IntroductionThe terrestrial orchid genus Nervilia is diagnosed by its hysteranthous pattern of emergence but is nested among leafless myco-heterotrophic lineages in the lower Epidendroideae. Comprising ca. 80 species distributed across Africa, Asia and Oceania, the genus remains poorly known and plagued by vague and overlapping species circumscriptions, especially within each of a series of taxonomically intractable species complexes. Prior small-scale, exploratory molecular phylogenetic analyses have revealed the existence of cryptic species, but little is otherwise understood of origin, the scale and timing of its biogeographic spread, or the palaeoclimatic factors that have shaped its ecology and given rise to contemporary patterns of occurrence.MethodsHere, we sample widely throughout the generic range, including 45 named taxa and multiple accessions referable to several widespread ‘macrospecies’, as well as material of equivocal identity and probable undescribed status, for the first time enabling an evaluation of taxonomic boundaries at both species and sectional level. Using nuclear (ITS) and plastid (matK, trnL-F) sequence data, we conduct phylogenetic (maximum parsimony and Bayesian inference) and ancestral area analysis to infer relationships and resolve probable origin and colonisation routes.ResultsThe genus is strongly supported as monophyletic, as are each of its three sections. However, the number of flowers in the inflorescence and other floral characters are poor indicators of sectional affinity. Dated ancestral area analysis supports an origin in Africa in the Early Oligocene, with spread eastwards to Asia occurring in the Late Miocene, plausibly via the Gomphotherium land bridge at a time when it supported woodland and savanna ecosystems.DiscussionTaxonomic radiation in Asia within the last 8 million years ties in with dramatic Himalayan-Tibetan Plateau uplift and associated intensification of the Asia monsoon. Multiple long-range migrations appear to have occurred thereafter, as the genus colonised Malesia and Oceania from the Pliocene onwards. The bulk of contemporary species diversity is relatively recent, potentially explaining the ubiquity of cryptic speciation, which leaves numerous species overlooked and unnamed. Widespread disjunct species pairs hint at high mobility across continents, extinction and a history of climate-induced vicariance. Persistent taxonomic challenges are highlighted.

Understanding drivers of plant diversity and distributions is critical for their conservation, particularly among changing environments. While plants' responses to disturbances are relatively well-studied, in-depth analyses of how they respond to habitat recovery are surprisingly scarce. This is particularly true for one of the most diverse, sensitive, and threatened plant families: the Orchidaceae. To address this knowledge gap, we evaluated the diversity and distribution of terrestrial orchid species within a recovering tropical forest landscape in the Republic of Palau. We tested the hypotheses that orchid abundance, richness, and diversity vary across a forest successional gradient and that orchid species exhibit specificity and/or fidelity to particular tree species. Surveys yielded distribution data for 23 orchid species and General Linear Models revealed that habitat type and tree abundance, diversity, and size significantly affected orchid abundance. Habitat type and tree abundance also affected orchid richness and diversity. Indicator analysis showed that only two orchid species were significantly associated with individual tree species. The local landscape-scale study established that orchid communities varied across habitats and that mature forests had greater orchid abundance, richness, and diversity. Interestingly, tree abundance had a stronger influence on orchid communities than tree diversity, tree size, or specific tree species. The study demonstrated that orchids can occupy a range of successional habitats and indicated that reservation strategies paired with restoration efforts utilizing various tree species for reforestation will benefit orchid communities over potentially shorter timeframes than might occur without active management.

Abstract Generalization is difficult to quantify, and many classifications exist. A beta diversity framework can be used to establish a numeric measure of generalist tendencies that jointly describes many important features of species interactions, namely spatiotemporal heterogeneity. This framework is promising for studying generalized symbiotic relationships of any form. We formulated a novel index, turnover importance (T). T describes spatiotemporal heterogeneity in interactor assemblages, an inherent feature of generalist relationships that is not captured by available metrics. We simulated the behaviour of T relative to other available metrics, calculated T for native North American orchid‐insect relationships, and tested correlations between T and eco‐geographic variables. We performed case studies to demonstrate applications of T for conservation and eco‐evolutionary studies. T behaves predictably across simulations, and dynamically interacts with site number, gamma diversity, and species range sizes. T is moderately sensitive to sampling depth. Orchids with higher T scores occupy larger ranges and broader climatic niches. Alternative interactor‐specific measures of generalism are best employed for local‐level community networks over short timespans. While these interactor metrics can assess use versus availability in local communities, T can be used to measure spatiotemporal patterns of variation in interactor assemblages across a focal species' range. This study provides a roadmap for future work focused on better understanding the patterns and consequences of generalized relationships.

