Behavioural flexibility in migratory behaviour in a long-lived large herbivore
Behavioural flexibility in migratory behaviour in a long-lived large herbivore
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DOI：
10.1111/1365-2656.12495
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发表时间：
2016-05-01
影响因子：
4.8
通讯作者：
Merrill, Evelyn H.
中科院分区：
文献类型：
--
作者：
Eggeman, Scott L.;Hebblewhite, Mark;Merrill, Evelyn H.
与非迁徙动物相比，迁徙动物预计将通过获得更高质量的饲料和/或降低捕食风险来增强终生健康。尽管有证据表明在其他分类群中存在行为灵活性，但之前对大型哺乳动物的研究往往假设迁徙行为是一种固定的行为特征。对于许多物种来说，迁徙行为可能是可塑性的，尽管很少有研究通过对标记的个体进行长期监测来测试个体水平的灵活性，特别是在大型哺乳动物中，如有蹄类动物。我们利用加拿大阿尔伯塔省部分迁徙的雅哈廷达种群中223只成年雌性麋鹿(Cervus Elaffus)的10年遥测数据集，测试了个体迁徙行为的变异性。我们使用净平方排水量(NSD)对每个麋鹿年的迁徙策略进行分类。个人在移民和居民策略之间的转换平均每年有15%，而且移民比居民更有可能转换策略。然后，我们测试了外在因素(气候、麋鹿/狼的数量)和内在因素(年龄)如何影响迁徙的可能性，其次，影响在迁徙策略之间切换的决定。在630个麋鹿年中，在严冬之后，在狼数量较多的年份，随着年龄的增长，单个麋鹿迁徙的可能性增加。在单个麋鹿的水平上，我们观察到了至少2年监测到的430个可能的转换中的148个转换事件。我们发现，迁徙的转变依赖于密度，在低麋鹿丰度时，候鸟转向栖息地策略，而在麋鹿丰度高时，候鸟更多地转向候鸟策略。前一年夏季的降水有微弱的结转效应，在夏季较潮湿后，迁徙的移民略多一些，而居民则表现出相反的模式。年长的迁徙麋鹿很少更换，而留宿麋鹿在年长的时候更频繁地更换迁徙。我们的结果表明，有蹄类动物的迁徙行为是一种个体可变的特征，可以对内在的、环境的和密度相关的力量做出反应。不同的战略对密度依赖和内在驱动因素有相反的反应，为维持这一人口的部分移徙和人口适宜性提供了稳定机制。
Migratory animals are predicted to enhance lifetime fitness by obtaining higher quality forage and/or reducing predation risk compared to non-migratory conspecifics. Despite evidence for behavioural flexibility in other taxa, previous research on large mammals has often assumed that migratory behaviour is a fixed behavioural trait. Migratory behaviour may be plastic for many species, although few studies have tested for individual-level flexibility using long-term monitoring of marked individuals, especially in large mammals such as ungulates. We tested variability in individual migratory behaviour using a 10-year telemetry data set of 223 adult female elk (Cervus elaphus) in the partially migratory Ya Ha Tinda population in Alberta, Canada. We used net squared displacement (NSD) to classify migratory strategy for each individual elk-year. Individuals switched between migrant and resident strategies at a mean rate of 15% per year, and migrants were more likely to switch than residents. We then tested how extrinsic (climate, elk/wolf abundance) and intrinsic (age) factors affected the probability of migrating, and, secondly, the decision to switch between migratory strategies. Over 630 individual elk-years, the probability of an individual elk migrating increased following a severe winter, in years of higher wolf abundance, and with increasing age. At an individual elk level, we observed 148 switching events of 430 possible transitions in elk monitored at least 2years. We found switching was density-dependent, where migrants switched to a resident strategy at low elk abundance, but residents switched more to a migrant strategy at high elk abundance. Precipitation during the previous summer had a weak carryover effect, with migrants switching slightly more following wetter summers, whereas residents showed the opposite pattern. Older migrant elk rarely switched, whereas resident elk switched more frequently to migrate at older ages. Our results show migratory behaviour in ungulates is an individually variable trait that can respond to intrinsic, environmental and density-dependent forces. Different strategies had opposing responses to density-dependent and intrinsic drivers, providing a stabilizing mechanism for the maintenance of partial migration and demographic fitness in this population.