高海拔水电开发对生态环境质量的影响及其驱动因子研究

Study on effect of high-altitude hydropower development on ecological environment quality and its driving forces

摘要

【目的】准确评估水电开发对高海拔生态敏感区的生态环境影响，对于维护该地区的生态安全屏障具有重要意义。基于此，提出一种改进型遥感生态指数(IRSEI)模型研究青藏高原某水电建设对区域生态环境质量的影响。【方法】以青藏高原某水电站为研究对象，鉴于高海拔地区土壤脆弱、地形复杂的生态环境特性，构建归一化差值山地植被指数(NDMVI),同时引入土壤侵蚀模数作为土壤侵蚀指标，提出一种针对高海拔水电开发区的改进型遥感生态指数(IRSEI),采用Theil-Sen斜率估计、Mann-Kendall趋势分析、Hurst指数等方法，评估IRSEI的时空动态及其驱动因素。【结果】IRSEI使用NDMVI替代NDVI并引入土壤侵蚀指标，更适用于地形复杂地区的生态质量监测：水电开发对流域内景观结构造成严重影响，特别是草地和林地，导致其面积降低；IRSEI均值由水电站建设前的0.53下降为建设后的0.42,建设第二年生态质量退化最显著，在运行期回升至0.57;流域林地和草地IRSEI等级主要为优和良，建设用地和耕地等区域主要为差和较差；未来IRSEI发展趋势趋于稳定，维持不变的区域面积占比60%以上；年均降水量、年均温度、NDVI和土地利用类型变化是研究区IRSEI空间分异的主控因子。【结论】工程建设期，水电开发对研究区景观格局和IRSEI造成严重影响。水电站运行期间，研究区生态环境整体呈现良性变化，生态恶化区域主要集中在城镇区域。未来应加强该流域的生态系统治理力度，并综合人类活动和气候变化开展生态保护与修复工作。研究成果可为因地施策落实流域生态保护与高质量发展提供理论依据和数据支持。

Abstract

[Objective] Accurately assessing the ecological and environmental effects of hydropower development in high-altitude, ecologically sensitive regions is essential for maintaining the ecological security barriers of these areas. Therefore, an improved Remote Sensing Ecological Index(IRSEI) model is proposed to study the effect of hydropower construction on regional ecological environment quality in a specific area of the Qinghai-Xizang Plateau. [Methods] Taking a hydropower station in the Qinghai-Xizang Plateau as the study object, and considering the fragile soil and complex topography of high-altitude regions, a normalized difference mountain vegetation index(NDMVI) was established. At the same time, soil erosion modulus was introduced as a soil erosion indicator. An improved remote sensing ecological index(IRSEI) for high-altitude hydropower development areas was proposed. The spatiotemporal dynamics of the IRSEI and its driving factors were analyzed using method such as Theil-Sen slope estimation, Mann-Kendall trend analysis, and Hurst exponent. [Results] By replacing NDVI with NDMVI and incorporating the soil erosion indicator, IRSEI was more suitable for ecological quality monitoring in areas with complex topography. The results showed that hydropower development significantly affected the landscape structure of the basin, particularly grasslands and forests, leading to a reduction in their area. The average IRSEI value decreased from 0.53 before hydropower construction to 0.42 after construction, with the most significant ecological degradation occurring in the second year of construction. During the operational period, the value increased to 0.57. The IRSEI grades of forests and grasslands in the basin were mainly excellent and good, while construction and cultivated land areas were mainly poor and very poor. The future development trend of IRSEI was expected to stabilize, with more than 60% of the basin area remaining unchanged. The main controlling factors for the spatial differentiation of IRSEI in the study area were annual precipitation, average annual temperature, NDVI, and land use changes. [Conclusion] During the construction phase, hydropower development significantly affects the landscape pattern and IRSEI of the study area. During the operation of the hydropower station, the ecological environment of the study area shows an overall positive change, with ecological deterioration mainly concentrated in urban areas. In the future, it is essential to enhance ecological restoration in this basin, taking into account human activities and climate change, and ecological protection and restoration efforts should be carried out. The research findings provide theoretical and data support for implementing targeted ecological protection and promoting high-quality development in the basin.

关键词

水电开发 / 青藏高原 / 谷歌地球引擎(GEE) / 改进遥感生态指数 / 地理探测器 / Hurst指数 / 影响因素

Key words

hydroelectric development / Qinghai-Xizang Plateau / Google Earth Engine(GEE) / improved remote sensing ecological index / geodetector / Hurst exponent / influencing factors

基金资助

青藏高原华能集团在建工程项目(JC2022/ D01)

西藏基地与人才项目(XZ202401JD0003)

国家自然科学基金(32271856)