Predicting the potential geographical distribution of Erythrophleum fordii in China based on SSPs

  Objective  As a rare hard wood species, the natural forest resources of Erythrophleum fordii have been seriously damaged due to its precious wood. Its distribution range is sharply reduced and the E. fordii is rare. Therefore, it is listed as the second class protected rare tree species in China. We studied the impacts of climate change on the geographical distribution of E. fordii in order to provide some theoretical knowledge for the protection and introduction of its natural resources.

  Method  Based on 55 distribution stands of E. fordii, using the BCC-CSM2-MR climate model and shared socio-economic pathways (SSPs) as climate data, combining with elevation, soil and human activity data, the MaxEnt model was used to predict the growth distribution of E. fordii under three scenarios of SSP1_2.6, SSP2_4.5 and SSP5_8.5 in 2041−2060 (2050s) and 2081−2100 (2090s).

  Result  The prediction results were relatively reliable when the feature combination was HPT and the regularization multiplier was 2.5. Comprehensive contribution rate, permutation importance and jackknife test showed that temperature annual range, precipitation in January, elevation, annual precipitation, mean diurnal range were the dominant factors affecting the geographic distribution of E. fordii. The total growth-suitable area of E. fordii decreased under SSP1_2.6 and SSP2_4.5, while the total growth-suitable area of E. fordii increased under SSP5_8.5, and there was a growth advantage under this scenario. The northern part of the original growth-suitable areas of Fujian, Guangxi and Guangdong, the southern small part of Yunnan and Tibet, and the southern part of Sichuan Basin will become the potential suitable areas of E. fordii. By analyzing the direction of centroid migration in the three scenarios during 2050s and 2090s, the centroid had a tendency to migrate more and more northward.

  Conclusion  Temperature, precipitation and elevation were the dominant factors affecting the geographic distribution of E. fordii under current and future climate scenarios. The temperature and humidity increase caused by extreme climate change can promote the growth of E. fordii to a certain extent, the low mountains and hills in the northwest of Guangdong and Guangxi, Xishuangbanna in Yunnan can be introduced and cultivated in order to expand the planting area of E. fordii in the whole country. it is necessary to strengthen the protection of E. fordii in time and take active and effective measures to reduce the negative impact of climate change on E. fordii in order to cope with the uncertainty brought by climate change.