to beta diversity in a temperate forest region

Aims: The variation of species composition among communities, commonly known as beta diversity, is central to ecology because of its role in explaining community assembly processes. However, traditional species-centered beta diversity predominantly focuses on the variation in species abundance while neglecting functional and phylogenetic characteristics. This study presents a new approach that integrates functional and phylogenetic characteristics into the traditional beta diversity framework.

Location: Northeastern China.

Methods: We extend the traditional beta diversity framework by introducing the concept of community-weighted mean pairwise distance (CWMPD) that incorporates species’ functional and phylogenetic information. Using observations from a large forest observational network, we estimate beta diversity based on a) species, b) functional traits, and c) phylogenetic information. Then, total beta diversity is partitioned into species (SCBD) and local contributions to beta diversity (LCBD) to estimate the ecological uniqueness of species and locations, respectively. We used regression analysis and variation partitioning to determine the underlying processes that drive specific patterns of SCBD and LCBD.

Results: We found that the patterns of beta diversity, SCBD and LCBD differed among species, functional and phylogenetic information. Species-based metrics help to identify species with specific distributions, and locations with unique species compositions. Functional- and phylogenetic-based metrics aid in identifying species and locations with distinctive ecological and evolutionary attributes. Deterministic as well as stochastic processes contribute to specific diversity patterns. However, after integrating functional and evolutionary information, the relative effect of environmental filtering and dispersal limitation became more apparent.

Main conclusions: Tested on an extensive set of observations, our research provides a new opportunity to characterize the ecological uniqueness of species and locations. Functional- and phylogeny-based metrics offer distinct perspectives beyond species-based metrics. This study thus provides a new basis for a deeper understanding of community assembly processes that may be helpful in guiding biodiversity conservation and vegetation management.