Body mass and mast abundance influence foraging ecology of the American black bear (Ursus americanus) in Maine

作者：Seger R L^*; Servello F A; Cross R A; Keisler D H

来源：Canadian Journal of Zoology, 2013, 91(7): 512-522.

DOI：10.1139/cjz-2012-0326

• American black bear
• Ursus americanus
• nitrogen stable isotope
• carnivore
• body mass
• alternate-year cycle
• mast abundance
• beechnuts

We studied nutritional ecology of American black bears (Ursus americanus Pallas, 1780) in Maine, including active and hibernating bears during 5 years, across three study areas, using nitrogen stable isotope analyses of blood samples (n = 152). Our central finding, in two study areas, is positive correlation between body mass and delta N-15. This suggests use of large body size to acquire or guard food resources that have relatively high delta N-15, consistent with importance of ungulates as food for the largest bears in Maine. In these two study areas, hibernating bears across the spectrum of body mass showed greater delta N-15 during 2 years of beechnut (Fagus grandifolia Ehrh.) scarcity compared with 2 years of beechnut abundance. Adiposity, measured by serum leptin, was greater in hibernating bears following a season of beechnut abundance compared with one of beechnut scarcity. Total litter mass correlated positively with maternal serum leptin and negatively with maternal delta N-15, supporting the importance of mast, including beechnuts, to reproductive success of bears in Maine. In the third study area, bears across the spectrum of body mass had greater delta N-15 in all years, consistent with food resources relatively high in 15N that were available to bears of all sizes.

• 出版日期2013-7