Data from: Demography, traits, and vulnerability to urbanization: can we make generalizations?

1. Human-induced land cover change threatens species diversity and ecosystem services. The rapid pace of current change makes predicting species’ declines imperative, but leaves little time for thorough study of all species. One solution is to make generalizations about species’ vulnerability to urbanization based on traits common among studied species in decline. 2. To date, most generalizations about traits associated with species’ declines in response to urbanization are based on presence or abundance, or detailed studies of a few species. If these generalizations broadly reflect responses to urbanization, they should hold across the mechanisms driving patterns of abundance, such as survival or reproduction. 3. Across 68 bird species in the northeastern USA, we investigated how food preference, nest location, habitat preference, migration distance, number of broods, clutch size, body mass, and an interaction between urbanization and these traits affected survival and reproduction. 4. Mass was the strongest predictor of survival, followed by number of broods, migration distance, and nest location. Nest location was the strongest predictor of reproduction, followed by migration distance. No interaction between urbanization and species’ traits affected survival; however, differences in response to urbanization among species with different food preferences, migration distances, masses, nest locations, and number of broods were important in predicting reproduction. 5. Synthesis and applications. We found that some traits influenced demographic rates even though they were not associated with urbanization; identifying differences in species’ baseline demographic rates, irrespective of urbanization, is needed to guide management objectives. Reproduction, but not survival, was influenced by urbanization, suggesting that management in our region of study should target increasing suitable nest sites and reducing nest predation. Determining traits associated with demographic rates and urbanization across broad geographic extents can provide new insights for species’ management, and help guide conservation initiatives.

1. 人类活动诱导的土地覆盖变化（land cover change）正严重威胁物种多样性与生态系统服务（ecosystem services）。当前变化速率迅猛，令物种衰退预测工作刻不容缓，却几乎没有充足时间对所有物种开展系统研究。一种可行的解决路径是，依据已被研究的衰退物种共有的性状，归纳物种对城市化（urbanization）的脆弱性规律。2. 截至目前，多数关于物种响应城市化衰退相关性状的归纳结论，均基于物种的存在与否、种群丰度，或是对少数物种的详尽研究。若此类归纳能够广泛反映物种对城市化的响应，则其应适用于驱动种群丰度格局的各类机制，例如存活与繁殖过程。3. 我们以美国东北部的68种鸟类为研究对象，探究了食物偏好、巢位选择、栖息地偏好、迁徙距离、窝数（number of broods）、窝卵数（clutch size）、体重，以及城市化与上述性状的交互作用如何影响物种的存活与繁殖。4. 体重是影响物种存活的最强预测因子，其次依次为窝数、迁徙距离与巢位选择。巢位选择则是影响繁殖的最强预测因子，其次为迁徙距离。城市化与物种性状的交互作用并未对存活产生显著影响；然而，不同食物偏好、迁徙距离、体重、巢位选择及窝数的物种，其对城市化的响应差异，对繁殖的预测具有重要意义。5. 总结与应用。本研究发现，部分性状会影响种群动态速率（demographic rates），即便其与城市化并无关联；无论城市化与否，明确物种基线种群动态速率的差异，可为管理目标制定提供指导。城市化仅对繁殖而非存活产生影响，这表明本研究区域的管理工作应聚焦于增加适宜巢位与降低巢捕食（nest predation）压力。在更广的地理范围内明确与种群动态速率及城市化相关的物种性状，可为物种管理提供新视角，并助力推动保护举措（conservation initiatives）落地。