The response of vascular epiphyte communities following natural or human disturbance has been little studied. Over 5 y, we evaluated the post-stripping recolonization of vascular epiphytes in cloud forest. Vascular epiphytes were experimentally removed from branch and trunk plots (1 m in length) on five trees in two secondary cloud forest fragments in southern Mexico. Similarity between colonizer and established communities was compared in each fragment using a further five trees with no stripping. All seedlings were recorded yearly. Non-vascular epiphyte cover was estimated in each plot. The recolonization rate was very high; after 5 y, epiphyte density of the colonizer community (27.4 ± 6.8 individuals per segment) reached similar values to those of the established community (26.7 ± 3.3) in nearby trees. While similarity (composition and abundance) between the colonizer community and established community was high (81%), diversity accumulation curves indicated that the colonizer community presents a lower diversity of epiphytes (5.5 equivalent species) than the established community (11.4). Colonization of xerophytic bromeliads was high, while pteridophytes and orchids presented reduced recovery. The immediately surrounding source of propagules had a strong influence on recolonization. In both the colonizer and established communities, dominance rank was bromeliads > peperomias > pteridophytes. The results show that the recovery capacity of epiphytic vegetation in secondary forest is high, if propagule sources are close by. However, at 5 y after disturbance, it is unclear whether the colonizer community would present the same species composition as the established community or if it would give rise to a different community.

Plant facilitation can improve the diversity of plant communities in several ecosystems, especially in stressful environments. The establishment of tree species on rocky outcrops can be limited by several biotic and abiotic factors. The richness and abundance of forest trees species on rocky outcrops surrounded by a large forest remnant in south Brazil were correlated with the cover of Bromelia balansae, a spiny stoloniferous species commonly occurring at forest–grassland transitions. Sixty plots were established on three flat rocky outcrops (20 in each). In each plot the coverage of bromeliads was estimated into three classes (0%, 1–50% and 51–100%) and all seedlings (individuals 10–30 cm in height) were counted and identified. ANOVAs with randomization tests were performed to establish the effect of different bromeliad cover classes on the richness and abundance of seedlings. The cover of bromeliads was positively related to the richness and abundance of young pioneer tree species. Evidence suggests that B. balansae can act as a nurse plant for tree seedlings, but manipulative experiments are needed to confirm this.

Biotechnological techniques comprise useful tools for the conservation of endangered plant genetic resources. In the present work, polymorphism and usefulness of amplified fragment length polymorphism (AFLP) markers in assessing the genetic diversity in populations of Billbergia zebrina were investigated in nodular cultures and adult plants of the species. AFLP markers revealed moderate-to-high genetic diversity based on the estimations of Nei's gene diversity (mean He = 0.28), Shannon index of diversity (mean HS = 0.48) and the number of polymorphic fragments (mean of 56.17 polymorphic fragments over six primer pairs). In comparison to published studies of population genetics performed in other bromeliad species, the present study suggests that natural populations of B. zebrina likely maintain high levels of genetic diversity, an important feature towards conservation of plant genetic resources. The results obtained reveal that AFLP markers comprise a powerful tool in order to assess the levels of genetic diversity in natural populations of this endangered species. Integrating AFLP markers with in vitro propagation techniques is understood as an adequate strategy for conservation programmes of this species.

The abundance of epiphytes has been assumed to be important in explaining the high diversity of tropical canopy arthropods. In this study we assessed the possible role that the presence of epiphytes may have on the diversity and abundance of canopy insects in an experimental study conducted in a coffee plantation in Coatepec, Veracruz, Mexico. Epiphytes were removed from trees in one of two plots in two sites of the coffee plantation. In each plot we collected insects from three Inga jinicuil trees by knockdown insecticide fogging. Insects were sorted to morphospecies, counted and measured. Trees with epiphytes had significantly higher numbers of species and individuals and insects larger than 5 mm were also more species-rich and abundant in trees with epiphytes. The magnitude of the enhancement was surprisingly large with the epiphyte plot samples having on average 90% more individuals and 22% more species than plots without epiphytes. These differences were even greater for large (>5 mm) insects (184% and 113% respectively). Our results support the tenet that epiphytes provide valuable resources to arthropods, which we have illustrated for canopy insects in shade trees of coffee plantations.