The co-occurrence of orchids and bryophytes at occupied sites on host trees has been documented on several occasions, particularly in the tropics, and it may represent an important symbiotic relationship that supports epiphytic orchid populations. Despite continuing interest from ecologists, the specific life history traits that are affected by associations of orchids with bryophytes, and how they are affected, remain unclear. Clarifying the nature of the association will improve our understanding of orchid ecology and have practical implications for applied conservation efforts, particularly for rare species in restricted habitats. In this study, we explored the relationship between the abundance of bryophyte cover on host trees and various life history traits related to size, survival and reproduction of a rare tropical epiphytic orchid, Lepanthes caritensis. The results demonstrated that bryophyte abundance on host trees had variable effects on individual aspects of an orchid's life history. Orchid recruitment was positively correlated with the abundance of bryophyte cover, but survival and flower production were negatively correlated with bryophyte abundance. Our findings revealed that an apparent commensal symbiotic relationship between L. caritensis and bryophytes exists at the recruitment stage, but this is lost during later life stages, when the abundance of bryophytes appears to negatively affect this species.

Local communities often conserve nearby natural areas to support recreational activities and other benefits these areas provide. Areas protected by local communities could contribute to wider efforts to achieve large-scale conservation goals, such as biodiversity protection, provided the ecological conditions on-site are compatible with achieving these goals. To explore the potential contribution of locally established protected areas, we focus on areas protected by local communities in California, USA, using ballot initiatives, a form of direct democracy. We compare the ecological condition of wooded habitat on protected areas funded by local communities through the ballot box to that of similar habitats on protected areas funded by a state conservation agency. As an indicator of ecological condition, we focus on coverage by exotic plant species. We examine whether protected area characteristics or aspects of human-mediated onsite disturbance related to recreational use explain exotic plant cover found on each type of protected area. Exotic plant cover did not differ between areas protected by local communities and those protected by our larger scale conservation actor. Instead, elevation was the best predictor of exotic plant cover. Our results suggest protected areas established by local communities may be in no worse a condition than those established by a state public agency and warrant inclusion when tracking progress towards large-scale conservation goals for protected areas.

SummaryProtected area systems include sites preserved by various institutions and mechanisms, but the benefits to biodiversity provided by different types of sites are poorly understood. Protected areas established by local communities for various reasons may provide complementary benefits to those established by large-scale agencies and organizations. Local communities are geographically constrained, however, and it remains unclear how effectively they protect biodiversity. We explored this issue by focusing on protected areas established through direct democracy via local ballot initiatives whereby communities vote to tax themselves for open space preservation. We compared the effectiveness of local ballot-protected areas to areas protected by a large-scale conservation actor, The Nature Conservancy (TNC). We evaluated how well the two protected area types correspond with amphibians, reptiles, birds, mammals and special status elements of natural diversity. Local ballot-protected areas differed from those of TNC in terms of size, location, proximity to urban areas and habitat diversity. In terms of potential habitat coverage, local ballot-protected areas outperformed TNC sites for all species groups with the exception of special status elements of natural diversity. While not necessarily targeting wildlife and habitats, we conclude that locally established protected areas can make an important contribution to biodiversity conservation.

