Walker’s Manihot, Manihot walkerae, is an endangered plant that is endemic to the Tamaulipan thornscrub ecoregion of extreme southern Texas and northeastern Mexico. M. walkerae populations are highly fragmented and are found on both protected public lands and private property. Habitat loss and competition by invasive species are the most detrimental threats for M. walkerae; however, the effect of climate change on M. walkerae’s geographic distribution remains unexplored and could result in further range restrictions. Our objectives are to evaluate the potential effects of climate change on the distribution of M. walkerae and assess the usefulness of natural protected areas in future conservation. We predict current and future geographic distribution for M. walkerae (years 2050 and 2070) using three different general circulation models (CM3, CMIP5, and HADGEM) and two climate change scenarios (RCP 4.5 and 8.5). A total of nineteen spatially rarefied occurrences for M. walkerae and ten non-highly correlated bioclimatic variables were inputted to the maximum entropy algorithm (MaxEnt) to produce twenty replicates per scenario. The area under the curve (AUC) value for the consensus model was higher than 0.90 and the partial ROC value was higher than 1.80, indicating a high predictive ability. The potential reduction in geographic distribution for M. walkerae by the effect of climate change was variable throughout the models, but collectively they predict a restriction in distribution. The most severe reductions were 9% for the year 2050 with the CM3 model at an 8.5 RCP, and 14% for the year 2070 with the CMIP5 model at the 4.5 RCP. The future geographic distribution of M. walkerae was overlapped with protected lands in the U.S. and Mexico in order to identify areas that could be suitable for future conservation efforts. In the U.S. there are several protected areas that are potentially suitable for M. walkerae, whereas in Mexico no protected areas exist within M. walkerae suitable habitat.

We assessed the diversity, vertical distribution, and the effect of structural and geographical factors on the diversity of vascular epiphyte assemblages (VEAs) in two forest types in the “El Cielo” Biosphere Reserve. We found 2839 epiphyte individuals from 15 species on 240 host trees (27 species) in the semideciduous forest and 5085 individuals from 8 species on 215 host trees (12 species) in the pine–oak forest. Epiphytes showed a preference for the middle zone of the host trees. The diversity of VEAs was uneven in both forest types, although the VEA in the semideciduous forest was the most diverse. VEAs across forests were slightly similar in their composition (30% mean overlap), but very different in their structure (i.e., they did not share very abundant species). The variation in species richness among VEAs was influenced by forest structure, independently of forest type. Compositional differences of VEAs among forest types were explained by geographic distance and host-tree identity (31% and 28% variation explained, respectively). By characterizing the diversity of VEAs we provide a basic understanding of the factors influencing epiphyte diversity in these understudied ecosystems.