Buxus vahlii Baillon is an endangered plant species endemic to Puerto Rico and St. Croix (USVI). There are five known populations, three in Puerto Rico (Rincón, Isabela and Bayamón) and two in St. Croix (Frederiksted and Christiansted). The populations status was studied in order to provide information on the ecology of the species. Data regarding associated vegetation and habitat was obtained at all populations. Height, diameter and reproductive status were only measured in Puerto Rico. The species showed the ability to adapt to different environmental conditions. Such adaptations include shrub-like growth in dry areas where it forms part of the understory (Rincón, Frederiksted and Christiansted), but can also grow in a tree-like form in high precipitation areas (Isabela and Bayamón). Identified human impacts on the studied populations were: development (Frederiksted), illegal immigrants and fires (Rincón), and rock climbing and introduced species (Bayamón). The Isabela and Christiansted populations were not human impacted since both populations are located in places with poor accessibility. Hurricanes impact was minimal for B. vahlii in the two studied populations (Rincón and Isabela); therefore, this event should not be considered as an imminent threat for the species. An actualization of the management plan is suggested for reversing the decline of this species and restore the populations to a stable, secure, and self-sustaining status.

Key words: Buxus vahlii, Puerto Rico, St. Croix