Black bear (Ursus americanus) ecology in Southern Grand Teton National Park
Frattaroli, Leslie Marie
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Black bears (Ursus americanus) in Grand Teton National Park (GRTE), Wyoming occupy an environment that is changing due to human pressure and environmental variability. I analyzed activity patterns, food habits, and habitat use of black bears in southern GRTE, trying to identify if human recreation impacted these patterns. I studied 9 black bears equipped with spread spectrum technology (SS) collars from June, 2005 to October, 2006. Each collar contained -15° head to tail activity switch, a GPS radio receiver, and an independent very high frequency (VHF) transmitter. I used logistic regression on a sample of bear locations that were field-verified as active or resting to determine a break point to classify all locations as resting or active based upon activity counts. My discriminant analysis indicated that bears were likely resting if their recorded activity count was <16.5. I used logistic regression to determine which factors were most responsible for missed fixes. Overall, bear activity levels were consistent regardless of their distance from roads, human developments, and trails. Bears fed on a wide range of foods including vegetation, insects, and mammals that were seasonally abundant. Graminoids and ants were important food sources for black bears in the spring and summer. I used the Mahalanobis Distances Factor Analysis (MADIFA) to quantitatively break down the D ² statistic into linear combinations to determine the impact of each variable on D ². My models displayed areas of high use (i.e. larger D ² values), in forested regions adjacent to trails and roads. Several axes in different linear combinations, including habitat and human use covariates, are present in the analysis. This suggests that a complexity exists for black bear habitat use, beyond proximity to human use activities. Therefore it would be an oversimplification to conclude that black bears only utilize areas close to trails and/or roads in southern GRTE.