Assessing Stress and Population
Genetics Through Noninvasive
Samuel K. Wasser
Kathleen E. Hunt
Christine M. Clarke
Monitoring changes in animal abundance, the presence of pathogens, and physiological well-being of wildlife is critical for effective management of wildlife diseases. Monitoring animal abundance enables one to recognize when a potential die-off is occurring. Pathogen monitoring enables one to examine potential causes of the mortality. Monitoring physiological stress alerts investigators to conditions that could increase susceptibility to disease. Monitoring reproductive function can do this as well, in addition to alerting investigators to other problems such as endocrine disruption resulting from exposure to pollutants. These latter measures may also rule out alternative diseases that may present clinical signs similar to those of emergent diseases.
Obtaining this information can be difficult even for the most observable species. Available methods have been invasive, severely limiting the sampling frequencies required to effectively carry out such monitoring. Noninvasive techniques for acquiring DNA and hormones from wildlife living in remote areas can greatly facilitate the above monitoring needs. These techniques enhance sample accessibility, which is invaluable for a wide variety of monitoring purposes. DNA acquired from hair or feces can be used to identify individuals and can be applied to mark-recapture models to estimate animal abundances (Kohn et al. 1999; Woods et al. 1999; Mowat and Strobeck, 2000). Fecal DNA may also prove useful for detecting pathogens shed in feces, providing an early warning system for emergent diseases. Adrenal and gonadal hormones in feces can be used to measure physiological stress in response to environmental disturbances (Wasser 1996); they can also be used as indices of other disease states such as endocrine disruption in response to pollutants.