Resonance-induced multimodal body-size distributions in ecosystems

Area of Science:

• Ecology
• Theoretical Ecology
• Ecological Energetics

Background:

• Body size distribution is a key factor in ecosystem structure and function.
• Multimodal body-size distributions are common, often attributed to niche separation.
• Existing theories struggle to explain multimodal distributions in ecosystems with shared niches.

Purpose of the Study:

• To propose a generic mechanism for multimodal body-size distributions.
• To explain how size-dependent trade-offs can generate multiple peaks within a single niche.
• To demonstrate the universality of this mechanism across different ecosystems.

Main Methods:

• Development of a theoretical model based on the size-dependent trade-off between reproduction and resource utilization.
• Analysis of empirical data from diverse ecosystems (phytoplankton, metazoans, arthropods).
• Comparison of model predictions with observed body-size distributions.

Main Results:

• A size-dependent trade-off creates an inherent resonance, leading to multimodal distributions.
• This resonance can induce multiple peaks even when species compete within the same niche.
• The model accurately fits empirical data, showing periodically peaked distributions at larger sizes and a smooth tail at smaller sizes.
• A universal pattern in size distributions was observed across different scales and taxa.

Conclusions:

• A generic resonance mechanism, driven by reproduction-resource trade-offs, explains multimodal body-size distributions.
• This mechanism provides an alternative to niche separation for understanding peak formation.
• The findings suggest that multimodal distributions are a fundamental outcome of ecological interactions, influenced by local competition and global migration.