The Louisiana black bear (Ursus americanus luteolus) is one of 16 recognized subspecies and is listed as threatened under the Endangered Species Act. As part of the recovery plan, Joseph Clark designed a monitoring program to estimate population size and the demographic contributions to population growth. As is true of most species, estimating population size is challenging because a direct census is impossible and thus indirect methods must be used to sample the population. In this case, 128 hair sampling stations were established in 2007 and each year hair samples are genotyped to identify individual bears so that capture-recapture models can be used for inference.
We have developed a class of spatially explicit integrated population models that can be used to not only estimate abundance, density, and vital rates; it can also be used to model spatial variation in these parameters and forecast population size under future environmental conditions and management scenarios. A paper describing the model was just accepted at Methods in Ecology and Evolution. Future work will involve applying the model to inform population recovery efforts.
Joseph D. Clark, USGS Southern Appalachian Research Branch
Jared Laufenberg, University of Tennessee Knoxville