Biodiversity and ecosystem functioning in food webs: the vertical diversity hypothesis

Area of Science:

• Ecosystem Ecology
• Community Ecology
• Theoretical Ecology

Background:

• Integrating multitrophic community complexity into ecosystem functioning remains a challenge.
• Existing paradigms often focus on bottom-up nutrient supply effects.

Purpose of the Study:

• To develop a theoretical framework linking food web structure to ecosystem functioning.
• To propose the Vertical Diversity Hypothesis (VDH) for ecosystem functioning.

Main Methods:

• Combined food-web and allometry theories.
• Modeled primary production as total nutrient uptake in multitrophic communities.
• Investigated the role of vertical diversity and community size distribution.

Main Results:

• Primary production is determined by vertical diversity (max trophic level) and structure (species/abundance/metabolic rate distribution).
• Community size distribution dictates vertical patterns and nutrient uptake.
• The VDH predicts exponential increase in nutrient uptake with max trophic level and power-law increase with max body size.

Conclusions:

• The VDH highlights top-down regulation's impact on primary production, complementing bottom-up theories.
• The VDH offers a synthetic framework for understanding vertical diversity and ecosystem functioning.
• This framework aids in predicting global change impacts on multitrophic ecosystems.