The Current Status and Potential Spread of an Invasive Exotic Species: Chinese Yam (Dioscorea batatas)

Field work is integrated with Geographic Information System (GIS) techniques to report the status, spread, and potential to spread of an invasive non-native species, the Chinese yam (Dioscorea batatas), in the Great Smoky Mountains National Park (GRSM). Field work results show that D. batatas primarily occurs in the lower elevations in areas of disturbance such as old homesites and the sides of roads, trails, and streams. Comparisons with earlier research conducted by Clements, Clebsch, and Wofford in 1987-1988 show that D. batatas has spread and continues to affect the herbaceous understory by shading or crowding. To determine potential spread, I developed a predictive computer model using IDRISI GIS software. This is the first known use of GIS to model the potential spread of an invasive plant species within the park. Results from the potential-spread model show that D. batatas sites in the northeastern region of GRSM have the highest potential for spread. Results are used to generate target site lists which aid in determining management strategies for D. batatas within the Great Smoky Mountains National Park. This approach of combining GIS analysis with field work investigation is recommended for future natural resource planning.