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Description of Dichelacera (Dichelacera) lamasi n. sp. (Diptera: Tabanidae), a new species from the state of Mato Grosso do Sul, Brazil
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A 30-year study of the effects of selective logging on a stem-less palm (Astrocaryum sociale) in a central-Amazon forest
No full textWe studied the long-term effects of different selective-logging intensities on the stem-less palm Astrocaryum sociale in a central Amazonian forest 90 km north of Manaus. The experiment consisted of three blocks of 24 ha, each divided into six 4 ha plots in which the treatments were allocated randomly. Each block had a control plot. Within each block, commercial timber was logged with intensities of 44%, 50% and 67% of basal area in 1987, 1988 and 1993 respectively. Stem-less palms in each plot were measured in 1996 and 2016. The number of individuals decreased slightly from 3229 in 1996 to 2997 in 2016, and there was an increase in the proportion of large palms. The degree of change in size structure was related to time since logging (p = 0.012), which also affected the total number of leaves (p = 0.0001), the sum of all leaf lengths (p = 0.01) and the number of adults (p = 0.056). The volume of timber extracted and in standing dead trees was not related to size-structure change. In the control block, the number of individuals changed slightly during the study period. As the different cutting intensities had little, if any, effect of the size-structure of this understory palm up to 30 years after logging, management concessions can contribute to the conservation of some elements of palm biodiversity. © 2018 Elsevier B.V
Avaliação da atividade antioxidante e antibacteriana de extratos de folíolos e ramos de Parkia nitida Miq. (Fabaceae)
No full textSystematics and biogeography of the genus Scaria Bolívar, 1887 (Orthoptera: Tetrigidae: Batrachideinae)
No full textThe Amazon rainforest is the world's most extensive tropical rainforest, holding a considerable ecological and taxonomic diversity. Speciation in this region arises from multiple factors, such as topography, climate fluctuations, oceanic transgression, vegetation and the delimitation of zones circumscribed by sub-basins within the greater Amazon basin. Different scenarios have been proposed to better understand the diversification of Amazonian taxa, whether by Pleistocene refugia or by areas of endemism. The genus Scaria is distributed mostly in Amazonia, with a single species that ranges from the Tumbes-Chocó- Magdalena ecoregion well into Central America all the way to southern Nicaragua. Eight species are currently recognized, with three additional described here as new: Scaria rafaeli sp. nov., S. jonasi sp. nov. and S. granti sp. nov., and the status of S. laeta stat. resurr. is revalidated. Two new combinations are established: S. verutum comb. nov. (formerly placed in Rehnidium Grant, 1956) and Batrachidea brevis comb. nov. (formerly placed in Scaria). New synonym is proposed: Batrachidea brevis (Hancock, 1909) = Batrachidea inermis Hebard, 1923 syn. nov. Lectotypes and paralectotypes were selected for S. laeta, S. maculata and S. lineata, as well as the neotypes for S. hamata and S. boliviana. An updated key to species of Scaria is also provided. A cladistic analysis for 15 species was performed (12 in the inner group and 3 in the outer group) with 40 morphological characters, confirming the monophyly of Scaria. A biogeographical analysis of dispersion-vicariance indicates that the origin of the genus was probably in the Inambari endemism center as the only reconstruction of the resulting ancestral distribution, five dispersions and three vicariance events being postulated. These suggest that both types of events are equally important in the current configuration of the distribution in Scaria. Vicariance events arise mostly by isolation of the species because of the uplift of the Andes and the dispersion events comprise four waves originating from the ancestral range into central and east Amazonia. © 2019 Magnolia Press
Mudanças temporais na precipitação afetam a composição taxonômica e funcional de assembleias de peixes em igarapés da Amazônia central
