关键词: 白栎, Maxent, AICc, 末次盛冰期, 适生区

Abstract: [Objective] Quercus fabri is a deciduous tree species of the genus Quercus in China, with high economic and ecological value. At present, most studies focus on the exploitation and utilization of Q. fabri resources, however, there is little research on the geographical distribution pattern of Q. fabri. In this study, we used the optimized Maxent model to predict the suitable areas of Q. fabri and understand the effect of climatic factors on the distribution of Q. fabri. As the same time, we discuss the cultivation zoning and introduction zoning of Q. fabri in combination with the PHZM, and provide some theoretical basis for the introduction and cultivation of Q. fabri.[Method] We used AICc index to screen feature and beta multipliers,and then establish the optimal model. Based on the 484 distribution records and 10 environmental variables, we simulatedthe potential distribution areas of Q. fabri during the Last Glacial Maximum, Mid-Holocene, Present and the year 2070 and investigated the environmental factors affecting the distribution of suitable habitat of Q. fabri by means of percent contribution, permutation importance, and Jackknife test, Limiting Factors.[Result] 1) The parameters of the optimal model were set as follows:feature is LQP and the β multiplier is 1.5. 2) Jackknife test showed that Annual mean temperature, Precipitation of the driest month, Temperature annual range were the key factors; the top three environmental variables of percentoge contribution rate were Mean diurnal range, Temperature annual range, and Annual mean temperature; the top three of permutation importance were Annual mean temperature, Temperature annual range, and isothermaling.Mean diurnal range the environmental limiting factors affecting the potential distribution in the present were Annual precipitation, and precipitation of the driest month; Precipitation of the driest month, and max temperature of the warmest monthwere the environmental limiting factors of potential distribution of future. 3) The highly suitable region for the present distribution covered Chongqing, part of Guizhou, Hunan, southern Hubei, Jiangxi, southern Anhui, northern Fujian, and the Yangtze River Delta region. In the Last Glacial Maximum, the highlysuitable areas of Q. fabri were scattered in Hunan and Jiangxi, which is less than the present distribution areas by 28.28%. In the middle reached Holocene, the highly suitableregion was similar to the present one, but it'sareas increased by 6.44% and the are to the maximum of the four periods. In the prediction of future suitable distribution areas, Liaoning did not have a suitable area in the present but there is a small part of the low suitable areas in the future. Temperature may rise in 2070, the suitable distribution area would expand to the north and the highly of the suitable areas of Q. fabri decreased by 6.44%.[Conclusion] Annual mean temperature, mean diurnal range, temperature annual range, and precipitation of the driest monthare important environmental factors that restrict the distribution pattern of Q. fabri. The environmental limiting factors affecting the distribution in the present and future prediction are annual precipitation, precipitation of the driest month and max temperature of the warmest month. The highly suitable areas of Q. fabri in the last glacial maximum are concentrated in central China, and then gradually moved to the north with the warming of the climate. The whole suitable areas reachto the maximum in the Mid-Holocene. The future temperature would rise, and the suitable areas of Q. fabri may be the trend of northward expansion, and Q.fabri in high altitude in is more susceptible to climate. According to the distribution pattern of Q. fabri and the PHZM in China, Xinjiang, Beijing and Tianjin may be suitable for the introduction and cultivation of Q. fabri.

Key words: Quercus fabri, Maxent, AICc, last glacial maximum, suitable distribution area