Status of Goldenseal, Hydrastis canadensis (Ranunculaceae), in Canada

Abstract

Although found throughout a large area of eastern North America south of the Great Lakes, the perennial woodland herb, Goldenseal (Hydrastis canadensis L.), was apparently only abundant in the central portion of its range in Ohio, West Virginia, Indiana, and northern Kentucky. In Canada, it is resticted to southwestern Ontario where 26 native populations have been reported representing the northern limit of its range. During a 1998 field survey, 21 populations were located, two were not surveyed, and the remaining three could not be found and are assumed extirpated. Attempts to discover additional populations with newly acquired ecological data failed suggesting that there are relatively few overlooked populations. Despite recent and rapid increase in the popularity of Goldenseal as an herbal remedy, there appears to have been little if any decline in Ontario populations since it was officially listed as threatened in 1991. Increasing use of the plant has increased the potential threat to Canadian populations and the actual global threat has also increased. Goldenseal generally occurs in isolated patches in slightly acid or neutral soil in rich mesic woodlands, often where disturbances such as tree removal or flooding have occurred. Restriction to isolated patches may be a consequence of loss of disturbance of the type caused by severe flooding of bottomland forests, fires, and impacts of extinct and extirpated fauna. Current research is aimed at understanding the limitations to its spread which may enable populations to be increased and facilitate development of a Canadian agricultural crop thus reducing pressure on natural populations.