岷江上游土地利用变化下的生态系统敏感性研究

为研究岷江上游土地利用变化对生态系统敏感性的影响,首先利用土地利用动态度分析了青藏高原东缘岷江上游近11 a来的土地利用变化趋势;其次基于生态系统服务价值当量测算了研究区的生态系统服务价值,并借助生态系统传统敏感性系数对测算结果进行检验;最后利用交叉敏感性系数定量评估了土地利用变化对生态系统服务价值的影响程度及方向。结果表明:(1)2000~2005年研究区的土地利用变化主要是耕地转为森林、灌丛和草地,生态系统服务价值增加约0.46亿元;2005~2010年的土地利用变化主要是森林、耕地转为灌从、草地和荒漠,生态系统服务价值减少约0.57亿元。(2)研究期内森林的生态系统服务价值最高,其次是灌丛和草地;各生态系统服务功能类型中气候调节和水文调节的生态系统服务价值最高,食物生产和维持养分循环的生态系统服务价值最低。(3)研究期内岷江上游生态系统传统敏感性系数均小于1,大小依次为:C_(森林)C_(灌丛)C_(草地)C_(水域)C_(耕地)C_(荒漠)C_(裸地)。(4)导致岷江上游生态系统交叉敏感性最高的土地利用变化是森林和水域、草地和水域的相互转换,交叉敏感性系数均大于1,大部分土地利用转换的生态意义并不明显,但水域和其他地类相互转换的生态意义略有上升。研究结论有望为岷江上游土地利用宏观调控及生态系统综合管理提供一定科学依据。

Land-use change related ecosystem sensitivity study in upper reaches of Minjiang River

To research the land use change-related ecosystem sensitivity in the upper reaches of the Minjiang River on the eastern edge of Qinghai-Tibet plateau, firstly ,this paper analyzes the land use variation tendency in recent 11 years using land use data; secondly, the ecosystem service value (ESV) is calculated based on ecosystem service value equivalent and the calculation results are checked with traditional ecosystem sensitivity coefficient; in the last, the influence degree and variation tendency of land use change on ecosystem sensitivity are quantitatively evaluated using cross-sensitivity coefficient. The results were as follows: (1) From 2000 to 2005, the land use in the study area mainly changed from arable land to forest, shrub and grassland, with an increasing ESV of 0.046 billion yuan; from 2005 to 2010, the land use in study area mainly changed from arable land and forest to shrub land, grassland and desert, with a decreasing ESV of 0.057 billion yuan. (2) During the study period, the ESV of forest in the upper reaches of the Minjing River was the highest, followed by shrub land and grassland; among the ecosystem services, climate regulation and hydrological regulation presented the highest in ESV and the lowest for grain production and nutrient-cycle maintenance. (3) The traditional sensitivity coefficients of various land use types were all less than 1, and in the order as forest > shrub land > grassland > water > arable land > desert > bare land. (4) From the perspective of cross-sensitivity coefficient, the most sensitive land use change was the mutual conversion between forest and water as well as grassland and water, all cross-sensitivity coefficients were larger than 1 and the ecological significance of most land use conversion was not obvious, however, the ecological significance of the mutual conversion between water and other land types rose slightly. The study conclusions are expected to provide a scientific basis for land use and ecosystem management in the upper reaches of the Minjiang River.