This research focuses on developing methods to measure resilience in wild deer mice (Peromyscus maniculatus). Resilience is defined as the capacity to cope with multiple, cumulative stressors. Developing methods to measure resilience in wildlife populations will improve our understanding of how wildlife are coping with anthropogenic disturbance in their environment.

 

This project utilizes the definition of ecological resilience, which is the capacity of a system to retain is characteristic structure and function in the face of disturbance and the ability of that system to return to its baseline after such a disturbance. Taking this concept and applying it to the physiology of the individual animal, we hypothesized that dynamic systems of the body that work to maintain homeostasis in the face of perturbation, such as the stress response axis, may be used to measure individual resilience.

 

We tested multiple downstream markers of the stress response in deer mice to determine if these biomarkers could be used as dynamic indicators of resilience (DIORs) for individuals. These markers captured effects of stress on metabolism, immune function, and oxidative stress. Markers that had a strong dynamic response (i.e., response and recovery) to acute stress were considered strong candidate DIORs and were further tested in their response to chronic repeated stressors. Captive deer mice were randomized into different stress treatment groups that simulated stressors wild populations may encounter, such as nutritional stress, predation attempts, temperature stress and microclimate fluctuations.  Blood was collected from the mice before and after treatment to analyze the response of the stress biomarkers in order to determine if the candidate DIORs were strongly reflecting individual resilience. Analysis of the results is still ongoing.