Mitracarpus polycladus is a small shrub that is known to occur in aggregations where soil and water accumulate on exposed limestone areas.

At the time of listing in 1994, Mitracarpus polycladus was only known to occur in two populations, Puerto Rico and Saba Island (The Netherlands) with an unknown number of individuals. The Service is now aware of over 20,000 individuals in three populations – Puerto Rico, Saba Island and Anegada Island (British Virgin Islands). About 89 percent of the plants in the Puerto Rico population occur in areas managed for conservation, where threats due to habitat modification from urban development are substantially reduced. The remaining 11 percent of Mitracarpus polycladus in Puerto Rico and the plants on Saba and Anegada Islands occur on private property and are more vulnerable to the threat of urbanization and development.

The Service is reclassifying Mitracarpus polycladus from endangered to threatened under the Endangered Species Act (ESA) due to successful conservation efforts. In addition, the Service is enacting a 4(d) rule that tailors take prohibitions to those that provide conservation benefits for the species. The 4(d) rule will apply the prohibitions for endangered plants with standard exceptions to the prohibitions to allow partners to work with cultivated seeds on recovery actions.

The Service completed five-year reviews in 2011 and 2018 with recommendations to reclassify the shrub from endangered to threatened.

The ESA defines an endangered species as one in danger of extinction, and a threatened species as one likely to become endangered within the foreseeable future. Based on evaluation of the best available scientific and commercial information, the Service has determined the species’ status has significantly improved, and it no longer meets the definition of endangered under the ESA, but it does meet the definition of threatened. 

The primary threats to Mitracarpus polycladus are habitat destruction and modification due to road and trail maintenance, trampling (intense trail use), fires, non-native invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.

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Multiple partners have been working with the Service on recovery efforts for Mitracarpus polycladus, including the Puerto Rico Department of Natural and Environmental Resources (PRDNER) and the Royal Botanic Gardens (Kew), in collaboration with the National Park Trust of the Virgin Islands. The Service will continue to work with PRDNER and private landowners and other partners on the monitoring and surveying of unexplored Mitracarpus polycladus habitat to develop sound conservation strategies and proactively identify priority areas for conservation.  

The Service also encourages continued surveys in areas critical to Mitracarpus polycladus survival, and further conservation agreements, including the development and implementation of conservation measures to avoid or minimize adverse effects on the species and its habitat.

For a threatened species, the Service uses the flexibility provided under the ESA’s section 4(d) to tailor take prohibitions to those that provide conservation benefits for the species. This targeted approach can reduce ESA conflicts by allowing some activities to continue that may benefit and not significantly harm the species, while focusing efforts on the threats that slow the species’ recovery. These customized protections minimize the regulatory burden while maximizing the likelihood of recovery for threatened species.  

The 4(d) rule for Mitracarpuspolycladus will apply the prohibitions for endangered plants (50 CFR 17.61) with standard exceptions to the prohibitions to allow partners to work with cultivated seeds on recovery actions.