Competition and resource breadth shape niche variation and overlap in multiple trophic dimensions.

Area of Science:

• Ecology
• Biodiversity Research
• Evolutionary Biology

Background:

• Competition is crucial for biodiversity maintenance.
• Niche theory suggests niche contraction/divergence aids local coexistence.
• Resource diversity and multidimensionality are key factors influencing competition dynamics.

Purpose of the Study:

• To investigate how resource breadth and competition influence multidimensional niche variation and overlap.
• To understand the interplay between available prey diversity and interspecific competition in shaping realized niches.
• To explore the drivers of niche variation within and between individuals in tropical frog populations.

Main Methods:

• Modeled realized niches using prey size and carbon stable isotopes in 42 tropical frog populations.
• Quantified two-dimensional resource breadth by sampling available food resources.
• Analyzed variation in niche width at both population and individual levels.

Main Results:

• Observed a 14-fold variation in multidimensional population niche width, primarily driven by within-individual diet variation.
• Individual niche breadth increased with resource breadth and decreased with competitor density.
• Interspecific niche overlap decreased with increasing population total niche width.

Conclusions:

• Multidimensional niche variation is significantly influenced by the interaction between resource availability and competitive pressure.
• Within-individual diet variation is a major contributor to overall niche breadth.
• Findings offer novel insights into the coexistence mechanisms of similar species in local communities.