Prediction of the potentially suitable areas of Litsea cubeba in China based on future climate change using the optimized MaxEnt model

Litsea cubeba is an important woody oil plant. The essential oils (EOs) can be extracted from its flowers, leaves and peels and, by volume, it is the most exported natural EOs from China. Thus, L. cubeba has important economic and medicinal value. Although there is demand for the rapid expansion of L. cubeba production, there has been a sharp reduction in natural resources. Therefore, determining the potentially suitable area for L. cubeba and expanding its cultivation will help meet the growing demand for volatile oil. Based on 453 distribution records of L. cubeba in China and 16 major environmental factors, we simulated the distribution pattern of the potentially suitable area of L. cubeba under three different climate change scenarios (SSP126, SSP370 and SSP585) in three time periods: the current period, 2050 s, and 2070 s. The analysis was implemented using the MaxEnt model, optimized using the ENMeval package. The jackknife test, percent contribution and response curve were used to determine the most important environmental factors and response intervals affecting the distribution of L. cubeba. We found that the parameter settings of the optimal model were RM = 2.5 and FC = LQH. The results of the MaxEnt model exhibited a high prediction accuracy and a low degree of overfitting. Precipitation of the driest quarter, annual precipitation, temperature annual range and minimum temperature of the coldest month were the dominant factors affecting the distribution of L. cubeba, and their thresholds were >= 36.21 mm, >= 905.95 mm, <= 32.44 degrees C and >= -3.73 degrees C, respectively. The results showed that the total potentially suitable area of L. cubeba in China was 208.19 x 104 km2 under current climate conditions. The predicted potentially suitable area was mainly concentrated in the 19 provinces and cities in the Yangtze River Basin and its southern area. Under future climate change conditions, the predicted potentially suitable area of L. cubeba increased with time, and the centroid of the predicted potentially suitable area of each grade moved northward. The results of this study can be used to guide the selection of future introductions, as well as the development, artificial cultivation and resource conservation of L. cubeba.