The Neotropical region has been subjected to massive urbanization, which poses high risks for some global biodiversity hotspots and losses of ecosystem functions and services. In this study, we investigate how distance from large patches of native forests (source areas) and vegetation (green)/and infrastructure (gray) characteristics affect bird species richness and functional diversity in São Paulo megacity, southeastern Brazil. We analyzed the effects of source areas and green/gray characteristics on species richness and functional diversity (richness, evenness, and divergence) indices. We detected 231 bird species, and our data confirmed our predictions: (1) bird species richness in urbanized habitats was found to be (~ 50–85%) lower than in source habitats; (2) species richness and trait composition significantly decreased as the distance from the source area increased, while functional richness was not affected by this metric; and (3) shrub and herbaceous covers and maximum height of trees were positively correlated with species richness and unique functional traits regarding habitat, diet, foraging and nesting strata and dispersal ability of birds in the forest-urban matrix. The number of buildings was negatively correlated with bird species richness and functional richness. Maximum height of buildings caused dramatic declines in functional evenness. Functional divergence was notably lower in sites with high shrub cover. Our study stresses the complexity of vegetation embedded in large Neotropical urban settlements and the need to maintain large protected areas surrounding megacities to mitigate the impacts of urbanization on birds.

新热带地区经历了大规模的城市化进程，对一些全球生物多样性热点地区和生态系统功能和服务的丧失构成了高风险。在这项研究中，我们调查了与大片原生森林（源区）和植被（绿色）/和基础设施（灰色）特征的距离如何影响巴西东南部圣保罗特大城市的鸟类物种丰富度和功能多样性。我们分析了源区和绿色/灰色特征对物种丰富度和功能多样性（丰富度、均匀度和发散度）指数的影响。我们检测到 231 种鸟类，我们的数据证实了我们的预测：(1) 城市化栖息地的鸟类物种丰富度低于源栖息地（约 50-85%）；(2) 物种丰富度和性状组成随着距源区距离的增加而显着降低，而功能丰富度不受该指标影响；(3) 灌木和草本覆盖率和最大乔木高度与森林-城市矩阵中鸟类的栖息地、饮食、觅食和筑巢地层的物种丰富度和独特的功能性状以及鸟类的传播能力呈正相关。建筑物数量与鸟类物种丰富度和功能丰富度呈负相关。建筑物的最大高度导致功能均匀度急剧下降。在灌木覆盖率高的地点，功能差异显着降低。