Reduction of first-year survival threatens the viability of the Mariana Crow Corvus kubaryi population on Rota, CNMI
Reduction of first-year survival threatens the viability of the Mariana Crow Corvus kubaryi population on Rota, CNMI
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第一年存活率的下降威胁着北马里亚纳群岛罗塔州马里亚纳乌鸦 Corvus kubaryi 种群的生存能力
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
R. Ha
中科院分区：
文献类型：
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作者：
J. Ha;A. Butler;R. Ha
摘要：马里亚纳乌鸦是一种森林乌鸦，最初只在西太平洋马里亚纳群岛的关岛和罗塔岛附近发现。快速和持续的下降导致它在2008年被世界自然保护联盟列为“极度濒危”物种。使用在21年期间标记和重视的97只鸟，我们发现在1990到2010年间，第一年(雏鸟到一岁)的存活率从0.7迅速下降到0.4，死亡率翻了一番，同期成鸟存活率从0.86下降到0.82。基于Leslie矩阵的种群模型包含了灾难性事件的影响，如台风和人工繁殖的人类筑巢。所有的模拟都预测了未来种群数量的急剧下降，而包括移巢在内的野生种群的寿命只会缩短几年。确定存活率下降背后的潜在过程是关键的研究优先事项，鉴于持续快速下降的可能性不可避免，养护行动应侧重于通过圈养繁殖或圈养野生出生的雏鸟来确保物种的未来，并确保适应性管理养护方案侧重于对抗目前被认为影响第一年存活率和生产力的因素(例如捕食)。未来的研究可能会找出玛丽安娜乌鸦数量下降的其他原因，保护计划应该足够灵活，以适应不断变化的需求。
Summary The Mariana Crow Corvus kubaryi is a species of forest crow originally found only on the adjacent islands of Guam and Rota in the Mariana Islands of the western Pacific Ocean. Rapid and continuing declines led to it being listed by IUCN as "Critically Endangered" in 2008. Using 97 birds marked and resighted over the course of a 21 year period, we showed there was a rapid decline in first-year (fledgling to one year old) survival from 0.7 to 0.4 between 1990 and 2010, representing a doubling in mortality, and a smaller reduction in adult survival from 0.86 to 0.82 over the same period. A population model based on Leslie matrices incorporated the effects of catastrophic events, such as typhoons and human nest removal for captive breeding. All simulations predicted a precipitous decline in future populations and the inclusion of nest removals only shortened the life of the wild population by a few years. Identifying the underlying processes behind the decline in survival is the key research priority and, given the inevitable likelihood of a continuing rapid decline, conservation action should focus on securing the future of the species through captive breeding or captive rearing of wild-born chicks and ensuring that an adaptive management conservation programme is focused on countering the factors (e.g. predation) that are currently thought to impact first-year survival and productivity. Future research may identify other causes behind the Mariana Crow’s decline and the conservation programme should be flexible enough to adapt to changing needs.