Northern Wild Monkshood

Aconitum noveboracense

Description

Northern wild monkshood, Aconitum noveboracense, is a perennial herb growing from tuberous roots and producing blue or purple flowers on a long, slender, branched flower stalk. Leaves are few and deeply toothed. Monkshood derives its name from its hood-shaped flowers, which are adapted to pollination by bumblebees. Flowers are present from June through September.

The roots and leaves of all members of the genus Aconitum, contain poisonous alkaloids that can cause paralysis to the nervous and circulatory systems. These plants have a long history of use in folk medicine and pharmacology. The roots of several Old World monkshoods were used by the ancient Greeks and Romans to make an arrow poison; the stems and leaves were the source of the drug aconite, used by witches during the Middle Ages to induce the sensation of flying.

Habitat

Northern monkshood is found in deep shade within mature deciduous or pine forests in a specific habitat type, known as algific or "cold soil" habitat. Algific habitat is created when cool air from a permanent layer of subsurface ice circulates upward through loose cliffside talus slopes. These very localized conditions generate a constant high relative humidity and significantly cooler air temperatures that are essential for the growth of monkshood.

These factors—ample water, deep shade, and algific soils—support a large group of associated plants and wildlife, many with unique or unusual characteristics. Common plant associates include eastern hemlock, white snakeroot, wood nettle, willow herb, fowl manna grass, small enchanter's nightshade, and many fern varieties.

Distribution

Six species of the genus Aconitum are found in North America. Northern monkshood is restricted to the unglaciated portions of Iowa and Wisconsin, glaciated northern Ohio, and the Catskill Mountains of New York. Of 24 historically known sites, 22 still survive.

Although the northern wild monkshood ranges over half the continent from Iowa to New York, the entire population occurs on about 500 acres (200 hectares) in small habitats comprised of cliff faces, talus slopes, and streams. The number of plants at these sites range from three to 10,000. The small number of cliff habitats possessing the correct combination of exposure, cold and root-zone microclimate, and the requirements for seed germination appear to be the factors limiting the species' distribution. The plants are slow growing and not very viable when transplanted.

The largest concentrations of northern wild monkshood are found in southwestern Wisconsin and in northeastern Iowa. Six monkshood populations are known from southwestern Wisconsin in Grant, Richland, Sauk, and Vernon Counties. The largest extant population is found along Chase Creek in Grant County. In 1985 the Wisconsin population was estimated at 6,000.

Ten populations are found in the Driftless Area of northwestern Iowa in Allamakee, Clayton, Dubuque, Jackson, and Delaware Counties. A recent study indicated that this region of nearly 200,000 acres (80,940 hectares) might yet contain significant pockets of algific habitat. The Driftless Area has not been entirely surveyed. Two small populations are found in the Ohio counties of Portage and Summit, and four populations occur in Ulster County, New York.

Because populations are found in sites of great natural scenic beauty, much of the northern monkshood's habitat is already protected as part of a state park, a national forest, or a designated nature preserve. Only about half of the northern monkshood sites—including all sites in New York—are on private land. The 10 populations in 1985 were estimted at 2,200 individuals.

Threats

In 1966 a dam project on the Kickapoo River in Wisconsin, proposed by the U. S. Army Corps of Engineers, threatened to inundate several of the largest populations of northern wild monkshood. This threat stimulated state botanists to propose the species for protection under the initial Endangered Species Act. Subsequent surveys conducted by the Wisconsin Department of Natural Resources led to a federal designation of threatened status for the plant. Listing delayed completion of the dam indefinitely, and the conflict has yet to be resolved.

The plant is threatened primarily by its highly restrictive habitat requirements. Any activities that disturb the habitat, such as stream impoundments, logging, or quarrying, will adversely impact the northern wild monkshood. The key to recovery is protecting the habitat.

Conservation and Recovery

Since the Kickapoo Dam controversy, much of the impetus for recovery has been in Iowa. A large population site along Buck Creek (in Clayton County) was donated by a private landowner to the Nature Conservancy to establish a refuge. In 1986 the Nature Conservancy, the U. S. Fish and Wildlife Service, and the Iowa Conservation Commission jointly initiated a program to protect algific habitat in the Driftless Area of northern Iowa. Under this program, landowners were asked to voluntarily protect occurrences of algific habitat on their lands. Nearly three-fourths of those contacted agreed to register their properties with the Nature Conservancy.

Following up on this success, the state of Iowa applied for and received a federal grant to purchase a 13-acre (5.3-hectare) site near St. Olaf that supports an estimated 10,000 northern monkshood plants. The site also protects the federally listed endangered Iowa Pleistocene snail (Discus macclintocki ).

The recovery plan for the northern wild monkshood recommends many actions, which include zoning protection for all the species' habitats; minimizing threats to populations; creating a landowner monitoring program for all populations; searching for additional populations; continuing research on the life process of the species; and strengthening the legislation protecting the species for plant administration on federal lands.

Two of the Iowa populations are in state parks (Maquoketa and Bixby State Parks) which became the sites for a 1979 study of the species. Based on soil type, geology, and land use, it was determined that there is 190,000 acres (77,000 hectares) of potential habitat for the species, and that other populations may survive.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1 Federal Drive
BHW Federal Building
Fort Snelling, Minnesota 55111
Telephone: (612) 713-5360
http://midwest.fws.gov/

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035-9589
Telephone: (413) 253-8200
Fax: (413) 253-8308
http://northeast.fws.gov/

References

Brink, D. 1982. "Tuberous Aconitum (Ranunculaceae) of the Continental United States: Morphological Variation, Taxonomy, and Disjunction." Bulletin of the Torreya Botanical Club 109 (1): 13-23.

Hardin, J. W. 1964. "Variation in Aconitum of Eastern United States." Brittonia 16: 80-94.

U. S. Fish and Wildlife Service. 1983. "The Northern Monkshood Recovery Plan." U. S. Fish and Wildlife Service, Twin Cities, Minn.