关键词: 海南岛, 植被景观, 斑块特征, 分维数

Abstract:

With the aid of the GIS tool ARC/INFO, based on the Hainan vegetation map at the scale of 1∶500 000, the characteristics of the patch size and shape in Hainan vegetation landscape were analyzed. Several basic descriptive statistics including number of patches, average patch size, standard deviation, total patch size, minimum patch size, maximum patch size, range, skewness, kurtosis, medium, mode and etc., were chosen to describe the size features of patches. And some kinds of probability distribution including normal, Gamma, lognormal, Weibull, and exponential, were chosen to characterize the patch size distributions for all patch types in Hainan. In Hainan island, there were 36 lower level patch types in total, and they belong to 7 higher level patch types, namely tropical needle forests, broadleaves forests, shrub, brushwood, cropland, man made forests, water vegetation, which contained 6, 85, 112, 67, 101, 95 and 3 lower level patch types respectively. Most of the patches were positive skewed, and comparatively, the lognornal distribution could be used to characterize the patch size distribution in Hainan. At the same time, the patch complexity was examined for all kinds of vegetation types in Hainan. According to the two methods proposed by Krummel et al . (1987) and Li (1992), Klinkengerg (1994), the fractal dimension could be calculated effectually. For those low level vegetation types with more patches, the fractal dimension D₂ has a positive relationship with the average patch size, a negative relationship with the standard deviation, maximum patch size, range, skewness for each patch type. Among the 7 high level patch types, the fractal dimension of tropical needle forests was the highest, next were broadleaves forests, brushland, shrub and man made forests, and the fractal dimension of cropland was very low. Although there were not significant differences in fractal dimension between shrub and broadleaves forests, and between shrub and man made forests, significant or very significant differences existed between every two of the other patch types. Moreover, the domains of scales were identified. Patches with larger than 7.4km² had more complex shape than those with smaller than 7.4km².

Key words: Hainan Island, Vegetation landscape, Patch characteristics, Fractal dimension