Eco-Evolutionary Buffering: Rapid Evolution Facilitates Regional Species Coexistence despite Local Priority Effects

Area of Science:

• Ecology
• Evolutionary Biology
• Theoretical Ecology

Background:

• Inhibitory priority effects, where early species exclude later ones, are believed to boost regional diversity through community divergence.
• However, theory posits these effects hinder regional coexistence without constant immigration, an often-unrealistic scenario.

Purpose of the Study:

• To propose and model an eco-evolutionary hypothesis explaining regional species coexistence despite local priority effects.
• To investigate the role of evolutionary trade-offs in overcoming limitations imposed by priority effects.

Main Methods:

• Developed a metacommunity model incorporating interspecific interference and local priority effects.
• Included two genotypes per species: one with higher resistance to interference but a fitness cost.
• Simulated evolutionary responses to regional commonness and local patch dynamics.

Main Results:

• Species evolved reduced resistance to interference as they became regionally common, due to fitness costs.
• This evolution, termed "eco-evolutionary buffering," allowed rare species to invade local patches and increase regional frequency.
• Regional coexistence was achieved without external immigration.

Conclusions:

• Eco-evolutionary buffering provides a mechanism for regional species coexistence under strong local priority effects.
• This buffering is most effective in small, infrequently connected local communities.
• The findings challenge the necessity of continuous immigration for maintaining diversity in metacommunities.