The Analysis Of Landscape Patterns And Their Scaling Effects In Small Watersheds Of Loess Hilly Area

The comprehensive management with the small watershed as fundamental unit is the effective management method of loess plateau region. It can achieve the Rational distribution of the landscape pattern, the stable of the ecosystem and the ecology health of the small watershed through the comprehensive management of the the small watershed. At the same time, the degree of the Watershed management can be reflected through researching the distribution of the landscape pattern. This paper based on the RS and GIS, investigated the landscape pattern and the spatial heterogeneity of landscape index of three small watersheds in the loess hilly-gully region including the Yangquangou watershed, Zhifanggou watershed and Yangou watershed, and assessment landscape pattern of small watershed. The main research contents and major findings are as follows:(1) According to the actual situation of Yangquangou, Zhifanggou and Yangou watersheds in the loess hilly-gully region, the land covers were classified to lay the foundation for landscape pattern analysis.(2) The characteristics of landscape patterns were analyzed based on the 2009 ALOS satellite images ,through changing the accuracy of the landscape gradally on the method of resampling and coarse the grain size. At the same time, using FRAGSTATS software to analyze the landscape pattern of the three watersheds. The results showed that: Yangquangou, Zhifanggou and Yangou have formed the landscape patterns which were composed of forest, thickets and grass. It was also found that the quantitative analysis was has strongly dependencet on with the grain size.(3) The characteristics of landscape patterns were analyzed based on the 2007 SPOT merged image at resolution of 5m, the 10m spatial resolution of ALOS satellite image, the 25m spatial resolution of P6 satellite image, the 30m spatial resolution of TM satellite image, and the 50m spatial resolution of P6 satellite image, using FRAGSTATS software to analyze the landscape pattern of the three watersheds, according to the change of source resolution. The results showed that: With the lower of resolution, the landscape of Yangquangou, Zhifanggou and Yangou have changed, and the pattern of spatial resolution has an important effect on landscape spation structure, the 25m resolution is an appropriate scale to observed Yangquangou, Zhifanggou and Yangou watershed. It was also found that analysis the structure of the landscape by different data source could give a good expression on the landscape pattern of Yangquangou, Zhifanggou and Yangou watershed.(4) By selecting 2006 resolution merge image of SPOT with spatial resolution of 5m, the semivariogram of the edge density index, landscape diversity index and aggregation index at different extents were simulated by using the geostatistical analyst of GIS. Result indicated that the edge density index, landscape diversity index and aggregation index have the similar characteristics at different extents, and all the scales have spatial dependency. The semivariogram models of different indices had remarkable difference at the same scale.