Denning Chronology of Female Black Bears: Effects of Food, Weather, and Reproduction
Denning Chronology of Female Black Bears: Effects of Food, Weather, and Reproduction
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雌性黑熊的丹宁年表：食物、天气和繁殖的影响
DOI：
10.2307/1382569
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发表时间：
1994
影响因子：
1.7
通讯作者：
W. Krohn
中科院分区：
文献类型：
--
作者：
R. Schooley;C. Mclaughlin;G. J. Matula;W. Krohn
我们研究了1982年至1988年期间影响缅因州三个地区104只雌性黑熊（Ursus americanus）登巢时间的因素。在北方缅因州的两个地区，进入洞穴遵循一个交替的模式，大多数熊在10月中下旬山毛榉（山毛榉）稀缺时，在11月中下旬坚果丰富的第二年。这种模式可能已经发生了≥11年，以前没有报告过黑熊种群。从1986年到1988年，栖息地的使用模式反映了对山毛榉作物的另一种行为反应;熊在坚果丰富的秋天更多地使用硬木森林。在秋季，洞穴入口的年度变化与天气模式没有很强的相关性。在缅因州中部山毛榉树不太常见的地方，巢穴入口和栖息地的使用多年来变化较小。怀孕的雌性往往比其他雌性更早进入洞穴。登出现的生殖类之间是相似的，一般发生在4月内7天的最后一次融雪。个体的丹宁期为134至197天。我们的结论是，黑熊通常在秋季保持活跃，直到出现负能量平衡，但我们假设怀孕的雌性熊可能会在储存足够的脂肪储备用于繁殖后筑巢。
We studied factors affecting the chronology of denning by 104 female black bears ( Ursus americanus ) from three areas in Maine from 1982 to 1988. At two areas in northern Maine, entry into dens followed an alternate-year pattern with most bears denning in mid to late October when beechnuts ( Fagus grandifolia ) were scarce, and in mid to late November the next year when nuts were abundant. This pattern may have occurred for ≥11 years and has not been reported previously for a black bear population. From 1986 to 1988, patterns of habitat use reflected another behavioral response to beechnut crops; bears used hardwood forests more during autumns when nuts were abundant. Annual variation in den entry was not strongly associated with weather patterns during autumn. Where beech trees were less common in central Maine, den entry and habitat use varied less among years. Pregnant females tended to den earlier than other females. Den emergence was similar among reproductive classes, generally occurring during April within 7 days of the final snow melt. Denning periods for individuals ranged from 134 to 197 days. We concluded that black bears generally remain active in autumn until a negative energy balance occurs, but we hypothesized that pregnant females may den after they store adequate fat reserves for reproduction.