Predicting the distribution of dwarf mistletoe (Arceuthobium sichuanense) with GARP and MaxEnt models

Sichuan dwarf mistletoe (Arceuthobium sichuanense) is a plant that parasitizes Picea trees. Recently, this dwarf mistletoe has caused serious damage to spruce trees in Sanjiangyuan area, Qinghai Province. In this study, based on the data on the reported sites, we applied GARP and MaxEnt niche models to predict and analyze the distribution area of A. sichuanense in China. The predicted results were then tested by ROC curves. The results showed that the predicted area by GARP model was more extensive while the area by MaxEnt model was more detailed. Thus, GARP and MaxEnt models were combined with a weight ratio 4:1 to predict the distribution area of A. sichuanense. The AUC value of GARP-MaxEnt model was 0.937, indicating that the precision of prediction was high. Based on the GARP-MaxEnt prediction model, it is shown that the distribution area of A. sichuanense is mainly in Qinghai, Gansu, Sichuan and Tibet. The junction area of Qinghai, Gansu and Sichuan was the most suitable area for A. sichuanense parasitism. The results will benefit our understanding of the distribution area of A. sichuanense, and have an guiding significance for monitoring the disease and making scientific strategy to control this dwarf mistletoe.