The sampling of epiphytes is fraught with methodological difficulties. We present a protocol to sample and analyse vascular epiphyte richness and abundance in forests of different structure (SVERA). Epiphyte abundance is estimated as biomass by recording the number of plant components in a range of size cohorts. Epiphyte species biomass is estimated on 35 sample-trees, evenly distributed over six trunk diameter-size cohorts (10 trees with dbh > 30 cm). Tree height, dbh and number of forks (diameter > 5 cm) yield a dimensionless estimate of the size of the tree. Epiphyte dry weight and species richness between forests is compared with ANCOVA that controls for tree size. SChao1 is used as an estimate of the total number of species at the sites. The relative dependence of the distribution of the epiphyte communities on environmental and spatial variables may be assessed using multivariate analysis and Mantel test. In a case study, we compared epiphyte vegetation of six Mexican oak forests and one Colombian oak forest at similar elevation. We found a strongly significant positive correlation between tree size and epiphyte richness or biomass at all sites. In forests with a higher diversity of host trees, more trees must be sampled. Epiphyte biomass at the Colombian site was lower than in any of the Mexican sites; without correction for tree size no significant differences in terms of epiphyte biomass could be detected. The occurrence of spatial dependence, at both the landscape level and at the tree level, shows that the inclusion of spatial descriptors in SVERA is justified.

The arthropod fauna inhabiting 90 individuals of three different species of epiphyte was investigated in the moist lowland forest of the Barro Colorado National Monument in Panama. In total, 3694 arthropods belonging to 89 morphospecies and 19 orders were collected. While arthropod abundance was primarily a function of host plant biomass irrespective of epiphyte species, there were pronounced differences in species richness, species composition and guild structure of the arthropod faunas of the three epiphyte species. Although all study plants were growing in close proximity on the same host tree species, there was remarkably little overlap in the species assemblages across epiphyte taxa. The inhabitant species also differed dramatically in their ecological functions, as feeding guild and hunting guild analyses indicated. The influence of plant size, structure and impounded leaf litter on arthropod diversity is discussed. We conclude that epiphytes are microhabitats for a diverse and numerous fauna, and that different species of epiphytes foster both taxonomically and ecologically very distinct arthropod assemblages.

Bromeliads are common as epiphytes in warm neotropical forests (Benzing 1990). Species native to relatively wet forests impound water in a central cup and/or in seperate leaf axils. These tanks receive enough leaf litter and rainwater to support aquatic life (Maguire 1971). In these complex microcosms many groups of freshwater organisms ranging from algae, fungi, bacteria and protozoa through insects to frogs are represented and constitute considerable animal populations (Frank 1983, Laessle 1961, Maguire 1971, Picado 1913, Richardson 1999). Nutrients originating from the decomposition of litter and animal waste are absorbed by specialized trichomes on the bases of the leaves which form the tanks (Benzing 1980, 1990).

Phytotelmata habitats have been the focus of much research and are utilized by a wide variety of taxa. In the past 15 years numerous studies in many geographic regions and covering various types of phytotelmata have greatly increased our understanding of these unique habitats. The most recent summary of phytotelmata inhabitants included over 20 families of insects. A review of the literature and extensive work in lowland Ecuador shows the family level diversity is in fact at least twice that reported earlier. A reassessment of previous phytotelmata classification schemes, as well as an extensive bibliography, is provided.

Nutrient inputs into tank bromeliads were studied in relation to growth and productivity, and the abundance, diversity and biomass of their animal inhabitants, in three forest types along an elevational gradient. Concentrations of phosphorus, potassium and calcium in canopy-derived debris, and nitrogen and phosphorus in phytotelm water, declined with increasing elevation. Dwarf forest bromeliads contained the smallest amounts of debris/plant and lowest concentrations of nutrients in plant tissue. Their leaf turnover rate and productivity were highest and, because of high plant density, they comprised 12.8% of forest net primary productivity (0.47 t ha−1 y−1), and contained 3.3 t ha−1 of water. Annual nutrient budgets indicated that these microcosms were nutrient-abundant and accumulated < 5% of most nutrients passing through them. Exceptions were K and P in the dwarf forest, where accumulation was c. 25% of inputs. Animal and bromeliad biomass/plant peaked in the intermediate elevation forest, and were positively correlated with the debris content/bromeliad across all forest types. Animal species richness showed a significant mid-elevational peak, whereas abundance was independent of species richness and debris quantities, and declined with elevation as forest net primary productivity declined. The unimodal pattern of species richness was not correlated with nutrient concentrations, and relationships among faunal abundance, species richness, nutrient inputs and environment are too complex to warrant simple generalizations about nutrient resources and diversity, even in apparently simple microhabitats.