Taxonomic and functional homogenization of farmland birds along an urbanization gradient in a tropical megacity

Urbanization is a major driver of land use change and biodiversity decline. While most of the ongoing and future urbanization hot spots are located in the Global South, the impact of urban expansion on agricultural biodiversity and associated functions and services in these regions has widely been neglected. Additionally, most studies assess biodiversity responses at local scale (α-diversity), however, ecosystem functioning is strongly determined by compositional and functional turnover of communities (β-diversity) at regional scales. We investigated taxonomic and functional β-diversity of farmland birds across three seasons on 36 vegetable farms spread along a continuous urbanization gradient in Bangalore, a South Indian megacity. Increasing amount of grey area in the farm surroundings was the dominant driver affecting β-diversity and resulting in taxonomic and functional homogenization of farmland bird communities. Functional diversity losses were higher than expected from species dec...城市化是土地利用变化与生物多样性下降的主要驱动因素。尽管当前及未来的城市化热点区域多集中于全球南方（Global South），但学界对该区域城市扩张对农业生物多样性及其相关功能与服务的影响，长期以来却遭到广泛忽视。此外，多数研究仅在局域尺度的α多样性（α-diversity）层面评估生物多样性响应，然而生态系统功能在很大程度上由区域尺度下群落的组成与功能周转所决定，即β多样性（β-diversity）。本研究针对印度南部大都市班加罗尔（Bangalore）境内、沿连续城市化梯度分布的36座蔬菜农场，于三个季节中调查了农田鸟类的分类与功能β多样性。农场周边灰色区域占比的提升，是影响β多样性的主导驱动因子，并最终导致农田鸟类群落的分类与功能均质化。功能多样性的损失程度高于物种衰减所预期的水平……