WASHINGTON (CN) - The U.S. Fish and Wildlife Service has proposed endangered status for a rare fern, due to threats from development and sea level rise. The agency said it would publish a separate rule to designate critical habitat in the near future, according to the proposal.
The proposed listing was spurred by a 2011 settlement agreement between the USFWS and the Center for Biological Diversity (CBD) that resulted in a five-year work plan to fast track listing decisions for hundreds of species. "The intent of the agreement is to significantly reduce a litigation-driven workload," the agency said in its press release.
The Florida bristle fern, a candidate species under the Endangered Species Act (ESA) since 2009, has only two known population groups, separated by approximately 250 miles. The USFWS conducted genetic analysis and determined that the two widely separated groups are the same subspecies. The group in Miami-Dade County has four populations and the group in Sumter County has only two populations.
The imperiled plant is threatened by development, agricultural conversion, drainage projects, canal installations and rising sea-levels.
The ferns require moist, heavily shaded areas with exposed limestone. They grow in rootless mats of thin, filmy leaves. The bristle fern gets it name from the bristly growths that jut from the spore-producing structures. It grows on other plants or on rocky outcroppings, and is often found on the steep sides of limestone solution holes formed by the collapse of surface rock after the limestone below has been dissolved away.
The plants live in low-lying areas and are at risk from increasingly strong storm surges and hurricanes due to climate change. The sea level has risen along the Florida coastline more than nine inches over the past 100 years, according to the listing proposal. Due to the porous nature of limestone, the rising sea level also signals an increase of the salinity in the groundwater and soil, which can affect both the ferns and the canopy plants around them that provide the shade the ferns require to survive. The increasing soil salinity could also favor invasive plants that may have a higher tolerance for salt levels.
The agency determined that the bristle fern meets the definition of an endangered species under the ESA because it faces a combination of threats throughout its range, which, combined with the species' small populations, means it is currently in danger of extinction.
The CBD hailed the proposed protections for the fern. "This is great news for this important plant," CBD attorney Jaclyn Lopez said in the group's response to the listing proposal. "Endangered Species Act protection well help ensure its survival in the face of increasing development pressures and sea-level rise."
The agency requests information and comments by Dec. 8.
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