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Breakdown of green and senescent leaves in Amazonian streams: a case study
No full textAllochthonous organic matter in low-order streams is, in general, mainly composed of senescent leaves. However, in tropical streams green leaves can represent an important source of energy. The present study evaluated the decomposition of green and senescent leaves in Amazonian streams using leaves of three plant species: Inga stipularis D.C. 1876, Tococa guianensis Aubl. 1775 and Vochysia ferruginea Mart. 1826. The leaves were incubated for 120 days in four streams in the municipality of Santarém in western Pará State, Brazil. Senescent leaves were collected using nylon nets suspended 1 m above the ground, while green leaves were collected manually, directly from the trees. Green leaves exhibited better nutritional status: higher values for nitrogen and phosphate and lower values for carbon. Toughness and percentages of tannin and lignin of the green and senescent leaves varied among the studied species. Mass loss of green leaves was ~ 3.5 times higher than that of senescent leaves after 120 days. Higher values of phosphate and nitrogen and lower values of carbon, tannin, and lignin in green leaves were fundamental in explaining the difference in decomposition between green and senescent leaves. These differences reinforce the importance of understanding the role of green leaves in aquatic environments. © 2020, The Japanese Society of Limnology
Effect of rosewood plantation chronosequence on soil attributes in Central Amazonia
Full text linkRosewood (Aniba rosaeodora Ducke) is an endangered Amazonian tree species that produces a commercially valuable essential oil, used mainly in cosmetics and fine fragrances production. The species can also be used in reforestation programs, which generate jobs and as a source of income and reduce the pressure of exploitation on natural rosewood populations. The objective of this study was to verify the influence of rosewood stands on physical and chemical soil attributes. This study was conducted at a rural farm in the Maués municipality, 350 km from Manaus, Amazonas State, Brazil. Samples were collected in five areas; 4-, 10- and 20-year-old rosewood stands, and 15- and 60-year-old secondary forests. The latter two served as control treatments, reflecting natural spontaneous succession conditions over time. Soil was sampled at 10 equidistant points within each area to measure physicochemical attributes, and at the center of each one, a soil profile was dug for description and classification of morphological characteristics. Based on the profile description, the soils were classified as Xanthic Hapludox. The results show that soil conditions under 20-year-old rosewood stand resembled those beneath the 60-year-old secondary forest, and likewise for the soil under the 10-year-old rosewood stand and the 15-year-old secondary forest. The soil bulk density ranged from 0.81 to 0.99 g cm−3 among all areas and no significant difference was found (P = 0.052). With exception to 4-year-old stand, the organic matter (2.68–5.87%) and carbon stock (18.57–31.71 Mg ha−1) did not differ significantly between stands and control treatments. For the soil macronutrients, nitrogen (0.10–0.22%), phosphorus (1.17–11.70 mg kg−1), calcium (0.03–0.31 mg kg−1) and magnesium (0.02–0.16 mg kg−1) were higher or equal in the rosewood stands in comparison to the two controls, while the potassium values (0.03–0.36 mg kg−1) were significantly higher in 60-year-old secondary forests only compared to the 10-year-old rosewood stands (P = 0.005). The soil beneath the 4-year-old rosewood stand, however, differed from the other four areas, having significantly higher natural clay content (>600 g kg−1) and higher topsoil chemical concentrations, associated with the more recent burning. This result represents the first step in addressing concern about sustainable soil use in rosewood forestry economics. Consequently, this kind of rosewood plantation can be recommended as an appropriate use of historically exploited areas, providing economic return from local biodiversity. © 2019 Elsevier B.V
A protocol for fish lipid analysis using nuclear magnetic resonance spectroscopy
Full text linkThis article reports on an easy-to-follow methodology for fish lipids analysis, including the biological sample collection, lipid extraction, sample preparation, nuclear magnetic resonance (NMR) spectroscopy analysis and statistical data analysis, with details on parameters used for the NMR analysis and the care needed in each step execution. As an example of the biological matrix of lipids, for the entire procedure, we have used two Amazonian fish samples. Phenotype factor was taken into account when lipid contents of the Amazonian fish samples were evaluated, such as fish-eating habits in distinct Amazon seasonal periods, the flood and the drought. Results demonstrated the applicability of NMR as a powerful and useful tool for fish oil analysis. The omnivorous (T. elongatus) and the piscivorous (C. monoculus) Amazonian fish differ in composition and distribution of lipids, which show differences not only because of the different eating habits between the two species, but also by the availability and quantity of food along the year, i.e., during the flood and drought Amazon periods. ©2020 Sociedade Brasileira de Químic
