Within-year and among-year variation in impacts of targeted conservation management on juvenile survival in a threatened population
Within-year and among-year variation in impacts of targeted conservation management on juvenile survival in a threatened population
复制标题
有针对性的保护管理对受威胁种群中幼年生存影响的年内和年际变化
DOI：
10.1111/1365-2664.13998
复制
发表时间：
2021
影响因子：
5.7
通讯作者：
Fenn S
中科院分区：
文献类型：
--
作者：
Fenn S
有针对性的保护干预措施对种群增长率（λ）的总体影响将取决于目标个体暴露于干预措施的年内和年间变化，以及干预措施在增加暴露个体生命率方面的有效性。幼龄动物存活率是一个关键的生命率，通常在年内和年间变化很大，因此导致λ的变化。然而，针对性干预措施对潜在移动的青少年的全人口生存概率的年内、年间和总体影响很少量化，排除了对干预措施的全面评估和循证改进。我们将多状态标记-再捕获模型应用于8年的环-来自受威胁红嘴鸦Pyrrhocorax pyrrhocorax种群的重新定位数据，以量化青少年暴露于目标干预的年内和年间变化的补充喂养和寄生虫治疗，并估计在增加少年生存概率的功效。然后，我们结合并放大这些估计的影响，以评估8年干预对整个人群生存概率和由此产生的人群规模的影响。在所有年份的年度生物周期中，高比例的存活青少年（>70%）暴露于干预。暴露与整个年度周期的较高短期生存概率相关。因此，管理使估计的全种群年度青少年存活率增加了约0.14。然而，这种影响仅在总体年存活率较低的队列中明显。人口模型预测，这些对年度青少年存活率的影响大大减少了人口下降，因此，在8年干预结束时，人口规模约为未管理时的两倍。我们的研究结果表明，年内和年间暴露和有针对性的保护干预措施的有效性变化的复杂模式可以出现并扩大到影响人口水平的结果。我们证明了联合补充喂养和寄生虫治疗干预对重点山鸦种群的总体积极影响，但也强调了提高疗效的潜在途径，例如，通过更精确地针对环境条件年间变化的背景下的干预措施和农业管理行动。
Overall impacts of targeted conservation interventions on population growth rate (λ) will depend on within‐year and among‐year variation in exposure of target individuals to interventions, and in intervention efficacy in increasing vital rates of exposed individuals. Juvenile survival is one key vital rate that commonly varies substantially within and among years, and consequently drives variation inλ. However, within‐year, among‐year and overall impacts of targeted interventions on population‐wide survival probabilities of potentially mobile juveniles are rarely quantified, precluding full evaluation and evidence‐based refinement of interventions.We applied multi‐state mark–recapture models to 8 years of ring–resighting data from a threatened red‐billed choughPyrrhocorax pyrrhocoraxpopulation to quantify within‐year and among‐year variation in juvenile exposure to a targeted intervention of supplementary feeding and parasite treatment, and to estimate efficacy in increasing juvenile survival probability. We then combined and up‐scaled these estimated effects to evaluate the impact of the 8‐year intervention on overall population‐wide survival probability and resulting population size.High proportions of surviving juveniles (>70%) were exposed to the intervention across the annual biological cycle in all years. Exposure was associated with higher short‐term survival probabilities through the full annual cycle. Consequently, management increased estimated population‐wide annual juvenile survival by approximately 0.14. However, such effects were only evident in cohorts with low overall annual survival.Population models projected that these impacts on annual juvenile survival substantially reduced population decline, such that population size at the end of the 8‐year intervention was approximately double that without management.Synthesis and applications. Our results show how complex patterns of within‐year and among‐year variation in exposure and efficacy of targeted conservation interventions can arise and scale up to affect population‐level outcomes. We demonstrate overall positive effects of a joint supplementary feeding and parasite treatment intervention on the focal chough population, but also highlight potential routes to improve efficacy, for example, through more precise targeting of interventions and agricultural management actions in the context of among‐year variation in environmental conditions.