Research On Effects Of Landscape Pattern And Its Dynamic Process On Soil-water Conservation Service

At the background of the increasing population,rapidly developing economy and changingclimate in global,human demands of ecosystem services increase continuously,which cause the supply of many ecosystem services is not adequate.Humans modify the structure and function of ecosystem services to improve and sustain regional ecosystem services,and at the same time,human activities frequently disturb landscape patterns.The rapid and sharp change of landscape patterns affects the ability of ecosystems to provide services,which are detrimental to the sustainable development of ecosystem services.Soil provides multiple ecosystem services for humans,meanwhile,it is also the foundation for the generation and production of ecosystem services.In the past 50 years,the declining rate of regulating services,such as soil-water conservation is relatively high,soil erosion is worsening.In this context,how to effectively modify landscape patterns and manage ecosystems,so that improve the amounts of soil conservation,is becoming a tricky issue.This research selects Luanchuan County,which at the upper reaches of the Yi River basin,as thestudy area.Starting with landscapes patterns variation,the land use changes from 1995 to 2015 in the study area,and the transforming situation among each land use type are analyzed.Revised universal soil loss equation（RUSLE）is used to stimulate the process of soil erosion in study area,and the amounts and module of soil erosion in 1995,2005 and 2015 are calculated respectively.Then,correlation analysis is taken in order to reveal the relationship between land use types and soil conservation amounts,for discussing the effects of landscape pattern variations on soil-water conservation services in Luanchuan County during 20 years.Results show that:1)Soil erosion is high in Luanchuan County.The erosion load of 1995,2005 and 2015 was5.84×10⁷t·α^-1,3.81×10⁷t·α^-1 and 3.38×10⁷t·α^-1 respectively.This is related to the characteristics of the study area,such as big elevation difference,complex topography and plentiful rainfall.2)Effects of different land use types on soil-water conservation services are different.Soilconservation amounts of each land use types are:forest land>grassland>farmland>unused land>urban area.Forest land can provide the best soil conservation function as it has high vegetation coverage,and abundant vegetation type.The impervious surface in the urban area is very large,surface water flow takes the rainfall into water body instead of infiltrating into the soil,so soil conservation ability of the urban area is relatively poor.3)From 1995 to 2015,soil conservation function is generally stable in Luanchuan County.In1995,soil erosion intensity of the whole county is light erosion.After a series of artificial regulation,such as“return the grain plots to forestry”and“aerial seeding afforestation”,in 2005 and 2015,soil erosion intensity of the whole county is down to slight erosion,which represents that during the 20-year period,soil conservation in Luanchuan County has significant effectiveness.4)Correlation analysis between the area of land use type and soil erosion amounts show that,thearea of farmland and grassland have significant negative correlation with soil erosion amounts（P<0.05）,while the area of forestland and urban area have no significant correlation with soil erosion amounts.5)Soil nutrient conservation amounts of different land use types are different either.Three elements,N,P and K are analyzed,and the result shows that soil nutrient conservation amount of each land use types are:forestland>grassland>farm land>urban area.Luanchuan County is the national ecological county,and also it is the best region that saved natural forest in Henan Province.These emphasize the importance and necessity for protecting the ecosystems in Luanchuan County.Soil erosion amount is influenced by vegetation coverage,rainfall,soil structure and human disturbance,any factors change would cause the change of soil erosion intensity.This study can help to understand the contribution of different land use types to soil-water conservation services and its sustainable development.Meanwhile,appropriate human intervention,ecosystem structure modification,increasing vegetation coverage and plant biodiversity protection are all helpful to improve soil conservation,which provide theoretical support to land use planning and ecosystem management in Luanchuan County.