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The U.S. Fish and Wildlife Service’s, Caribbean Ecological Services Field Office has been collaborating with the British institution the Royal Botanic Garden, Kew, for nearly a decade to define and implement sound conservation efforts aimed toward the recovery of Puerto Rico’s threatened and endangered plant species. This collaboration seeks to build capacity and to promote communication and exchange of knowledge between Puerto Rican and international institutions, including the University of Puerto Rico at Mayagüez (UPRM), Puerto Rico Department of Natural and Environmental Resources (PRDNER), the University of Portsmouth, the National Parks Trust of the British Virgin Islands (BVI), Vieques National Wildlife Refuge, and the Service.
In September, 2019, colleagues from the Service, Kew, UPRM, and Vieques NWR initiated the first living ex situ collection (in cultivation) to aid in the conservation of two rare plants: Varronia bellonis and Varronia rupicola. Varronia bellonis, which is listed as endangered under the Endangered Species Act (ESA), is endemic to the moist serpentine soils and moist limestone forests of Puerto Rico. Varronia rupicola, listed as threatened under the ESA, is found in the dry limestone forests of Puerto Rico and the island of Anegada in BVI.
The source of the V. bellonis material for the collection came from the Susúa Commonwealth Forest, a population that remained unaccounted for about two decades and was suspected to have disappeared until recently, when it was found as part of efforts to study the species’ distribution and habitat in Puerto Rico. Meanwhile, the seed material of V. rupicola came from Vieques NWR, and was a genetically unique population. In the case of V. rupicola, one of the main objectives of the germination trials is to produce planting material to enhance that small relic population found in Puerto Ferro at the refuge.
The team developed a methodology and set germination experiments for these two plants. The germination trials were conducted at the UPRM Conservation Greenhouse and lab facilities to test different treatments (e.g., scarification) and soil variables. This is the first case study using the seed bank facilities at UPRM, a project sponsored by Kew’s Millennium Seed Bank, which provided lab equipment and training to the UPRM and PRDNER staff. Moreover, this collaboration supports both undergraduate and graduate students from UPRM, thus providing continuity to plant conservation efforts in Puerto Rico.
Additional conservation efforts include addressing the population genetics, biogeography, and reproductive biology of V. bellonis through a graduate student research. Camera trapping techniques also are being used to address the role of endemic or native bird species in the dispersal of V. bellonis and V. rupicola. Baseline data suggests the Puerto Rican bullfinch , llorosa, and reina mora are the main seed dispersers of these plants and play a key role in the viability of their populations.
All of these collaborative efforts will provide essential information to guide the recovery of both rare plants.
