Understanding a migratory species in a changing world: climatic effects and demographic declines in the western monarch revealed by four decades of intensive monitoring
Understanding a migratory species in a changing world: climatic effects and demographic declines in the western monarch revealed by four decades of intensive monitoring
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DOI：
10.1007/s00442-016-3600-y
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发表时间：
2016-07-01
期刊：
影响因子：
2.7
通讯作者：
Forister, Matthew L.
中科院分区：
文献类型：
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作者：
Espeset, Anne E.;Harrison, Joshua G.;Forister, Matthew L.
迁徙动物对保护生物学家提出了独特的挑战，我们有很多关于迁徙物种如何应对全球变化驱动因素的知识。研究对北美东部帝王蝶（Danaus plexippus）种群的稳定性提出了质疑，但西方帝王蝶并没有得到深入的研究。使用贝叶斯分层模型，目击西方君主在大约40年的夏季飞行记录从10个站点沿着在北方加州的海拔样带进行了调查。对多个天气变量进行了检查，包括当地和区域温度和降水量。从10个焦点网站和一个子集的西部越冬地点的人口趋势进行了比较，夏季和越冬数据从东部迁移。记录显示，随着时间的推移，西部越冬地和西部繁殖地有负面趋势，下降集中在繁殖季节早期，可能比东部种群更严重。西方君主的时间变化似乎也在很大程度上独立于（不相关）的动态在东方。对于我们的焦点网站，温暖的温度在冬季和春季有积极的影响，降水在春季有积极的影响。这些气候关联增加了我们对迁徙蝴蝶生物-非生物相互作用的理解，但不断变化的气候条件并不能解释我们数据中观察到的总体、长期、负种群轨迹。
Migratory animals pose unique challenges for conservation biologists, and we have much to learn about how migratory species respond to drivers of global change. Research has cast doubt on the stability of the eastern monarch butterfly (Danaus plexippus) population in North America, but the western monarchs have not been as intensively examined. Using a Bayesian hierarchical model, sightings of western monarchs over approximately 40 years were investigated using summer flight records from ten sites along an elevational transect in Northern California. Multiple weather variables were examined, including local and regional temperature and precipitation. Population trends from the ten focal sites and a subset of western overwintering sites were compared to summer and overwintering data from the eastern migration. Records showed western overwintering grounds and western breeding grounds had negative trends over time, with declines concentrated early in the breeding season, which were potentially more severe than in the eastern population. Temporal variation in the western monarch also appears to be largely independent of (uncorrelated with) the dynamics in the east. For our focal sites, warmer temperatures had positive effects during winter and spring, and precipitation had a positive effect during spring. These climatic associations add to our understanding of biotic-abiotic interactions in a migratory butterfly, but shifting climatic conditions do not explain the overall, long-term, negative population trajectory observed in our data.