Ecological Monitor And Benefit Evaluation Of The Integrated Management In The Karst Rocky Desertification Regions

Aiming at the practical conditions in karst rocky desertification regions of the Southwestern China, The paper chooses six small catchments, including Shiqiao small catchment in Bijie (upper reaches of Wu Jiang), Longba small catchment in Zunyi (middle reaches of Wu Jiang), Lizishui small catchment in Yanhe (lower reaches of Wu Jiang), Wangjiazhai and Yangchangdong small catchments in Qingzhen (karst plateau basin) and Chaeryan small catchment in zhenfeng (karst gorge region) on the basis of the small catchment units. The paper adopts probability statistics, systematic engineering theory, ecology theory, water and soil conservation theory and geomorphology, etc. to monitor, evaluate and analyze the ecological function and configuration to establish the ecological evaluation index system of karst rocky desertification management. In the end the paper bring forwards scientific models and technological systems of the eco-environment management and ecosystem reconstruction for the different grades on the rocky desertification with karst features, which obviously improved the use and equipment and eco-environment within the small catchments.Ⅰ.During the process of the rocky desertification management, the vegetation cover rate for the different grades showed: intensive rocky desertification > moderate rocky desertification >gentle rocky desertification > potential rocky desertification on time succession. On the spatial succession, the amplitude is indicated: intensive rocky desertification > moderate rocky desertification >gentle rocky desertification > potential rocky desertification. As far as the shrub biomass and grass biomass are concerned, they were increased in the whole on the time succession, namely potential rocky desertification> gentle rocky desertification >moderate rocky desertification >intensive rocky desertification. The biodiversities were increased with the increase of rocky desertification grades in the preliminary phase of karst management. With the extent of the management, biodiversities taken on: moderate rocky desertification >intensive rocky desertification > gentle rocky desertification > potential rocky desertification. And species abundance taken on: intensive rocky desertification > moderate rocky desertification >gentle rocky desertification > potential rocky desertification in the four small catchments of the preliminary phase of karst management. With the extent of the management, biodiversities taken on: moderate rocky desertification > gentle rocky desertification >intensive rocky desertification > potential rocky desertification.Ⅱ. The change rules for the soil nutrient between gorge region and plateau basin were followed as: the equipment for each soil nutrient was best in original samples. And the contents of organize content, total nitrogen and radily avaible nitrogen were directly proportional to rocky desertification grades, namely intensive rocky desertification > moderate rocky desertification >gentle rocky desertification > potential rocky desertification. The change rules for the soil nutrient among Shiqiao small catchment in Bijie, Longba small catchment in Zunyi, Lizishui small catchment in Yanhe were followed as: original samples >intensive rocky desertification > potential rocky desertification > moderate rocky desertification >gentle rocky desertification. The result was consistent to other karst regions. At the same time another rules are upper reaches > middle reaches > lower reaches, but the difference was not large with complicate microtopography.Ⅲ. On the time succession, the air dinural range will increase with the grade increase. On the spatial succession, amplitude of the air dinural range of intensive rocky desertification is biggest, namely intensive rocky desertification > potential rocky desertification > moderate rocky desertification >gentle rocky desertification. As far as the relative humidity was concerned, there are obvious differences among the different rocky desertification. And relative humidity increased along with the lower of rocky desertification. The amplitude of potential rocky desertification was bigger among all grades. The change rule for the soil temperature were reached that the soil temperature difference in 0-15cm is less, and one in 15-20cm just began to lightly decreased, which are obviously taken on in intensive rocky desertification and gentle rocky desertification. With the extension of the management, soil configuration, moisture conditions and thermal properties were perfectly improved. So the air dinural rage of surface soil (5cm) was dwindled, but the air dinural rage of deeper soil (20cm) was bigger, so the temperature of the whole mellow soil layer was enhanced. And the results were taken on in intensive rocky desertification and moderate rocky desertification.Ⅳ. On the spatial succession, there are obvious differences for the soil erosion extent among the different rocky desertification, which will increase with the grade increase, namely intensive rocky desertification > moderate rocky desertification >gentle rocky desertification > potential rocky desertification. On the time succession, with the extension of the management, the soil erosion extent trend for the lower grade. Taking Chaeryan small catchment as example, the area proportion for the intensive erosion, moderate erosion and gentle erosion were respectively dwindled by 0.63%, 6.52% and 1.55% from 2000 to 2005, so water and soil erosion areas were effectively controlled. The average erosion modulus in whole region was decreased from 412.8 t/ km2·a in 2000 to 162.4 t/ km2·a in 2005, therefore eco-environment are gradually improved and the benefits for the rocky desertification management were gradually obvious.Ⅴ. According to the local practical conditions and the complication of the karst regions, the paper established the indexes and standards of the ecological benefit evaluation, which is a suit of relatively perfect system meeting to the karst eco-environment management. The system includes sixteen indexes belonging to four parts, namely biology benefit indexes, soil benefit indexes, microclimate benefit indexes and hydrological benefit indexes. And the system provides a suit of feasible evaluation models for the eco-environment benefit evaluation and plays a reference function in some similar technological assessment and benefit evaluation.Ⅵ. Putting forward the scientific models and technological systems of the eco-environment management and ecosystem reconstruction for the different grades on the rocky desertification: the closing land for plantation and ecological rehabilitation assisted by manual work are practiced in the intensive rocky desertification regions; the effective plating for the forest, shrub and grass and the abduction technology of ecological succession are carried out in the moderate rocky desertification regions; the equipment of forest and grass and grassed stockbreeding technology are implemented in the gentle rocky desertification regions; the water and soil conservation and Silvopastoral management technology are introduced in the potential rocky desertification regions.