Soil Erosion Process And Landscape Ecology Assessment In Changting County

At present,studies on soil erosion of Changting mostly focus on the evaluation of governance effectiveness,dynamic simulation and prediction,governance measures and pattern exploration,The research on the evaluation of regional landscape ecological quality and the governance process of soil erosion in combination is also relatively rare.And the evaluation system of landscape ecological quality for Changting has not been established yet,then unable to learn about the change of local landscape ecological system’s quality well.For this reason,based on the view of landscape ecology,this paper analyzes the landuse,vegetation coverage,soil erosion governance of Changting in 1999,2006 and 2012,and accordding to PSR model,selects the appropriate index,establishes the evaluation system of landscape ecological quality for Changting,evaluates the landscape ecological quality changes since the governance job.The main conclusions are as follows:(1)Through remote sensing interpretation,we can get three periods of landuse data for statistical anaysis,the main landuse types are forest and farmland,the proportion of forest is more than 81%.The changed rate for landuse types are sorted from high to low and the order is construction land,other land,grass land,orchard land,farmland,water and forest;As the transfer matrix shows,farmland,forest and other land are the main transfer type from 1999 to 2006,and farmland,grass land and forest are also the main transfer type from 2006 to 2012;Each landuse type’s landscape pattern indice has different changes;For the regional landscape,equalization degree between the landscape types gradually improves,and the fragmentation degree decreases,landscape edge shape tends to be complex,then the ability of resisting external interference enhances,but landscape coefficient varation decreases from 327.65 in 1999 to 151.70,this result reflects that the self-control ability and landscape pattern stability of study area has improved.(2)Use the dimidiate pixel model to extract three years’ vegetation coverage,1999～2012,the area of low coverage vegetation(<0.3)and medium coverage vegetation(0.3～0.6)has decreased,then area of high coverage vegetation(>0.6)has significantly increased;Compare the changed proportion of vegetation coverage between typical soil and water conservation and Changting county,we find that vegetation coverage’s change in conservation area plays an important role in the change of Changting vegetation coverage.It indicates the governance job of soil ersion has a big effect on vegetation coverage in Changting.(3)1999-2012,the soil erosion area in Changting drops from 70117.32 hm2 to 37728.63 hm2,and it reduces 2491.44 hm2 every year;Both 1999～2006 and 2006-2012,stable patches are always in the dominant proportion,and the proportion of relif patches is over than intensive patches’ proportion,degree of soil erosion gradually decreases and soil erosion trends to be controlled.According to the erosion area of each landuse type,the top three landuse type are forest,slope farmland and orchard;but from the perspective of the erosion rate,the top three landuse type are slope farmland,other land and orchard.(4)By using the PSR model,we establish the evaluation system of regional landscape ecological quality,calculate weight based on the mean variance decision method and the entropy weight method,and then evaluate the landscape ecological quality of Changting in 1999,2006,2012.The result shows that landscape ecological quality scores in two methods are in the upward trend and Changting’s landscape ecology has greatly improved.(5)Find the main factors of influencing landscape ecology by the index diagnosis method:In 1999,the affected factors include high land degradation degree,serious soil erosion,large area of diseased component,big landscape variation coefficient,weak self-control ability,unreasonable structure and so on.In 2006,with the urbanization level increasing,human disturbance becomes more frequent,then the other affected factors are same to 1999.In 2012,urbanization is still an affected factor.In addition,construction land occupies forest,and it leads that largest patch index of forest gradually becomes an negative factor.As a result,forest ecological function begins to decline.(6)The effect which governance measures makes on landscape ecological quality mainly reflects on the state and response indice,and it is nothing with the pressure indice.1999-2012,the state and response indice scores of conservation area increase by 22.32 and 6.54,then the pattern state scores increase from 28.31 to 38.68.The governance of soil erosion plays an important role in the improvemet of landscape ecological quality.