城市化对哺乳动物丰富度影响的研究——以长三角城市群为例

以不透水面占比作为城市化强度(UI)的定量指标, 采用全球哺乳动物丰富度网格数据集, 结合气候因素和生境特点, 研究我国长三角城市群哺乳动物丰富度沿城乡梯度的空间分布格局。通过对比长三角城市群及其所处自然地理区(华东)哺乳动物丰富度的分布格局和驱动因素, 分析城市化和背景气候的贡献。结果表明: 1) 哺乳动物丰富度沿城乡梯度均呈水平“S”型分布; 2) 在背景自然地理区域, 气候因素(如年平均降水和最冷月最低温等)对丰富度分布起主导作用(R²=88.2%); 3) UI在华东地区与丰富度负相关, 在长三角城市群则弱正相关(P<0.001), 林地对丰富度存在正面影响, 耕地存在负面影响。因此, 城市化对哺乳动物丰富度影响在城市群尺度更为明显, 应更多关注如何区分城市化和背景气候对生物多样性的影响。

Urbanization Effects on Mammal Richness: A Case Study of Yangtze River Delta Urban Agglomeration

Taking the fraction of impervious surface area as a quantitative indicator of urbanization intensity (UI), using the global mammal richness girds data set and combined with climatic variables and habitat characteristics, this paper studied the spatial distribution pattern of mammal richness along the urban-rural gradient in Yangtze River Delta urban agglomeration. The contribution of urbanization and background climate were analyzed by comparing the richness distribution pattern and driving forces of Yangtze River Delta urban agglomeration and the geographic region (East China) where it located. The results were as follows. 1) There was a horizontal “S” distribution pattern of mammal richness along the urban-rural gradient at both spatial scales. 2) In background geographic region, climatic variables (e.g, annual precipitation and min temperature of coldest month) played a dominant role in richness distribution (R²= 88.2%). 3) There was a negative correlation between UI and richness in East China while a weakly positive correlation in Yangtze River Delta (P<0.001); woodland had positive impacts on richness, while arable land had negtive impacts. The urbanization effects on mammal richness were more pronounced in Yangtze River Delta. Future research should pay more attention to how to disentangle the impacts of urbanization from background climate on biodiversity.