The strength of the biodiversity-ecosystem function relationship depends on spatial scale

Area of Science:

• Ecology
• Conservation Biology
• Spatial Ecology

Background:

• Current understanding of biodiversity-ecosystem functioning (BEF) relationships is primarily limited to fine spatial scales.
• Extending BEF knowledge to broader spatial scales is essential for informing conservation decisions.
• Scale dependence in BEF relationships necessitates further investigation.

Purpose of the Study:

• To examine the conditions that lead to scale dependence in BEF relationships using simulations.
• To assess how BEF relationship metrics (slope and R^2) change with spatial aggregation of habitat patches.

Main Methods:

• Utilized simulation models to explore the drivers of scale dependence in BEF.
• Analyzed changes in the BEF relationship's slope and R^2 as habitat patches were spatially aggregated.
• Examined three specific mechanisms contributing to scale dependence: local diversity variation, spatial variation in local BEF relationships, and incomplete species turnover.

Main Results:

• Identified three key mechanisms causing scale dependence: variation in local diversity, spatial heterogeneity in local BEF relationships, and incomplete species compositional turnover.
• Observed that variation in local diversity and spatial heterogeneity in BEF relationships lead to a moderate increase in the BEF slope with spatial scale.
• Found that incomplete species turnover causes stronger scale dependence, with the BEF relationship initially rising and then saturating.
• Empirical data from Cedar Creek grassland showed a positive, saturating relationship slope with scale.

Conclusions:

• The biodiversity-ecosystem functioning relationship is demonstrably scale-dependent.
• Scale dependence arises from variations in local diversity, spatial heterogeneity of BEF, and species turnover.
• Findings highlight the importance of considering spatial scale in ecological research and conservation planning.