Aim We conduct a biogeographical assessment of orchids in a global biodiversity hotspot to explore their distribution and occurrences of local hotspots while identifying geographic attributes underpinning diversity patterns. We evaluate habitat characteristics associated with orchid diversity hotspots and make comparisons to other centres of orchid diversity to test for global trends. The ultimate goal was to identify an overall set of parameters that effectively characterize critical habitats to target in local and global orchid conservation efforts. Location Costa Rica; Mesoamerica. Taxon Orchidaceae. Methods Data from an extensive set of herbarium records were used to map orchid distributions and to identify diversity hotspots. Hotspot data were combined with geographic attribute data, including environmental and geopolitical variables, and a random forest regression model was utilized to assess the importance of each variable for explaining the distribution of orchid hotspots. A likelihood model was created based on variable importance to identify locations where suitable habitats and unidentified orchid hotspots might occur. Results Orchids were widely distributed and hotspots occurred primarily in mountainous regions, but occasionally at lower elevations. Precipitation and vegetation cover were the most important predictive variables associated with orchid hotspots. Variable values underpinning Costa Rican orchid hotspots were similar to those reported at other sites worldwide. Models also identified suitable habitats for sustaining orchid diversity that occurred outside of known hotspots and protected areas. Main conclusions Several orchid diversity hotspots and potentially suitable habitats occur outside of known distributions and/or protected areas. Recognition of these sites and their associated geographic attributes provides clear targets for optimizing orchid conservation efforts in Costa Rica, although certain caveats warrant consideration. Habitats linked with orchid hotspots in Costa Rica were similar to those documented elsewhere, suggesting the existence of a common biogeographical trend regarding critical habitats for orchid conservation in disparate tropical regions.

Orchids of Palau: A field guide by Ann Hillmann Kitalong and Makoto Uesugi. Middletown, DE: The Environment, Inc., 2017. 112 pp. Soft Cover. ISBN 978-982-98016-5-4. £19.00 Micronesian orchid communities are gaining attention from researchers and enthusiasts alike (see, e.g., Raulerson & Rinehart, 1992; GPEPP, 2017; Crain, 2018), however, readily accessible field guides for many of the individual islands or archipelagos are limited in availability. Moreover, 30 to 100 years have passed since much of the literature on Micronesian orchids has been published (e.g., Schlechter, 1921; Tuyama, 1939; Fosberg & Sachet, 1987), during which time numerous changes have taken place in orchid taxonomy that have not been compiled in an easily manageable source. Orchids of Palau: A field guide proficiently fills this void for an important component of orchid diversity in Micronesia. Palau's orchid flora is rich with showy, rare, and endemic species, but given that the islands’ remarkable marine environments often overshadow potential interests in their plant communities, it is encouraging to see that their orchids are being documented and showcased for a broad audience in a convenient field guide. Following the preliminary material [Credits, Acknowledgements, Table of Contents], an Introduction is presented that includes brief sections on Physical Geography, Vegetation of the Islands, History of Palauan Orchids (which includes an interesting list of botanists that have made taxonomic contributions), The Orchid Flora, The Structure of Orchids, The Flower, The Inflorescence, The Seed Capsule, and Vegetative Morphology, most of which include color photos. The main body of the text (Species Descriptions) follows the Introduction and consists of 39 species accounts, organized alphabetically. Each account includes two sections with information on the species’ distribution and habitat (globally and locally) and a species description that includes information on synonymy (in some cases), growth form, stems, leaves, flowers, and phenology. Multiple color photographs of growth form, leaves, flowers, and capsules from co-author Makoto Uesugi and several other contributors also accompany each species account and offer sufficient detail to permit recognition of plants in the field. Although the guide is limited in that it only provides descriptions for less than half of the known orchid species in Palau, it makes up for this in part through a subsequent section of Orchid Plates that includes photos of an additional 12 species. Furthermore, a checklist of 80 recorded species follows the plates section and is a very useful element for consolidating information on the orchids specifically found in Palau. The checklist includes details on phenology (including a monthly calendar) and information on distribution status (Native, Endemic, Introduced, Invasive). The field guide concludes with a Glossary emphasizing orchid morphology and a References section. As with any first edition book, particularly those that cover subjects such as floristics and taxonomy, which are continuously in flux and subject to updates, occasional limitations and errors have inevitably found their way into the publication. In a few instances, photos appear to be captioned incorrectly (e.g., Taeneophyllum palawense, p. 13). Another limitation is that some of the more cryptic species are not included in the Species Descriptions section or in the Plates Section, making it difficult to compare and differentiate closely related species in the field based on the information and photos provided, particularly in the absence of a dichotomous key. In some cases, the taxonomic nomenclature needs to be updated as well, although some of the potential changes are currently under debate (e.g., Oberonia spp., Moerenhoutia spp.). The caption for the checklist also has some missing information for species status symbology (status G), which is omitted. Lastly, it should be noted that the phenology dataset is incomplete, something the authors recognize, and thus it only documents when a species has been observed in bloom by the authors, but not necessarily the true seasonality of the species. Nevertheless, the authors acknowledge that the guide is a work in progress and assert that they are gathering new photographs and added information on seasonality for updated volumes in the future. Despite minor issues with the first edition, I strongly recommend this field guide for any biology department or natural history institute with interests in the flora of Micronesia or southeast Asia. I believe that this book is a valuable resource for botanists focusing on the orchids or flora of Micronesia and a convenient field guide for ecotourists and natural history guides in the Republic of Palau.

