Analysis of Gradient Change of Landscape Characteristics in Farm-Forest Ecotone-A Case Study on Mudanjiang in Heilongjiang Province

Farm-forest ecotone is proven to be ecologically sensitive areas, where there is obvious change from environmental gradient. The landscape characteristic is mainly influenced by elevation, slope and human activities. Taking Mudanjiang in Heilongjiang Province as example, this paper analyzes spatial-temporal distribution of landscape characteristics in elevation and slope by using the technology of GIS and RS, and the method of trend surface analysis and landscape pattern analysis. The results show that dynamic process of land for agriculture and forestry has a direct influence on the changing rate and direction of landscape characteristics in Mudanjiang. Landscape patch number, fragmentation and diversity index have a peak value in elevation gradient, and the value appears in those whose elevation is less than 800 meters; other indices gradually decrease with the slope increasing except patch number, which has a lesser peak value. Trend surface Analysis of ecological potential power can conclude that gradient change of landscape was concentrated in low-altitude and high-slope region from 1976 to 1988; on the contrary, mainly concentrated in the high-altitude and low-slope region from 1988 to 2000. Thus, the prominence of landscape gradient change is distributed in the regions where there are frequent human activities