ESR 18:89-94 (2012)  -  DOI: https://doi.org/10.3354/esr00442

ABSTRACT: Lepanthes caritensis is a small epiphytic orchid endemic to Puerto Rico. Although this species is very rare and demographic studies show that its numbers are declining, it is not protected under the United States Federal Endangered Species Act (ESA). Furthermore, questions remain regarding its distribution, population size and ecological interactions, including host-specificity, which could influence its likelihood of extinction. The primary objective of this study was to document the overall population size and distribution of this orchid to determine whether it warrants federal listing. To this end, extensive surveys were conducted to document the current distribution and population size of L. caritensis. These data were used to classify the species’ rarity status according to criteria outlined by Rabinowitz, NatureServe and the IUCN. Results of these surveys indicate that the overall population of L. caritensis is larger and more widely distributed than previously thought. In addition, the species is not host-specific outside its originally described range, and is found on at least 4 different host species. Nevertheless, this species is indeed rare: it meets the criteria for the NatureServe category ‘critically imperiled’ and the IUCN category ‘Critically Endangered’. Consequently, the most important conclusion of this study is that this species warrants legal protection under the ESA, particularly if its population continues to decline.

KEY WORDS: Critically imperiled species · Endangered species · Rarity status · Epiphytes · Caribbean flora · Host specificity · Rare plant distribution