Analysis of spatial heterogeneity of agricultural landscape in the lower Yellow river plains based on characteristic scale

Heterogeneity and stability of the agricultural landscape is the premise to maintain the stability and high-efficient of agricultural ecosystem. Disturbance regimes have been recognized as the causes of the landscape heterogeneity. In this paper, the Fengqiu County, a typical agricultural region in the lower reaches of the Yellow River plains, was selected as the study area. Based on the TM imagery interpretation results of the study area and by the software of ArcGIS 9.3, GS+ 7.0, and Fragstats 3.3, the characteristics scale for the study of landscape composition and configuration of the study area was discussed. By means of the landscape trajectory built by landscape evenness and contagion index, and the buffer zones divided from the south to north of the Yellow river, we analyzed the landscape heterogeneity and gradient changes of disturbance intensity of the study area. The study results are as follows: (1) the characteristics scale of the study area was 2500m. At this characteristic scale, the evenness and contagion index showed a negative correlation, and formed a certain spatial pattern; (2) the disturbance intensity was increasing from south to north of the Yellow River, and its spatial difference continuously decreased; (3) the configuration of landscape patches become gradually complicated along the spatial gradient. The composition uniformity of landscape patches showed gradually decreased. Meanwhile, the landscape configuration was more and more sensitive for the changes of landscape composition.