Notes on Eucryptotermes with a new species from central Amazonia (Isoptera: Kalotermitidae)

Eucryptotermes breviceps, new species, is described from central Amazonia. Both imagoes and soldiers of this new species have only two apical spurs on the foretibia, a condition previously unknown for Kalotermitidae. The soldier of E. breviceps has a peculiar and extremely phragmotic head. The geographical distribution of E. wheeleri is expanded with new records, and measurements of soldiers and imagoes of this species are presented for the first time. E. wheeleri is a native of the Atlantic forest of southeastern Brazil, from Santa Catarina to Rio de Janeiro, but it has been recorded in urban areas and may be an occasional minor pest.

Comparing river basins world-wide and contrasting inland fisheries in Africa and Central Amazonia

An analysis of covariance relating basin area (A, km2) to river length (L, km) and discharge rate (D, m3 s-1) was performed for two continents and showed that the two covariates (L and D) were highly significant and that the strength of the relationship changed between continents. For comparison, D was excluded but the result remained the same. Although geomorphological models are useful for establishing global levels of production, these regressions should be applied with caution. Historically, simple statistical models were developed to predict fish catches in rivers. These, based upon regression of catches on channel length or basin area for Africa and Central Amazonia, are contrasted in this paper because of their generally similar approach.

Comparative study of the zooplankton composition of two lacustrine ecosystems in Southwestern Amazonia

The zooplankton communities of two lacustrine ecosystems in southwestern Amazonia (Lago Amapá and Lago Pirapora) were studied based on samples collected over an 11-month period. The general aim of the present work was to contribute to the knowledge of the zooplankton fauna in southwestern Amazonia, by studying the occurrence of certain species; and to improve the knowledge of the Rio Acre tributaries. The total number of taxa included 38 species of rotifers, 6 cladocerans and 7 copepods. Most of the species were from the rotifer family Brachionidae. Jaccard's similarity index was similar for the two lakes at 0.6964 The constancy index defined the species Keratella cochlearis, Filinia cf. terminate, Filinia opoliensis, Hexarthra intermedia braziliensis, Ceriodaphnia cornuta, Moina minuta, Diaphanosoma spinulosnm, and immature forms (nauplii and copepodites) as the constant in these lakes. The presence of zooplankton with higher number of species occupying the middle depths, during morning and night periods.

The igapó of the Negro River in central Amazonia: Linking late-successional inundation forest with fluvial geomorphology

Despite important progress on Amazonian floodplain research, the flooded forest of the Negro River igapó has been little investigated. In particular, no study has previously focused the linkage between fluvial geomorphology and the floristic variation across the course of the river. In this paper we describe and interpret relations between igapó forest, fluvial geomorphology and the spatial evolution of the igapó forest through the Holocene. Therefore, we investigate the effect of geomorphological units of the floodplain and channel patterns on tree diversity, composition and structural parameters of the late-successional igapó forest. Our results show that sites sharing almost identical flooding regime, exhibit variable tree assemblages, species richness and structural parameters such as basal area, tree density and tree heights, indicating a trend in which the geomorphologic styles seem to partially control the organization of igapó's tree communities. This can be also explained by the high variability of well-developed geomorphologic units in short distances and concentrated in small areas. In this dynamic the inputs from the species pool of tributary rivers play a crucial role, but also the depositional and erosional processes associated with the evolution of the floodplain during the Holocene may control floristic and structural components of the igapó forests. These results suggest that a comprehensive approach integrating floristic and geomorphologic methods is needed to understand the distribution of the complex vegetation patterns in complex floodplains such as the igapó of the Negro River. This combination of approaches may introduce a better comprehension of the temporal and spatial evolutionary analysis and a logic rationale to understand the vegetation distribution and variability in function of major landforms, soil distributions and hydrology. Thus, by integrating the past into macroecological analyses will sharpen our understanding of the underlying forces for contemporary floristic patterns along the inundation forests of the Negro River. © 2013 Elsevier Ltd.

Metabolismo energético do camarão da amazonia, Macrobrachium amazonicum

Pós-graduação em Biologia Geral e Aplicada - IBB

Population Dynamics of Lepidoptera Pests in Eucalyptus urophylla Plantations in the Brazilian Amazonia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Decay of interspecific avian flock networks along a disturbance gradient in Amazonia

Our understanding of how anthropogenic habitat change shapes species interactions is in its infancy. This is in large part because analytical approaches such as network theory have only recently been applied to characterize complex community dynamics. Network models are a powerful tool for quantifying how ecological interactions are affected by habitat modification because they provide metrics that quantify community structure and function. Here, we examine how large-scale habitat alteration has affected ecological interactions among mixed-species flocking birds in Amazonian rainforest. These flocks provide a model system for investigating how habitat heterogeneity influences non-trophic interactions and the subsequent social structure of forest-dependent mixed-species bird flocks. We analyse 21 flock interaction networks throughout a mosaic of primary forest, fragments of varying sizes and secondary forest (SF) at the Biological Dynamics of Forest Fragments Project in central Amazonian Brazil. Habitat type had a strong effect on network structure at the levels of both species and flock. Frequency of associations among species, as summarized by weighted degree, declined with increasing levels of forest fragmentation and SF. At the flock level, clustering coefficients and overall attendance positively correlated with mean vegetation height, indicating a strong effect of habitat structure on flock cohesion and stability. Prior research has shown that trophic interactions are often resilient to large-scale changes in habitat structure because species are ecologically redundant. By contrast, our results suggest that behavioural interactions and the structure of non-trophic networks are highly sensitive to environmental change. Thus, a more nuanced, system-by-system approach may be needed when thinking about the resiliency of ecological networks.

