Sensitive joint vetch rediscovered at Colonial National Historical Park
By Charles D. Rafkind and Betsie Blumberg

NPS photo by Virginia Institute of Marine Science, College of William and Mary

Jamestown Island, part of Colonial National Historical Park (Virginia), is the site of the first permanent English colony in North America. The 400th anniversary of the founding of Jamestown will be celebrated in 2007. Among other preparations for the anniversary, the park has initiated a series of natural resource inventories with different partners. The Virginia Division of Natural Heritage, under a cooperative agreement, resurveyed the area for rare, threatened, and endangered plants and animals to ensure that construction and renovation activities to be undertaken for the celebration on and around Jamestown Island will not impact these species.

The first find, actually a rediscovery, was of sensitive joint vetch (Aeschynomene virginica), an annual, bushy member of the Fabaceae (legume) family endemic to mid-Atlantic tidal wetlands (photo above). The plant was last observed in the park in 1938. In 2000, approximately 15 plants were found near the 1938 site. Sensitive joint vetch is rare throughout its range and is currently on the federal list of threatened species. The Virginia Natural Heritage program ranks the species as very rare and imperiled both statewide and globally.

As of 2004 the plant appears to be thriving. To protect sensitive joint vetch during construction activities for the Jamestown 2007 celebration, the park partnered with the Virginia Institute of Marine Science. The institute’s Dr. James Perry and a summer intern observed more than 100 plants in June 2004 (photo below); by September they counted more than 200. The population expansion may be due to two seasons of unusually high rainfall, which reduced the salinity of the water. The park is considering experimenting with methods to enhance sensitive joint vetch habitat and to increase its chances to thrive and expand. Future research may include clearing away early-season vegetation that shades the late-blooming vetch, and planting its seed to expand the area where it grows. The park has also moved the path of a proposed boardwalk away from the vetch habitat, and it is being monitored to ensure that celebration activities do not harm this survivor.

NPS photo by Virginia Institute of Marine Science, College of William and Mary