Collaborative Research: Forest fragmentation and climate change result in understory warming that adversely affects tropical avian biodiversity at the BDFFP.

热带鸟类正处于困境之中，尤其是那些主要以昆虫为食的鸟类。大片和小片森林的人口都在下降，尽管小森林或“碎片”的下降速度更快。沿着碎片边缘暴露在阳光下会导致它们的内部变得更热更干燥，这降低了许多鸟类的栖息地质量。科学家们不知道更温暖和更干燥的条件到底是如何给鸟类带来麻烦的，但他们认为这是由于食物减少和压力增加所致。在这项研究中，研究人员将研究更长和更热的旱季是否导致连续森林中鸟类的减少，以及哪些物种最容易受到气候变化的影响。为此，他们将收集生理数据，并将其与过去40年的气候数据结合起来，以了解气候和森林条件对鸟类饮食、健康和生存的相对作用。结果将提高我们对森林丧失和气候变化如何影响鸟类的理解，以及我们可能减轻生物多样性丧失的方式。PI假设，森林碎片中的残留鸟群落是未来连续森林中鸟类聚集的先兆。在全球变化下，增加的生理应激和/或饮食专业化可能是鸟类存活和繁殖成功的决定因素。该项目有三个目标：(1)通过将40年来的气候和鸟类环带数据纳入一系列生存模型，评估气候变化作为连续森林中鸟类长期减少的主要驱动因素的影响。(2)通过人口统计模拟，确定气候变化和片断化对BDFFP鸟类种群生存能力的交互影响。(3)测量模式鸟类的饮食和行为专门化(两种正在经历衰退的白头鸟和威利斯鸟，以及两种正在经历种群增长的Calyptorhynchus spirurus和Pithys albirons)如何与林下小气候的变化相互作用来影响适合度。研究人员将使用EDNA和同位素生态位分析(从粪便样本、羽毛和脚趾指甲)相结合来测量饮食，并使用B-OH丁酸盐、甘油三酯和皮质酮的组合来测量压力，跨越季节，在连续和零散的森林之间。结果将产生对生态位专业化和林下干燥在推动热带鸟类对森林碎片化和气候变化的人口统计反应方面所起的作用的机械性见解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Tropical birds are in trouble, especially those that eat mostly insects. Population declines are taking place in both large and small areas of forest, although at a faster rate in small forests or “fragments”. Exposure to sun along the edges of fragments causes their interior to become hotter and drier, which reduces habitat quality for many birds. Scientists do not know exactly how warmer and drier conditions cause trouble for birds, but they think it is due to less food and more stress. In this study, researchers will study whether longer and hotter dry seasons are responsible for the decline of birds in continuous forests and which species are most susceptible to changes in climate. To do this, they will collect physiological data and combine it with climate data from the past forty years to understand the relative role of climate and forest condition on birds’ diet, health and survival. Results will improve our understanding of how forest loss and climate change affect birds, and ways in which we might mitigate the loss of biodiversity. The PIs posit that remnant bird communities in forest fragments are a precursor of future bird assemblages in continuous forest. Increased physiological stress and/or dietary specialization are likely determinants of avian survival and reproductive success under global change. This project has three objectives: (1) Assess the impact of climate change as the primary driver of long-term bird declines in continuous forest at the Biological Dynamics of Forest Fragmentation Project (BDFFP) through the inclusion of 40 years of climate and bird banding data in a series of survival models. (2) Determine the interactive effects of climate change and fragmentation on the viability of bird populations at BDFFP through demographic modeling. (3) Measure how dietary and behavioral specialization of model bird species (two experiencing declines: Turdus albicollis and Willisornis poecilinotus, and two experiencing population growth: Calyptorhynchus spirurus and Pithys albifrons) interact with variation in understory microclimates to affect fitness. Researchers will measure diet using a combination of eDNA and isotopic niche analysis (from fecal samples, feathers, and toe nails) and stress using a combination of B-OH butyrate, triglyceride, and corticosterone, across seasons and between continuous and fragmented forests. Results will yield mechanistic insights into the role that niche specialization and understory drying play in driving demographic responses of tropical birds to forest fragmentation and climate change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.