合肥市小微湿地鸟类多样性的时空格局及其影响因素

The spatial-temporal patterns of bird diversity and its determinants in the small wetlands in Hefei City

小微湿地是城市生态系统的重要组成部分,也是生物多样性的重要庇护场所。鸟类作为城市小微湿地生态系统的指示类群,其多样性时空格局受多种环境因子影响。本研究于2020年8月至2021年7月采用样点法对合肥市45个小微湿地鸟类的种类、数量分布和生境因子进行了调查,并获取湿地面积、湿地形状、建筑面积比例、植被面积比例、环境噪声、人为干扰和城市化指数等生境变量。通过α多样性和β多样性分析,研究城市小微湿地鸟类多样性的时空特征及其决定因素。采用信息论模型选择和模型平均法以及基于距离矩阵的多重回归模型进行计算,确定影响鸟类群落α多样性和β多样性及其组分的主要环境因子。结果显示,研究区域共有鸟类13目39科102种,其中水鸟31种,国家二级重点保护鸟类2种,安徽省重点保护鸟类17种, IUCN濒危物种红色名录中的易危(VU)物种1种。湿地面积和城市化指数对小微湿地陆地鸟类和水鸟的α多样性、β多样性及其组分均具有显著影响,其中陆地鸟类物种丰富度在中度和低度城市化之间的小微湿地中达到最高值,面积超过4ha的小微湿地能维持较多的水鸟物种。植被面积比例对陆地鸟类多样性具有重要的影响,而建筑面积比例对水鸟多样性具有显著影响。此外,总体β多样性及其组分计算结果显示物种周转组分占明显优势,表明城市小微湿地群作为城市复合生态系统的重要组成部分,加强整体保护更为必要。研究结果对于加强城市鸟类保护和提高城市生态环境质量具有指导意义。

Aims: Small wetlands are an important part of urban ecosystems and important shelters for wildlife. Bird diversity as an indicator of urban small wetland ecosystems, its spatial and temporal patterns are affected by many environmental factors. In this study, we studied urban small wetlands and their birds to identify the key environmental factors that affect the spatial and temporal patterns of bird diversity in small wetlands. We then make suggestions on the construction and management of urban small wetlands to promote the protection of urban birds and their habitat restoration.Methods: A total of 45 small wetlands in Hefei City were taken as research units, and we used the fixed radius method to investigate the distribution of bird species and their abundance from August 2020 to July 2021. A number of environmental factors were also measured, including wetland area, wetland shape, proportion of construction area,proportion of vegetation area, environmental noise, man-made disturbance, and urbanization index. The spatial and temporal characteristics of bird diversity in urban small wetlands were studied by α and β diversity analyses. Then, the model selection and model averaging based on information theory were used to determine the main environmental factors affecting α diversity of bird communities, and the multiple regression model based on distance matrix were used to determine the main environmental factors affecting β diversity of bird communities and their components. Results: A total of 13 orders, 39 families, and 102 bird species were found in the surveyed wetlands, including 31 waterbird species. There were 2 species in the List of National Second-Class Key Protected Wild Animals, 17 species in the List of Key Protected Wild Animals of Anhui Province, and 1 Vulnerable(VU) species on the IUCN Red List of Species. The results indicated that the α diversity and β diversity of terrestrial birds and waterbirds in small wetlands were both significantly affected by wetland area and urbanization index. The proportion of vegetation area had a strong effect on terrestrial bird diversity, while the proportion of construction area had a significant effect on waterbird diversity. Meanwhile, the species richness of waterbirds and terrestrial birds were both positively correlated with wetland area. The species richness of waterbirds was negatively correlated with the urbanization index, while the species richness of terrestrial birds increased initially and then decreased as urbanization increased. The species richness of terrestrial birds peaked at the small wetlands between intermediate urbanization intensities and low urbanization intensities. When the area of the wetland was about 4 ha, the wetlands could maintain more waterbird species. In addition, terrestrial bird species richness was positively correlated with the proportion of vegetation area, while waterbird species richness was negatively correlated with the proportion of construction area. Beta diversity and species nestedness increased with the increase of key environmental factors, while species turnover exhibited an opposite trend. Furthermore, the results of total β diversity and its compositions indicated that the turnover component of species was predominant, signifying that small wetlands have important conservation significance as a meta-ecosystem. Conclusion: Our study indicates that wetland area, urbanization index, the proportion of construction area, and the proportion of vegetation area were the key environmental factors affecting bird diversity in small wetlands. On the premise of protecting all small wetlands, we suggest that small wetlands with large areas should be retained and constructed. We must pay more attention to protect small wetlands with intermediate and low urbanization intensities. In addition, the area of natural vegetation should be retained and increased during the management and construction of small wetlands, and the number of artificial structures should be reduced.