Non-Natives Threaten Rare Georgia Flower

     WASHINGTON (CN) – The U.S. Fish and Wildlife Service has proposed listing Georgia rockcress as a threatened species under the Endangered Species Act, with 786 acres of critical habitat, as part of a 2011 settlement agreement.
     The agreement between the USFWS and the Center for Biological Diversity (CBD), one of the most frequent litigants against the agency, resulted in a five-year workplan to facilitate listing decisions on hundreds of species across the country.
     The agency announced in 1975 that it would review the rockcress due to a report by the Smithsonian Institution on endangered and threatened plant species. The rockcress, a three-foot tall perennial plant with tiny white flowers, was eventually listed as a Category 2 candidate species, meaning that listing was possibly appropriate, but the agency lacked sufficient information to make a listing proposal. The CBD petitioned the agency in 2004, and the rockcress became part of the settlement workplan in 2011, according to the group’s statement.
     “After 38 years on a waiting list, Georgia rockcress is finally getting its day in the sun,” Tierra Curry, a biologist at the CBD was quoted as saying in the group’s press release.
     Only about 5,000 of the plants still exist. It generally grows on steep river bluffs with shallow soils overlaying rock. The plant grows where there is a gap in the canopy of trees, and where the steepness of the terrain prevents leaf litter buildup. Unfortunately, it faces stiff competition from invasive non-native species.
     “While Georgia rockcress needs small-scale disturbances with slightly increased light, limited competition for water, and exposed soils for seed germination, the species is a poor competitor and is easily outcompeted by aggressive competitors,” the action noted.
     Since the plant is adapted to take advantage of increased light due to gaps in the forest canopy, when those gaps close due to the natural growth of the trees, the rockcress population declines.
     Since there are only 18 known populations scattered through Georgia and Alabama, with 12 of those having less than 50 plants, the loss of any population can have an impact on the genetic diversity of the species and result in inbreeding.
     “The 18 surviving populations of rockcress are threatened by habitat degradation from development, logging, quarrying, camping, invasive species and hydropower dams,” the CBD said.
     Quarrying destroys bluff habitat by removing the canopy and soil, while other human activities provide an invitation for non-native species, the action said.
     “Disturbance, associated with timber harvesting, road building, quarrying, grazing, and hydropower dam construction, creates favorable conditions for the invasion of exotic weeds, especially Japanese honeysuckle,” the agency noted in its statement.
     In a separate action, the agency has proposed 786 acres of critical habitat for the plant in a mix of private and state/federal lands. The USFWS is working with Fort Benning in Georgia, which has the largest population of the rockcress (1,600 plants), to develop an Integrated Natural Resource Management Plan. The agency proposed 62 acres on Fort Benning as critical habitat. Another large population of about 1,000 plants is on land managed by Georgia Power, and the agency proposed 79 acres of critical habitat on its holdings in Harris and Muscogee Counties. The remaining proposed critical habitat designations are on private land.
     For both actions, comments are due by Nov. 12, with written public hearing requests by Oct. 28.

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