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This article provides new evidence for the sources of regional income inequalities in Brazil throughout the wage distribution, taking into account the regional differentials in purchasing power. We use a unique and recent regional purchasing power index to adjust nominal values of Brazilian metropolitan regions and consider recentred influence function (RIF) regressions to measure the contributions of different determinants of wages to the inequality between the São Paulo metropolitan region in the Southeast (the richest one, apart from Brasília) and each of the most important metropolitan regions of the Northeast and North (Fortaleza, Recife, Salvador and Belém). [ABSTRACT FROM AUTHOR]

Forest soils have a large capacity of stocking and cycling carbon, incorporated by organic matter and evaded by roots and soil microbiota as CO2. Soil respiration can indicate ecosystem processes, but little is known about the successional, seasonal and diurnal variation in CO2 flux. This study presents estimations of soil CO2 efflux in a seasonal Atlantic forest fragment (FF) and an adjacent 15 years-old restoration site (RS), in two seasons (winter-dry and summer-rainy), during 24-hour periods, in southern Brazil. Measurements were performed with an infrared gas analyser at 2-hour intervals. Respiration rates were 50% higher in the rainy season, both in FF (261, against 135 mg m-2 s-1 in the dry season) and RS (237 and 127 mg m-2 s-1), indicating that higher humidity and temperature promoted higher soil biota activity. The soil respiration was higher at FF only in the dry season, revealing that this environment may be less sensitive to water limitation. Greater overnight respiration was observed in the dry season for both sites, likely reflecting more intense microbial metabolism at night in this season. There was no rainy season diurnal variation. Seasonal and daily variation suggests that soil respiration in the RS is more sensitive to warmer and dryer conditions. [ABSTRACT FROM AUTHOR]

Forest fragmentation is the main cause of biodiversity loss in the Anthropocene and it is triggering a top-down cascade effect that may influence leaf litter decomposition. However, the link between biodiversity loss and changes in ecosystem processes is not fully understood. We conducted an experiment to evaluate whether the exclusion of vertebrates affects the decomposition rates of different litter types (grass, a pioneer species and a mix of litters from a well preserved secondary forest). To answer this question, we placed litter bags inside artificial exclusion plots that were built in two types of vegetation coverage (abandoned pastureland and preserved forest) in the Atlantic forest of southeast Brazil. Our hypothesis is that vertebrate exclusion will change decomposition rates of different litter types due to the top-down cascade effect on soil invertebrates. We found out that vertebrate exclusion did not affect decomposition rates, possibly due to the overlap of ecological functions in the soil fauna responsible for the decomposition process. Furthermore, grass litter was decomposed faster (k value), possibly due to its initial nutrient content and hence litter quality which plays a significant role on decomposition rates. [ABSTRACT FROM AUTHOR]

Cellulosic ethanol is an alternative for increasing the amount of bioethanol production in the world. In Brazil, sugarcane leads the bioethanol production, and to improve its yield, besides bagasse, sugarcane straw is a possible feedstock. However, the process that leads to cell wall disassembly under field conditions is unknown, and understanding how this happens can improve sugarcane biorefinery and soil quality. In the present work, we aimed at studying how sugarcane straw is degraded in the field after 3, 6, 9, and 12 months. Non-structural and structural carbohydrates, lignin content, ash, and cellulose crystallinity were analyzed. The cell wall composition was determined by cell wall fractionation and determination of monosaccharide composition. Non-structural carbohydrates degraded quickly during the first 3 months in the field. Pectins and lignin remained in the plant waste for up to 12 months, while the hemicelluloses and cellulose decreased 7.4 and 12.4%, respectively. Changes in monosaccharide compositions indicated solubilization of arabinoxylan (xylose and arabinose) and β-glucans (β-1,3 1,4 glucan; after 3 months) followed by degradation of cellulose (after 6 months). Despite cellulose reduction, the xylose:glucose ratio increased, suggesting that glucose is consumed faster than xylose. The degradation and solubilization of the cell wall polysaccharides concomitantly increased the level of compounds related to recalcitrance, which led to a reduction in saccharification and an increase in minerals and ash contents. Cellulose crystallinity changed little, with evidence of silica at the latter stages, indicating mineralization of the material. Our data suggest that for better soil mineralization, sugarcane straw must stay in the field for over 1 year. Alternatively, for bioenergy purposes, straw should be used in less than 3 months. [ABSTRACT FROM AUTHOR]