Participation of phosphoryl transfer network on branchial energetic imbalance of matrinxã (Brycon amazonicus) exposed to air: Notable involvement of creatine kinase
No full textManipulation of wasp (Hymenoptera: Vespidae) behavior by the entomopathogenic fungus ophiocordyceps humbertii in the atlantic forest in Ceará, Brazil1
No full textBehavioral manipulation of hosts by parasites is important to increase the parasite fitness. Some species within the genus Ophiocordyceps, notably pathogens of ants, induce changes in the host's behavior, leading the host to die outside the colony and locking its mandibles on the edge of leaves. This study was conducted in Massif of Baturité, and for the first time, we describe the interaction between fungi and wasps in Northeastern Brazil. We found 24 specimens, eight of each species of wasp, all infected with Ophiocordyceps humbertii. The wasps were Agelaia pallipes, Apoica flavissima, and Polybia chrysothorax. All the hosts were found with their mandibles biting along the edges of leaves. © 2020 BioOne. All rights reserved
How Habitat Filtering Can Affect Taxonomic and Functional Composition of Aquatic Insect Communities in Small Amazonian Streams
No full textResponses in taxonomic and functional composition of communities were analysed in small Amazonian streams at the small and large scale (habitat patches, river segment scale, and catchment scale). We hypothesised that similar responses in community structure to local environmental factors were a correlation between taxonomic and functional composition. To evaluate the response of taxonomic composition to environmental variables, redundancy analysis (RDA) and RLQ analysis were performed to investigate the response of community abundance (L) as a function of the environment (R) and traits (Q). The fourth-corner analysis was applied to summarize specific interactions between environmental variables and traits. Then, community taxonomic composition was associated with models at multiple scales of habitat (i.e. riparian/channel, substrates, and water variables). Likewise, the fourth-corner tests and RLQ axes showed associations between trait composition and environmental variables related to variables, such as riparian cover and channel morphology followed by variation in substrate size and composition. Unexpectedly, these results did not show specific associations between unique environmental variables and traits. At last, results showed that local conditions of stream habitat regulated community structure and functional composition of aquatic insects. Thus, these findings indicate that the local environmental filtering appears to be strongly associated with selected species traits adapted to occur in a range of habitat conditions. Despite the low number of analysed streams, these results provide important information for understanding the simultaneous variation in functional trait composition and community composition of aquatic insect assemblages. © 2020, Sociedade Entomológica do Brasil
Honey botanical origin of stingless bees (Apidae Meliponini) in the Nova América community of the Sateré Mawé indigenous tribe, Amazon, Brazil
No full textThis study analysed the pollen present in honey samples collected from colonies of stingless bees (Meliponini) from the meliponary of the Nova América community of the Sateré Mawé tribe, located on the Maruá River, Maués municipality, Amazonas state, Brazil (03° 39ʹ 45.00″ S, 57° 20ʹ 17.99″ W). Collections were made directly from honey storage pots. A total of 47 pollen types were identified, belonging to 22 plant families. Bees with the largest number of pollen types were Melipona seminigra (31 collected pollen types), followed by Melipona sp. (27 pollen types), Scaptotrigona sp. (25 pollen types), and Melipona dubia (19 pollen types). Plant families most commonly collected were: Anacardiaceae, Arecaceae, Burseraceae, Chrysobalanaceae, Dichapetalaceae, Dilleniaceae, Euphorbiaceae, Fabaceae, Lecythidaceae, Melastomataceae, Myrtaceae, Rhamnaceae and Salicaceae. Scaptotrigona sp. had the highest pollen types diversity (H′ = 2.32) and, consequently, greatest between-collection uniformity. Trophic niche overlap was significant between the following pairs of bees: M. seminigra and M. dubia (Oi = 0.93); M. seminigra and Scaptotrigona sp. (Oi = 0.79) and M. dubia and Scaptotrigona sp. (Oi = 0.69). These data demonstrate the importance of these shared groups of plants for the maintenance of these bees and, consequently, for the development of meliponiculture in Brazilian Amazonia. © 2020, © 2020 Collegium Palynologicum Scandinavicum
Streamflow variability in colombian pacific basins and their teleconnections with climate indices
