Prediction Of The Distribution Area For Eichhornia Crassipes Based On Ecological Niche Model

Along with the globalization of economic, information and culture,communicationsbetween the various countries in the world are becoming more and more frequent.Increasedthe phenomenon of introduction among different areas, parts of a them outbreak after losingcontrol,increased the probability of alien species invasion successfully, destroyed the localecology,particularly causing losses of local species diversity，genetic diversity and ecosystemdiversity, also caused huge economic losses to farming, forestry, animal husbandry andfishery. Biological invasion is the second reason which has resulted in the loss ofbiodiversity,which is also one of the three major environmental issuest.Eichhornia crassipes originating in the stream or lake of the tropical and subtropical,it isone of the most harmful and widely distributed invasive aquatic species in China.Using theGARP and ENFA model as methods,based on the existing distribution point data ofEichhornia crassipes in China and suitable environment layers selected to predict itspotential distribution area.The study indicated that layers such as slope,annual averagetemperature, the coldest temperature and annual average precipitation have great influence onthe results.The existing data show that it is more efficient to prevent the biological invasionthan to try to control it after invasion.The ecological characteristics of Eichhornia crassipes made it is difficult to prevent andcontrol its invasion,in addition it’s always costs lot.So it’s more economical and effective toprevent its invasion.The purpose of this paper is to predict the diffusion region,which can helpus to prevent the invasion more effective and control measures in advance.Nowadays there are many climate prediction models based on the climate matchingmethod to be used to predict the potential distribution of species, this paper is based on GARPand ENFA ecological niche model and predicted the potential distribution of Eichhorniacrassipes in Chinese range.Using ROC curve to evaluate the forecasting results according tothe obtained AUC values.It indicated the results is reliable.Give this two results modeldifferent weights of0.6and0.4,next made layers superimposed then we get the potential distribution of Eichhornia crassipes.At first it was considered to divide into five categoriesaccording to the overlap value,namely the serious threat zone (OV≥90%), the potential threatof zone (70%≤OV<90%), suitable for growing zone (50%≤OV<70%), growth zone (30%≤OV<50%) and not suitable for growing area (OV<30%).After a comprehensive analysis ofits potential distribution area in China, it was considered to divide into5risk levels accordingto the percentage of the threatened area in different province:The threatened area (Percentage≥98%), the diffusion area (90%<Percentage<98%), suitable area (30%≤Percentage<90%,)growth area (0<Percentage<30%), the security area (Percentage=0)， then do the sameanalysis Shandong.Every province put forward corresponding prevention measures inaccordance with different levels of risk.With governance as the main mode to controlEichhornia crassipes in the threatened and diffusion area.Suitable and growth areain shouldcontrol its outflow and outbreaks,in the province in the security area improve the preventionawareness of residents through publicity.