Rare Plant Monitoring
The map shown to the right delineates the known locations of more than 100 rare plant populations of 32 different taxa (Caplow and Beck 1996; Hall 1998). These populations include taxa listed by Washington Natural Heritage Program as Endangered, Threatened, or Sensitive within Washington State and the locations of populations of taxa that are listed as Review Group 1 (taxa in need of additional field work before status can be determined) (Washington Natural Heritage Program 1997). Six of these 32 taxa, including the two endemic species, Eriogonum codium and Lesquerella tuplashensis, have been designated as species of concern in the Columbia River Basin Ecoregion by the U.S. Fish and Wildlife Service.
In addition to the rare plant populations, several areas on the Hanford Site are designated as special habitat types with regard to potential occurrence of plant species of concern. These include areas that potentially could support populations of rare annual forbs found in adjacent habitat. The degree of protection from disturbance afforded to the Hanford Site over the past 50 years has resulted in an "island of biodiversity" for plant resources (Caplow and Beck 1998).
The areas of occurrence of rare plants and special habitats are designated as Level III biological resources under the Biological Resource Management Plan. Level III biological resources-because of their state listing, potential for federal or state listing, uniqueness, special administrative designation, or environmental sensitivity-require mitigation under the National Environmental Protection Act. Thus, any potential impacts to rare plant populations or special habitat areas should be avoided or minimized. Entry into these areas should be minimized and restricted to foot traffic except along improved roadways.