Abstract: Michelia martinii is an arboreal tree belonging to the genus Michelia of Magnolia family. It has high ornamental value and is an excellent tree for spices and wood. However, its wild resources were not well preserved, and it was listed as one of the rare and endangered plants of national grade Ⅱ (1999). Now its protection level is Near Threatened (NT). The prediction of the effects of climate change on its distribution could provide a scientific basis and reference for the conservation and sustainable utilization of this wild resource. In this study, ArcGIS 10.4 and MaxEnt 3.4.1 model were used to analyze the potential distribution of Michelia martinii across the country, which was compared with Bioclim and Domain models of DIVA-GIS 7.5 software. The MaxEnt model with the best prediction results was then selected, and the distribution of suitable areas under four climate scenarios (RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5) in the 2050s and 2070s was predicted. The results show that the MaxEnt model could predict the potential habitat distribution accurately, and the AUC (area under ROC Curve) value of the ROC (receiver operating characteristic) training set was 0.977. Precipitation of driest month, altitude, monthly mean temperature diurnal range, and annual precipitation were the main environmental factors affecting the distribution of Michelia martinii, and the contribution rates were 43.8%, 20.7%, 15.2%, 8.8%, respectively. The high, middle and low suitable growth regions of Michelia martinii spread around Guizhou Province, covering a total area of about 5.7×10⁵ km². In the 2050s and 2070s, the distribution pattern of suitable growth regions will remain unchanged. In the 2050s, except for scenario RCP 8.5, the area of low and medium suitable areas and the total area of suitable areas of Michelia martinii under the other three scenarios will be increased. In the 2070s, the areas of medium and high fitness areas and total suitable areas of Michelia martinii will be decreased under all the four scenarios. In the future, global warming will significantly reduce the high suitable area of Michelia martinii. Under most scenarios in the future, the distribution centroid of Michelia martinii will have a trend moving to the northeast. The difficulty of protecting Michelia martinii was that its habitats are isolated and far away from each other, which intensifies the possibility of extinction. In the future, the protection of endangered resources of Michelia martinii should be combined with the prediction results of geographical distribution, from the aspects of the investigation of wild resources, ex situ protection of field return, establishment of protected areas in situ, research on reproduction and cultivation techniques, etc.

Key words: Michelia martinii, climate change, MaxEnt model, geographic distribution, suitable habitat