Rare species are important targets for biodiversity conservation efforts because rarity often equates to small populations and increased endangerment. Rare species are prone to stochastic extinction events and may be particularly susceptible to catastrophes. Therefore, understanding how rare species respond to disturbances is critical for evaluating extinction risk and guiding conservation managers. Population viability analyses (PVAs) are essential for assessing rare species' status yet they seldom consider catastrophic events. Accordingly, we present a PVA of a rare tropical epiphyte, Lepanthes caritensis (Orchidaceae), under simulated disturbance regimes to evaluate its demographics and extinction risk. We aimed to test how demographic models incorporating catastrophes affect population viability estimates. Our goal was to better guide management of these orchids and other rare plants. Results revealed L. caritensis numbers have declined recently, but projected growth rates indicated that most subpopulations should increase in size if undisturbed. Still, projection models show that moderate catastrophes reduce growth rates, increase stochasticity in subpopulation sizes, and elevate extinction risk. Severe catastrophes had a more pronounced effect in simulations; growth rates fell below replacement level, there was greater variation in projected population sizes, and extinction risk was significantly higher. PVAs incorporating periodic catastrophes indicate that rare species may have greater extinction probabilities than standard models suggest. Thus, precautionary conservation measures should be taken in disturbance prone settings and we encourage careful monitoring after environmental catastrophes. Future rare plant PVAs should incorporate catastrophes and aim to determine if rescue and reintroduction efforts are necessary after disturbances to insure long-term population viability.

Premise of research. Tropical epiphytes are susceptible to climatic changes, as evidenced by documented population declines, range contractions, and range shifts; however, physiological changes in individual plants may also be indicative of deteriorating climate conditions. Consequently, physiological analyses of tropical epiphytes whose natural habitats are constrained by climatic conditions are warranted to evaluate their responses to potential changes in these conditions, to assess their vulnerability, and to guide conservation actions.Methodology. Here we investigate photosynthetic processes in Puerto Rican Lepanthes species, a group of Neotropical epiphytic orchids, as a model system to determine whether altered microclimate conditions elicit adverse physiological responses. We tested for differences in chlorophyll fluorescence, measured as F-v/F-m, as an indication of plant stress under modified temperature, humidity, and air vapor pressure deficit.Pivotal results. Mean F-v/F-m was positively correlated with mean relative humidity and negatively correlated with mean temperature and air vapor pressure deficit. Collectively, plants exposed to altered microclimate conditions had significantly lower mean F-v/F-m than plants in unaltered conditions. Plants in altered microclimate conditions were also more likely to exhibit declines in F-v/F-m over time, and they exhibited greater reductions in F-v/F-m over the course of the study.Conclusions. Epiphytic plant species such as Lepanthes could exhibit declines in F-v/F-m and experience greater stress in their natural habitats if current warming and drying trends continue as anticipated in Puerto Rico and elsewhere. Declining F-v/F-m is a robust indicator of plant stress, and several studies show that increased stress can promote leaf loss, limit reproduction, and lower survival rates. Thus, analyses of F-v/F-m can be advantageous for monitoring epiphytic orchids and other vulnerable plant species by offering a valuable means for detecting adverse responses to climate change.