Get PDFThe effects of climate changes in local assemblages are poorly known. In the Amazon basin, changes in the rainfall pattern in the last decades are expected to affect the hydrological dynamics of forest streams, which strongly depends on the local rainfall regime. Such changes may alter limnological and structural characteristics of the streams and, consequently, disturb local fish assemblages. Here we present results of four repeated surveys of stream fish assemblages conducted along a time interval of 17 years (2001-2018) to investigate the dynamics of fish taxonomic and functional composition and the possible influences of local hydrological regime changes. Fish samplings and environmental variables measurements were conducted with a standardized protocol. Temporal changes in the taxonomic and functional composition of fish assemblages among the four surveys were evaluated regarding its magnitude, direction and congruence of trajectories along time. Throughout the two last decades, the total annual rainfall increased, and stormy days (with rainfall greater than 20mm) were more frequent. The taxonomic and functional composition of local fish assemblages changed among the four surveys, and differences were stronger between the first (2010) and last (2018) surveys. Changes in fish assemblages affected the relative abundance of some of the most abundant species and were apparently mediated by alterations in the substrate composition (i.e. shifting from predominantly covered by litter banks to open sand). Functional changes were associated to traits related to food acquisition, locomotion and habitat use, resulting in lower relative abundances of species that occupy open water habitats in the stream channel and higher abundances of species able to use the lateral ponds and shallow marginal areas. These results provide evidence of a directional change in fish assemblage composition resulting from the effects of increased precipitation and a higher frequency of stormy days over the last decades. Considering the short time interval evaluated and the subtleness of the climatic changes analyzed in this study, these findings can be surprising and point out to the need for the maintenance of long-term ecological research programs in tropical regions, which concentrate most of the planet’s biodiversity.Os efeitos das mudanças climáticas nas assembleias biológicas locais são pouco conhecidos. Na Bacia Amazônica, as mudanças no padrão de precipitação nas últimas décadas devem afetar a dinâmica hidrológica dos igarapés, que dependem fortemente do regime local de chuvas. Tais mudanças podem alterar as características limnológicas e estruturais dos riachos e, consequentemente, perturbar as assembleias locais de peixes. Apresentamos aqui resultados de quatro eventos de amostragens repetidas de assembleias de peixes de igarapés realizadas em um intervalo de 17 anos (2001-2018) para investigar a dinâmica da composição taxonômica e funcional dos peixes e as possíveis influências das mudanças locais no regime hidrológico. As amostragens de peixes e a mensuração das variáveis ambientais foram realizadas por meio de um protocolo padronizado. Mudanças temporais na composição taxonômica e funcional das assembleias de peixes entre os quatro eventos de amostragem foram avaliadas quanto à magnitude, direção e congruência das trajetórias ao longo do tempo. Ao longo das duas últimas décadas, a precipitação total anual aumentou e os dias de tempestades (com precipitação superior a 20 mm) foram mais frequentes. A composição taxonômica e funcional das assembleias locais de peixes mudou entre os quatro eventos de amostragem, e as diferenças foram mais fortes entre o primeiro (2001) e o último (2018) ano de amostragem. As alterações nas assembleias de peixes afetaram a abundância relativa de algumas das espécies mais abundantes e foram aparentemente mediadas por alterações na composição do substrato (ou seja, mudando de áreas predominantemente cobertas por bancos de liteira para áreas de areia). Mudanças funcionais foram associadas a características relacionadas à aquisição de alimentos, locomoção e uso do habitat, resultando em menores abundâncias relativas de espécies que ocupam habitats de águas abertas no canal principal do igarapé e maior abundância de espécies capazes de usar as poças laterais e áreas marginais. Estes resultados fornecem evidências de uma mudança direcional na composição das assembleias de peixes, resultante dos efeitos do aumento da precipitação e uma maior frequência de tempestades nas últimas décadas. Considerando o curto intervalo de tempo avaliado e a sutileza das mudanças climáticas analisadas neste estudo, esses achados podem ser considerados surpreendentes e apontam para a necessidade da manutenção de programas de pesquisa ecológica de longo prazo em regiões tropicais, que concentram grande parte da biodiversidade do planeta
