JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2024, Vol. 48 ›› Issue (2): 27-36.doi: 10.12302/j.issn.1000-2006.202204038

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Changing features and influencing factors of small and micro wetlands in Wuxi City

ZHANG Jiamin1(), LIU Xiaoyan1, DENG Yi2, FENG Yao2, ZHU Bin1, CHU Lei1, ZHANG Zengxin1,*()   

  1. 1. Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, College of Forestry and Grassland, College of Soil and Water Conservation, Nanjing Forestry University, Nanjing 210037, China
    2. Wuxi Natural Resources and Planning Bureau, Wuxi 214023,China
  • Received:2022-04-15 Revised:2022-06-13 Online:2024-03-30 Published:2024-04-08

Abstract:

【Objective】 Small and micro wetlands provide several important ecological functions, such as habitat support for key species, biological transfer, hydrological regulation and water purification, education and rest. Wuxi City in China contains numerous wetlands, of which most over 8 hm2 have been protected in recent years. However, not all small and micro wetlands have been protected in Wuxi City, and research regarding spatiotemporal changes in these habitats under various factors is lacking. Thus, analyzing the temporal and spatial characteristics and driving forces of small and micro wetlands can provide a theoretical basis for wetland ecological restoration and protection construction.【Method】 Based on Landsat satellite images in 2000, 2010 and 2020, patch information of small and micro wetlands in Wuxi City were extracted using support vector machine classification and other methods. Combined with meteorological and land use data, the spatiotemporal evolution of small and micro wetlands in Wuxi City and its influencing factors were analyzed.【Result】 (1) Within the past two decades, the total wetland area in Wuxi City has decreased from 178 000 hm2 in 2000 to 104 000 hm2 in 2020. Among them, the total area of small and micro wetlands has decreased from 19 000 hm2 in 2000 to 15 000 hm2 in 2020. (2) In terms of spatial distribution, small and micro wetlands in Wuxi were mainly distributed in the county-level city Yixing, which accounted for 40.0% of the area of Wuxi City. Small and micro wetlands in Wuxi City predominantly consisted of natural wetlands, accounting for up to 61.0% and displayed marked seasonal variation characteristics. In 2020, the proportion of seasonal small and micro wetlands in the total area of small and micro wetlands was as high as 73.8%. (3) The dynamic of small and micro wetlands in Wuxi City were positively correlated with temperature and precipitation due to natural factors and human activities. Specifically, human activities had a significant impact on the decline of small and micro wetland areas, and the transformation between wetland and other land types accelerated the decline of wetlands.【Conclusion】 Wuxi City is rich in small and micro wetland resources, which are in rapid decline due to seasonal and land use changes. Thus, the protection and restoration of small and micro wetlands must be enhanced to mitigate the negative impacts imposed by different factors.

Key words: small and micro wetland, land use, spatial and temporal distribution, Wuxi City

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