Ninety-five percent of orchid species associated with fynbos shrublands of South Africa's Cape Floristic Kingdom have been assessed for the IUCN Red List, yet aspects of their demography and population biology remain poorly understood. We conducted a 6-year demographic study of the Critically Endangered Disa procera, a cryptic, terrestrial species from South Africa with a global population of c. 50 individuals known from a single location. We aimed to provide management recommendations that would facilitate its persistence. Our findings indicate that the population of D. procera is larger than previously thought, and the species occurs at two distinct locations. These orchids exhibit high interannual variation in population size and turnover of individuals, potentially indicative of a species with a short life span, and still meet the criteria for Critically Endangered status. The species benefits from disturbances, such as brush cutting along trails, or fire, which open up clearances in the vegetation. However, physical damage to plants during their aboveground growing season (September-January) is particularly detrimental and should be avoided in habitat management for the species. Fire had beneficial effects at the population and individual levels and is recommended at 10-25-year intervals, outside the orchid's growing season. The species exhibited comparatively high rates of fruit set (68%), suggesting that pollination limitation does not currently constrain its performance. Its patchy distribution may, however, indicate constraints on dispersal or recruitment. We recommend that management strategies should include continued protection and monitoring of both populations, studies on pollination, habitat requirements and mycorrhizal associates, and a prescribed disturbance regime.

AimThe aim of this analysis was to identify strategies that will maximize efficiency and effectiveness in conservation planning. As many orchids are threatened with extinction for various reasons, our primary objective was to combine hotspots analyses with stochastic extinction modelling to highlight possible conservation priorities for Lepanthes spp. (Orchidaceae) based on patterns of richness, rarity and threat. Our subsequent objective was to identify potential conservation surrogates and variables that are the best predictors of extinction probabilities. The ultimate goal was to determine which factors should be emphasized in conservation planning to prevent species extinctions.LocationLatin America; the Caribbean.MethodsWe used herbarium records and ArcGIS to map the distribution of Lepanthes spp. and to identify hotspots of richness and rarity. We forecasted extinction patterns with Koopowitz's stochastic extinction model and calculated extinction probabilities in each country. We used a randomForest regression model in R to assess the importance of richness, rarity and threat for explaining extinction probabilities.ResultsHotspots of Lepanthes richness and rarity occurred in north-western South America and southern Central America and largely overlapped with each other. The highest extinction probabilities occurred in northern Central America, Haiti and Ecuador, and generally, hotspots of richness and rarity did not correspond with patterns of threat. Habitat loss was the most important variable for explaining extinction probabilities, followed by measures of rarity.Main conclusionsConservation efforts will be most efficient in richness and rarity hotspots, and because they overlap, rarity hotspots could act as surrogates for protecting overall Lepanthes diversity. Hotspots rarely occurred in the most threatened areas, and therefore, conservation efforts are more urgent in non-hotspot areas. Conservation efforts will be most effective if they combine ex situ strategies in locations with high habitat conversion rates with reservation strategies in rarity and richness hotspots, particularly where they overlap.

Effective conservation of rare plant species requires a detailed understanding of their unique distributions and habitat requirements to identify conservation targets. Research suggests that local conservation efforts may be one of the best means for accomplishing this task. We conducted a geographical analysis of the local distributions of rare plants in Napa County, California, to identify spatial relationships with individual habitat types. We measured the potential contribution of individual habitats to rare plant conservation by integrating analyses on overall diversity, species per area, specificity-weighted richness, presence of hotspots, and the composition of the rare plant community in each habitat type. This combination of analyses allowed us to determine which habitats are most significant for rare plant conservation at a local scale. Our analyses indicated that several habitat types were consistently associated with rare plant species. In broad terms, grasslands, oak forests, coniferous forests, wetlands, serpentines, chaparral, and rock outcrops were most consistently highlighted. No single habitat stood out in every analysis however, and therefore we conclude that careful selection of an assemblage of habitats that best represents diverse, restricted and unique rare plant communities will be the most efficient approach to protecting rare plant habitat at local scales. Accordingly we present a means of identifying conservation targets and protecting global biodiversity through local efforts.

