甘南草地类型的生态经济价值与功能及其分类经营

根据山区景观所具有的3层次功能和指标体系选取的原则,从美学、社会、生态3个方面,初步构建了4个层次的评价指标体系。在此基础上建立综合评判模型,应用于北京市怀柔区9个乡镇,得到如下结果:景观功能评价综合指数处在"较好"标准的有宝山镇和怀北镇;在"一般"标准的有喇叭沟门乡、雁栖镇、九渡河镇、长哨营乡;处在"较差"标准的有渤海镇、玻璃庙镇、汤河口镇。评价结果基本与实际相符,说明建立的评价指标体系与模型是可行的。

Ecological Economic Value and Functions and Classification Management for Grassland in Gannan Prefecture,Gansu Province

Gannan prefecture, located on the edge of northeast Qinghai-Tibetan Plateau with cold climate, is of the upper reaches of Yellow and Yangtze River.Management of grassland plays an important role in husbandry, water conservation, biodiversity and ecological safety of the headwater regions. Due to the mismanagement in the past decades, grassland has seriously degraded and has further led to many eco-environmental issues. Grassland is multi-functional and every grassland type usually has many functions. Some functions contribute to ecological benefits, and others to economic benefits. For each kind of grassland, the importance of each function is different. For example, the main functions of alpine deserts and alpine meadow are ecological, including nature reserves, a genetic pool, and soil conservation, but the economic are insignificant. On the basis of grassland functions, ecological services and productive value of each grassland type are different in Gannan prefecture.To aid management of grassland, Gannan grassland is classified into three management sectors. One is ecological, mainly devoting to ecological and social values; the second is economic, focusing on economic benefits; the third is mixed with ecological and economic effects. Ecological grassland makes up 468.5 thousand ha,or 18% of Gannan regions. Economic grassland is 676.6 thousand ha, taking up 25%. Mixed grassland with 57% 1 483.4 thousand ha. Management strategies are proposed for three kinds of grassland respectively. Absence of grazing and cropping is predominant in the management of ecological grassland, to restore degenerated areas and protect grassland with high ecological value, and further to improve the environment. Agricultural measures, like fertilizer and irrigation are used to enhance the productivity of intensively economic grassland. Rotational grazing is used on mixed grassland.