关键词: 景观格局, 沙漠化土地, 沙漠化过程

Abstract: The effects of landscape pattern, landscape diversity, and patches have been studied in this paper. The indices of landscape pattern, fractal dimension and modified fractal dimension, have been used to describe and analyze the distribution of the desertification land and the landscape of sandy land. The more value of fractal dimension and modified fcactal dimension is, the more complex pattern of landscape is. They are good indicators for us to study the relationship between landscape pattern and desertification process. Different patch patterns have different perimeters and effects in desertification processes when its area is constant, because patches perimeter dramatically influence the migration and flow of seed, energy, and nutrient materials. Suppose there are equal shifting sand dune areas in two places that areas are same too, the distribution of shifting sand dune randomly scatter in first region and its distribution in second place concentrate than first one since the large area of shifting sand dune severely destroy pasture, cropland, and woodland around it. In other hand, species more easily colonize shifting sand dune in first place than second because there are larger perimeter and provide many chance for seeds to migrate and colonize. In addition, landscape diversity have important effects too in desertification process. The more complex landscape composition is, the more high landscape diversity is. Meantime, the relationship between landscape pattern and desertification process can be studied by means of quantitative description of sandy land patches and landscapes. However, landscape patterns, landscape diversity, and patches closely correlate with desertification process, it is a keystone for us to evaluate the desertified degrees in the assessment of desertification.

Key words: Landscape pattern, Desertified land, Desertification process