No full textOceanic-atmospheric phenomena of different time scales concurrently might affect the streamflow in several basins around the world. The Atrato River Basin (ARB) and Patia River Basin (PRB) of the Colombian Pacific region are examples of such basins. Nevertheless, the relations between the streamflows in the ARB and PRB and the oceanic-atmospheric factors have not been examined considering different temporal scales. Hence, this article studies the relations of the climate indices and the variability of the streamflows in the ARB and PRB at interannual and decadal timescales. To this, the streamflow variability modes were obtained from the principal component analysis (PCA); furthermore, their linear dependence with indices of the El Nino/Southern Oscillation (ENSO), precipitation (PRP), the Choco low-level jet (CJ), and other indices were quantified through (a) Pearson and Kendall's tau correlations, and (b) wavelet transform. The PCA presented a single significant mode for each basin, with an explained variance of around 80%. The correlation analyses between the PC1s of the ARB and PRB, and the climate indices showed significant positive (negative) high correlations with PRP, CJ, and Southern Oscillation Index (SOI) (ENSO indices). The wavelet coherence analysis showed significant coherencies between ENSO and ARB: at interannual (2-7 years) and decadal scale (8-14), preferably with the sea surface temperature (SST) in the east and west Tropical Pacific Ocean (TPO). For PRB with the SST in the central and western regions of the TPO in the interannual (4-8 years) and decadal (8-14 years) scales, the decreases (increases) in streamflow precede the El Nino (La Nina) events. These results indicate multiscale relations between the basins' streamflow and climate phenomena not documented in previous works, relevant to forecast the extreme flow events in the Colombian Pacific rivers and for planning and implementing strategies for the sustainable use of water resources in the basins studied. © 2020 by the authors
Melatonin reduces aggressiveness and improves oxidative status of matrinxã (Brycon amazonicus) subjected to social challenge
No full textMelatonin is a hormone that can modulate aggressive interactions in fish, stimulate antioxidant enzymes, and neutralize the biological damage caused by high free radical production. Fish, especially those kept in artificial environments, are subject to damage caused by free radicals resulting from stressful conditions, such as a social challenge. The matrinxã (Brycon amazonicus) arouses great commercial interest and has been widely used in farming systems. However, these animals have a high frequency of aggressive behavior and cannibalism, which is considered a limiting factor for the production system. Thus, we evaluated the influence of melatonin on aggressiveness and oxidative stress parameters in matrinxã juveniles, testing whether melatonin increases glutathione concentrations and reduces lipid peroxidation (thiobarbituric acid–reactive substances) during social challenge. For this, 24 fish were subjected to three concentrations of melatonin in water: control (0 μmol/L), low MEL (1 μmol/L), and high MEL (10 μmol/L), with eight replicates each. The fish were isolated for 96 h, subjected to the mirror test (social challenge), and then euthanized and dissected to remove the liver. Melatonin reduced total aggressive interactions in animals treated with melatonin (P = 0.036), increased glutathione concentrations (P = 0.002), and decreased levels of lipid peroxidation (P = 0.001). We concluded that melatonin reduces aggressiveness and acts as a potent antioxidant in matrinxã juveniles, contributing to the reduction in stress levels and thus improving the maintenance conditions of animals in production systems. © 2020, Springer Nature B.V
A global database for metacommunity ecology, integrating species, traits, environment and space
Full text linkThe use of functional information in the form of species traits plays an important role in explaining biodiversity patterns and responses to environmental changes. Although relationships between species composition, their traits, and the environment have been extensively studied on a case-by-case basis, results are variable, and it remains unclear how generalizable these relationships are across ecosystems, taxa and spatial scales. To address this gap, we collated 80 datasets from trait-based studies into a global database for metaCommunity Ecology: Species, Traits, Environment and Space; “CESTES”. Each dataset includes four matrices: species community abundances or presences/absences across multiple sites, species trait information, environmental variables and spatial coordinates of the sampling sites. The CESTES database is a live database: it will be maintained and expanded in the future as new datasets become available. By its harmonized structure, and the diversity of ecosystem types, taxonomic groups, and spatial scales it covers, the CESTES database provides an important opportunity for synthetic trait-based research in community ecology. © 2020, The Author(s)