FIGURE 4.

Ecological niche models of (a) Camellia japonica and (b) C. rusticana using MaxEnt. The environmental variables used were those estimated from the Community Climate System Model 3.0 (CCSM) (Collins et al. 2006) for the last glacial period. A mesh size of 4.5 km was used in WorldClim v. 1.4. The resulting distribution prediction model was evaluated by calculating the area under the curve (AUC) from the ROC analysis. The selection of environmental variables included annual average temperature, average temperature during the four summer months, average temperature during the four winter months, annual precipitation, precipitation during the four rainy months and precipitation during the four dry months. The AUC values calculated by ROC analysis ranged from 0 to 1, with values closer to 1 indicating higher accuracy of the model. The background range and cell size (1 km²) of all layers, including the environmental variable values, were uniformly prepared using the ArcGIS software.