Predicting Potential Geographic Distribution of Tibetan Incarvillea younghusbandii Using the Maxent Model

Incarvillea younghusbandii is a well-known Tibetan medicinal plant with considerable development and research value distributed widely throughout the Tibetan plateau. It is important to study spatial distribution patterns of the plant in order to develop effective protection measures. Based on field survey work and environmental data, the potential geographic distribution of Incarvillea younghusbandii was delineated using a Maximum Entropy (Maxent) model with 28 environmental variables that screened for climate, topography, human activity and biological factors. Our results showed that the main geographic range of Incarvillea younghusbandii included the valley between the Yarlung Zangbo river and the Duoxiong Zangbo river, the valley in the middle section of the Himalaya Mountains, and the area between the north side of the east section of the Himalayas and the south bank of the middle reach of the Yarlung Zangbo river. Distribution may spread to parts of the eastern Himalayas. The Jackknife test indicated that soil types, ratio of precipitation to air temperature, extreme atmospheric pressure differences and annual precipitation were the most important predictive factors for the model, while other variables made relatively small contributions.