蒙古人民共和国主要生态系统类型及动态

THE MAIN TYPES AND TRENDS OF THE ECOSYSTEMS IN THE PEOPLE' S REPUBLIC OF MONGOLIA

对蒙古国自然条件的特点、生态系统的主要类型的现状及变化趋势进行了阐 述，并探讨了这些变化趋势对中国相近地区的借鉴意义。

Influenced by human activities, the order of destroyed degree of the desert ecosystem in Mongolia is steppe desert>typical desert>extremely arid desert. The destroying ways include grazing, firewood gathering, covering of roads, urban and industrial construction, opencast mining, land reclaiming, negative effects of irrigation, etc. The destroyed degree of the pasture ecosystem is closely related to the distance from the centres of economic pursuits. In planting industry, dry farmland can be easily eroded by wind, so the loss of humus is serious; some advantages may be brought about but some negative effects may occur also in irrigated farmland. Forest fires and deforestation are the main causes of the destruction of forest ecosystem, the degree, recovery speed and evolution orientation are different from various regions. Precipitation fluctuation results in an increase or decrease of humidity, a dry or humid period is roughly for 20 years in Mongolia. In this paper, some features of the natural conditions, the main types and trends of the ecosystems in Mongolia are discussed by extracting, translating, stueling and editing the relating literature. Among the many types of Republic of Mongalia, the desert ecosystem, pasture ecosystems in the people's ecosystem and agricultural ecosystem are mainly discussed in the paper.