The Impact of Climate Change on the Suitable Growth Zone of Macadamia integrifolia in Yunnan Province

Yunnan Province is the largest global cultivation region for Macadamia integrifolia, with significant development potential. Predicting changes in suitable habitats for macadamia in Yunnan under future climate scenarios will provide a scientific basis for the transformation of existing orchards and the selection of new plantation sites. Based on 70 geographical distribution records of macadamia in Yunnan and 15 environmental variables, a Maximum Entropy (MaxEnt) model was employed to assess and predict suitable habitats for macadamia in Yunnan. The model evaluated the current suitable habitats and identified key influencing factors through the contribution rates of environmental variables. Quantitative analysis was conducted to compare the distribution of suitable habitats under two future climate scenarios (SSP1-2.6 and SSP3-7.0) for the 2050s. The results indicate that, under current climatic conditions, the total suitable area for macadamia is approximately 14.49×10⁴ km², accounting for 36.8% of Yunnan's land area, primarily distributed in southern, southwestern, and western regions, including Dehong, Baoshan, Pu'er, Lincang, Xishuangbanna. Under the two future climate scenarios, the suitable habitats for macadamia are projected to decrease by 0.85×10⁴ km² and 2.05×10⁴ km², accounting for 2.2% and 5.2% of Yunnan's land area, respectively. The centroid of the total suitable area shows a tendency to shift toward higher altitudes, with greater east-west migration observed across different suitability levels compared to north-south migration.