Potential Suitable Area And Distribution Patterns Of Prunus Mira Koehne In China Under The Context Of Climate Change

This thesis uses a maximum entropy model to predict the historical,current and future distribution of potential suitable area for P.mira.The spatial variation of P.mira in the suitable areas of China under the background of climate change is predicted,and provides a scientific basis for the development of P.mira industry in response to climate and environmental changes.In this study,216 distribution data and 34 environmental factors of P.mira were screened using R language and Arc GIS.The ENMeval package was invoked to optimize the parameters of the maximum entropy ecological niche model(Maxent);and a correlation analysis of 34 environmental factors was conducted to screen the environmental factors involved in the modelling and to assess the environmental dominant factors in the P.mira habitat using the Jackknife.The optimized model was used to analyze the geographical distribution of the current habitat of P.mira,to project the potential habitat of P.mira during the Last glacial maximum and the Mid Holocene,and to analyze the changes in its historical potential geographical distribution.Based on the IPCC 6th climate the model was also used to predict the future distribution trends of P.mira under different climate scenarios.The main results of the study showed that:(1)The ENMeval optimisation results show that the optimal model has a combination of linear,quadratic,fragmented,product and threshold features and the regulation radio is 1.5.The AUC of the optimised model for the subject work characteristic curve analysis method is 0.976,with a low training omission rate,low complexity and prediction results that are generally consistent with the actual findings,shows that the prediction model is extremely reliable and has excellent accuracy.(2)The Jackknife results showed that Isothermality,Annual difference in temperature,Annual precipitation,Maximum temperature in the hottest month and Altitude were the main environmental factors influencing the distribution of P.mira in China,and that temperature and altitude were the main factors influencing the distribution of P.mira suitable area;their contribution values were significantly greater than those of precipitation and soil factors,both of which determine the potential geographical distribution of P.mira in China on a large scale.(3)Comparing the suitable area of P.mira in China under two historical periods and three future climatic scenarios,we conclude that the suitable area of P.mira shrank considerably during the LGM to MH,and the distribution area also shifted to higher altitude areas.In the future climate scenario,as the warming intensifies,some of the low latitude suitable areas of the P.mira will become unsuitable areas,and the suitable areas will migrate to higher altitudes.Global warming has changed the distribution pattern of P.mira in China,and the expanded and lost areas of P.mira suitable area are located at the edge of the suitable area,which are sensitive areas and need to be paid adequate attention to these areas.As for the reserved area,it is possible to consider establishing a resource protection zone in this area to provide scientific guidance for the conservation and breeding of P.mira.