关键词: 呼伦贝尔草原, 沙漠化土地, 过度放牧, 天然樟子松林, 综合整治区划

Abstract: The sandy desertified lands in Hulunbuir Steppe are now developing from grade Ⅱ to grade Ⅲ,which are mainly caused by overgrazing,and have so large developing potential and danger that there is a necessity to rehabilitate the sandy desertified lands with comprehensive measures.Here,overgrazing not only desertifies vast stretches of sandy grassland seriously but also hinders the natural renewal and expansion of Pinus sylvestris var.mongolica strongly.Accordingly,it is necessary for grazing to be made a scientific plan and strict regulation.In the light of such principles as:① combining the zonality with azonality,② genesis,③ dominance,④ integrating the scheme into existing relative regionalization schemes,author divides the whole region into 2 subregions and 5 provinces of comprehensive rehabilitation,i.e.Ⅰ the comprehensive rehabilitation subregion with natural Pinus sylvestris var.mongolicaⅠ₁ northern sanddune zone provinceⅠ₂ eastern sanddune area provinceⅠ₃ eastern section province of southern sanddune zone Ⅱ the comprehensive rehabilitation subregion without natural Pinus sylvestris var.mongolica Ⅱ₁ western sanddune zone province Ⅱ₂ the province of middle and western section of southern sanddune zone.Therefore,it is requisite to strengthen effective manipulation on natural renewal of Pinus sylvestris var.mongolica,to harness shifting sand at important sites,to promote grassland construction and corresponding regulation,to graze on divided areas rotationally and to strictly limit the cultivation for agriculture in province Ⅰ₁;there is a necessity to strengthen scientific regulation on grazing,improve sandy desertified lands,manipulate the renewal and upbringing of those forest patches and fence them if necessary in province Ⅰ₂;as for province Ⅰ₃,the main tasks are to properly regulate the grazing on the meadow between the forests and increase artificial managing standard on the forest zone.The principal aims for province Ⅱ₁ are to fence and rehabilitate serious sandy desertified lands intentionally,to build shelterbelts,to regulate grazing and construct intensive well managed grasslands;similarly,the main measures of comprehensive rehabilitation in province Ⅱ₂ are fencing and transforming shifting sand dune,strengthening grassland construction and grazing regulation,rationaly exploiting the sandy grasslands in warm season and forbidding raising domestic animals in cities and towns.

Key words: Hulunbuir Steppe, sandy desertified lands, overgrazing, natural Pinus sylvestris var.mongolica forest, comprehensive rehabilitational regionalization