State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049，China.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049，China; Beijing Urban Ecosystem Research Station, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
Sci Total Environ. 2020 Sep 15;735:139308. doi: 10.1016/j.scitotenv.2020.139308. Epub 2020 May 12.
Urban rivers and lakes, in combination with nearby green spaces, provide important habitat for urban birds, but few urban studies have focused on forest and water birds simultaneously along an urban intensity gradient. In this study, we randomly chose 39 rivers and lakes along an urban gradient of Beijing to examine bird community parameters in relation to aquatic and terrestrial habitat conditions, aquatic life data, and water quality data. We selected models with the AICc (corrected Akaike information criterion) method, bivariate linear or generalized linear regressions, and structural equation modeling to determine distribution patterns of avian communities along an urban gradient and bird-environment relationships. We found that both forest and water bird species and individuals peaked at intermediate urbanization intensities, especially for abundance of both forest and water bird and water bird species richness and abundance. We suggest that the differences in the strength of response to urbanization and the similarities in the gradient distribution pattern between forest and water birds should receive more attention in future urbanization gradient studies. Significant correlation ship between species richness of resident water birds, fish foragers, and insectivore-frugivores, abundance of insectivores, insectivore-frugivores (negative), and granivores (positive) and impervious surface proportion within 1-km radius buffer of sampled sites became more evident after coverage of artificial surfaces exceeded a 50% threshold. Regressions showed that distance from the urban center, number of islands in waterbody, and proportion of gross or unarmored shoreline length were significantly and positively related to species richness and abundance of both forest and water birds. The availability of unarmored shoreline is a critical pathway through which urbanization detrimentally impacts avian diversity. Our results demonstrate how the urban intensity gradient affects the relative availability of food resources and habitat, which could provide practical applications for urban landscape planning and avian biodiversity conservation in urban areas.
城市河流和湖泊与附近的绿地相结合，为城市鸟类提供了重要的栖息地，但很少有城市研究同时关注森林鸟类和水鸟沿城市强度梯度的分布。本研究随机选择了北京沿城市梯度的 39 条河流和湖泊，以检验鸟类群落参数与水生和陆地生境条件、水生生物数据和水质数据之间的关系。我们选择了具有 AICc（校正的 Akaike 信息准则）方法、双变量线性或广义线性回归以及结构方程模型的模型，以确定鸟类群落沿城市梯度的分布模式和鸟类与环境的关系。我们发现，森林鸟类和水鸟的种类和个体数量都在中等城市化强度下达到峰值，特别是森林鸟类和水鸟的数量、水鸟的物种丰富度和数量。我们建议，在未来的城市化梯度研究中，应该更加关注森林鸟类和水鸟对城市化的反应强度差异以及它们在梯度分布模式上的相似性。在采样点 1 公里半径缓冲区范围内，常住水鸟、鱼类捕食者、食虫-食果者的物种丰富度，食虫者、食虫-食果者（负相关）和食谷者（正相关）的数量与不透水面比例之间存在显著的相关性，当人工表面覆盖度超过 50%的阈值时，这种相关性变得更加明显。回归分析表明，与城市中心的距离、水体中的岛屿数量以及未设防岸线的比例与森林鸟类和水鸟的物种丰富度和数量呈显著正相关。未设防岸线的可用性是城市化对鸟类多样性产生不利影响的关键途径。我们的研究结果表明了城市强度梯度如何影响食物资源和栖息地的相对可利用性，这可为城市景观规划和城市地区的鸟类生物多样性保护提供实际应用。
