Consumer trophic diversity as a fundamental mechanism linking predation and ecosystem functioning

Area of Science:

• Ecology
• Ecosystem Science
• Food Web Dynamics

Background:

• Ecosystem functioning relies on primary production and decomposition.
• Food web interactions influence these processes but are often studied in isolation.
• Traditional studies may underestimate the complexity of food web impacts on ecosystem processes.

Purpose of the Study:

• To investigate how consumer trophic diversity mediates predator effects on ecosystem functioning.
• To assess the indirect impacts of predation on primary production and decomposition.
• To evaluate cross-sub-web effects in coastal saltmarsh invertebrate communities.

Main Methods:

• Conducted a mesocosm experiment and a field study.
• Utilized North Atlantic coastal saltmarsh invertebrate assemblages.
• Manipulated prey communities (herbivores alone, detritivores alone, or both) to measure predation impacts.

Main Results:

• Primary consumers influence ecosystem process rates within and across green (production) and brown (decomposition) sub-webs.
• Generalist predators feeding on diverse consumers can diffuse impacts on decomposition and primary production.
• Functional diversity among primary consumers alters traditional trophic cascade outcomes.

Conclusions:

• Ecosystem process rates are influenced by consumer diversity across different food web compartments.
• The detritus-based sub-web plays a crucial role in driving plant production.
• Compartmentalized food web studies may limit predictions of ecosystem functioning.