FUNCTIONAL DIVERSITY SHAPES THE STABILITY OF REEF FISH BIOMASS UNDER GLOBAL CHANGE.

Mahaut L., Loiseau L., Villeger S., Auber A., Hautecoeur C., Maire A., Mellin C., Mouquet N., Stuart-Smith R., Violle C., and Mouillot D. (2025).

Proceedings of the Royal Society B, 292, 20250252, doi/10.1098/rspb.2025.0252

Key message : Here, we examine both direct and indirect, trait-mediated effects of environmental variability and human impacts on species biomass stability and asynchrony in 215 Australian shallow reefs. These communities span a 10 degree sea surface temperature (SST) gradient and have been monitored over 14 years. Our results indicate higher asynchrony in tropical reefs owing to higher trait diversity and trait redundancy and higher species stability in colder, temperate communities owing to higher mean trophic level. Human impacts, through their negative effects on species stability and trait diversity, were the main destabilizing factor of fish community biomass. Temporal change in SST destabilized species biomass while increasing mean trophic level in fish communities. Overall, our findings show that a comprehensive analysis of the multiple facets of functional diversity is crucial to better understand and forecast the long-term stability of marine ecosystems under global change.

Structural equation model relating abiotic factors, functional diversities and temporal biomass stability of shallow reefs fish communities. Abiotic factors include mean annual sea surface temperature (SST), site depth, SST change, CV_SST and CV_Chlorophyll as well as human impacts. Functional diversity facets include trait diversity, trait redundancy, Community Weighted Mean (CWM) values of trophic level, maximal depth and maximum length. The sizes of arrows are proportional to the effects, with path coefficients indicated. Blue lines: positive relationships. Red lines: negative relationships. Dark colours: direct relationships. Light colours: indirect effects. r. indicates the proportion of the variance explained by the structural equation model in the response variables.

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OTHER TOPICS: Aesthetics of Biodiversity, Biogeography, Macroecology & Ecophylogenetics, Experimental Evolution, Functional Biogeography, Functional Rarity, Nature for Future, Metacommunities, Metaecosystems, Reviews and Synthesis, Trophic Biogeography & Metaweb