Department of Biology, Center for Ecosystem Sentinels, University of Washington, Seattle, WA 98195.
Botswana Predator Conservation, Maun, Botswana.
Proc Natl Acad Sci U S A. 2022 Jul 5;119(27):e2121667119. doi: 10.1073/pnas.2121667119. Epub 2022 Jun 27.
Understanding the degree to which animals are shifting their phenology to track optimal conditions as the climate changes is essential to predicting ecological responses to global change. Species at low latitudes or high trophic levels are theoretically expected to exhibit weaker phenological responses than other species, but limited research on tropical systems or on top predators impedes insight into the contexts in which these predictions are upheld. Moreover, a lack of phenological studies on top predators limits understanding of how climate change impacts propagate through entire ecosystems. Using a 30-y dataset on endangered African wild dogs (), we examined changes in reproductive phenology and temperatures during birthing and denning over time, as well as potential fitness consequences of these changes. We hypothesized that their phenology would shift to track a stable thermal range over time. Data from 60 packs and 141 unique pack-years revealed that wild dogs have delayed parturition by 7 days per decade on average in response to long-term warming. This shift has led to temperatures on birthing dates remaining relatively stable but, contrary to expectation, has led to increased temperatures during denning periods. Increased denning temperatures were associated with reduced reproductive success, suggesting that a continued phenological shift in the species may become maladaptive. Such results indicate that climate-driven shifts could be more widespread in upper trophic levels than previously appreciated, and they extend theoretical understanding of the species traits and environmental contexts in which large phenological shifts can be expected to occur as the climate changes.
了解动物在多大程度上通过改变物候来跟踪最佳条件以适应气候变化，对于预测生态系统对全球变化的响应至关重要。理论上，低纬度或高营养级的物种预计会比其他物种表现出较弱的物候反应，但对热带系统或顶级捕食者的有限研究阻碍了对这些预测在哪些情况下成立的深入了解。此外，缺乏对顶级捕食者的物候研究限制了对气候变化如何通过整个生态系统传播的理解。本研究利用 30 年的濒危非洲野犬（）繁殖物候学和分娩及洞穴时期温度数据，研究了繁殖物候和分娩及洞穴时期温度随时间的变化，以及这些变化可能对野犬产生的适应后果。我们假设，随着时间的推移，野犬的物候学将发生变化，以跟踪稳定的热范围。来自 60 个犬群和 141 个独特犬群年的数据显示，野犬的分娩时间平均每十年延迟 7 天，以应对长期变暖。这种转变导致分娩日期的温度相对稳定，但与预期相反，导致洞穴时期的温度升高。洞穴温度升高与繁殖成功率降低有关，这表明该物种的持续物候学转变可能变得不适应。这些结果表明，与以前的认识相比，气候驱动的转变在较高营养级中可能更为普遍，并且扩展了物种特征和环境背景的理论理解，这些特征和环境背景可能导致随着气候变化而发生较大的物候转变。
