A new species of Dichaea (Orchidaceae) for northern Brazil

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 ombrifila e floresceu em cultivo. O epíteto é em homenagem ao Dr. Pedro Ivo Soares Braga (in memorian), orquidilogo que realizou vários estudos na Amazônia brasileira. A nova espécie possui afinidade com espécies de Dichaea serão Dichaeopsis, contudo são diferenciadas vegetativamente e na morfologia do labelo

Predation on Cacajao ouakary and Cebus albifrons (Primates: Platyrrhini) by harpy eagles

Predation of tropical arboreal mammals is rarely observed. Here, we report the first observation of predation of a member of the genus Cacajao, and add to the knowledge of eagle predation in the genus Cebus. We compare responses to predation by Cacajao ouakary and Cebus albifrons with previous studies of congenerics and with other close relatives, and compare the alarm vocalizations of C. ouakary with those of other pitheciines. Reactions to non-predating raptors are reported. Constraints on primate anti-predator responses in flooded and non-flooded habitats are considered. © 2011 by Walter de Gruyter Berlin New York

Expansion of the geographical distribution of Notylia angustifolia (Orchidaceae): first record for the Amazonas state (AM), Brazil

Volume: 15Start Page: 323End Page: 32

Apparent environmental synergism drives the dynamics of Amazonian forest fragments

Many contemporary ecosystems are likely to be affected by multiple environmental drivers, complicating efforts to predict future changes in those ecosystems. We studied long-term changes (1980-2012) in forest dynamics and liana (woody vine) abundance and biomass in fragmented and intact forests of the central Amazon. We did so by contrasting trends in 33 permanent 1-ha plots near forest edges (plot center <100 m from the nearest edge) with those in 36 1-ha plots in intact-forest interiors (150-3300 m from nearest edge). In fragmented and edge-affected forests, rates of tree (>= 10 cm diameter at breast height) mortality and recruitment were often sharply elevated, especially in the first 10-15 years after fragmentation. Lianas (>2 cm stem diameter) also increased markedly in abundance (mean 6 SD = 1.78 +/- 1.23% per yr) and biomass (1.30 +/- 1.39% per yr) over time, especially in plots with high edge-related tree mortality. However, plots in undisturbed forest interiors, which were originally established as experimental controls, also experienced long-term changes. In these plots, tree mortality and recruitment rose significantly over time, as did liana abundance (1.00 +/- 0.88% per yr) and biomass (0.32 +/- 1.37% per yr). These changes were smaller in magnitude than those in fragments but were nonetheless concerted in nature and highly statistically significant. The causes of these changes in forest interiors are unknown, but are broadly consistent with those expected from rising atmospheric CO2 or regional climate drivers that influence forest dynamics. Hence, the dynamics of Amazonian forest fragments cannot be understood simply as a consequence of forest fragmentation. Rather, the changes we observed appear to arise from an interaction of fragmentation with one or more global-or regional-scale drivers affecting forest dynamics. Both sets of phenomena are evidently increasing forest dynamics and liana abundances in fragmented forests, changes that could reduce carbon storage and alter many aspects of forest ecology

Long-term changes in liana abundance and forest dynamics in undisturbed Amazonian forests

Lianas (climbing woody vines) are important structural parasites of tropical trees and may be increasing in abundance in response to global-change drivers. We assessed long-term (∼14-year) changes in liana abundance and forest dynamics within 36 1-ha permanent plots spanning ∼600 km2 of undisturbed rainforest in central Amazonia. Within each plot, we counted each liana stem (≥2 cm diameter) and measured its diameter at 1.3 m height, and then used these data to estimate liana aboveground biomass. An initial liana survey was completed in 1997–1999 and then repeated in 2012, using identical methods. Liana abundance in the plots increased by an average of 1.00% ± 0.88% per year, leading to a highly significant (t = 6.58, df = 35, P < 0.00001) increase in liana stem numbers. Liana biomass rose more slowly over time (0.32% ± 1.37% per year) and the mean difference between the two sampling intervals was nonsignificant (t = 1.46, df = 35, P = 0.15; paired t tests). Liana size distributions shifted significantly (χ2 = 191, df = 8, P < 0.0001; Chi-square test for independence) between censuses, mainly as a result of a nearly 40% increase in the number of smaller (2–3 cm diameter) lianas, suggesting that lianas recruited rapidly during the study. We used long-term data on rainfall and forest dynamics from our study site to test hypotheses about potential drivers of change in liana communities. Lianas generally increase with rainfall seasonality, but we found no significant trends over time (1997–2012) in five rainfall parameters (total annual rainfall, dry-season rainfall, wet-season rainfall, number of very dry months, CV of monthly rainfall). However, rates of tree mortality and recruitment have increased significantly over time in our plots, and general linear mixed-effect models suggested that lianas were more abundant at sites with higher tree mortality and flatter topography. Rising concentrations of atmospheric CO2, which may stimulate liana growth, might also have promoted liana increases. Our findings clearly support the view that lianas are increasing in abundance in old-growth tropical forests, possibly in response to accelerating forest dynamics and rising CO2 concentrations. The aboveground biomass of trees was lowest in plots with abundant lianas, suggesting that lianas could reduce forest carbon storage and potentially alter forest dynamics if they continue to proliferate

Evidence of reward production and pollination by Centris in Encyclia (Orchidaceae: Laeliinae): the reproductive biology of Encyclia mapuerae

Encyclia is a neotropical orchid genus distributed from Florida to South Brazil and comprises ∼120 taxa, including Encyclia mapuerae (Huber) Brade & Pabst. Besides its diversity and wide distribution, conclusive data on pollinators and reproductive biology of this orchid genus is scarce. Furthermore, nothing is known about the production of floral reward in Encyclia but the pollinators of their species are assumed to be attracted through food deception. Based on data on phenology, floral morpho-anatomy, histochemistry, pollinators, pollination mechanisms, and breeding system, the reproductive biology of E. mapuerae was studied in a nature reserve at Central Amazonia, Brazil. The flowers of E. mapuerae show longitudinal lines on the labellum that act as a nectar guide. The secretory epidermis has papillae whose cells are covered by an ornamented cuticle. The subtended tissue is composed of a tree-layered collenchyma. The flowers attract several species of Hymenoptera. However, a single species of Centris was recorded as pollinator. The bees collect the nectar produced inside the cuniculus. When the bees leave the flower the pollinarium is attached to their heads. Encyclia mapuerae is self-compatible and pollinator-dependent. The reproductive success in natural conditions is low because of deficient pollen transference due to the scarcity of pollinators. As far we know this is the first study that reports and production of floral reward in Encyclia. This discovery provides new insights on the function of the cuniculus in Laeliinae, and sheds light on the evolution of floral rewards and pollination mechanisms within this diverse group of Neotropical orchids. © 2017 CSIRO