Interaction capacity as a potential driver of community diversity

Area of Science:

• Ecology
• Ecological Networks
• Community Ecology

Background:

• Understanding community diversity patterns is a fundamental ecological question.
• Interspecific interactions are recognized as crucial for community diversity.
• Empirical evidence from high-diversity systems remains limited due to methodological challenges.

Purpose of the Study:

• To investigate the drivers of community diversity in high-diversity ecosystems.
• To introduce and test the 'interaction capacity' hypothesis.
• To explore the influence of environmental factors on interaction capacity and network structure.

Main Methods:

• Analysis of time-varying interaction networks reconstructed from DNA-based ecological time series.
• Utilized empirical dynamic modeling with 1197 species from experimental rice plots.
• Introduced and quantified 'interaction capacity' (sum of a species' interaction strengths).

Main Results:

• Community diversity and the number of interactions increase exponentially.
• Mean interaction capacity saturates as diversity increases, leading to weaker interspecific interactions.
• Total DNA abundance and temperature nonlinearly influence interaction capacity and connectance, explaining observed diversity patterns.

Conclusions:

• Proposes the 'interaction capacity hypothesis' where interaction capacity and network connectance are fundamental drivers of community diversity.
• Provides mechanistic explanations for community diversity patterns.
• Highlights the utility of analyzing ecological data through the lens of interaction capacity for new insights.