First record of Vanilla labellopapillata (Orchidaceae: Vanilloideae) in the state of Amazonas, Brazil

The first record of Vanilla labellopapillata is presented for the state of Amazonas, Brazil, in the region of Manaus, now the western limit of the species, which was previously known only from the type locality in the state of Pará. A brief description is provided and taxonomic and ecological aspects of the species are discussed in the light of this new finding. (AU)

Spatial and temporal structure of diversity and demographic dynamics along a successional gradient of tropical forests in southern Brazil.

Analysis of the structure, diversity, and demographic dynamics of tree assemblages in tropical forests is especially important in order to evaluate local and regional successional trajectories.We conducted a long-term study to investigate how the structure, species richness, and diversity of secondary tropical forests change over time. Trees (DBH ≥ 5 cm) in the Atlantic Forest of southern Brazil were sampled twice during a 10-year period (2007 and 2017) in six stands (1 ha each) that varied in age from their last disturbance (25, 60, 75, 90, and more than 100 years). We compared forest structure (abundance and basal area), species richness, alpha diversity, demographic rates (mortality, recruitment, and loss or gain in basal area), species composition, spatial beta diversity, and temporal beta diversity (based on turnover and nestedness indices) among stand ages and study years.Demographic rates recorded in a 10-year interval indicate a rapid and dynamic process of species substitution and structural changes. Structural recovery occurred faster than beta diversity and species composition recovery. The successional gradient showed a pattern of species trade-off over time, with less spatial dissimilarity and faster demographic rates in younger stands. As stands grow older, they show larger spatial turnover of species than younger stands, making them more stochastic in relation to species composition. Stands appear to split chronologically to some extent, but not across a straightforward linear axis, reflecting stochastic changes, providing evidence for the formation of a nonequilibrium community. Policy implications. These results reiterate the complexity and variability in forest succession and serve as a reference for the evaluation and monitoring of local management and conservation actions and for defining regional strategies that consider the diversity of local successional trajectories to evaluate the effectiveness of restoration measures in secondary forests of the Atlantic Forest biome.

Twigs occupied by Pheidole Westwood, 1839: Is there a difference between species? / Galhos ocupados por Pheidole Westwood, 1839: há diferença entre espécies?

Abstract: Pheidole is a genus with wide geographical distribution and diversity, especially in the leaf litter of neotropical forests, where nests are found at the soil-litter interface, in the soil and vegetation, among leaves, seeds, and twigs. Despite the availability of twigs and Pheidole species diversity in the leaf litter, most of this resource is not occupied, which suggests the existence of filters. This study analyzes whether twigs occupied by Pheidole species differ for the outer structure and anatomy of the wood. Twigs were collected from preserved Atlantic Forest fragments in southeastern Brazil. Twigs with Pheidole colonies were measured and the wood anatomy analyzed. We collected 224 twigs with Pheidole colonies, but the analysis was done at 41% due to wood decomposition. Five species were recorded in these twigs, which differ for the outer structure and anatomy of the wood. These results suggest the existence of preference in the occupation of twigs determined by wood structure.

Resumo: Pheidole é um gênero com ampla distribuição geográfica e diversidade, especialmente na serapilheira das florestas da Região Neotropical, onde os ninhos são encontrados na interface solo-serapilheira, solo, vegetação, entre folhas, sementes e galhos. Apesar da disponibilidade de galhos e diversidade de espécies de Pheidole na serapilheira, a maior parte deste recurso não é ocupada, o que sugere a existência de filtros. Neste trabalho analisamos se galhos ocupados por espécies de Pheidole diferem em relação à estrutura externa e anatomia da madeira. A coleta de galhos foi realizada em fragmentos conservados de Mata Atlântica na região Sudeste do Brasil. Os galhos com colônias de Pheidole foram mensurados e a anatomia da madeira analisada. Foram coletados 224 galhos com colônias de Pheidole, mas a análise foi realizada em 41% devido à decomposição da madeira. Nestes galhos foram registradas cinco espécies, que diferem em relação à estrutura externa e anatomia da madeira. Estes resultados sugerem a existência de preferência na ocupação do galho determinada pela estrutura da madeira.

