We should not necessarily expect positive relationships between biodiversity and ecosystem functioning in...

Area of Science:

• Ecology
• Conservation Biology
• Ecosystem Science

Background:

• Empirical understanding of biodiversity-ecosystem function relies on experiments (positive relationships) and observational data (variable relationships).
• Variable relationships in observational data have led to skepticism about the utility of biodiversity-ecosystem function (BEF) research for conservation.
• Lack of observed local biodiversity declines further complicates interpretation of observational data.

Purpose of the Study:

• To review ecological theory and re-analyze biodiversity datasets.
• To address the interpretability challenges of ecosystem function correlations with local diversity in observational field data.
• To propose a framework for linking BEF theory and experiments with observational data.

Main Methods:

• Review of ecological theory on community assembly and species interactions.
• Re-analysis of existing biodiversity datasets.
• Examination of the role of biotic interactions and species filtering in community assembly.

Main Results:

• Ecosystem function correlations with local diversity in observational data are often difficult to interpret due to biotic filtering.
• Biotic interactions can lead to significant biodiversity effects on functioning even with low observed local diversity.
• Observational field data may not show a direct relationship between local biodiversity and ecosystem function.

Conclusions:

• A high biodiversity effect on ecosystem functioning can occur despite low observed local diversity.
• Interpreting observational field data requires considering the regional species pool, which influences local community assembly.
• Biodiversity loss at regional scales can negatively impact ecosystem functioning, even if local diversity remains stable.