Fine‐scale functional metacommunity dynamics: Analysing the role of disturbance‐driven environmental variability in grasslands
Résumé
Methods: We monitored fine-scale spatio-temporal community changes in small plots (i.e. local communities) distributed within six grassland paddocks (i.e. metacommunities) subject to two treatments (mown or grazed). We simultaneously monitored three key environmental variables: light, nitrogen and water, to assess how environmental heterogeneity impacts species compositional changes. We then inferred the metacommunity drivers of these changes in taxonomic and functional composition using a path analysis.
Results: Managed grasslands are dynamic within a year, and spatially heterogeneous within a paddock, with spatial and temporal β diversities totalling more than half of the taxonomic diversity. Mowing events caused sudden decreases of total vegetation cover resulting in taxonomical and functional changes. In grazed paddocks, community changes were mainly spatial due to spatially heterogeneous light-structured filtering conditions. In both treatments, environmental heterogeneity only partially explained community changes that were also greatly impacted by dispersal limitation, but not ecological drift.
Conclusions: Our study demonstrates that the fine-scale analysis of community spatio-temporal changes allows disentangling the relative importance of environmental filtering, dispersal limitation and ecological drift in community dynamics. Applying this approach to communities experiencing other kinds of disturbance regimes may allow gaining a general understanding of plant community assembly processes.
Auteurs, date et publication :
Auteurs Célia Pouget , Julien Pottier , Franck Jabot , Jodi Price
Publication : Journal of Vegetation Science
Date : 2023
Volume : 32
Issue : 4