Moose (Alces alces) have experienced considerable declines along the periphery of their range in the northeastern United States. In Vermont, the population declined 45% from 2010 to 2017 despite minimal hunter harvest and adequate habitat. Similarly, nearby populations recently experienced epizootics characterized by >50% mortality. Declines have largely been associated with the effects of winter ticks (Dermacentor albipictus), but uncertainty exists about the effects of environmental and other parasite-related conditions on moose survival. We examined patterns of moose survival among a radio-collared population (n = 127) in Vermont from 2017 to 2019. Our objectives were to estimate causes of mortality and model survival probability as a function of individual and landscape variables for calves (<1 yr) and adults (≥1 yr). Observed adult survival was 90% in 2017, 84% in 2018, and 86% in 2019, and winter calf survival was 60% in 2017, 50% in 2018, and 37% in 2019. Winter tick infestation was the primary cause of mortality (91% of calves, 25% of adults), and 32% of all mortalities had evidence of meningeal worm (Parelaphostrongylus tenuis). Other sources of mortality such as vehicles, harvest, predation, deep snow, and other parasitic infections were negligible. The best supported calf model included sex differences and negative effects of tick engorgement (%/week) and parasite level (roundworm and lungworm). The best supported adult model included the effect of cumulative tick engorgement (cumulative %/week), which negatively affected survival. Our results indicate that winter tick engorgement strongly affects survival, and is probably compounded by the presence of meningeal worm and other parasites. Reduced tick effects may be achieved by decreasing moose density through harvest and managing late winter habitat to minimize tick density. Management of white-tailed deer (Odocoileus virginianus) density may also affect the transmission of meningeal worm. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society.

中文翻译：

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美国佛蒙特州冬季蜱虫和体内寄生虫对驼鹿生存的影响

驼鹿（Alces alces）在美国东北部的分布范围周边经历了相当大的下降。在佛蒙特州，尽管狩猎收获最少且栖息地充足，但从 2010 年到 2017 年，人口下降了 45%。同样，附近的人群最近经历了以 > 50% 死亡率为特征的流行病。下降主要与冬季蜱（Dermacentor albipictus）的影响有关，但环境和其他寄生虫相关条件对驼鹿生存的影响存在不确定性。我们研究了戴无线电项圈的驼鹿生存模式 ( n = 127）从 2017 年到 2019 年在佛蒙特州。我们的目标是估计死亡原因和模型生存概率作为小牛（<1 年）和成人（≥1 年）的个体和景观变量的函数。2017年观察到的成体存活率为90%，2018年为84%，2019年为86%，2017年冬犊存活率为60%，2018年为50%，2019年为37%。冬季蜱虫感染是死亡的主要原因（91% 的小牛，25% 的成年人）和 32% 的死者有脑膜蠕虫（细小细副圆线虫）的证据）。其他死亡来源，如车辆、收获、捕食、深雪和其他寄生虫感染，可以忽略不计。最受支持的小牛模型包括性别差异和蜱虫充血 (%/周) 和寄生虫水平 (蛔虫和肺虫) 的负面影响。最受支持的成人模型包括累积蜱充血的影响（累积 %/周），这对生存产生了负面影响。我们的结果表明，冬季蜱虫充血强烈影响存活，并且可能因脑膜蠕虫和其他寄生虫的存在而加剧。通过收获和管理冬末栖息地以最小化蜱密度来降低驼鹿密度，可以减少蜱的影响。白尾鹿（Odocoileus virginianus）的管理) 密度也可能影响脑膜蠕虫的传播。© 2021 作者。由 Wiley Periodicals LLC 代表野生动物协会出版的《野生动物管理杂志》。