SIMULATION MODELING OF AMERICAN MARTEN (MARTES AMERICANA) POPULATIONS- VULNERABILITY TO EXTINCTION

American marten (Martes americana) are medium-sized mammalian carnivor es inhabiting forest communities across northern North America. Marten s are susceptible to local extinction from habitat alterations, trappi ng, and other factors. We (RCL) developed a population model called VO RTEX to estimate extinction probabilities for marten populations as a management tool. The model permits managers to simulate various levels of timber harvesting, commercial trapping, and other factors to estim ate their effects on marten populations. This paper describes this mod el and illustrates its benefits by using marten data from the Greater Yellowstone Ecosystem of northwestern Wyoming. Results are preliminary . Populations of 50 and 100 martens were simulated. The most optimisti c scenario with populations of 100 individuals, no trapping, no loggin g, and no migrants showed a probability (66%) of surviving 100 years. Extinction probabilities were sensitive to immigration and emigration rates. Numerous scenarios were simulated and showed a range of results . Results of population viability analysis can be translated into area requirements if densities are known or can be estimated. In turn, var ious habitat patches and interconnecting corridors can be examined for their ability to support viable marten populations. Population modeli ng is invaluable to ''adaptive management'' of martens as well as othe r species.