1988~2008年青海湖生态服务功能对于土地利用变化的响应

Responses of Ecosystem Service to Land Use Change in the Qinghai Lake Region from 1998 to 2008

作为青藏高原东北部的重要生态屏障,青海湖地区是一个生态环境极为脆弱的区域,也是全球气候变化与人类活动的敏感区域。评估青海湖地区土地利用变化对于生态服务功能的影响,对于了解人类活动对于当地生态系统的扰动有重要意义。本文以青海湖环湖区为研究区,利用该区1988年、2000年和2008年土地利用数据,运用中国生态系统服务价值当量因子表和该区单位面积农田生态系统在1988年、2000年和2008年3期提供的食物生产服务的平均经济价值,对该区生态系统服务价值进行了评价。结果表明:1) 1988~2008年间,青海湖环湖区用地结构的变化为:林地和草地面积不断下降,建设用地和耕地逐渐增加,未利用土地基本保持不变;1988~2000年间,经济发展和农业开垦是该区用地结构变化的主要驱动因素,建设用地和耕地的动态度分别达0.55%和0.46%,面积较1988年增加了522.67 hm2和7936.65 hm2;同期草地和林地面积分别减少了11,702.74 hm2和1203.77 hm2,动态度均为?0.02%;自2000年以来,该区在一系列生态治理工程的作用下,建设用地和耕地的扩张减缓,动态度较前期分别下降了0.44和0.17个百分点,林地和草地的减少速度下降,动态度较前期均提高了0.01个百分点,面积分别减少了3380.54 hm2和500.04 hm2。2) 青海湖环湖区生态服务价值总体呈上升趋势,与1988年相比,2000年和2008年分别增加了84.13万元和128.44万元,其中草地和水域在生态系统服务总价值的比例最大,累计约占81%以上;不同的用地类型中,草地和林地的服务价值分别下降了2855.65万元和777.27万元,耕地、建设用地和未利用土地的服务价值分别提高了2341.38万元、1469.30万元和34.81万元。

As one of significant ecological barriers in the northeastern Qinghai-Tibet Plateau, Qinghai Lake Region is an ecologically fragile area which is sensitive to global climate change and human activi-ties. Assessing the effect of land use change on ecosystem service is of great importance for under-standing the disturbance of human activities on local ecosystems. Based on land use data in 1988, 2000 and 2008, the table of equivalent value per unit area of ecosystem services in China, and the economic value of food production per hectare in study areas, the ecosystem services value (ESV) in the Qinghai Lake Region was estimated. It was found that: 1) the area of forestland and grassland continuously decreased while the area of construction land and cultivated land continuously increased. The area of unused land was almost unchanged. From 1988 to 2000, economy devel-opment and agriculture reclamation were the two main factors driving land use changes. The dy-namic indexes of construction land and cultivated land were 0.55% and 0.46%, with an increase in areas of 522.67 hm2 and 7936.65 hm2, respectively. However, the area of forestland and grassland decreased 11,702.74 hm2 and 1203.77 hm2 respectively with the same dynamic index of ?0.02%. Since 2000, a series of environmental restoration projects were launched to improve ecosystem and environment. Due to these projects, the increase in area of construction land and cultivated land slowed down, with dynamic index dropping by 0.44 and 0.17 percentage points, respectively. The degradation speed of forestland and grassland was also slower than before, with dynamic index both increased by 0.01 percentage points. 2) The total ESV exhibited an increasing trend in the Qinghai Lake Region, with an increase of 84.13 ×104 CNY and 128.44 ×104 CNY, respectively, compared with that in 1988. Grassland and water areas accounted for over 81% of total ESV in the Qinghai Lake Region. The ESV of construction land, cultivated land and unused land increased by 2341.38 ×104 CNY, 1469.3 ×104 CNY and 34.81 ×104 CNY respectively, while that of forestland and grassland decreased by 2855.65 ×104 CNY and 777.27 ×104 CNY, respectively.