Wed, Aug 04, 2021:On Demand
Background/Question/Methods
Biodiversity-ecosystem functioning (BEF) and food-web complexity-stability
relationships are central to ecology. However, they remain largely untested in
natural context. Here we study the links among environmental conditions,
richness, food-web structure, annual biomass and its temporal stability using a
standardized monitoring dataset of 99 stream fish communities spanning from 1995
to 2018.
Results/Conclusions We first reveal that both richness and average trophic level are positively related to annual biomass, with effects of similar strength. Second, we show that food-web structure affects community stability, with a positive effect of mean trophic level, and contrary to expectation, a destabilizing effect of species richness. Finally, we find that environmental conditions affect both biomass and its stability via effects on richness and network structure. Strikingly, effects on stability are mediated by changes in population stability rather than synchrony, which contrasts with results from single-trophic communities and might be characteristic of multi-trophic communities.
Results/Conclusions We first reveal that both richness and average trophic level are positively related to annual biomass, with effects of similar strength. Second, we show that food-web structure affects community stability, with a positive effect of mean trophic level, and contrary to expectation, a destabilizing effect of species richness. Finally, we find that environmental conditions affect both biomass and its stability via effects on richness and network structure. Strikingly, effects on stability are mediated by changes in population stability rather than synchrony, which contrasts with results from single-trophic communities and might be characteristic of multi-trophic communities.