Prediction of Suitable Habitats for Sapindus delavayi Based on the MaxEnt Model

Sapindus delavayi (Franch.) Radlk. (S. delavayi) is an important biological washing material and biomass energy tree species with a peel rich in saponins and a kernel high in oil content. We used the maximum entropy model (MaxEnt) to predict the suitable habitats for S. delavayi in China, screen the dominant environmental factors affecting its distribution, and analyze the changes in its suitable habitats under future climate change. The results provide a scientific basis for its introduction, cultivation, and germplasm resource collection and protection. Twenty-two environmental variables and China distribution data for S. delavayi were used to construct the species distribution model, and the receiver operating characteristic (ROC) curve was used to verify the model's accuracy. The dominant environmental factors were screened through the jackknife method, then a geographical information system (ArcGIS) was used to determine the level of suitable habitat division and area calculation. The results showed that the MaxEnt model had an excellent predictive effect for which the area under the ROC curve (AUC) value was as high as 0.959. The annual precipitation (Bio18), minimum temperature of the coldest month (Bio6), temperature seasonality (Bio4), and precipitation of the coldest quarter (Bio19) were the dominant environmental factors that affected the distribution of S. delavayi. Under the current climate, the suitable area for S. delavayi is 1,321,308.07 km(2), and under the four climate scenarios for the 2050s and 2090s, the suitable area is predicted to change by -3.97%similar to 2.57%. Overall, the centroids of the highly suitable habitats will shift by different degrees to the southwest in the future.

Automated summary

In this study, the maximum entropy model was used to predict the suitable habitats for Sapindus delavayi in China. The dominant environmental factors affecting its distribution were identified. The results provide important insights for its introduction, cultivation, and protection of germplasm resources.