Soil Erosion Characteristics And Sensitivity Evaluation In Tongbai-Ddabie Mountainous Area

In order to provide scientific basis for the regional environmental protection of Huangqian river, present situation of landscape pattern in 2008 and its dynamical characteristics from the year of 1987 to 2008 were analysised, dynamical changing trend of landscape pattern was predicted, and landscape planning and design was proposed in this paper, which chosen Huangqian river basin as the study area, took TM images in 1987 and ALOS images in 2008 as the main source of information, combined with field investigation and other natural , social and economic supporting data, based on geographic information system's strong spatial analysis function.The main results are as follows:1 The present situation and change of landscape pattern of Huangqian river basin was clarified.(1)The main landscape pattern types were shelter forest and economic forest in Huangqian River. In 2008, the total landscape area of Huangqian river was 292.2 km~2, of which cultivated area accounted for 5.41% and shelter forest accounted for 33.47%. Area of economic forest was 145.97km~2, accounting for 49.96% of the total landscape area, and area of other types of land was smaller. Therefore, in Huangqian River the general characteristics of landscape pattern were based on shelter forest and economic forest which constituted the dominant landscape types in the study area. Of the main types, other types were mosaic distribution and nursery land and bare rockare were less.(2)On the whole, type and diversity of landscape were abundant in study area, and to some degree, structure composing of landscape in this area was complex. Patch density of traffic land, town and village land, and industrial and mining land was largest. Meanwhile, the average patch area of these types of land was smallest and their fragmentation degrees were larger than other landscape types. Economic forest and shelter forest were dominate types of the landscape which had the highest values of the maximum patch index. The shape index and fractal dimension of traffic land were biggest. This type of land was disturbed most and had the most complex geometric shape. Oppositely, landscape shape index of nursery land was smallest and its landscape shape was regular. Economic forest had the biggest similar adjacent percentage and aggregation indice and patch biding degree index, and higher aggregation indice of landscape factor type. In the same time, patches of economic forest land distributed concentratively and spacally connected well.(3) In study period, landscape type structure changed significantly, area of economic forest land, town and village land, industrial and mining land and traffic land increased while area of farmland and shelter forest.etc decreased. The dominate landscape type changed from shelter forest into economic forest. Area proportions of farmland, shelter forest, waters and water conservancy facilities land and unutilized land occuping the total landscape land decreased while that of economic forest, town and village and traffic land occuping the total landscape land increased. The increase of economic forest area main come from shelter forest and farmland. In the same time, there was about 9.8km~2 of economic forest changed into other landscape types such as shelter forest, town and village and industrial and mining land and traffic land. The changing rate of town and village and industrial and mining land and traffic land, which increased averately 3.17% each year, was largest. The farmland's changing rate decreased 2.43% averately every year and its decreased part mainly changed into economic forest, town and village and industrial and mining land and traffic land.(4)Landscape patterns in Huangqian river changed obviously during the research period. In Study period, the patch density and edge density showing an overall increase, the largest patch index and mean patch size decreased gradually which prove a serious landscape fragmentation in the study period. Fractal dimension increase, landscape shapes tend to complex and irregular, and creased extent of the boundary increase gradually, Shannon diversity index increased, the landscape is becoming more extensive use, the degree of landscape heterogeneity increase. Shannon evenness index reduce, landscape structure tend to the uneven development, the proportion of different landscape types increased. With contag index decreasing and IJI index increasing, the spatial distribution of landscape elements are not balanced, the proportion of dominant patch type is decreased, and several other types increased, patch became ever more diffuse.2. Changing trend of landscape pattern in Huangqian river basin was predictedThe results of calculation using the Markov chain model indicated that the area of farmland, shelter forest, waters and water conservancy facilities and unutilized land would keep decreasing trend in a long time from now on. In addition, amplitude of shelter forest decreasing would remain large and the proportion of economic forest would increase clearly on the whole. As the promotion of industrial structure, macro-economy in Huangqian river basin would keep stable increasing in the future 10 years. The predicted trend indicated that landscape structure changed significantly in the background of economy and society rapidly developing, which characterized by the increase of economic forest and decrease of shelter forest and farmland. Therefore, contradiction between urbanization, economic construction and farmland protection would be more prominent, and landscape pattern planning and optimizing would face with greater challenges.3. Proposals of landscape ecological planning in Huangqian river basin was proposedIn accordance with landscape functions of the Huangqian river basin, associated with the surrounding spatial landscape pattern, the study area was divided into different functional zones from the spatial structure, and planning advices of each zone was posed. On the planning of ecological and environmental protection zone, existing forest should be protected first, then forest tending be strengthened and different species of life forms and growth forms be introduced. On the planning of economic forests, valuable cash crops should be continue to developed, form commercial economic base be formed and economic base of the Huangqian river basin be established. On the planning of agricultural cultivation area, high-yield, high-efficiency and high-quality agriculture should be developed and water saving irrigation agriculture be extended. Based on artificial landscape innovation and design, with the method of combining landscape design and gardening design, the water system secenic area should be established tourism scenic area which would center by comprehensive development and be maily used to tourism. It is worth noting that water quality management should be strenthened as Huangqian river is the main drinking water source of Taian.