Service Proposes Removal of Puerto Rican Fern from List of Threatened and Endangered Plants

Press Release
Service Proposes Removal of Puerto Rican Fern from List of Threatened and Endangered Plants
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Today, the U.S. Fish and Wildlife Service is proposing to remove the Adiantum vivesii from the Endangered Species Act (ESA). After a review of the best available scientific and commercial data, including the 5-year status review, the Service has found that Adiantum vivesii is a sterile hybrid of two common fern species. As such, it does not meet the statutory definition of a species under the ESA.

“The Service’s work is grounded in thorough, objective science with a goal of conserving natural resources for future generations.” said Leopoldo Miranda-Castro, the Service’s Regional Director. “An integral part of our statutory framework is to make delisting decisions when appropriate and to revise accordingly. Delisting species that do not qualify for ESA protections allows the Service to allocate resources responsibly for on-the-ground conservation efforts, recovery planning, 5-year reviews, and other protections for species that require protection under the ESA.”

Adiantum vivesii is a fern native to the limestone-karst region of northwestern Puerto Rico. First described in 1985, the fern was only known from one population on a privately-owned limestone hill in Quebradillas. The fern was listed as endangered in 1993 and at the time of its listing, the only known population was thought to be comprised of about 1,000 plants.

Since its listing, research conducted on Adiantum vivesii led to a determination that the plant is not a discrete taxonomic entity. Although approximately 1,000 stems of the plant were present at the site of the only known population, excavation found that all above-ground stems were connected below-ground through rhizomes or underground stems. Additional investigation determined the plant to be a single, sterile hybrid resulting from the hybridization between two common fern species. Adiantum vivesii therefore no longer qualifies for protection under the ESA as it does not have the capacity to establish a lineage that could be lost to extinction.

The proposed rule will publish in the Federal Register on July 30, 2021, opening a 60-day comment period. The Service will consider comments from all interested parties received by September 28, 2021. Information on how to submit comments is available on by searching for docket number FWS-RX-ES-2020-0125.

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Endangered and/or Threatened species