Conservation Genetics

Human population growth and expansion have led to the restriction of many wildlife species on a small portion of their historic ranges. Wide-ranging mammals are particularly susceptible to range contractions, since even large parcels of land may only support small populations. In North America, wide-ranging mammals such as black bear, caribou, elk, grizzly bear, and pronghorn have lost up to 74% of their historic range over the past 150 years. Precious few examples exist of reintroduction programs which are considered successful in both ecological and genetic terms. Some of the most widely cited examples of successful reintroduction programs, such as the Alpine ibex, have resulted in populations with comparatively low levels of genetic diversity. Genetic diversity is the "currency" of evolution, as it allows species to adapt to environmental change. Conversely, low levels of genetic diversity are associated with increased extinction rates. A major focus of my research is understanding how we can manage wildlife species in discontinuous populations to best promote long-term conservation.

American bison as a model species

Private and government activists in the late 19th and early 20th centuries successfully prevented the imminent extinction of the American bison (Bison bison). The effort is considered one of the first examples of a concerted conservation movement to save a species. Nearly all modern bison populations are derived from the lineages represented in publicly-maintained populations (state and federal herds in Canada and the US), most of which contain genetic evidence of historic hybridization with domestic cattle. As such, the preservation of those populations free of domestic cattle introgression is of paramount importance in the long-term conservation of the bison species. Long-term preservation of genetic integrity in these small, closed public populations, however, requires intensive and continuous genetic management. Recently, we examined the distribution of genetic variation within and among U. S. federal bison populations and evaluated the effects of various management strategies on genetic variability. Through continued monitoring and appropriate management actions, changes in genetic diversity can be assessed over time to ensure the long-term genetic conservation of North American bison.