Résumé
Understanding how environmental and human pressures impact the temporal
stability of fish community biomass on shallow reefs is essential for
effective conservation and management. These pressures influence community
stability directly, by affecting species stability and asynchrony in
species’ fluctuations. However, their effects may also indirectly depend
on the functional traits of the species composing the community, which
remains poorly understood. 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 due to higher trait diversity and trait
redundancy and higher species stability in temperate communities due to
higher mean trophic level. Human impacts, through its negative effects on
species stability and trait diversity, was the main destabilising factor
of fish community biomass. Temporal change in SST destabilised 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 the long-term
stability of marine ecosystems under global change.