Abstract:

Taking the landscape pattern in Fengxian County of Jiangsu Province as the research subject, we applied buffer analysis and spatial overlay to investigate how the location of administrative center influences the landscape pattern with the support of ArcGIS 93 software and Fragstat 3. We selected seven landscape indices that can reflect landscape fragmentation, the regularity of landscape patch, the degree of aggregation and the diversity & heterogeneity of the landscape. The results show that: a) Cultivated land is the dominant land use type of the landscape and settlement landscape is one of the most important landscape patterns in Fengxian County. The degree of aggregation of cultivated lands and garden plots is higher than forest lands and the other agricultural lands. Natural reserved areas are minimally fragmented and suffered a mild influence from human activities. However, the degree of fragmentation is the highest for the other agricultural lands. The distance to the administrative center is near, the anthropogenic landscapes occupy a big proportion in the landscape area of the buffer zone, that is to say there is a characteristic of spatial attraction. However, the proportion of natural landscapes is lower, which is much smaller than the present proportion. In other words, there exists the effect of spatial repulsion. b) The distance to the town government expands, the degree of fragmentation, aggregation and the regularity of landscape patch tend to be strengthened in the first phase and then weakened. And the impact on landscape diversity and landscape heterogeneity can be so small if the distance to the town government is longer than 1 000 meters. With increasing distance to the county government, the degree of fragmentation presents a “weakenedenhancedstable” pattern. The degree of the complexity of the landscape shape increases gradually and accumulation degree decreases and then stable. Just like the changes in the landscape diversity and landscape heterogeneity which are affected by the distance to the town government, the two landscape indices can hardly change when the distance to the county government is more than 2 500 meters. The two different grinds of administrative center are of little influence on the diversity and the heterogeneity of the landscape. Overall, the distance to the county government would have more impact on the landscape pattern of land use than the distance to the town government. c) In a word, the two different levels of administrative center can affect the fragmentation degree, the shape character of patches, the aggregation level and the landscape diversity. The effective influence radius of the two different grinds of administrative center trend to be 1 500 meters and 3 000 meters after taking all the changes in the chosen landscape indexes into consideration