Increasing climate‐driven taxonomic homogenization but functional differentiation among river macroinvertebrate assemblages. (22nd October 2020)

• Record Type: Journal Article
• Authors: Mouton, Théophile L.; Tonkin, Jonathan D.; Stephenson, Fabrice; Verburg, Piet; Floury, Mathieu
• Is Part Of: Global change biology. Volume 26:Number 12(2020)
• Page Start: 6904
• Page End: 6915
• Publication Date: 2020-10-22
• Subjects: β‐diversity -- biotic homogenization -- climate change -- freshwater macroinvertebrates -- functional diversity -- human disturbance; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.15389
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Global change is increasing biotic homogenization globally, which modifies the functioning of ecosystems. While tendencies towards taxonomic homogenization in biological communities have been extensively studied, functional homogenization remains an understudied facet of biodiversity. Here, we tested four hypotheses related to long‐term changes (1991–2016) in the taxonomic and functional arrangement of freshwater macroinvertebrate assemblages across space and possible drivers of these changes. Using data collected annually at 64 river sites in mainland New Zealand, we related temporal changes in taxonomic and functional spatial β‐diversity, and the contribution of individual sites to β‐diversity, to a set of global, regional, catchment and reach‐scale environmental descriptors. We observed long‐term, mostly climate‐induced, temporal trends towards taxonomic homogenization but functional differentiation among macroinvertebrate assemblages. These changes were mainly driven by replacements of species and functional traits among assemblages, rather than nested species loss. In addition, there was no difference between the mean rate of change in the taxonomic and functional facets of β‐diversity. Climatic processes governed overall population and community changes in these freshwater ecosystems, but were amplified by multiple anthropogenic, topographic and biotic drivers of environmental change, acting widely across the landscape. The functional diversification of communities could potentially provide communities with greater stability, resistance and resilience capacity to environmental change, despite ongoing taxonomic homogenization. Therefore, our study highlights a need to further understand temporal trajectories in both taxonomic and functional components of species communities, which could enable a clearer picture of how biodiversity and ecosystems will respond to future global changes. Abstract : We investigated temporal changes (1991–2016) in the taxonomic and functional spatial β‐diversity of macroinvertebrate assemblages across New Zealand's mainstem rivers. We observed temporal trends towards taxonomic homogenization but functional differentiation among assemblages. Climatic processes governed population and community changes in these ecosystems, but were amplified by multiple anthropogenic, topographic, and biotic drivers of environmental change, acting widely across the landscape. Our study raises questions as to how the taxonomic and functional components of species communities will respond to future global changes.