The influence of winter severity, predation and senescence on moose habitat use
The influence of winter severity, predation and senescence on moose habitat use
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DOI：
10.1111/1365-2656.12000
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发表时间：
2013-03-01
影响因子：
4.8
通讯作者：
Millenbah, Kelly F.
中科院分区：
文献类型：
--
作者：
Montgomery, Robert A.;Vucetich, John A.;Millenbah, Kelly F.
栖息地利用是众所周知的影响，非生物和生物因素，如气候，人口密度，觅食机会和捕食风险。个体生物的生活史状态对生境利用的影响还不太清楚，尤其是陆生哺乳动物。有充分的理由预期，生活史状态会影响栖息地的使用。例如，表现出与衰老相关的不良状况的生物体对捕食的脆弱性增加，并且已知这种脆弱性会改变栖息地使用策略。我们评估了生活史阶段对栖息地利用的影响，732驼鹿（Alces alces）狼（Canis lupus）在50年的时间里在皇家岛国家公园，在上级湖，美国的岛屿生态系统。我们开发了回归模型，以评估死亡的位置如何与驼鹿的生活史阶段（壮年或衰老），存在或不存在衰老相关的病理（骨关节炎和颌骨坏死），以及冬季严重程度，驼鹿密度和驼鹿与狼的比例的年度变化，这是捕食风险的指标。与衰老的驼鹿相比，壮年驼鹿往往更多地利用远离皇家岛海岸线的栖息地。这一结果在生态学上是相关的，因为皇家岛的海岸线栖息地往往为驼鹿提供更好的觅食机会，但也与增加的捕食风险有关。在严酷的冬季，壮年驼鹿往往更多地利用栖息地，这是更接近海岸的关系，衰老的驼鹿。此外，这两个年龄段的驼鹿更有可能死在风险较高的，海岸线的栖息地在几年捕食风险较低的前一年。我们的研究结果突出了生活史，年龄结构的人口动态和栖息地相关的行为之间的复杂联系。我们的分析还说明了为什么种内竞争不应该是密度依赖的栖息地利用的假设机制，如果捕食风险与密度有关，因为它预计在许多系统。
Habitat use is widely known to be influenced by abiotic and biotic factors, such as climate, population density, foraging opportunity and predation risk. The influence of the life-history state of an individual organism on habitat use is less well understood, especially for terrestrial mammals. There is good reason to expect that life-history state would affect habitat use. For example, organisms exhibiting poor condition associated with senescence have an increased vulnerability to predation and that vulnerability is known to alter habitat use strategies. We assessed the influence of life-history stage on habitat use for 732 moose (Alces alces) killed by wolves (Canis lupus) over a 50-year period in Isle Royale National Park, an island ecosystem in Lake Superior, USA. We developed regression models to assess how location of death was associated with a moose's life-history stage (prime-aged or senescent), presence or absence of senescent-associated pathology (osteoarthritis and jaw necrosis), and annual variation in winter severity, moose density and ratio of moose to wolves, which is an index of predation risk. Compared to senescent moose, prime-aged moose tend to make greater use of habitat farther from the shoreline of Isle Royale. That result is ecologically relevant because shoreline habitat on Isle Royale tends to provide better foraging opportunities for moose but is also associated with increased predation risk. During severe winters prime-aged moose tend to make greater use of habitat that is closer to shore in relation to senescent-aged moose. Furthermore, moose of both age classes were more likely to die in riskier, shoreline habitat during years when predation risk was lower in the preceding year. Our results highlight a complicated connection between life history, age-structured population dynamics and habitat-related behaviour. Our analysis also illustrates why intraspecific competition should not be the presumed mechanism underlying density-dependent habitat use, if predation risk is related to density, as it is expected to be in many systems.