Napa County contains particularly high levels of biological diversity in a variety of categories and is considered one of ten localized areas in California that contain the highest numbers of native and endemic plant species. Here we present a floristic summary based on a new annotated checklist of the flora of this uniquely diverse region. The checklist was developed by combining several local and statewide floristic data sources that represent herbarium collection records and other observations from Napa County. The final checklist of vascular plants for Napa County consists of 1,716 taxa, including 1,418 native taxa from 101 different families. Alarmingly, 126 native taxa in Napa County were listed as rare or threatened to some degree. The results of this study demonstrate that for its size, Napa County contains remarkably high levels of plant diversity as well as high concentrations of special status taxa as compared to other areas within the California Floristic Province, the State of California as a whole, and other regions within global biodiversity hotspots characterized by Mediterranean climates. In particular, this analysis highlights the floristic significance of Napa County at global and local levels, and thus, this review is an important step to help promote and facilitate long term research and conservation planning in the area.

Once considered only a human behavior, reports of tool use by a variety of animals have accumulated. Likewise, various definitions of tool use have also amassed. Although some researchers argue that understanding the evolutionary drivers of tool use is more important than identifying and describing these behaviors, the central issue of defining what constitutes tool use has not been fully addressed. Here we analyze prominent definitions of tool use and review the application of these definitions in scientific and educational literature. We demonstrate that many behaviors recently described as tool use do not meet criteria for prevalent definitions, while other neglected behaviors may constitute a form of tool use. These examples show how the use of inconsistent definitions of tool use in research can result in different conclusions from the same observations. Our aim is to demonstrate that a universally acceptable definition of tool use based on traditional, evolutionary, and operational understanding of behavior is needed. The rationale is that this review will stimulate the consistent and explicit use of specific terminology in tool use research. This would help define specific examples of each natural observation from a common measuring stick, allowing better comparative studies and classification of these unique behaviors.//

This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross-tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis.

More than a decade has passed since the catastrophic population decline in Gyps species was reported from South Asia, but much uncertainty remains about quantifying their short-term extinction risk. To estimate the future extinction risk of the white-rumped vulture Gyps bengalensis in Nepal, we conducted counts at 7 nesting colonies between 2002 and 2012. We compared 3 methods of estimating abundance based on count data and calculated mean population growth rates and cumulative probabilities of extinction given the abundance estimates from each method. The first 2 methods of abundance estimation were traditional indices: mean and maximum values of all counts. The third method was a mixture modeling approach that corrected raw counts by a detection parameter. The results of the traditional indices were characterized by high uncertainty levels as reflected in the wide confidence intervals, which limited their capacity to make predictions about the fate of the populations with any confidence. The mixture modeling method provided more reliable results; there was a 51% probability of populations facing quasi-extinction (i.e. ≤20 vultures) in 13 yr and a 99% probability of quasi-extinction in 18 yr. Because the mixture modeling method provided more precise predictions while requiring minimal additional effort, population biologists using count data are encouraged to employ such model-based estimators. The white-rumped vulture populations in Rampur are in danger of disappearing within 2 decades, so conservation efforts should be expedited to prevent the loss of this species.

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 18:89-94 (2012) - DOI: https://doi.org/10.3354/esr00442 NOTE Update on the distribution of Lepanthes caritensis, a rare Puerto Rican endemic orchid Benjamin J. Crain1,*, Raymond L. Tremblay2 1Department of Biology, University of Puerto Rico-Rio Piedras, San Juan 00936, Puerto Rico 2Department of Biology, University of Puerto Rico-Humacao, Humacao 00792, Puerto Rico *Email: bcrainium@gmail.com 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 Full text in pdf format PreviousCite this article as: Crain BJ, Tremblay RL (2012) Update on the distribution of Lepanthes caritensis, a rare Puerto Rican endemic orchid. Endang Species Res 18:89-94. https://doi.org/10.3354/esr00442 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 18, No. 1. Online publication date: July 30, 2012 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2012 Inter-Research.