摘要:
为了解半干旱农牧交错区土地利用格局的时空变化,该文以半干旱农牧交错区的内蒙古伊金霍洛旗为例,采用景观生态学的研究方法,从土地利用的角度分析了该旗近20年来景观和景观要素变化的特征和规律.结果表明,整个景观正从单一的人为景观向多样化的近自然景观过渡,其中前期（1977—1987年）变化主要发生在梁滩相间区,后期（1987—1998年）变化则发生在整个区域内,整个景观趋于稳定.从土地利用结构上来看,前期乔木林地的变化以面积变化为主,而后期则以空间分布格局的变化为主.前期灌木的过度利用和后期灌木大面积种植则对整个景观的变化产生了十分显著的影响,这表明治沙造林的观念正在由以往的大面积营造乔木林向灌木林转化.营造灌木林将是整个半干旱农牧交错区受损景观恢复和重建的最为有效的方法和手段.与此同时,近20年来流动沙地的面积呈现显著降低的趋势.从空间分布上看,未治理的流动沙地变得越来越集中,治理难度可能也越来越大.维持这些流动沙地的存在,可能有助于增加景观稳定性,并实现半干旱区有限资源利用的优化.
Abstract:
Tempo-spatial change of land use pattern in sem-i arid agro-pastoral mosaic areas is one of determining factors for land degradation and its productivity,and this change is very significant in recent 20 years since land contract policy has been implemented.This paper,taking Ejin Holo Banner as a case study,aims at the tempo-spatial change of sem-i arid agro-pastoral landscape.The results show that the whole landscape is conversing from simple and man-made to diversified and near-natural landscape,in which change in early period (1977-1987) occurs in hilly-floodplain mosaic area,whereas change in later period (1987-1998) in the whole landscape.Changes of land use structure demonstrate that change of woodland focus on area in early period and on spatial distribution in later period,woodland is not the dominant type for sand control, meanwhile,over-cutting of shrub in early period and the large-scale plantation of shrub in later period give a good explanation of change of the whole landscape,which proves that shrub plantation will be the optimum measure for restoration and reconstruction of damaged sem-i arid landscape.At the same time,the area and spatial distribution of mobile sandland are both decreasing,the convergence of mobile sandland,however,may increase the difficulty of sand control.On the other hand,the intactness of these mobile sandland may be helpful to increase the stability of the whole landscape and to optimize the utility of limited resources in the sem-i arid area.
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