The Study On Forest Landscape Pattern And Its Dynamic Changes Based On RS And GIS

In this paper,Changbai Mountain National Nature Reserve and its four neighboring forestry bureaus(named Baihe,Lushuihe,Quanyang and Songjianghe)were regarded as the study area which was divided into two parts:the area inside the reserve and the area outside the reserve.Based on Landsat remote sensing images of 1994,2004 and 2015,RS&GIS technology and landscape ecology principles were used to analyze landscape pattern and its changes of shape,area,type conversion,fragmentation and diversity in the study area.The relationships between forest landscape distribution and topographic factors were studied with DEM data.The results showed that:(1)The main landscape type was coniferous forest landscape in the reserve,while coniferous and broad-leaved mixed forest landscape outside the reserve.Due to that the human disturbances in the reserve were less than that outside the reserve,the forest landscapes were more complete and connected,and their shapes were more regular,while the landscape was less fragmented,diverse and heterogeneous in the reserve.(2)In the reserve and four forestry bureaus,coniferous forest landscape transformed into coniferous and broad-leaved mixed forest gradually,and its area was greatly reduced,and coniferous and broad-leaved mixed forest gradually converted to broad-leaved forest.The non-forest lands outside the reserve extended significantly and occupied some forest lands.During the study period,the total area of the forest outside the reserve decreased by 2655 ha,while the total area of the forest in the reserve was almost unchanged.In the reserve,there was a tendency that the tundra was invaded by coniferous forest and bare land gradually,and its area decreased.Over the past two decades,the landscape in the reserve tended to be more fragmented and diverse,while the landscape in the forestry bureaus showed the opposite trend.The landscape changes varied among the forestry bureaus:In Lushuihe and Songjianghe forestry bureaus,the landscape turned to be more connected and less fragmented,diverse and heterogeneous,while the landscape changes in Quanyang forestry bureau showed the opposite trend,and appropriate measures were needed for optimizing its landscape pattern.(3)Each kind of landscape types was almost distributed on the flat and gentle slopes.Coniferous forest,coniferous and broad-leaved mixed forest and water were more distributed on shady and semi-shady slopes,and the broad-leaved forest,tundra and construction land were more distributed on sunny and semi-sunny slopes.The changes appeared evenly on each slope.The vertical distribution of vegetation was showed obviously in the study area.The distribution gradients of altitudinal of broad-leaved forest,coniferous and broad-leaved mixed forest,coniferous forest and tundra were 1100m or less,700-1100m,1100-1650m and 1650m respectively,and the distribution gradients of these landscape types were becoming higher consistently.