Ecological versatility and the assembly of multiple competitors: cautionary notes for assembly inferences

Area of Science:

• Ecology
• Community Ecology
• Theoretical Ecology

Background:

• Community assembly studies often link species dissimilarity to niche differences and competition.
• Previous theories on competition and species similarity were based on limited pairwise interactions, not complex natural systems.
• Species versatility, the ability to use marginal resources, can reduce niche overlap and escape competition.

Purpose of the Study:

• To develop a coexistence theory for multispecies competition with varying versatility.
• To simulate community assembly patterns using this new theory.
• To investigate the relationship between species similarity, versatility, and competition.

Main Methods:

• Developed a theoretical framework for simultaneous multispecies competition.
• Utilized computer simulations to model community assembly.
• Analyzed species similarity using mean nearest taxon distance (SES.MNTD) and mean pairwise distance (SES.MPD) metrics.

Main Results:

• Simulated communities showed varied species similarity (more, less, or equal) compared to null models using SES.MPD.
• Consistently observed species overdispersion using SES.MNTD, regardless of whether differences reflected niche or fitness.
• High ecological versatility strongly promoted niche differences and overdispersion, enabling coexistence by compensating for fitness disparities.

Conclusions:

• Ecological versatility plays a critical role in enabling species coexistence by facilitating niche differentiation.
• Minimum niche differences and resource consumption versatility are vital for species in complex interaction networks.
• The study highlights the importance of considering species versatility in understanding community assembly and biodiversity patterns.