Associações entre epífitas vasculares e seus hospedeiros em três ambientes florestais na Amazônia Central, Brasil

The goal of this study was to investigate how habitat type (lowland, slope, upland), host tree composition, bark characteristics and soil fertility influence community attributes of vascular epiphytic plants in a central Amazonian Forest. Previous studies in other neotropical regions have shown that these variables have different levels of influence on the composition, richness and abundance of epiphytes in relation to habitat type; however such quantitave studies have yet to be conducted in the central Amazonia. In the Adolpho Ducke Forest Reserve the abundances of all species of vascular epiphytes were recorded from 300 host trees with DBH > 30 cm. The host trees were distributed among 30 sample plots established in lowland, slope and upland habitats, and the epiphytic species were classified into 3 vegetative types (holo-epiphytes, primary hemiepiphytes and secondary hemiepiphytes). Overall 21, 000 individuals representing 122 species distributed in 66 genera and 20 families of epiphytic vascular plant taxa were registered during the course of the study. Our results show that in central Amazonia, lowland habitats are distinct in species richness, abundance and composition when compared to both slope and upland environments. Multiple regression techniques (General Additive Models) demonstrate that host tree composition, phosphorous (P) and nitrogen (N) availability together explain 70% of the variation in species richness and 73% of compositional variation for all epiphyte species, 50 % of the variation in species richness and 73% of the compositional variation for holo-epiphytes. Furthermore, null models demonstrate that a majority (76% in positive and 96% in negative associations) of the epiphyte taxa do not exhibit neither preferences nor for five types of bark texture classified in the study. In central Amazonia habitat types have a strong influence on epiphyte community attributes principally among lowland-slope and lowland-upland environments. Host plant composition in concert with edaphic conditions, specifically N and P availability, are apparently the strongest predictors of composition, richness and abundance of epiphytes in central Amazonian forests. Few significant positive and negative associations between substrate type and epiphyte taxa were detected suggesting that differences in epiphyte community structure in relation to host plant composition is due to phylogenetic or other unmeasured physical/environmental factors such as host plant architecture or microclimatic differences. This study corroborates with other experimental studies which have demonstratd both the direct (throughfall effects) and indirect (host tree composition) effects of soil fertility on epiphyte community attributes.O objetivo deste estudo foi investigar como unidades de habitat (baixio, vertente e platô) e composição de árvores hospedeiras, características da casca e fertilidade do solo influenciam a estrutura da comunidade de epífitas vasculares em uma floresta na Amazônia central. Estudos anteriores em outras regiões neotropicais demonstraram que estas variáveis influenciam a composição, riqueza e abundância de epífitas em relação ao tipo de habitat. Métodos: Na Reserva Florestal Adolpho Ducke, onde a abundância de todas as espécies de epífitos vasculares foi registrada 300 árvores hospedeiras com DAP> 30 cm. As árvores hospedeiras foram amostradas dentro de 30 parcelas estabelecidas em baixa altitude, inclinação e habitat de terras altas, e as espécies epifíticas foram classificadas em quatro tipos hábitos vegetativos (Todas as epífitas vasculares, holoepífitas, hemiepífitas secundárias e primárias). No total foram registrados 21.000 indivíduos, 122 espécies distribuídas em 66 gêneros e 20 famílias de epífitas vasculares. Nossos resultados mostram que na Amazônia central, o habitat baixio é distinto na riqueza de espécies, abundância e composição quando comparado com ambos os ambientes de vertente e platô. As análises de regressões Gam Generalized Additive Modelling demonstram que as variáveis composição da árvore hospedeira, fósforo (P) e Nitrogênio (N) juntas explicam 70% da variação na riqueza de espécies e 73% da variação de composição para todas as espécies epífitas, 50% da variação na riqueza de espécies e 73% da variação de composição do holoepífitas. Além disso, modelos nulos demonstram que a maioria (76%) em positivas e 96% em associações negativas) das espécies de epífitas não apresentam preferências pelos cinco tipos de textura da casca classificados no estudo. Os tipos de habitat Amazônia central tem uma forte influência na comunidade epífita principalmente entre baxio e vertente e baixio- platô. A composição de árvores hospedeiras em conjunto com as condições edáficas, especificamente disponibilidade de N e P, são aparentemente fortes preditores da riqueza, composição e abundância de epífitas em uma floresta na Amazônia central. Poucas associações significativas tanto positivas e negativas entre os tipos de substratos e entre as espécies de epífitas foram detectadas. Sugerimos que as diferenças na estrutura da comunidade epífitas em relação às árvores hospedeira são devido a fatores filogenéticos ou físicos-ambientais, como a arquitetura da planta hospedeira ou diferenças microclimáticas. Este estudo corrobora com outros estudos experimentais que mostraram os efeitos diretos (água de gotejamento) e indiretos (composição árvore hospedeira) da fertilidade do solo na comunidade epifítica

Phylogenetic diversity and the structure of host-epiphyte interactions across the Neotropics

