Feds to Protect Georgia Flower From Invasives

     WASHINGTON (CN) – The U.S. Fish and Wildlife Service listed Georgia rockcress as a threatened species under the Endangered Species Act (ESA) due to severe encroachment by invasive species. The listing action and critical habitat designation for 732 acres of river bluff habitat were published Friday. The plant grows only in Georgia and Alabama.
     The listing is part of a 2011 settlement agreement between the federal agency and the Center for Biological Diversity (CBD) that resulted in a five-year workplan to speed listing decisions for hundreds of species across the country. The CBD petitioned for the plant’s protection in 2004.
     The USFWS first reviewed the plant’s status in 1975 due to a report by the Smithsonian Institution on endangered and threatened plant species. “After it spent 39 years on a waiting list, I’m excited Georgia rockcress finally has the protection it needs to survive,” Tierra Curry, a senior scientist at the CBD, was quoted as saying in the group’s response to the listing.
     The USFWS said the plant has been on a candidate list under the ESA since 2000, in its press release, but the discrepancy is likely due to changes in the way the agency determines candidate status. The USFWS eliminated candidate categories in 1996 and some species that had previously been on the candidate list were dropped. The rockcress was “again elevated to candidate status” in 1999, according to the 2013 proposed listing rule.
     The rangy three-foot tall herb has tiny white flowers and it grows on steep river bluffs and rock outcroppings in areas that contain a mixture of sun and shade beneath hardwood trees. Gaps in the canopy are important for the survival of the plants, which grow in shallow soil and are not good competitors, according to the listing action.
     Disturbance of habitat areas due to logging, road and dam construction, quarrying, grazing, and development has opened the door for invasion of exotic species that are strong competitors for the rockcress’ habitat. Japanese honeysuckle, Chinaberry, kudzu, mimosa, Japanese and Chinese privets, Japanese climbing fern and Nepalese browntop are only some of the aggressive non-natives that can easily crowd out the rockcress. “Japanese honeysuckle was observed growing on individual plants of Georgia rockcress at three sites … at a fourth site, [rockcress] plants growing in a mat of Nepalese browntop declined in number from 27 individuals in 1995 to 3 in 2006,” the action said.
     Of the 18 surviving populations, 14 are threatened by nonnative species. There are less than 5000 plants total, and 12 of the populations have less than 50 plants.
     The plants are found in three river system areas, the North Georgia group, the Middle group, and the Alabama group. The middle group holds the Goat Rock Dam and Fort Benning populations, which are the strongest with around 1,000 plants at Goat Rock and 1,600 plants at Ft. Benning. The North Georgia and Alabama groups are extremely important to maintain genetic viability for the species, but they are more vulnerable to local extinction due to the small size and fragmentation of the populations. “A genetic bottleneck would result in reduced genetic diversity with mating between closely related individuals, which can lead to reduced fitness due to inbreeding depression,” the agency said.
     In a separate action, the agency designated 732 acres of critical habitat for the plants in five counties in Georgia and six counties in Alabama. Both actions are effective Oct. 14.

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