Eco-Benefit Of Ecological Restoration And Reconstruction In Mining Area

From 1986 to 2008, different forms of ecological restoration and reconstruction on phosphorite mining areas were implemented in Kunyang three, times. But no comprehensive study or analysis has" been put forwards on the assessment and characteristics of ecological restoration and reconstruction in those areas.Funded by the project of "Technology Research and Demonstration of Ecological Restoration Integrated Control for Abandoned Mines" (No.2006SG24),phosphorite mining areas in Kunyang were selected as our research object, it synthetically studied and analysised the methodology and results of ecological benefits' assessment and characterization for ecological reconstruction in mining area from three aspects-soil conservation benefit, soil improvement effect and landscape pattern change. And the field observation, temporal substitution, samples monitoring and remote sensing analysis are the main methods.By the method of erosion nails, it monitored the slopes with and without vegetation of 2005,2006 and 2007. The result shows that when the area reclamated in 2005,2006 and 2007, the soil erosion modulus of the units covered by vegetation accounts for 63%,61% and 66% respectively of the ones without the vegetation. Meanwhile, by the method of temporal substitution, the soil erosion was reached to 30716 t/a before the implementation of ecological restoration-and reconstruction, and it decreased to 1607 t/a after it. So, it is considered that ecological restoration and reconstruction can control the soil erosion effectively for abundant mining areas of Kunyang.By the analysis of the soil fertility from the plantation of different years, the soil organic matter and TN in the different soil layers from the plantation developed in 1986, the soil fertility of plantations in three different types developed both in 1986 and 2005, it shows that ecological restoration and reconstruction is one of the most effective methods to improve soil fertility although the effects of soil fertility improvement are varied with different species composition. Meanwhile, the improvement effects of soil organic matter and TN are mainly concentrated in the surface layer between 0 and 20cm.Through the interpretation of remote sensing images of 1988,2002 and 2006, and the analysis of the transformation process among forest, bush forest and mining area, it shows that the ecological restoration and reconstruction made great contributions to the increase of forest land. Meanwhile, the analyses of patch type-level index and landscape-level index show that the change of the landscape pattern index can response to the process of the spatial pattern change in the study area. And the ecological restoration and reconstruction improved the landscape pattern index.All results show that:(1) the implementation of ecological restoration and reconstruction in mining area is one of the key measures to achieve the sustainable development of mining areas. And it exerts important functions and significant eco-benefits on soil and water conservation, and improves soil fertility and optimizes landscape pattern; (2) the effects of water conservation, improvement of soil fertility and the optimization of landscape pattern are three comprehensive indexes for the assessment and characterization for ecological reconstruction in mining area; (3) The landscape pattern index analysis is an effective to study the spatial pattern change of the study area and it will become one of the most important environmental management methods.