The Change Of Urban Green Space Ecosystem And Urban Typical Parks Ecological Service Value In Shenyang

The ecosystem provides almost all the elements for human well-being,is an important guarantee for human survival which contains enormous service value.Urban green space,as an infrastructure with self-purification,automatic regulation and vitality in urban ecosystems,has provided many ecological services.What's more,urban parks as an important part of urban green space has provided people with many functions,such as rest and entertainment.Their ecological services functions play an important role in playing in urban environmental quality;however,it also inevitably brings various environmental pollution in the process of urbanization.Ecosystem services not only show positive services,but also present negative effects.For example,urban park soils are polluted by heavy metals from various sources.This study takes Shenyang City,the largest old and heavy industrial base in Northeast China,as a research object,which has selected eight ecological service value evaluation indexes.Including water source conservation,carbon sequestration,oxygen release,SO₂ absorption,NO_X absorption,dust retention,noise reduction and temperature reduction,build an ecological service value assessment system and calculate the ecological service value sub-index and comprehensive index to carry out quantitative evaluation and time dynamic comparison study of Shenyang urban green space system.At the same time,in order to use the equivalent factor method to quantify the ecological service value of 11 urban typical parks in Shenyang,then evaluate and compare the results.Simultaneously,evaluate the status of soil heavy metal pollution and ecological risk in 11 urban typical parks by using soil sampling,laboratory sample measurement and data processing,and using pollution indexes and potential ecological risk index.Research indicates:1.The total value of ecological service of green space system in Shenyang increased from 911.69×10⁶yuan?2004?to 1085.25×10⁶yuan?2014?.The individual sub-indices of ecological service value of urban green space system in Shenyang from2004²014 increased year by year,among which water conservation value sub-index,oxygen release value sub-index and noise reduction value sub-index were all high.During eleven years,the comprehensive index of ecological service value of green space system in Shenyang was 0.000,0.007,0.039,0.086,0.123,0.474,0.559,0.417,0.877,0.883,and 0.750.The calculation results indicated that the value of greenbelt ecosystem services in Shenyang often fluctuated upward trend and the whole value presented upward tread during 2004²014.2.The 11 urban typical parks in Shenyang is 587.9hm²,and the total value of ecological service value is 3042.05×10⁴ yuan.For different land use types,t he service value of water bodies is the highest,being 1718.67×10⁴ yuan,account ing for 56.5%of the total value;followed by forest land and grassland,accounti ng for 27.34%and 16.11%of the total value respectively;the service value of b are land is very small,only 0.05%of the total value.The order of the total val ue of ecological services in different parks is from high to low:Beiling Park>You th Park>Nanhu Park>Wanquan Park>Labor Park>Kepu Park>Dongling Park>Zhon gshan Park>Construction Park>Changqing Park>East Tower Park.3.The average contents of six heavy metal elements Cr,Ni,Cu,Zn,Pb and Cd in the typical parks of Shenyang 11 cities were 55.97,72.37,124.26,195.45,128.74 and0.96 mg·kg^?1,respectively,which were far above the background value.The main heavy metal pollution elements in Shenyang park soil are Cd,followed by Pb,Cu,Zn,Ni,and Cr pollution.In 11 parks,the most serious soil heavy metal pollution is Dongta Park and Wanquan Park,the least polluted.For Science Park,the only one is“slight ecological risk”,and the remaining 10 parks are“medium ecological risk”and“strong ecological risk”and should be given attention.