Understanding macroinvertebrate metacommunity organization using a nested study design across a mountainous river network

• Published in: Ecological indicators 2021-02, Vol.121, p.107188, Article 107188
• Main Authors: Li, Zhengfei, Heino, Jani, Chen, Xiao, Liu, Zhenyuan, Meng, Xingliang, Jiang, Xiaoming, Ge, Yihao, Chen, Juanjuan, Xie, Zhicai
• Format: Article
• Language: English
• Subjects: Dispersal limitation; Environmental filtering; Macroinvertebrate; Mass effects; Subtropical rivers
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2020.107188

[Display omitted] •We examined the relative role of environmental filtering, mass effects and dispersal limitation.•Overall metacommunity was decomposed into nine sub-metacommunities based on traits.•The relative importance of the three ecological processes depended on biological traits considered.•Different spatial processes and trait-based approaches improved our understanding of community assembly in river networks. Metacommunity ecology highlights the importance of integrating simultaneously environmental filtering and spatial processes, such as mass effects and dispersal limitation, into investigation of community assembly. However, few studies to date have tried to examine mass effects and dispersal limitation as independent ecological mechanisms along with environmental filtering in shaping biological communities in river networks. We examined the relative importance of three factor groups, i.e., environmental variables, within-river spatial factors (indicative of mass effects) and basin identity (referring to dispersal limitation) on a macroinvertebrate metacommunity and nine trait-based deconstructed sub-metacommunities from seven subtropical rivers. We applied redundancy analysis and variance partitioning to reveal the pure and shared effects of the three groups of factors on community variation. Environmental filtering, mass effects and dispersal limitation were all significant mechanisms affecting variation in macroinvertebrate communities, but their relative importance depended on biological traits. Environmental filtering explained more of the variation in the whole metacommunity, tolerant taxa and macroinvertebrate groups with weak dispersal ability (i.e., aquatic dispersal, aerial passive dispersal and large body size). In contrast, mass effects accounted for more variation in the communities of intolerant taxa and macroinvertebrate groups with strong dispersal ability (i.e., aerial active dispersal mode and medium body size). Dispersal limitation was more influential for sub-communities of moderately tolerant taxa and large-sized taxa. Our study highlights that simultaneously accounting for different spatial processes and using a trait-based approach are essential to improve our understanding of community assembly in river networks.