Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, USA.
Protect Ocean, Land and Water Program, The Nature Conservancy, Fort Collins, CO, USA.
J Anim Ecol. 2021 Feb;90(2):317-329. doi: 10.1111/1365-2656.13332. Epub 2020 Sep 28.
Climate change and habitat loss pose the greatest contemporary threats to biodiversity, but their impacts on populations largely vary across species. These differential responses could be caused by complex interactions between landscape and climate change and species-specific sensitivities. Understanding the factors that determine which species are most vulnerable to the synergistic effects of climate change and habitat loss is a high conservation priority. Here, we ask (a) whether and to what extent land cover moderates the impacts of winter weather on population dynamics of wintering birds, and (b) what role species' physiology might play in modifying their responses to changing weather conditions. To address these questions, we used thousands of observations collected by citizen scientists participating in Project FeederWatch to build dynamic occupancy models for 14 species of wintering birds. Populations of wintering birds were more dynamic, having higher rates of local extinction and colonization, in more forested landscapes during extreme cold-presumably enabling them to better track resources. However, urban areas appeared to provide refuge for some species, as demonstrated by increased local colonization during the harshest winter weather. Lastly, we found that species-specific differences in thermal tolerances strongly influenced occupancy dynamics such that species that are less cold-tolerant were more likely to go locally extinct at colder sites and during colder periods throughout winter. Together, our results suggest that species that are less cold-tolerant and populations occupying less forested landscapes are most vulnerable to extreme winter weather.
气候变化和栖息地丧失是生物多样性面临的最大当代威胁，但它们对种群的影响在很大程度上因物种而异。这些差异反应可能是由景观和气候变化之间的复杂相互作用以及物种特有的敏感性引起的。了解哪些物种最容易受到气候变化和栖息地丧失协同效应的影响是高度优先的保护事项。在这里，我们提出了以下两个问题：(a) 土地覆盖是否以及在何种程度上调节了冬季天气对越冬鸟类种群动态的影响；(b) 物种生理学在改变它们对变化的天气条件的反应方面可能发挥什么作用。为了解决这些问题，我们使用了数千名参与“喂鸟器观察计划”的公民科学家收集的数据来为 14 种越冬鸟类构建动态占有模型。在极寒天气下，越冬鸟类的种群动态更为活跃，局部灭绝和定居的速度更快，这可能使它们能够更好地跟踪资源。然而，城市地区似乎为一些物种提供了避难所，因为在最恶劣的冬季天气下，局部定居率有所增加。最后，我们发现热耐受能力的物种特异性差异强烈影响了占有动态，因此在较冷的地点和整个冬季较冷的时期，较不耐寒的物种更容易局部灭绝。总的来说，我们的研究结果表明，较不耐寒的物种和占据较少森林景观的种群最容易受到极端冬季天气的影响。