A new species of Dichaea (Orchidaceae) for northern Brazil / Uma nova espécie de Dichaea (Orchidaceae) para o norte do Brasil

Dichaea is the largest genus of the subtribe Zygopetalinae and holds it's the highest species diversity in South America. Therefore, this study aims to describe a new species of Dichaea, which occurs in northern Brazil, Dichaea bragae Valsko, Krahl & Holanda. The new species was collected in the north of Manaus in an area of ombrophilous forest and flowered when cultivated. The epithet honors Dr. Pedro Ivo Soares Braga (in memoriam), orchidologist who conducted several studies in the Brazilian Amazon. This new species show a affinity with Dichaea tenuis C. Schweinf., however it is differentiated both vegetatively and on labellum morphology.

Dichaea é o maior gênero da subtribo Zygopetalinae e possui sua maior diversidade de espécies na América do Sul. Diante disto, este trabalho teve o objetivo de descrever uma nova espécie de Dichaea ocorrente na região norte do Brasil, Dichaea bragae Valsko, Krahl & Holanda. A nova espécie foi coleta ao norte de Manaus em área de floresta ombrófila e floresceu em cultivo. O epíteto é em homenagem ao Dr. Pedro Ivo Soares Braga (in memorian), orquidólogo que realizou vários estudos na Amazônia brasileira. A nova espécie possui afinidade com espécies de Dichaea seção Dichaeopsis, contudo são diferenciadas vegetativamente e na morfologia do labelo.

Tree and shrub species of the Atlantic Forest on the slopes of Marambaia Island, Rio de Janeiro, Brazil / Espécies arbóreas e arbustivas da Floresta Atlântica sobre as encostas da Ilha da Marambaia, Rio de Janeiro, Brasil

This study describes the tree and shrub component of the Atlantic Forest on the slopes of Marambaia Island, RJ. It further evaluates which species are found at threatened species lists and the similarity that the studied forest component has with other nearby locations with similar vegetation. Data gathering relied on the joint effort of arbitrary walks and sampling units known as Transect. The same sampling criterion was applied at both approaches (DBH greater than or equal to 5 cm). A similarity analysis, followed by a Cluster analysis, was used to compare the studied vegetation component. Similarity calculations were based in the Bray-Curtis coefficient. We detected a total of 235 species. These are divided in 134 genera and 52 families. The richest families are Myrtaceae (38 spp.), Fabaceae (20 spp.) and Rubiaceae (20 spp.). The richest genera are Eugenia (16 spp.), Myrcia (8 spp.) and Ocotea (6 spp.). Nineteen of the detected species are currently listed as threatened and the studied forest component is mostly resembled to the vegetation at Rio Bonito (RJ). Our evidence shows that the evaluated tree and shrub layer seems to be well preserved and represents an important area for conservational efforts. The results additionally indicate that this vegetation seems to have a greater floristic resemblance to drier and further locations, rather than to more humid and close ones.

Este estudo descreve a florística do componente arbóreo e arbustivo da Floresta Atlântica sobre as encostas da Ilha da Marambaia, RJ. Também são avaliadas quais das espécies encontradas constam em listas de espécies ameaçadas e qual a semelhança deste componente da vegetação com locais próximos cobertos pelo mesmo tipo de vegetação. A coleta de dados se valeu do esforço conjunto de caminhadas arbitrárias e de unidades amostrais conhecidas como "Transect". O critério de inclusão na amostragem foi o mesmo para ambos os métodos (DAP igual ou maior a 5 cm). O componente estudado foi comparado a outras áreas através de uma análise de similaridade, seguida de um dendrograma. Os cálculos de similaridade foram baseados no coeficiente de Bray-Curtis. Detectamos, ao todo, 235 espécies, distribuídas em 134 gêneros e 52 famílias. As famílias mais ricas são Myrtaceae (38 spp.), Fabaceae (20 spp.) e Rubiaceae (20 spp.), enquanto os gêneros mais ricos são Eugenia (16 spp.), Myrcia (8 spp.) e Ocotea (6 spp.). Dezenove das espécies detectadas constam em listas de espécies ameaçadas de extinção e o componente estudado tem maior similaridade com a floresta em Rio Bonito (RJ). As evidências mostram que a vegetação estudada parece estar bem preservada e representa uma área importante para esforços conservacionistas. Os resultados indicam ainda que o remanescente florestal em questão aparenta ser mais semelhante a locais mais secos e distantes do que próximos e úmidos.