Study On Ecological Benefit Of The Ecological Rehabilitation Of The Karst Rocky Desertification In Small Karst Basin In Typical Catchments Of Guizhou Province

The tutorial chooses four small catchments typical ecological rehabilitation,they representing four different landforms style,including Shiqiao catchment in Bijie(karst plateau mountain),Wangjiazhai and Yangchangdong catchments in Qingzhen(karst plateau basin) and Chaeryan catchment in zhenfeng(karst gorge).The data is obtained from field monitoring and experiment in lab,and the paper analyses and evaluates the ecological benefit of the integrated rehabilitation in different landforms with theories of applied ecology,geomorphology,pedology,climatology and geographical information system.Through researching the temporal and spacial change of ecological benefit,the paper supports some suggestions and references for evaluating the ecological benefit and the integrated rehabilitation of the karst rocky desertification.This paper mainly includes the contents as follows:(1) contrasting the difference and analysing the reason for the change of ecological benefit;(2) contrasting the relationship between the ecological benefit of integrated rehabilitation and different rocky desertification in the same landform;(3) research on the temporal and spacial variational rule of ecological benefit.The following conclusions can be drawn as follows:(1) The vegetational cover is effectively increased,and the microclimate and the physical and chemic character is improved and the soil erosion is decreased through the the integrated rehabilitation of the karst rocky desertification.Especially in karst gorge with long time ecological rehabilitation,the ecosystem becomes stabilization and effctively weakens the extreme variety.And the configuration and function of ecosystem becomes rational and improves the ability for resisting disaster.(2) The variational rule for biological effect of the integrated rehabilitation of the karst rocky desertification:the karst gorge is located in ralatively ecological environment,but the configuration of vegetational type precedes the karst plateau basin and karst plateau mountain because of the long time rehabilitation,and the amount of vegetational type increases with the lower of rocky desertification.The vegetational cover increases obviously because of the rehabilitation,especially the gentle rocky desertification in karst gorge.(3) The variational rule for soil effect of the integrated rehabilitation of the karst rocky desertification:the pH of soil is influenced by the native rock and the maximum of PH is in karst gorge with limestone as native rock,and the maximum of organic matter content of soil is in karst gorge.The soil bulk density is followed as:karst plateau mountain＞karst plateau basin＞karst gorge,and the soil porosity is followed as:karst gorge＞karst plateau basin＞karst plateau mountain,which reflects that in high rate of vegetational cover the root system reconstructs the soil and increases the soil porosity and decreases soil compact.The total nitrogen decreases first and then increases gradually before and after the ecological rehabilitation.In karst gorge,the soil bulk density gradully decreases from 2001 to 2008,but the variational rule of soil porosity is reverse.(4) The variational rule for microclimate of the integrated rehabilitation of the karst rocky desertification:the daily soil temperature range of karst plateau basin and karst plateau mountain is equal in depth of 5cm and 20cm. And the minimum appears in karst gorge,which is associated with the vegetational cover which decreases the maximum temperature and increases the minimum temperature.The illumination of April,August and December is followed as:karst plateau mountain＞karst plateau basin＞karst gorge,and the illumination of different rocky desertification ranks decreases from 2007 to 2008,which reflects the effect of ecological rehabilitation and the illumination decreases because of the vegetational cover increased and the daily temperature range decreased.(5) The variational rule for hydrological effect of the integrated rehabilitation of the karst rocky desertification:the soil erosion modulus is followed as:karst plateau mountain＞karst plateau basin＞karst gorge,which is associated with the topography and the vegetational cover.The soil erosion thickness is followed as:intensive rocky desertification＞moderate rocky desertification＞gentle rocky desertification＞potential rocky desertification＞none rocky desertification and the variance among different rocky desertification ranks is gentle.The increased vegetational cover and biomass decreases surface runoff and soil erosion,which gradually improves the ability of water and soil conservation of ecosystem.(6) The soil nutrient content is changed because of the freezing disaster. The total kalium,total kalium and total phosphor in 2008 appears different variation according to former years,because the transforming route and efficiency from lither to soil nutrient is affected by the freezing disaster.And the soil nutrient content in 2008 is lower than that in 2007,and the amplitude of soil nutrient content of same karst rocky desertification rank is followed as: karst plateau basin＞karst plateau mountain＞karst gorge.And the amplitude of soil nutrient content is followed as:intensive rocky desertification＞moderate rocky desertification＞gentle rocky desertification＞potential rocky desertification＞none rocky desertification.And the total kalium,total kalium and total phosphor in different landforms and rocky desertification ranks change greatly comparing with before 2008.