An excess of niche differences maximizes ecosystem functioning.

Area of Science:

• Ecology
• Ecosystem Science
• Plant Community Ecology

Background:

• Ecologists propose niche and fitness differences drive biodiversity and ecosystem functioning.
• Rigorous empirical tests linking coexistence mechanisms to ecosystem functioning are limited.

Purpose of the Study:

• To empirically test how niche and fitness differences, which promote species coexistence, influence ecosystem functioning.
• To investigate the relationship between coexistence determinants and biodiversity effects (selection and complementarity).

Main Methods:

• Coupled field-parameterized competition models with a biodiversity-functioning experiment.
• Used 10 annual plant species under two contrasting environmental conditions.
• Analyzed links between niche/fitness differences and complementarity/selection effects.

Main Results:

• Complementarity effects positively correlated with niche differences; selection effects correlated with fitness differences.
• Niche differences also contributed to selection effects, and fitness differences to complementarity effects.
• Communities with excess niche differences showed increased biomass and decomposition rates under drought.

Conclusions:

• Mechanisms determining species coexistence are empirically linked to those maximizing ecosystem functioning.
• Niche differentiation is crucial for enhancing ecosystem functions, particularly under environmental stress.
• Complexity exists in the interplay between niche/fitness differences and ecosystem functions.