How well do herbarium data predict the locationof present populations? A test using Echinacea species in Missouri

The four native Missouri taxa of Echinacea were used as a model to test the predictive value of herbarium data with regard to present-day distribution. Specimens with label data considered potentially adequate to relocate the population were databased and the sites in question were visited. Most of the historical populations were not relocated, although a greater percentage of those collected post-1980 were found to still exist. Time since collection significantly affected the probability of relocation of E. purpurea and E. pallida var. pallida, the two native taxa commonly harvested for medicinal products. The collection rate for E. pallida var. pallida remained high over time. However, the collection rate for E. purpurea has been much reduced in recent decades. Few of the historical populations were relocated, and located populations on unprotected public land were very small, perhaps indicating that habitat loss or human activity is causing a decline in Missouri populations of E. purpurea.[PUBLICATION ABSTRACT]