半干旱区生态恢复关键生态系统识别——以内蒙古自治区和林县为例

我国土地退化严重,且大部分发生在干旱半干旱地区.恢复为何种生态系统类型是生态学研究的重要课题.采用生态功能区划,根据各个生态功能区主体生态系统功能,推导发挥此功能的生态系统类型的方法,识别关键生态系统类型.以内蒙古自治区和林县为例,采用文献调研、实地调查、3S技术等方法,在评价该县生态敏感性、生态服务功能重要性的基础上,将该县划分为3个一级生态区,11个二级生态功能区.根据各个生态功能区的主体生态系统服务功能,分析发挥该功能的可能生态系统类型.再根据全国自然植被区划、气候变化趋势模型以及现状植被类型,识别各个生态功能区的关键生态系统类型.

Identification of key ecosystem for ecological restoration in semi-arid areas: a case study in Helin County, Inner Mongolia

Abstract: Land degradation is widely distributed in China, mostly in arid and semi-arid areas. Identifying wWhich kind ecosystem types canshould be achieved through ecologically restoratione processes is the key to success in ecological restoration success. This theme is the research focus of ecology subject. Taking the Helin County of, Inner Mongolia, located in the semi-arid area ofin northern China, as an example, this article explores the method to identify key ecosystems through ecological functional zone planning, accompanied with an analysis of existing vegetation surveys, climate change and national vegetation regionalization. By integrating methods of document collecting, field surveys and 3S technology, based on analysis of eco-sensitivity and, eco-services, Helin County is classified into three eco-regions, and 11 sub eco-regions. The eco-regions are is decided by land topographic features, and the role which Helin County plays in the national ecological function regionalization of China. In the national ecological function regionalization of China, the ecosystem services in Helin County areis soilto conserveation soil (in most areas), supply of agricultural products supply, and conserve mountain water-source conservation (in small areas). The ecological score of how precipitation, slope degree, slope aspect, soil texture and vegetation index contributed to soil erosion sensitivity in the region is calculated, respectively and t. The sum of above-mentionedthese values with different weights is regarded as the value of soil erosion ecological sensitivity. The contribution of drought index, soil type,, drought index after 50 and 100 years, and vegetation cover to land desertification also are quantified and summed into values of land desertification ecological sensitivity. Then a vValue for protection importance of the ecosystem is calculated, and a value for water- supply also is calculated through hydrologic analysis. The sub eco-region is formed by the ecological sensitivity of soil erosion and, land desertification, the protected value of ecosystem, and the function of water supply. AThe areas with the same ecological value and same ecological problems areis put into the same sub eco-region. On the basis of the main ecosystem service function of every sub eco-region, the possible ecosystem type which produces such functions canhas been deduced. The vVegetation types of Helin County were classified according toin the Vegetation Zoning ofin China, a vegetation zoningdistribution map consideringed of climate, soil and water factors, and wereis used for the deduction of key vegetation ecosystems. Vegetation ecosystems existinged in the national vegetation zoning classification should be restored. The locations of ecological restoration should be limited into areas in which the vegetation ecosystem is different to thewith key ecosystem. TStill, the vegetation change under climate change is also simulated. An ecosystem that is different from the key ecosystem, if it is the same as the key ones after 50 or 100 yrs, such area should not be included in ecological restoration if it will be the same as a key ecosystem after 50 or 100 years. Compared with existinged vegetation identified byby field surveys, where ecosystems are obviously different from the key ecosystem, they should be restored. With these steps, the potential key vegetation ecosystems can be identified. Key words: Semi-arid area, Ecological function region, Eecological restoration, Key ecosystem, Helin County