Scale-dependent spatial heterogeneity of vegetation in Mu Us sandy land, a semi-arid area of China

To examine spatial scale-dependent variation in the vegetation in Mu Ussandy land, in the semi-arid area of NW China, two transects (5 kmin length, meeting at right angle) were set, and two vegetation attributes(quantitative descriptors), vegetation cover and number of plant species, wereinvestigated. The data were analyzed combining geostatistics and fractalgeometry. Nested spatial structures were revealed for both vegetationattributes, indicating the existence of multi-scale variations. The largefractal dimensions (> 1.70) commonly found in the vegetation suggest thedominance of small-scale variations. Shifting in fractal dimensions wasdetected, implying scale-dependent spatial variation of the vegetation, as wellas its hierarchical organization. Significant differences in spatial variationof the vegetation attributes between the different directions were also found,suggesting a zonal anisotropy of geomorphologic processes.