Collateral benefits of targeted supplementary feeding on demography and growth rate of a threatened population
Collateral benefits of targeted supplementary feeding on demography and growth rate of a threatened population
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DOI：
10.1111/1365-2664.13721
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发表时间：
2020-08-16
影响因子：
5.7
通讯作者：
Reid, Jane M.
中科院分区：
文献类型：
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作者：
Fenn, Sarah R.;Bignal, Eric M.;Reid, Jane M.
有效的循证保护需要充分量化有针对性的管理干预措施对重点人群的影响。这种影响可能超出目标个人的范围，还会影响非目标同种人群的人口比率(例如，不同年龄段)。然而，这种抵押品(即计划外的)影响很少得到评估，尽管它们有可能极大地改变保护结果。随后的管理决策可能缺乏信息，或者是错误的。我们使用了15年的基于个体的人口统计数据，在“控制前-控制-影响”(BACI)分析中，量化了一项有针对性的多年补充喂养计划的间接人口统计影响，该计划旨在提高亚成体的存活率，从而提高受威胁的小红嘴鸟种群的生存能力。具体地说，我们评估了干预是否也影响了成年动物的存活和繁殖成功，以及这种附带影响本身是否足以稳定种群数量，从而实现短期保护目标。在那些与补充喂养相关的幼崽中，成体存活和成功繁殖的概率在“喂食前”和“喂食期间”之间显著增加，但在其他情况下并不是如此。总体繁殖成功率(即每一块领地的羽毛数量)也趋于增加，即使孵化的雏鸟数量没有增加。这些只有通过BACI分析才能检测到的关系表明，针对亚成人的补充喂养对成人人口率产生了计划外的积极影响。为预测人口增长而设计的确定性矩阵模型表明，这些估计的附带影响足以对提高人口增长率和实现短期人口稳定作出重大贡献。合成与应用。我们的结果表明，有针对性的补充喂养干预对种群生存能力产生了实质性的积极间接影响，尽管事先没有预期非目标成年人是食物受限的。这一案例说明了对有针对性干预措施的附带影响的彻底评估如何影响对短期效力的评估，并揭示未来干预措施的新机会，从而为随后的管理决策提供信息。
Effective evidence-based conservation requires full quantification of the impacts of targeted management interventions on focal populations. Such impacts may extend beyond target individuals to also affect demographic rates of non-target conspecifics (e.g. different age classes). However, such collateral (i.e. unplanned) impacts are rarely evaluated despite their potential to substantially alter conservation outcomes. Subsequent management decisions may then be poorly informed or erroneous. We used 15 years of individual-based demographic data in a 'before-after control-impact' (BACI) analysis to quantify collateral demographic impacts of a targeted multi-year supplementary feeding programme designed to increase sub-adult survival and hence viability of a small, threatened red-billed choughPyrrhocorax pyrrhocoraxpopulation. Specifically, we assessed whether the intervention also affected adult survival and reproductive success, and whether such collateral effects were themselves sufficient to stabilize population size and hence achieve short-term conservation aims. The probabilities of adult survival and successful reproduction increased substantially between the 'before-feeding' and 'during-feeding' periods in those choughs associated with supplementary feeding, but not otherwise. Overall breeding success (i.e. number of chicks fledged per occupied territory) also tended to increase, even though brood sizes did not increase. These relationships, which were detectible only through BACI analyses, suggest that supplementary feeding targeted at sub-adults had unplanned positive impacts on adult demographic rates. Deterministic matrix models designed to project population growth demonstrate that these estimated collateral effects were sufficient to make a substantial contribution to increasing population growth rate and achieving short-term population stability. Synthesis and applications. Our results indicate substantial positive collateral impacts of a targeted supplementary feeding intervention on population viability, despite no a priori expectation that the non-target adults were food-limited. This casestudy illustrates how thorough assessment of collateral impacts of targeted interventions can affect assessment of short-term efficacy and reveal new opportunities for future interventions, thereby informing subsequent management decisions.