Evidence for decline in stature of American ginseng plants from herbarium specimens

American ginseng (Panax quinquefolius L.) has been harvested from the wild to supply the Asian herbal market for more than 200 years. As a CITES Appen dix II listed species, ginseng trade has been monitored since 1975 and evid ence for no detrimental effects of harvest is required annually by the US g overnment. One kind of evidence gathered to gauge harvest effects has been mean root size and age, however the short-term nature of the data set limit s possible inferences. In this study, 915 herbarium specimens from 17 herba ria were aged and measured to extend the time-transect to 186 years. Nine o f 11 size-related traits showed statistically significant declines, most of this change occurring since ca. 1900. Multivariate analyses confirmed the overall decline in plant size. Age of herbarium specimens did not significa ntly decline during the same interval. Plants collected from northern popul ations did not decline in size, while plants from midwestern, Appalachian a nd southern states showed sharp declines in stature. Assuming herbarium spe cimens are representative of a consistent portion of natural populations, e ither direct or indirect effects of environmental change or human harvest c ould explain the rapid change in ginseng stature. Understanding the implica tions of such plant stature changes will require examining the effects of s ize on harvest probability and reproduction in the context of population vi ability analyses. (C) 2001 Elsevier Science Ltd. All rights reserved.