“Connecting Appalachian Icons: The importance of conserving plant-animal mutualisms in a changing world.”

Hruska, Amy M., Michael C. Elza, and James B. McGraw. University of Hawai‘i at Mānoa.

(Presented at The Future of Ginseng and Forest Botanicals Symposium, July 12-14, 2017, Morgantown, WV)

Abstract

Alteration of mutualistic interactions can negatively affect population growth and persistence. As a declining species with economic and cultural value, and a life history similar to many other understory herbs, American ginseng has become a focal species for many demographic and conservation-based studies. However, little research has been conducted to understand a critical mutualism for ginseng populations: seed dispersal. Anecdotally, ginseng seeds have been classified as gravity dispersed; but, the production of red, fleshy-fruits suggest a mutualism with animals. Trail cameras were used to identify thrushes, particularly wood thrushes (Hylocichla mustelina), and small mammals as potential dispersers.  Through feeding studies, thrushes were identified as the primary seed dispersers, while small mammals were identified as predators. Radio transmitters were used to determine potential dispersal distances by wood thrushes and compared with field observations of wood thrush presence/absence and ginseng distribution at 28 populations. Wood thrushes were found to be predictive of ginseng distribution within a site. Dispersal by wood thrushes is likely to be important for the persistence of ginseng as harvest, deer browse, and climate change continue to threaten populations. However, wood thrushes are also a declining species – linking ginseng and wood thrush conservation.