Land Use/Cover Distribution And Dynamics Of Different Topographic Conditions In Jinfoshan Natural Reserve

Nature Reserves Building is the main measure for situ conservation of biological diversity, and is very important for maintaining ecological balance, soil and water conversation, climate regulating, improving people's living environment, promoting economic development and so on. As we know,there are some imbalances between people and land at presence, so the researches of nature reserves are of great importance.Based on four remote sensing images of 1978, 1988, 2000, 2008 of U.S. Land-sat series and the topographic maps(the scale is 1:50000)of Nanchuan District,Chongqing, and data from Nanchuan City Forestry Bureau and some other relevant information, with the support of software Arcgis 9.2 and Erdas imagine 8.5 for the remote sensing and GIS technology and reasonable classification, combined with DEM data extracted from the topographic map, this paper shows the Land Use/Cover distribution and dynamics of different topographic conditions in Jinfoshan Natural Reserve in detail. The conclusions are as follow:①The distribution of different land use/cover type is selective to topographic conditions: forest land tend to grow at steep areas of higher elevation; shrub tend to grow at the eastern slope with grade of slope inclined 60°and the elevation below 1800m; agricultural land, construction land, water tend to distribute over the plains, the western slope or the southern slope with lower elevation and gentle slope.From the perspective of elevation, forest land are concentrated in areas where the elevation is 1800m to 2100m or higher than 2100m, and with decreasing elevation, the coverage of forest land also decreases; the agricultural land, construction land, water are concentrated in lower areas, and the area of which increases with decreasing elevation. Shrubs are more widely distributed in the area where the elevation is less than 2100m; grass in all elevation zones are scattered.From the perspective of slope, shrub is dominant in slopes with different degrees, and more than 60% of the shrubs distributed in the slope which degree is less than 45°; Forest land and grassland are also distributed in most of the slopes, and are mainly distributed in the slopes of 30-45°; agricultural land, construction and water are distributed in the areas of relatively gentle slope, and the more high the slope is, the less these three categories of land use / cover type cover.From the perspective of aspect, the most coverage on south slope is forest land and the most coverage on east slope is shrub. More agricultural land is distributed in the plains or on west slope. Construction land is almost distributed in the plains or on south slope.②The change of land use/cover has topographic features. First,the change of land use/cover show a decreasing trend with increasing elevation and slope. Second, most of land use/cover change happened in slope less than 45°.Besides, the elevation and slope of these changes are consistent with the elevation and slope of the land use/cover change types those changes.From the angle of elevation, the conversion of forest to shrub are concentrated in the zones with a elevation of 800-2100m; most of the conversion of shrub to agricultural land, happened in the relatively lower zones with a elevation less than 1300m; the conversion of grassland to shrub, agricultural land to shrub, construction land to agricultural land, are all concentrated in the relatively lower area with a elevation less 1300m.From the perspective of slope, the conversion of frest land to shrub is concentrated in slope of 15-30°and 30-45°; The conversion of grass land to shrub are congcentrated in the shlope of less than 45°; The conversion of agricultural land to shrub is also concentrated in the slope 15-45°From the perspective of aspect, most conversion of frest land to shrub happened in east slope; most conversion of grass land to shrub happened in north and east aspect.And the conversion of construction land to shrub and water to agricultural land are all happened in flat areas.