Abstract:

Changes in lake area are key indicators of ecosystem function. Chaiwopu Lake is the largest freshwater lake in Urumqi City, and studying changes in its area has far-reaching significance in revealing the effectiveness of ecological restoration and in leading the rational allocation of water resources. In this study, the combined annual air temperature, annual average precipitation, potential evapotranspiration, NDVI, population, vegetation coverage using NDWI, Mann-Kendall test, structural equation model (SEM), and the area change characteristics and influencing factors of Chaiwopu Lake were analyzed. The results showed that: 1) in terms of interannual variation, the change in lake area can be divided into three periods: a stable period from 1987 to 2008, a shrinking period from 2008 to 2014, and a rising recovery period from 2014 to 2023. In terms of seasonal changes, the lake area is shrinking at a rate of 0.27, 0.34 and 0.29 km²·a⁻¹ in spring, summer and autumn from 1987 to 2023, respectively. However, the overall change in the lake area was less affected by seasonal changes. 2) In terms of spatial variation, the area for each orientation decreased slightly from 1987 to 2008. From 2008 to 2014, except for the southeast, the directions were severely shrunken; from 2014 to 2023, there was an increase in all directions. From 1987 to 2023, the lake area exhibited the most significant reduction on the western side and the least reduction on the eastern side of the lake. 3) Areas with medium and high vegetation coverage were significantly positively correlated with the change in lake area (p<0.05), and population was significantly negatively correlated with the change in lake area (p<0.05). 4) The increase in population and over-exploitation of groundwater are direct influencing factors of lake area shrinkage, whereas the measures of returning farmland to lakes, pressing grain and water conservation, and diverting floods to lakes are the main driving factors for lake area recovery.

Key words: Chaiwopu Lake, area change, Normalized Difference Water Index (NDWI), Structural Equation Model (SEM), population, vegetation coverage area

摘要：

湖泊面积变化是衡量生态系统功能的关键指标。柴窝堡湖作为乌鲁木齐市周边最大的淡水湖，研究其面积变化对揭示生态恢复成效、指导水资源合理配置等具有深远意义。结合年均气温、年降水量、潜在蒸散量、NDVI、人口数量、植被覆盖面积等要素，采用NDWI、Mann-Kendall检验、结构方程模型（SEM）等方法，对柴窝堡湖面积变化特征及影响因素进行分析。结果表明，1）在年际变化上，湖泊面积变化可分为3个时期，1987－2008年为稳定期，2008－2014年为萎缩期，2014－2023年为上升恢复期。在季节变化上，1987－2023年春夏秋季湖泊面积分别以0.27、0.34和0.29 km²·a⁻¹的速率在萎缩，但从整体看，湖泊面积的变化受季节更替的影响较小。2）在空间变化上，1987－2008年各方位面积萎缩的幅度较小;2008－2014年除东南面外，其余方位均严重萎缩;2014－2023年各方位都有所增长。1987－2023年湖泊面积在湖西面萎缩的最多，湖东面萎缩的最少。3）中高植被覆盖的面积与湖泊面积变化呈显著正相关（p<0.05），人口数量与湖泊面积变化呈显著负相关（p<0.05）。4）人口数量增长、地下水的过度开采是湖泊面积萎缩的直接影响因素，而退耕补湖、压粮保水、引洪补湖等措施是湖泊面积恢复的主要推动因素。

关键词: 柴窝堡湖, 面积变化, 归一化水体指数（NDWI）, 结构方程模型（SEM）, 人口, 植被覆盖面积