Stochastic community assembly causes higher biodiversity in more productive environments

Area of Science:

• Ecology
• Biodiversity Science
• Community Ecology

Background:

• Net primary productivity is a key driver of biodiversity, with higher productivity regions generally supporting more species.
• Beta-diversity, or compositional variation across sites, increases with productivity, but the underlying mechanisms remain unclear.

Purpose of the Study:

• To investigate the mechanisms driving the relationship between productivity and beta-diversity.
• To determine how ecological assembly processes change along a productivity gradient.

Main Methods:

• Utilized data from a long-term experiment conducted in replicate ponds.
• Analyzed changes in the relative importance of stochastic versus deterministic community assembly processes.

Main Results:

• Higher productivity was associated with increased beta-diversity.
• This increase in beta-diversity resulted from a stronger influence of stochastic assembly processes relative to deterministic ones as productivity increased.
• The observed shift in assembly mechanisms aligns with the hypothesis of intensified priority effects at higher productivity, potentially leading to multiple stable equilibria.

Conclusions:

• Shifts in community assembly mechanisms, particularly the increased role of stochasticity and priority effects, may explain the prominent biodiversity gradients observed across productivity gradients.
• Understanding these mechanisms is crucial for predicting biodiversity patterns in response to environmental changes.