Abstract:

The landscape dynamic was researched in Zhifanggou watershed of Ansai, a loess plateau, during last 25 years. The result showed that the landscapes were different in the different period, but the whole structure was not obviously changed. The landscape percentage of eco-protection type; pro-economics type and living-service type was relatively stable. The area of eco-protection type was the largest while that of pro-economics type was the smallest in 2005. The patch element quantity of each vegetation landscape was small, however the average area of patch element was large and the fragmentation degree was low. With the lapse of time, the diversity indices and evenness indices of vegetation landscape were increased first and then decreased, but the degree of dominance indices was decreased first and then increased. The landscape structure was reasonable in 2005. There were some achievements in conservation of vegetation. The conservation of vegetation ecology system reached to ideal degree. The proportion of forest, shrub and grass was rational. The agriculture product and the security of region ecology system were increased. Therefore this landscape structure would be as a model for local vegetation and ecology construction.

Key words: Zhifanggou, valley, landscape patch, landscape dynamic, landscape index