Hybridization and polyploidy are central processes in evolution and speciation. These mechanisms often lead to complex patterns of genetic variation and the creation of novel genotypes, which may establish if they become isolated from gene flow. However, in the absence of reproductive isolation, species boundaries might easily be disrupted. Here, we used a combination of AFLPs, chloroplast DNA markers and flow cytometry to investigate the evolutionary outcomes of hybridization between two endemic Ecuadorian species of Epidendrum (E. madsenii and E. rhopalostele) in three hybrid zones. Postmating isolation was also quantified to determine the role of this barrier in restraining gene flow between hybrids and the parental species. In addition, future ecological niche models were constructed to predict the outcomes of hybridization between these species.

• Premise of the study: The presence of compatible fungi is necessary for epiphytic orchid recruitment. Thus, identifying associated mycorrhizal fungi at the population level is essential for orchid conservation. Recruitment patterns may also be conditioned by factors such as seed dispersal range and specific environmental characteristics.• Methods: In a forest plot, all trees with a diameter at breast height >1 cm and all individuals of the epiphytic orchid Epidendrum rhopalostele were identified and mapped. Additionally, one flowering individual of E. rhopalostele per each host tree was randomly selected for root sampling and DNA extraction.• Key results: A total of 239 E. rhopalostele individuals were located in 25 of the 714 potential host trees. Light microscopy of sampled roots showed mycorrhizal fungi in 22 of the 25 sampled orchids. Phylogenetic analysis of ITS1‐5.8S‐ITS2 sequences yielded two Tulasnella clades. In four cases, plants were found to be associated with both clades. The difference between univariate and bivariate K functions was consistent with the random labeling null model at all spatial scales, indicating that trees hosting clades A and B of Tulasnella are not spatially segregated. The analysis of the inhomogenous K function showed that host trees are not clustered, suggesting no limitations to population‐scale dispersal. χ² analysis of contingency tables showed that E. rhopalostele is more frequent on dead trees than expected.• Conclusions: Epidendrum rhopalostele establishes mycorrhizal associations with at least two different Tulasnella species. The analysis of the distribution patterns of this orchid suggests a microsite preference for dead trees and no seed dispersal limitation.

Orchid seeds are presumably dispersed by wind due to their very small size and thus can potentially travel long distances. However, the few related studies indicate that seeds fall close to their mother plants. Because seed dispersal and colonization patterns can have relevant consequences for long-term species persistence, we assessed the fine-scale genetic structure of the epiphytic orchid Epidendrum rhopalostele to provide insight into these patterns. All individuals in the studied population were georeferenced and genotyped with AFLP-markers. Genetic structure was evaluated at two levels (forest and tree) using three approaches: principal coordinates analysis, model-based clustering, and spatial autocorrelation analysis. Results showed two genetic groups, composed of individuals from almost every tree with orchids. Spatial autocorrelation analysis at the forest level found no significant genetic structure when all individuals were considered, but a pattern of genetic patches was revealed when the analysis was performed separately for each group. Genetic patches had an estimated diameter of 4 m and were composed of individuals from more than one tree. A weak genetic structure was detected at the tree level at distances less than 1.5 m. These results suggest that many seeds fall close to the mother plant and become established in the same host tree. Additionally, a sequential colonization process seems to be the predominant mode of expansion, whereby progeny from orchids in one tree colonize neighboring trees. Thus, the existence of two distinct genetic groups and the presence of genetic patches should be considered when seed sampling for ex situ conservation.

We describe a new rainfrog species (Pristimantis), from the wetland complex Oña, Nabón, Saraguro and Yacuambi, in the Andes of southern Ecuador, at altitudes ranging between 3000–3400 m a.s.l. Pristimantis tiktik sp. nov. is a small frog, displaying sexual dimorphism (the males with dorsum of various shades of gray, brown, orange or green and a whitish or pinkish yellow venter; females with brownish gray or gray dorsum and a reticulated white and black venter), with SVL ranging between 19.7–20.4 mm in females (n = 3) and 16.1–18.4 mm in males (n = 6). The skin on dorsum is tuberculated, that on venter is coarsely areolate, dorsolateral folds are absent, tympanic membrane is absent but the tympanic annulus is evident, cranial crests are absent, discs on fingers just slightly expanded, heel is lacking enlarged tubercles, inner edge of tarsus is bearing a long fold, Toe V is slightly longer than Toe III and the iris coloration is bronze with fine black reticulations. The males have a large subgular vocal sac that extends onto the chest and vocal slits but lack nuptial pads. The unique advertisement call consists of long duration series of periodically repeated clicks: “tik”. Molecular analyses place the new species in the recently resurrected P. orestes group, as the sister species of the assemblage that contains P. bambu, P. mazar, P. simonbolivari and an undescribed species.

The diversity of genetic resources is essential to cope with environmental changes. However, despite forests play a crucial role in mitigating changes, genetic knowledge has scarcely been used for forest conservation. In this study, we used nuclear microsatellites to understand the patterns of genetic diversity and population genetic structure in Ocotea rotundata van der Werff (Lauraceae), an endemic Ecuadorian tree, highly affected by habitat changes and fragmentation. Our results show high levels of genetic diversity, except in one population. The level of genetic differentiation between populations was low and genetic clusters showed no apparent spatial pattern. In fact, a high degree of genetic admixture was found between most populations. Migration rates were asymmetric but overall high, except in one population, where outgoing gene dispersal was limited. Nevertheless, allelic fixation values suggested a general deficit in heterozygotes, probably due to an increase in the levels of mating between close relatives. Although long-lived organisms, such as trees, can often accumulate a surprising amount of genetic diversity, the results found here could be an early sign of a decline in the diversity of O. rotundata. These findings provide baseline information on genetic resources to support future restoration programs to mitigate the impacts of changes in O. rotundata populations.

Hybridization and introgression are complex evolutionary mechanisms that can increase species diversity and lead to speciation, but may also lead to species extinction. In this study, we tested the presence and genetic consequences of hybridization between the rare and Ecuadorian endemic O. loxensis van der Werff and the widespread O. infrafoveolata van der Werff (Lauraceae). Phenotypically, some trees are difficult to identify, and we expect that some might in fact be cryptic hybrids. Thus, we developed nuclear microsatellites to assess the existence of hybrids, as well as the patterns of genetic diversity and population structure in allopatric and sympatric populations. The results revealed high levels of genetic diversity, even in the rare O. loxensis, being usually significantly higher in sympatric than in allopatric populations. The Bayesian assignment of individuals into different genetic classes revealed a complex scenario with different hybrid generations occurring in all sympatric populations, but also in allopatric ones. The absence of some backcrossed hybrids suggests the existence of asymmetric gene flow, and that some hybrids might be more fitted than others might. The existence of current and past interspecific gene flow also explains the blurring of species boundaries in these species and could be linked to the high rates of species found in Ocotea.