乌鲁木齐河流域中下游生态系统服务价值动态变化

利用随机森林分类法解译乌鲁木齐河流域中下游地区1995-2015年5期遥感影像，分析其土地利用变化特征，并利用当量因子法定量评估该区生态系统服务价值。结果表明:1）1995-2015年，研究区土地利用以耕地、建设用地和未利用地为主，三者占总面积85%以上。综合土地利用动态度先降后升；城市化建设中大量耕地被占用，天然林草地逐步恢复，水域增加（增幅达4.2%），用地结构变化显著。2）研究区生态系统服务价值呈上升趋势（净增加7.08×10⁸元），耕地、林地和水域是主要构成部分；从贡献率来看，林地、草地和水域的生态服务价值贡献率不断提升，占总贡献率的75%以上，成为主要贡献体，推动着研究区生态系统向良性转变。3）各单项生态功能中水源涵养、废物处理和生物多样性保护功能的价值占总生态服务价值比重最大（54.87%），粮食生产等较小，研究区生态系统的服务性功能大于生产性功能。进一步贯彻国家退耕还林还草政策以及加强水域保护是保障流域未来可持续发展和生态安全文明建设的有效举措。

Dynamic Changes of aEcosystem Service Values of in the Middle and Lower Reaches of the Urumqi River

The Urumqi River Basin is a typical oasis ecosystem in the arid northwestern region in China.It is the basis for regional social,economic and environmental sustainable developments.Ecological protection is of great significance.The random forest classification was used to interpret the five-period remote sensing images of the middle and lower reaches of the Urumqi River from 1995 to 2015.The land use data were obtained,and the land use change characteristics were analyzed.The equivalent factor method was used to quantitatively evaluate the ecosystem service value of the area.The results showed that 1) from 1995 to 2015,the land use patterns in the middle and lower reaches of the Urumqi River were dominated by cultivated land,construction land and unused land,which accounted for more than 85% of the total area.The comprehensive land use dynamics first dropped and then rose; a large amount of cultivated land was converted to construction land during urbanization process,and the forests and grasslands gradually recovered,the waters increased (with an increase amplitude of up 4.2%),and the land use structure changed significantly.2) The value of ecosystem services in the study area presented a rising trend (with a net increase of 7.08×10⁸ yuan),and three sectors,including cultivated land,forest land and waters were the main components of the increase; the contribution rates of ecological service value of three sectors increased continuously,which accounted for more than 75% of the total,and became the major contributors to drive the benign transformation of the ecosystem of the study area.3) The value of water conservation,waste treatment and biodiversity conservation functions in each individual ecological function accounted for the largest proportion of total ecological service values (54.87%),and the function of grain production was small.The service function of the ecosystem in the study area was greater than that of production.Further implementation of the national policy of returning reclaimed farmland to forests and grasslands and strengthening waters protection are effective measures to ensure the future sustainable development of the river basin and the construction of ecological security and civilization.