A new genus and two new species of Opilioacaridae (Acari: Parasitiformes) from Amazonia, Brazil with a key to world genera

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Brasilacarus cocaris (Acari: Opilioacaridae), a new genus and species from Amazonia, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of the natural variation of 13C:12C ratio in leaves at Reserva Ducke Forest, central Amazonia

Investigation of carbon isotope fractionation by plants was carried out at two sub-areas located in Reserva Ducke, central Amazonia: open reserve (virgin forest with low density of plant species); and closed reserve (virgin forest with high density of plant species). Preliminary results (δ‰ 13C: 12C values, PDB) of leaf analysis at different plant heights indicate the following: Eschweilera matamata Hub. (Lecythidaceae), common name 'matamata', -31.55±0.61; Protium heptaplyllum March. (Burseraceae), common name 'breu branco', -32.34±1.39; Calophyllum brasiliense Camb. (Guttiferae), common name 'jacareúba', -30.72±0.23; Scleronema micrantthum Ducke. (Bombacaceae), common name 'cardeiro'. -28.81±0.68; and Carapa guianensis Aubl. (Meliaceae), common name 'andiroba', -31.07±0.51. It is possible that the plant species analysed belong to the C3 photosynthetic cycle. In general, the species in the open reserve show differences of the order of 1.66±0.34‰ (greater in 13C) as compared with the same species in the closed reserve. The old leaves show differences in the relative isotopic enrichment (δ) of the order of 1‰, being smaller in new leaves in both reserves. The probable occurrence of an isotopic gradient from the lower (2-5 m) to the upper part (15-20 m) of the plant, of the order of 1.3‰, smaller in 13C, in species from the dense forest was noted. However, only two plants from each species were analysed during a two-year period, data obtained to far are still preliminary, and results should, therefore, be revised. Moreover, according to the literature, the natural carbon isotope fractionation by plants shows metabolic, physiological and environmental dependence. © 1991.

Morphometric relationships and indirect determination of the length frequency structure of the pirarucu, Arapaima gigas (Cuvier), in Brazilian Amazonia

The pirarucu (giant red fish), Arapaima gigas (Cuvier), (Arapaimidae) is among the diverse fish resources of Amazonia which are threatened by over-exploitation. Little is known about the biology of this species despite its commercial importance. The present paper provides indirect information about the length-frequency structure of the stock which was estimated by sampling its tongue bone in craft shops and weighing fresh manias (processed fish product) in fish markets since these were the only remaining recognizable features of the fish. The length-frequency reconstruction was carried out using a regression analysis calculated by utilizing individuals caught in experimental fishing.

Morphometric relationships and indirect determination of the length frequency structure of the pirarucu, Arapaima gigas (Cuvier), in Brazilian Amazonia

The pirarucu (giant red fish), Arapaima gigas (Cuvier), (Arapaimidae) is among the diverse fish resources of Amazonia which are threatened by over-exploitation. Little is known about the biology of this species despite its commercial importance. The present paper provides indirect information about the length-frequency structure of the stock which was estimated by sampling its tongue bone in craft shops and weighing fresh manias (processed fish product) in fish markets since these were the only remaining recognizable features of the fish. The length-frequency reconstruction was carried out using a regression analysis calculated by utilizing individuals caught in experimental fishing.

Effect of Urucu oil (Brazilian Amazon) on the biomass of the aquatic macrophyte Eichhornia crassipes (Mart.) Solms (Pontederiaceae)

Os rios e lagos de várzea da província petrolífera de Urucu, na Amazônia Central, são amplamente colonizados por macrófitas aquáticas, que podem ser afetadas por acidentes durante a exploração e o transporte de petróleo. Entre as macrófitas, a espécie flutuante Eichhornia crassipes (aguapé) ocorre abundantemente na região; OBJETIVO: O objetivo desse estudo foi verificar o efeito de diferentes dosagens do petróleo de Urucu (0; 0,5; 1,5 e 3,0 L.m-2) na biomassa viva e morta de E. crassipes e em algumas características físicas e químicas da água; MÉTODOS: O experimento teve oitenta e quatro dias de duração. A cada sete dias foi determinada a biomassa (viva e morta) de E. crassipes e os valores de temperatura, pH, condutividade elétrica e oxigênio dissolvido da água; RESULTADOS: A dosagem de 0,5 L.m-2 foi suficiente para causar mortalidade parcial (48%) em E. crassipes após trinta e cinco dias de exposição ao petróleo. A dosagem de 3,0 L.m-2 causou mortalidade total (100%) em E. crassipes em oitenta e quatro dias de exposição. A decomposição do petróleo e da biomassa morta de E. crassipes provocam a redução do oxigênio dissolvido e do pH, e aumento da condutividade elétrica e de fósforo total na água; CONCLUSÕES: Nós concluímos que um derramamento de petróleo pode provocar mortalidade total em uma população de uma espécie de macrófita, mas não em uma outra. Isto pode alterar a diversidade de espécies de macrófitas na região impactada. No caso de Eichhornia crassipes e Pistia stratiotes, um derramamento de petróleo de Urucu pode favorecer E. crassipes, a espécie menos sensível ao petróleo.