Climate Impacts on Lake Food-Webs Are Mediated by Biological Invasions

Area of Science:

• Ecology
• Climate Change Biology
• Invasive Species Research

Background:

• Climate change and biological invasions are key drivers of biodiversity loss.
• Their individual impacts are well-studied, but their interactive effects remain unclear.
• Understanding these interactions is crucial for predicting ecosystem changes.

Purpose of the Study:

• To investigate how climate warming and exotic species influence fish community diversity (taxonomic, size, trophic).
• To determine if climate warming and invasions mediate current community diversity states.
• To assess the indirect role of biological invasions as an effect of climate warming.

Main Methods:

• Structural equation modeling was applied.
• An extensive nationwide dataset of 430 fish communities across 257 French lakes was used.
• Relative impacts and mediation effects were analyzed.

Main Results:

• Climate warming negatively impacts fish size and trophic diversity.
• These impacts are primarily mediated by warming-induced increases in exotic species richness.
• Exotic species richness positively influences total species richness.

Conclusions:

• Biological invasions act as a significant indirect pathway for climate change impacts on biodiversity.
• Climate change effects on diversity are obscured when considering only direct thermal impacts.
• Integrated approaches considering both climate change and biological invasions are essential for ecological predictions and management.