Study On Urban Typical Ecological Risk Assessment And Its Management Strategy

Ecological risk refers to the possibility of some adverse ecological effects due toone or more stress (physical,chemical and biological stress,etc.) Ecological riskassessment is the whole process,include conduct probability assessment of adverseecological effects,and implement risk management to prevent or reduce the risk.Itspurpose is to provide scientific information for risk management,and minimizedamage of pollution and ecological degradation.Early ecological risk assessmentfocus on the risk that human (or human environment) suffer.Recently risk assessmenton ecosystem attracts more and more attention due to the degradation of the globalenvironment.As most activities are centralized in the city,city is a typical complex ecosystemwith society system,economy system and nature system,which becomes the mainresearch target of ecological risk assessment.The reason causing urban ecologicalproblems include natural factors,such as global change,crustal movement etc.Anddisturbance from human production and daily life is another important reason.Theurbanization is an important step to realize regional sustainable development.Butthere are various conflicts and stress between the urbanization and ecologicalenvironment and ecological risk will occur simultaneously.It plays an important rolefor urban sustainable development to assess the ecological risk in the urbanizationprocess,and find out the laws of ecological risk.Urban pollution,climate change (such as floods etc.),and other ecological risk isthe major obstacle for urban development.At present the study about the regionalecological risk assessment mainly focus on natural ecosystems,the studys on urbanecological risk assessment are rare. As a typical coastal city,Laoshan district in Qingdao is selected as the study area.The ecological risk and the character in this area are analyzed.According to reliablemathematical theory,ecological risk assessment indicators and models are established.And the ecological risk is estimated including air pollution,change in temperature andchange in precipitation in Laoshan district.The characters of the above risk arepresented and forecast research is conducted according to Mean Generation Function,artificial neural networks and other modern mathematical tools.Based oninternational VaR model,EVR model of ecological risk management is establishedand it is applied in Laoshan District.Considering the response of human to ecologicalrisk and the character of coastal ecosystem,niche-fitness model is established and it'sused to assess the niche-fitness of the studied area and its trend.Finally,decisionsupport system software of ecological risk assessment in coastal city is developed andused for an important means for ecological risk management.The main results and conclusions are as follows:(1)According to reliable mathematical theory,urban ecological risk assessmentmodel is established including the following indicator:risk degree,reliability index,risk index,system continued stability index,system restoration index and the overallloss.This model has the character of clear indicators,calculated convenient,well-targeted.And application research is conducted in the Laoshan District.(2)According to ecological risk assessment model,air pollution and ecologicalrisk evolution in Laoshan district of Qingdao City from 2001 to 2005 is studied.Theresult indicates that a number of risk assessment indicators are no differences from2001 to 2005.But it is worth noting that the restoration index of air pollution in thisarea increases significantly.It increases from 45% in 2001,40% in 2002 to 60% in2004 and 50% in 2005.This reflects that more efforts in pollution control,theimprovement of capacity to deal with the unexpected pollution incidents,and thequick treatment for pollution.At the same time.the incidence of moderate pollutionaccidents also decrease significantly.which indicates that ecological quality improves.Therefore,the overall loss show a downward trend.reduced to 6.44% in 2004.In winter and spring,there is still high incidence of pollution accidence.Over the pastfive years,air quality in winter has not improved,but there is the trend of furtherlandslides.More attention should be paid to this problem.(3)The rainfall data in the past 50 years is analyzed using trend analysis,correlation analysis and other methods.And the precipitation forecast model isestablished using extreme estimates method,Mean Generation Function etc.Annualrainfall,the seasonal rainfall,drought and flood levels,frequency,such as the summerstorm in Laoshan district are forecast from 2005 to 2010.The forecast results arebasically consistent with the facts in 2006.The result shows that there are largerchanges in precipitation season in Laoshan District,and precipitation is mainlyconcentrated in the summer and autumn,and in winter and spring precipitation issignificantly less.Changes in precipitation in the past 20 years show a more stabletrend,but precipitation in summer and fall has decreased year by year.(4) The change in temperature in the past 50 years is analyzed.The result showthat the temperature increase occurred mainly in the past 20 years.From 1954 to1975,there is no obvious evidence of warming.But from 1981 to 2004 the minimum of theaverage annual increase in temperature is 0.035℃,the maximum is 0.092℃,andaverage annual increase is 0.052℃.This is obviously higher than the average level ofthe southeast coastal areas.A multi-output of two kinds of artificial neural networkmodel is established to predict the temperature trends in the next 10 years.(5) The result of niche-fitness research in Laoshan district shows that the averageniche-fitness is 57.40%,higher than the national average (50%).At the same time,wenote that the niche-fitness in this area has entered a period of rapid growth after ashort-term decrease.Especially in the last three years,niche-fitness are far higher thanthe national average,fully shows the area has strong competitive ability and capacityfor sustainable development.(6) Establish EVR model of ecological risk management,and conductapplication study in Laoshan district based on the Monte Carlo method. (7) Develop"Decision support system software of ecological risk assessment inLaoshan district of Qingdao"It is necessary to fully reflect the dominant position of human in urban ecologicalrisk assessment.It is recommended to conduct regional ecological risk assessmentaccording to the system engineering framework:Driver (D)-Pressor (P)-State(S-Response(R)-Control(C).The framework is an expansion of the current widely usedpressure (P)-Status (S)-Response (R) framework.Take population migration as themain indicators,human ecological momentum and niche-fituess model is establishedaccording to the dynamics mechanism of population migration.Based on analysis ofthe characteristics of regional population migration and clever use of small amountsof data,the change in niche-fitness in Laoshan district is analyzed.In addition,EVRmodel of ecological risk management fully draw the concept of risk management onthe financial markets,which is very important for regional risk management.