Vegetation Degradation And Ecological Restoration Mode In The Tongbo-Dabie Mountainous Area In Huaihe River Basin

Taking Tongbo-Dabie Mountainous area in Huaihe River Basin as the research object, comprehensive application of theory and methods of geographical informatics, ecology, forestry resource management science and Soil and Water Conservation, integrated use technological means of water and soil conservation 3S information monitoring and ground monitoring , forest resource inventory, plant community survey, experimental observation of water and soil conservation function and community interviews, this dissertation studied the mechanism of vegetation degradation and ecological restoration mode. The aim of this paper is to elucidate vegetation degradation types, structure and functions degradation characteristics, to reveal the driving mechanism of ecological degradation and the limiting factor to ecological restoration, to make ecological restoration suitability assessment and zoning and to suggest ecological restoration mode and key technologies. The results and conclusions are as follows:(1) Structural pattern of forest vegetations resources of Tongbo-Dabie mountain area①The forest coverage of Dabie mountain area is higher as 32.23%, but the distribution of the forest is not evenly. The forest coverage of Jinzhai County, Huoshan County, Shucheng County, Xin County, Guangshan County and Luoshan County is higher.②The forest category structure of Dabie mountain area, The ratio of timber forest of Liuan city is the highest, as 53.5%, however, the fuelwood forest is less and the ratio is 0.02%. Water and soil loss of forest land caused by this situation can not be neglect.③Although the forest coverage of Dabie mountain area is higher, the protection forest resources area is small. The ratio of protection forest to land is 9.7%, and to forest land is 28.1%. Soil and Water Conservation Forest and water conservation forest is less. The ratio of the two forest category to land is 9.4, and that to forest land is 27.2%. The general water and soil vegetation resources are scarce.④Although the ratio of economic forestto forest land is not high, as 16.7, Water and gravity gradient of Slope land is high. In the area short of water and soil conservation engineer and tillage measure, ecological degradation and water and soil loss of the forest land are more serious.⑤I n the forest resources of Tongbo-Dabie Mountainous area, the ratio of young forest and middle age forest is high, the ratio to forest land is 51% and 37%, but the ration near-mature-forest and mature forest is less, the ratio to forest land is 9.5% and 2.5%. This situation cause fragile structure and function of forest ecosystems.(2)The structure and hydrological function degradation characteristics of typical plant community①A iming at the ecological restoration research and practice need, we suggest under different human activities there are 12 typical vegetation degradation types in mountain and hilly areas, including 5 community degradation(regressive succession) types, 7 community recovery (positive succession) types.②T he plant community structure succession mainly depends on disturbed mode of human activities. In different disturbed mode and disturbed strength, the plant community structure degradation or recovery characteristics is oblivious. In all kinds intensive unreasonable human activities, the vegetation of downslope cultivation and economic forest land degrade most seriously, followed by wood chopping and grazing . Closing protection measures obliviously improves the community structure. For instance, implementation of forbidding grazing and banning deforestation to ecological forest, the herb layer coverage of forest land increased 17.7 times, species richness increased 52%, species diversity index increased 5 times.③The hydrological function of plant community of Dabie mountain area is influenced more seriously by human activities. In different human activities, disturbance strength and frequency, the hydrological function of various plant community has different degradation characteristics. The bulk density of soil of forest land for wood chopping and grazing, downslope cultivation and economic forest reached 1.71,1.70,1.65g/cm3 respectively; Their soil fractal dimension was 2.42, 1.998, 2.23 respectively; their soil non-capillary porosity was 5.75%,7.5%,8.15% respectively.④The plant community quantitative index and the hydrological function index had significant correlation, and correlation coefficient was all greater than 0.72; The canopy density and the water capacity of litter, soil porosity and soil fractal dimension had ad significant correlation, and correlation coefficient 0.718,0.858 and 0.693 respectively.(3)The ecological fragility and ecological degradation driving forces①The decreasing order of ecological fragility of different land cover is economic forest land , cultivated land, open forest, shrub, grassland and forest land.②Of the soil erosion factors, human factor is firstly, natural factor is secondly. Of the 11 natural and human affecting soil erosion factors, economic forest area per capita, the ratio of rural fuel wood, food production per capita and mean annual precipitation make the top four.③H uman unreasonable intensive disturbance activity is the main ecological degradation factors, and economic forest development, cultivated land development, wood chopping and grazing are the main ecological degradation forces.(4)Water and soil conservation ecological restoration suitability assessment and zoning①According to the leading driving force of ecological degradation and the limiting ecological restoration factors, we suggest a Water and soil conservation ecological restoration suitability assessment and zoning index system which is composed of altitude, land use type(vegetation cover type) and slope.②In the Tongbo-Dabie Mountainous area, according to altitude, three site types are classified including middle-mountain(1001～1800m), low mountainous (501～1000m)and hilly area(101～500m). By the land use type and vegetation type, 6 site types are classified including water source forest land, general ecological forest land, economic forest land, cultivated land, shrub and grassland and naked rocks. Ecological forest land, economic forest land, cultivated slope land are further classified to 2 types: slope degree is more than 25°and slope degree is less than 25°③Aiming at the ecological restoration research and practice need in Tongbo-Dabie Mountainous area, we constructed 27 ecological restoration suitability assessment unities system which was constructed by altitude, land use type(vegetation cover type) and slope. All unities were classified to suitability, temporary unsuitability and unsuitability. Sixteen ecological restoration suitability types and zones were proposed.(5)Ecological restoration mode and key technologies in the Tongbo-Dabie Mountainous①Aiming at the ecological restoration practice need, mountain area and hilly area were classified into 4 kinds water and soil conservation ecological restoration site types. They are ecological forest and grassland vegetation, wood chopping and grazing land, cultivated slope land and economic forest development.②According the intension and extension of water and soil conservation ecological restoration and ecological restoration suitability zoning, we proposed 2 types"attributes mode", 4 types"site mode"and 12"techniques mode"for water and soil conservation ecological restoration in the Tongbo-Dabie Mountainous. Further, key techniques for all kinds mode were suggested.