Biogeography and conservation status of the endangered species Varronia bellonis

Varronia bellonis (Boraginaceae) is a threatened (Critically Endangered) species, endemic to the Caribbean island of Puerto Rico where it’s restricted to the island’s western and central-north regions. Ongoing international collaboration is researching key aspects of the species phylogenetic placement, biogeography and conservation status to inform its conservation. Desk and field-based studies have provided the data (occurrence records, geology and land cover maps, protected area boundaries) necessary to develop a GIS and enable the study of population distribution, geology and land cover preferences. We found the species only occurs on three types of geology (Serpentinite, Lares limestone and Montebello limestone) and predominantly occurs in four land cover types. There is strong preference for Evergreen Forest on Serpentine with 66% of project records occurring on this land cover type. Extant individuals were found in and around Maricao, Susúa and Río Abajo State Forests, the three historical areas of distribution, as well as individuals in previously unrecorded locations in Arecibo, San German and Utuado. Within the extant preferred land cover types (area = 331km2) overlying the serpentine and limestone geology (area = 479km2) that support the species, 186km2 is within protected areas. This work provides information to develop an effective species conservation plan.