Multiscale wolf predation risk for elk: does migration reduce risk?
Multiscale wolf predation risk for elk: does migration reduce risk?
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DOI：
10.1007/s00442-007-0661-y
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发表时间：
2007-05-01
期刊：
影响因子：
2.7
通讯作者：
Merrill, Evelyn H.
中科院分区：
文献类型：
--
作者：
Hebblewhite, Mark;Merrill, Evelyn H.
虽然迁移被假设为减少有蹄类动物的捕食风险，但很少有直接的实证检验这一假设。此外，很少有研究探讨多尺度捕食风险规避迁移有蹄类动物，但最近的研究表明，捕食者-猎物的相互作用发生在多个尺度。我们测试捕食风险降低假说在两个空间尺度上的部分迁移麋鹿（马鹿）人口通过比较暴露的移民和居民麋鹿狼（犬狼疮）捕食风险。我们使用GPS和VHF遥测数据收集67移民和44居民麋鹿在2002年至2004年的夏天和邻近的班夫国家公园（BNP），加拿大。我们使用狼GPS和VHF遥测数据来估计捕食风险的函数的相对概率狼发生加权的空间密度模型，调整不同的包大小。我们使用被狼杀死的麋鹿的独立数据验证了捕食风险模型，并表明将狼的存在和空间密度结合起来可以最好地预测麋鹿可能被杀死的地方。夏季范围内的移民麋鹿捕食风险降低了70%，居民麋鹿夏季范围内。然而，由于狼避开了人类活动频繁的地区，居民麋鹿对人类活动频繁地区的精细选择将它们的捕食风险降低到仅比移民高15%，这一差异仅在三个夏天中的一个中显着。最后，在实际迁移过程中，麋鹿暴露于1.7倍以上的捕食风险比居民，即使迁移是快速的。我们的研究结果支持大规模迁移可以减少捕食的假设。然而，我们也表明，在捕食风险存在小规模的空间变化，nonmigratory麋鹿可能同样有效地降低捕食风险，移民在某些情况下。
While migration is hypothesized to reduce predation risk for ungulates, there have been few direct empirical tests of this hypothesis. Furthermore, few studies examined multiscale predation risk avoidance by migrant ungulates, yet recent research reveals that predator-prey interactions occur at multiple scales. We test the predation risk reduction hypothesis at two spatial scales in a partially migratory elk (Cervus elaphus) population by comparing exposure of migrant and resident elk to wolf (Canis lupus) predation risk. We used GPS and VHF telemetry data collected from 67 migrant and 44 resident elk over the summers of 2002-2004 in and adjacent to Banff National Park (BNP), Canada. We used wolf GPS and VHF telemetry data to estimate predation risk as a function of the relative probability of wolf occurrence weighted by a spatial density model that adjusted for varying pack sizes. We validated the predation risk model using independent data on wolf-killed elk, and showed that combining wolf presence and spatial density best predicted where an elk was likely to be killed. Predation risk on summer ranges of migrant elk was reduced by 70% compared to within resident elk summer ranges. Because wolves avoided areas near high human activity, however, fine-scale selection by resident elk for areas near high human activity reduced their predation risk exposure to only 15% higher than migrants, a difference significant in only one of three summers. Finally, during actual migration, elk were exposed to 1.7 times more predation risk than residents, even though migration was rapid. Our results support the hypothesis that large-scale migrations can reduce predation. However, we also show that where small-scale spatial variation in predation risk exists, nonmigratory elk may equally reduce predation risk as effectively as migrants under some circumstances.