Biocontrol and Climate Change
A new review study from members of the RISCC leadership team found no significant overall impact to biocontrol agent efficacy or target performance due to climate change induced temperature changes. Responses to temperature varied widely across systems and response types though, warranting more species specific studies to inform the potential effects of climate change on future biological control efforts.
Written by Matthew Fertakos, edited by Annette Evans
Summary:
Classical biological control is a management strategy that uses the deliberate introduction of natural enemies (agents) to control nuisance or invasive species (targets). This alternative to physical and chemical controls is particularly effective at broad spatial scales to reduce the abundance, reproductive output, or vigor of pests, weeds, or disease causing organisms. However, as our climate continues to change it could threaten the effectiveness of this strictly regulated management strategy. Through a systematic literature review, Evans et al. found that most of our current knowledge of climate change impacts on biocontrol agents comes from research that manipulates a single environmental variable (temperature) using agricultural arthropod biocontrol agents in laboratory settings. A subsequent meta-analysis of 18 studies found no overall effect of temperature changes on biocontrol agents or targets, but great variation in responses across systems and measured responses. This included cases where temperature changes had a net benefit for the target taxa and others with a net benefit for the biocontrol agent. These results highlight the importance of more species specific studies that test how changes in temperature and other environmental variables (such as moisture) may affect performance, survival, and reproduction of agents and their targets. Understanding these species-specific effects is critical for ensuring continuing success of biological control programs into the future. Increased communication and collaboration between natural resource practitioners and researchers could help identify high-priority biocontrol agents and targets that future experimental studies should focus on, support existing monitoring of biocontrol agents and target responses, and increase the amount of field based studies in natural systems.
Take-home points:
Most studies investigating impacts of climate change on biological control agents and their targets focus on how changes in temperature affect agricultural agents.
No overall effect of temperature change was found on biological control agents or their targets, but there was large variation across systems and response types.
The effects of climate change should be considered when evaluating potential biological control agents and their targets to ensure long term efficacy.
Management implications:
Biological control is a safe and effective strategy for managing non-native and nuisance species, particularly over broad spatial scales.
Current empirical evidence suggests many biological control agents will remain effective at managing target species despite a warming climate, provided that species continue to co-occur.
Increased communication between natural resource practitioners and researchers can help identify which biocontrol agents targets are a high priority for future climate change studies, particularly in natural field studies.
Collaborations between natural resource practitioners and researchers can help overcome funding and personnel challenges that currently limit monitoring and experimental data collection on both biological control agents and their targets.
Keywords:
Management efficacy, changing biotic interactions, biological control, biocontrol, meta-analysis, temperature effects