Predators mitigate the destabilising effects of heatwaves on multitrophic stream communities

Area of Science:

• Ecology
• Climate Change Biology
• Conservation Biology

Background:

• Global extinction crisis and climate change increase extreme climatic events like heatwaves.
• The impact of predator species loss on ecosystem responses to extreme events is largely unknown.

Purpose of the Study:

• To investigate how predator loss interacts with heatwaves to affect ecosystem stability.
• To understand the cascading effects of heatwaves on stream communities.

Main Methods:

• Exposed multitrophic stream communities (with and without a dominant predator) to simulated heatwaves.
• Monitored changes in algal and macroinvertebrate communities, algal biomass, and temporal variability.

Main Results:

• Heatwaves destabilized algal communities by increasing spatial homogeneity, but only when predators were absent.
• Delayed impacts on community structure and biomass emerged after heatwaves subsided.
• Predator presence buffered ecosystems against heatwave-induced destabilization.

Conclusions:

• Predator loss can amplify the ecological consequences of extreme climatic events like heatwaves.
• Ecosystem impacts of heatwaves can propagate through interaction networks over time.
• Conserving trophic structure is vital for maintaining ecosystem resilience in the face of climate change.