In a study published in Limnology and Oceanography, the research group led by Prof. XIE Zhicai from the Institute of Hydrobiology (IHB) of the Chinese Academy of Sciences revealed that different dimensions of beta diversity were determined by distinct ecological processes and mechanisms.  

Unraveling the potential mechanisms shaping community structure and diversity in the freshwater realm is a pivotal objective in biogeography, community ecology, and conservation biology. However, the relative importance of ecological drivers on multiple dimensions of beta diversity (taxonomic, functional, and phylogenetic) has not been fully explored in mountainous streams.   

To fill the gap, the researchers calculated taxonomic, functional, and phylogenetic beta diversities and their respective turnover and nestedness components for macroinvertebrates sampled in 130 stream reaches.  

They first examined the correlations between beta diversity dimensions using MSR-Mantel procedure. They found that different beta diversity dimensions were weakly correlated, indicating these diversity dimensions are independent measures which offer complementary information of community assembly.  

Afterwards, using redundancy analysis and variance partitioning, they examined the relative importance of local, catchment and climate environmental variables and spatial factors on variation in three dimensions of beta diversity. Results indicated that beta diversity were best explained by spatial and local environmental factors, while large-scale catchment and climate variables were less influential.  

Specifically, taxonomic and phylogenetic beta diversities were more strongly determined by spatial factors via dispersal limitation and historical effects, whereas functional beta diversity was mainly associated to local environments through habitat filtering.  

This is the first study analyzing the relative importance of hierarchical environmental variables and spatial factors on variation in multiple dimensions of macroinvertebrate beta diversity in mountainous streams of the East Asian monsoon region. It highlights the importance of considering various ecological factors and integrating multiple diversity dimensions into biodiversity, conservation, and environmental assessment research.