Understanding the mechanisms driving community assembly has been a major focus of ecological research for nearly a century, yet little is known about these mechanisms in commensal communities, particularly with respect to their historical/evolutionary components. Here, we use a large-scale dataset of 4,440 vascular plant species to explore the relationship between the evolutionary distinctiveness (ED) (as measured by the 'species evolutionary history' (SEH)) of host species and the phylogenetic diversity (PD) of their associated epiphyte species. Although there was considerable variation across hosts and their associated epiphyte species, they were largely unrelated to host SEH. Our results mostly support the idea that the determinants of epiphyte colonization success might involve host characteristics that are unrelated to host SEH (e.g., architectural differences between hosts). While determinants of PD of epiphyte assemblages are poorly known, they do not appear to be related to the evolutionary history of host species. Instead, they might be better explained by neutral processes of colonization and extinction. However, the high level of phylogenetic signal in epiphyte PD (independent of SEH) suggests it might still be influenced by yet unrecognized evolutionary determinants. This study highlights how little is still known about the phylogenetic determinants of epiphyte communities

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

Exotic tree monocultures play a limited role in the conservation of Atlantic Forest epiphytes

The Brazilian Atlantic Forest suffered a severe geographic contraction along the last five centuries that reduced drastically most vascular epiphyte populations. Among the range of man-made matrixes, tree monocultures have the potential to contribute positively to the maintenance of the regional epiphyte diversity. Here, we test the similarity in abundance, richness, and species composition between vascular epiphytic communities established in managed monocultures of exotic and native species with natural communities occurring in neighboring native Araucaria Forest patches. In the São Francisco de Paula National Forest (Rio Grande do Sul state, Brazil), we recorded 62 epiphyte species from 300 phorophytes occurring in 12, one-hectare plots of Araucaria Forest and managed plantations of Pinus, Eucalyptus and Araucaria. Species richness, rarefied richness and abundance were significantly higher in Araucaria Forest in comparison to the exotic stands. Species composition was also substantially differentiated as Araucaria Forest patches harbored a greater number of zoochorous species than those of the exotic stands. Additionally, plantations of Araucaria angustifolia, a native species, sustained more individuals and more species than the exotic plantations. Neither tree height nor DBH explained epiphyte richness; however, both phorophyte diversity and stand age together accounted for 92% of the among-site variation in epiphytic species richness. We conclude that substrate heterogeneity in combination with time available for colonization contribute significantly to beta-diversity of epiphytes in Araucaria forests. However, demographic experimental studies are necessary in order to disentangle the role of substrate quality from metapopulation processes, such as dispersal limitation, at both temporal and spatial scales. © 2011 Springer Science+Business Media B.V

A tangled web in tropical tree-tops: Effects of edaphic variation, neighbourhood phorophyte composition and bark characteristics on epiphytes in a central Amazonian forest

Question: How do soil fertility, neighbourhood host tree composition and bark characteristics influence community attributes of vascular epiphytes in a central Amazonian forest? Location: Adolpho Ducke Forest Reserve, Amazonas, Brazil. Methods: The abundances of all species of vascular epiphytes were recorded from 300 host trees with DBH >30 cm. Phorophytes were distributed among 30 sample plots established in lowland, slope and upland habitats, and bark characteristics were classified into five types (rough, peeling, fissured, smooth, rugose). The epiphytic species were also classified into three functional types (true epiphytes, hemi-epiphytes and nomadic vines) for separate analyses in an effort to highlight differences in ecological constraints in relation to neighbourhood phorophyte composition and edaphic variation. Results: More than 21 000 individuals representing 122 species distributed in 66 genera and 20 families of vascular epiphytes were recorded from 300 phorophytes during the course of the study. Multiple regressions demonstrated that neighbourhood phorophyte composition and edaphic variables, nitrogen (N) and phosphorus (P), together explained 65% of the variation in epiphytic species composition. However, edaphic factors were the only significant predictors of epiphytic species richness, accounting for 70% of this variation. Nearly one-third of the true epiphytes occurred only on phorophytes in soils with high P content. Null models demonstrate that a vast majority of the epiphyte species (76% in positive and 96% in negative associations) failed to exhibit a statistically significant preference for bark texture. Conclusion: Neighbourhood phorophyte composition, in concert with N and P availability, accounts for the vast majority of the variation in vascular epiphyte composition and abundance in central Amazonian forests. However, only N and P were shown to be significant predictors of epiphyte richness. Such results suggest that both biotic and abiotic variables influence epiphyte community structure (composition, abundance and richness) at differing intensities. Weak associations between bark type and epiphyte taxa suggest that epiphyte community variation may also be influenced by other unmeasured physical and environmental factors such as phorophyte architecture or microclimatic differences. Nonetheless, these results corroborate with other studies which report significant changes in epiphyte composition and richness as a result of experimentally manipulated ground soil fertility. © 2014 International Association for Vegetation Science

Impressões foliares pleistocenas de Malvaceae na área de abrangência do Aproveitamento Hidroelétrico Jirau, Rondônia, Brasil

This paper aims to describe the morphology and taxonomic identification of ten angiosperm leaf impressions collected in Rio Madeira Formation outcrop in the area from Jirau Hydroeletric Dam, found by the team of Paleontological Research, Monitoring and Rescue Program. Due to the preservation and based on morphology, the specimens were identified at the genus level. All specimens belong to the family Malvaceae, and nine specimens were identified as Luehea and one specimen belongs to the genus Theobroma. Two samples were taken from the layer below to the fossiliferous bed, in order to carry dating by method “Accelerator Mass Spectrometry” (AMS C14). The dating pointed ages between 15.910 and 14.850 years calibrated BP. The genus reported here are common in current forest cover in the region of AHE Jirau, and their presences are also confirmed by palynological data obtained for the upper part of the Rio Madeira Formation. © 2014, (publisher). All rights reserved