Study On The Potential Geographical Distribution Of Traditional Chinese Medicine Gentiana Macrophylla Based On Niche Model

Gentiana macrophylla is the perennial herbaceous plant which belongs to gentianaceae. In recent years, the demand of the Gentiana macrophylla continue to increase in medicine market, which lead to which the Gentiana macrophylla was excessive and wasteful mining in great quantities, the original production plant resources and its habitat was damaged in a certain degree, and was becoming an endangered medicine. Especially Gentiana macrophylla has been included in "the species list of wild medicinal which key protected by nation"and listed as the level3protection of wild medicinal species. But so far, at home and abroad the study of the Gentiana macrophylla mainly concentrated in the evaluation of the medicinal quality, the Morphology and Anatomy, the Breeding and Flowering biology, the pharmacology and drug efficacy, appraisal the varieties of medicinal materials, embryological studies, the tissue culture and cultivation techniques and so on. But there are few researches on the suitable. Habitat and distribution area of Gentiana macrophylla, especially there are not researches in the geographic distribution of nationwide.Because of the quickly innovation of the GIS technology and the widening of the application fields, the study of geographic distribution using the GIS technology increasingly brought to the attention of the people and have gained many good practical results. Compare with the survey methods of the traditional Chinese herbal medicine resources, there are a lot of advantages to use this new technology to survey the geographic distribution of Chinese herbal medicine.So this article using the GIS technology system study on the potential geographic distribution area of the level3protection of wild medical resources Gentiana macrophylla, and find out the differences of four level of suitable. Habitat for Gentiana macrophylla, and confirm the suitable. Environment and the leading climate factor,in order to provide some data supporting and the advice of protection for the conservation and sustainable utilization of resources of Gentiana macrophylla. Also providing some theory and data supporting for choosing and construction the wildlife tending GAP(Good Agriculture Practice) base location,and providing some references for the protection and researches of other Rare and endangered medicinal material resources.This article using the124distribution point records,22environmental assessment data and four ecological niche models Bioclim, Domain, GARP and MaxEnt, predicts the potential Distribution of Gentiana macrophylla in China,and end structures the best comprehensive prediction models by the comprehensive prediction results of each model.The specific content and the prediction results of this article as follows:(1) the four Ecological Niche Models Bioclim, Domain, GARP and MaxEnt was used to predict the potential distribution area of Gentiana macrophylla in china. The accuracy value of the prediction results are AUC (Bioclim)=0.878、AUC (Domain)=0.884、AUC (MaxEnt)=0.943、AUC (GARP)=0.923. If the value of AUC of each model significantly greater than0and close to1,the ability to predict of the potential distribution of Gentiana macrophylla in China of this four ecological niche models is more stronger, and the potential distribution of Gentiana macrophylla in China is close to the actual area. If the value of AUC of MaxEnt model is the biggest, the ability to predict of MaxEnt model of four models is the strongest, and it can more accurately predict the potential distribution area of Gentiana macrophylla in China. Form the prediction results, we can know that524160km2is the most suitable. For the environment which accounted for5.46%of the total land area of our country,and791040km2is the more suitable. for the environment which accounted for8.24%of the total land area of our country, and1584000km2is the suitable for the environment which accounted for16.5%of the total land area of our country, and6700800km2is not suitable for the environment which accounted for69.8%of the total land area of our country.(2) From the prediction results, the four of single Ecological Niche Model have highly consistency to the distribution area of Gentiana macrophylla in China. But there are some different in other areas.For example,the suitality types which predicted by four kinds of models is not consistant is Shuangcheng city in Heilongjing province.The prediction results of the Domain model show that this area is suitable type.The prediction of the GARP model shows that this area is low suitable type;The prediction of the MaxEnt and Bioclim shows that area is not suitable type.(3) As for the stability of the model, Bioclim model has significant effect on sample capacity. The stability of the model is poorer. But there is no effect on sample capacity of GARP, Domain, MaxEnt model. The change of the value of the AUC gradually, volatility small, the stability of the model is better. (4) Importing the prediction results of four models in the ArcGIS9.3, and constructing integrated model by weighted algorithm,the accuracy values of the prediction results AUC is0.971. The prediction results indicted the most suitable for the environment which accounted for3.26%of the total area of our country, the more suitable for the environment which accounted for10.53%of the total land area of our country, the suitable for the environment which accounted for14.96%of the total area of our country, the little suitable for the environment which accounted for71.25%of the total area of our country. The suitable environment mainly concentrate on the Loess Plateau of Shannxi,Shanxi,Ningxia,the east of Qinghai of subalpine and alpine meadows, mountain grasslands, mountain forest and subalpine and alpine shrubs. Thus it can be seen,Gentiana macrophylla distributed in different geographical and natural environment,and the drought is a common characteristic in these so this indicted that the magnitude of the ecological environment is wide and it like growing at a relatively arid climatic conditions.(5) According to MaxEnt’s Jackknife, Calculated factor contribution rate indicates that bio12、bio13、bio and biol are the important factor in the distribution of Gentiana macrophylla. The300～600mm of annual precipitation, the60～120mm of precipitation of wettest month, the1000～3800m of elevation, the3～14℃of annual mean temperature are suitable for the environment to the species.