Evolutionary Responses to Conditionality in Species Interactions across Environmental Gradients

Area of Science:

• Ecology
• Evolutionary Biology
• Theoretical Biology

Background:

• Species interaction outcomes are environmentally conditional, often shifting from mutualistic under stress to antagonistic in benign conditions.
• Ecological theories like resource-limited models and the stress-gradient hypothesis explain conditionality.
• The geographic mosaic theory of coevolution (GMTC) provides a framework for understanding coevolutionary patterns.

Purpose of the Study:

• To integrate theories of conditionality with GMTC to predict adaptation patterns along abiotic gradients.
• To differentiate between general and local adaptation in species interactions.
• To propose methods for testing these predictions and their application in conservation.

Main Methods:

• Combining predictions from resource-limited models, the stress-gradient hypothesis, and GMTC.
• Developing a framework to distinguish general vs. local adaptation.
• Utilizing simulations based on GMTC models to demonstrate methods.

Main Results:

• Predicts increased mutualistic adaptation in stressful environments due to aligned fitness benefits.
• Anticipates antagonistic coevolution or niche partitioning in benign environments.
• Highlights the importance of environmental context in shaping adaptive and coadaptive responses.

Conclusions:

• Environmental gradients systematically influence the direction and type of adaptation and coadaptation between interacting species.
• The proposed framework and methods can test these predictions across various conditional interactions.
• Findings have implications for understanding evolutionary dynamics and informing conservation strategies like assisted translocation.