Status of the Grizzly Bear (Ursus arctos) in Montana

Nick Jensen

               The Grizzly bear (Ursus arctos) is arguably one of the most controversial large carnivores in the United States. This species of bear has been the target of nearly every stereotype an animal can be attributed to whether it be: vicious man-eater, a mysterious and powerful symbol of the western United States, cute and loveable, etc, the result remains the same: most people vastly misunderstand this species, including wildlife biologists. In order to better help manage and understand Ursus arctos, a study is underway in Montana under the USGS and University of Montana. This study is the Northern Continental Divide Ecosystem Grizzly Bear Project. I was fortunate enough to work with the USGS this summer in Glacier National Park and received much insight into their studies. As with all wildlife projects, it has been met with some opposition, however; I believe this project to be immensely important to the proper management of Ursus arctos.

               The main goal of this project was to get a measure Ursus arctos’ growth rate. Growth rate, or “lambda” in statistics, is perhaps the most important factor to take into consideration when examining results of a project to determine the status of a population. It shows the growth over time of the species, which in turn, can help managers see how the species is doing and possibly how they will do in the future. They obtain the growth rate through non-invasive hair sampling over multiple consecutive years. The hair samples are obtained from bear rubs, and sent to a lab for DNA analysis.

               This project is so crucial for the Grizzly bear for multiple reasons. They have been subject to massive habitat loss through forest fragmentation, wildfires, and human development. Poaching and human interactions leading to the putting down of bears have also played a major role in their massive loss in population numbers. However, since they have been put on the Endangered Species List in 1975, they have been doing relatively well in the NCDE in Montana. One of the major concerns about this population is that the NCDE population of Grizzlies is the only remaining population that contiguous with the Canadian population and is a vital link for the species in North America as a whole. This studies goal of finding a solid population growth rate is also important because of how sensitive this species is to reproduction. The females give birth once about every 3 years. The litter is small ranging anywhere from 1-4 cubs. As stated by Montana Fish, Wildlife & Parks: “Grizzly Bears have one of the lowest reproductive rates among terrestrial mammals, resulting primarily from the late age of first reproduction , small average litter size, and the long interval between litters.” (1)

               Ursus arctos is an iconic symbol of the western United States, as well as North America as a whole. The insurance of its persistence for future generations is of the utmost importance and the Northern Continental Divide Ecosystem Grizzly Bear Project reflects that. Their method of non-invasive genetic sampling is a great way to get vital information such as population growth rate, population estimate, survival, distribution, etc in order to insure this sensitive species continues to thrive in this country. 

Sources

 

1.      "Summary of Grizzly Bear Biology." Montana Fish, Wildlife, & Parks, n.d. Web.

 

2.      "Noninvasive Methods to Monitor Bear Population Trends." USGS, 19 Apr. 2010. Web.

 

3.      Stetz, Jeffery B., Katherine C. Kendall, and Christopher Servheen. "Evaluation of Bear Rub Surveys to Monitor Grizzly Bear Population Trends." Wildlife Management (n.d.): 860-70. Northern Rocky Mountain Science Center (NOROCK). Web. 14 Sept. 2012. <http://www.nrmsc.usgs.gov/research/NCDEbeardna_detail.htm>.

 

4.      Kendall, Katherine C., Jeffery B. Stetz, John Boulanger, Amy C. Macleod, David Paetkau, and Gary C. White. "Demography and Genetic Structure of a Recovering Grizzly Bear Population." Wildlife Management (n.d.): 3-17. Northern Rocky Mountain Science Center (NOROCK). Web. 12 Sept. 2012. <http://www.nrmsc.usgs.gov/files/norock/products/Kendalletal2009_JWMv73n1.pdf>.