Population and community resilience in multitrophic communities.

Area of Science:

• Ecology
• Biodiversity research
• Ecosystem stability

Background:

• Diversity-stability relationships are debated, especially with rising biodiversity threats.
• Community resilience, the ability to recover from disturbance, is a key stability measure.
• The roles of species diversity, productivity, and their interactions in resilience are unclear.

Purpose of the Study:

• To investigate how species diversity, composition, and productivity affect population and community resilience in experimental aquatic food webs.
• To determine if diversity enhances resilience and how productivity influences this relationship.
• To explore the mechanisms driving diversity effects on resilience, such as sampling effects.

Main Methods:

• Experimental manipulation of species diversity, composition, and productivity in aquatic microcosms (bacteria, algae, protozoa, rotifers).
• Perturbation of communities via nonselective, density-independent mortality.
• Comparison of recovery trajectories between perturbed and control communities to measure resilience.

Main Results:

• Species diversity enhanced community-level resilience (total biomass), particularly in low-productivity conditions.
• Diversity's impact on resilience was driven by a sampling/selection effect, favoring rapid recovery by dominant species (algae).
• Species diversity did not affect population-level resilience; recovery depended on species composition. Productivity had no significant effect on resilience at either level.

Conclusions:

• Species diversity can bolster ecosystem stability at the community level, but this effect is context-dependent (e.g., productivity).
• The influence of diversity on stability is scale-dependent, appearing at the community but not population level.
• Species composition, rather than diversity or productivity alone, is critical for population recovery from disturbances.