Ecosystem anthropization is a main driver of biodiversity loss, but not all species are equally susceptible. Understanding and preventing biodiversity loss is particularly important in rapidly changing and biodiversity-rich areas like the Neotropics and requires exploring the role of both intrinsic and extrinsic vulnerability drivers. Here, we test how multiple potential intrinsic and extrinsic factors explain vulnerability to extinction in neotropical birds to provide a first insight into what makes these species susceptible to extinction and how they are responding to anthropization. Our analyses included data for 2268 neotropical birds. We characterized extinction risk based on the IUCN Red List categorization and tested the predictive value of seven intrinsic and four extrinsic variables using Bayesian MCMC Phylogenetic Generalized Least-Squares (PGLS) models. As hypothesized, we found higher intrinsic vulnerability to extinction among bigger and more specialized species which have low reproductive output and occupy smaller distribution ranges. Extrinsic drivers were also relevant predictors with more threatened species overlapping largely areas with fewer human activities (lower night light levels and lower human population densities). Our results show that the extinction risk of neotropical birds is correlated with both intrinsic and extrinsic factors. Intrinsic vulnerabilities were as expected associated with narrower, specialized niches and slower life histories. However, risk was not higher in more humanized environments, but instead more at-risk species were found in less disturbed areas that we suggest may represent refuges for birds that previously occurred in wider ranges and have now been excluded from the more anthropized regions. Our results contribute to our understanding of vulnerability predictors in birds and provide a first evaluation of neotropical birds that highlights the complex relationship between human pressure and biodiversity loss.

中文翻译：

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受威胁的新热带鸟类体型巨大，生态专业化，发现于人性化程度较低的避难区

生态系统人为化是生物多样性丧失的主要驱动因素，但并非所有物种都同样容易受到影响。了解和防止生物多样性丧失在新热带等快速变化和生物多样性丰富的地区尤为重要，需要探索内在和外在脆弱性驱动因素的作用。在这里，我们测试了多种潜在的内在和外在因素如何解释新热带鸟类对灭绝的脆弱性，以初步了解是什么使这些物种容易灭绝以及它们如何应对人类化。我们的分析包括 2268 只新热带鸟类的数据。我们根据 IUCN 红色名录分类对灭绝风险进行了表征，并使用贝叶斯 MCMC 系统发育广义最小二乘 (PGLS) 模型测试了七个内在变量和四个外在变量的预测值。正如假设的那样，我们发现更大、更专业的物种具有更高的内在灭绝脆弱性，这些物种的繁殖产量低，分布范围更小。外在驱动因素也是相关预测因素，受威胁的物种与人类活动较少的地区（夜间光照水平较低和人口密度较低）主要重叠。我们的研究结果表明，新热带鸟类的灭绝风险与内在和外在因素相关。正如预期的那样，内在脆弱性与更窄、专门的利基和较慢的生活史有关。然而，在更人性化的环境中，风险并没有更高，而是在较少受干扰的地区发现了更多的高危物种，我们认为这可能代表了以前出现在更广泛范围内的鸟类的避难所，现在已被排除在更人类化的地区之外。我们的结果有助于我们了解鸟类的脆弱性预测因子，并提供对新热带鸟类的首次评估，突出了人类压力与生物多样性丧失之间的复杂关系。