WASHINGTON (CN) - Three south Florida native plants are in imminent danger of extinction due to a complex of threats that are worsened by the effects of sea level rise, the U.S. Fish and Wildlife Service has said. The agency has listed the plants as endangered under the Endangered Species Act (ESA), according to a recent listing action.
The listing is part of a court-approved workplan resulting from a settlement between the agency and the Center for Biological Diversity (CBD) to fast-track listing decisions for 757 species over five years.
"These native plants are being squeezed out of existence, pressed between coastal development and rising sea levels. Protection under the Endangered Species Act will give them a role in South Florida's planning for rising seas," Jaclyn Lopez, a Florida-based CBD attorney was quoted as saying in the group's response to the listing.
The two cactus species, Aboriginal prickly-apple and Florida semaphore cactus, and the flowering perennial herb, Cape Sable thoroughwort, face threats from habitat loss from development and other human-caused impacts, non-native plants, non-native herbivores, climate change, storms and wildfires. The two cactus species also face specific threats from poaching by collectors, and the cactus moth is a significant threat to the semaphore cactus.
The three endangered plants are already being affected by the increased salinity of water tables underlying their habitats, caused by sea-level rise, and the effects over time are expected to be devastating.
Of the 12 historic populations of the blue-flowered thoroughwort, four have been wiped out by development. The other eight populations are vulnerable to sea level rise. "Seven of eight locations currently supporting [Cape Sable thoroughwort] will be completely inundated by the projected 1.8-m (5.8-ft) sea level rise by 2100," the agency said. (Parentheses in original.)
Of four historic populations of the tree-like Semaphore cactus, two were destroyed by development and poaching. There are six small existing populations due to reintroduction efforts, but four of these are expected to be inundated by salt water by the end of the century.
The sprawling prickly-apple is faring no better with all 12 of its remaining populations subject to poaching and increased salinity, with half of the populations expected to be wiped out by the rising sea level.
Because there are man-made barriers to dispersal, the remaining populations of these rare plants are small and isolated from one another. This creates genetic bottlenecks and increases the chance of entire populations being wiped out by storm surge or other extreme weather events.
Since the agency proposed listing the plants, the agency has reversed its position on designating critical habitat for the two cactus species. The 2012 proposal noted that the danger from poaching was a reason not to designate habitat due to the resulting publication of specific location information. Through comments received on the listing proposal, the agency determined that location information is already widely available. The agency plans to publish critical habitat designations for the three species in the near future.
"The ultimate goal of the ESA is the recovery of these three plants, so that they no longer need the protective measures of the ESA. The service will now develop a recovery plan for the three species and work cooperatively with partners to conserve their habitats," the agency said.
The listings are effective Nov. 25.