We devise a decomposition for the level of the unemployment rate that allows the assessment of the contributions of the various flow rates in the labor market over different time horizons. In particular, the decomposition allows one to recover the contributions of the flow rates in the long-run projection of the unemployment rate as in the steady-state decomposition widely used in the literature. We apply our methodology for data from the USA and Brazil. The results show that the relative contribution of the flows to the variance of the cyclical component of unemployment is sensitive to the time horizon of the projected unemployment rate. The changes in relative contributions of some flows are so prominent that their rankings change over time. These qualitative changes are more significant for Brazil than for the USA. Our results also evince that the steady-state approximation of the unemployment rate performs relatively worse in the former country. We take these findings as supporting evidence for considering the use of projected unemployment rate over shorter time horizons as an alternative to the steady-state approximation. [ABSTRACT FROM AUTHOR]

Headwater streams subjected to anthropogenic impacts are prone to environmental quality decay, which may affect stream functioning. To investigate the effects of loss of environmental quality in stream functioning, we tested the hypothesis that leaf breakdown is faster in streams with higher environmental quality, and that invertebrate community structure and microbial biomass are negatively affected by habitat simplification resulting from environmental degradation. We submerged Alchornea glandulosa leaves in litter bags in nine streams, in Southern Brazil, in an environmental gradient. We characterized breakdown rates (k), physical in-stream characteristics, abundance of invertebrate taxa, and functional groups and microbial biomass for each stream, with three mesh exclusions (fine, medium, coarse). Breakdown was faster in the most preserved stream (k = − 0.032 ± 0.005) and decreased towards the most disturbed stream (k = − 0.0034 ± 0.001). Breakdown rates were positively associated with underwater habitat complexity, equitability of macroinvertebrate taxa, and abundance of Stenochironomus sp., which together explained 51% of breakdown rate variability. Breakdown rates from the less disturbed streams (n = 7, excluding urban-influenced) were lowest in medium-mesh, intermediate in fine-mesh, and highest in coarse-mesh bags, and the only taxon that differed according to this pattern was the mining-chironomid Stenochironomus sp., which suggests that this taxon had a significant activity of leaf processing. [ABSTRACT FROM AUTHOR]

Eucalyptus plantations have replaced other (agro)ecosystems over 5.6 Mha in Brazil. While these plantations rapidly accumulate carbon (C) in their biomass, the C storage in living forest biomass is transient, and thus, longer‐term sustainability relies on sustaining soil organic matter (SOM) stocks. A significant amount of harvest residues (HR) is generated every rotation and can yield SOM if retained in the field. Yet, there is little information on how managing eucalyptus HR changes SOM dynamics. We used isotopic and molecular approaches in a 3‐yr field decomposition experiment where a native grassland has been replaced by eucalyptus plantations to assess how HR management practices influence content and chemistry of two distinct SOM fractions [particulate (POM) and mineral‐associated organic matter (MAOM)] at two soil depths (0–1 and 1–5 cm). The management practices investigated were HR removal (−R), only bark removal (−B), and retention of all HR (including bark, +B), combined with two levels of nitrogen (N) fertilization [0 (−N) and 200 (+N) kg/ha]. N fertilization inhibited HR decomposition (P = 0.0409), while bark retention had little effect (P = 0.1164). Retaining HR, especially with bark, increased POM‐C and MAOM‐C content (2.1‐ and 1.2‐fold, respectively), decreased POM‐δ13C (1.2‐fold), and increased inorganic N retention (1.7‐fold) compared with plots where HR had been removed. Inorganic N applications, however, diminished the positive impacts of bark retention. Although the influence of HR management was most pronounced in POM, retaining HR reduced potential soil C mineralization by up to 20%. POM and MAOM chemistry shifted over time and revealed distinct influence of HR on the formation of these fractions. We demonstrate that HR management alters SOM dynamics and that retaining HR, particularly including bark, enhances SOM retention. With continuing conversion of native grassland ecosystems to eucalyptus, long‐term sustainability will require careful HR and fertilizer management to balance total biomass harvest with sustaining belowground SOM concentrations. [ABSTRACT FROM AUTHOR]

Copyright of Investigación Económica is the property of Universidad Nacional Autonoma de Mexico, Facultad de Economia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The objective of this work was to analyze the income differential of the rural–urban worker in relation to the rural–rural worker and in relation to the urban–urban worker in the Brazilian labor market. Two databases were used, the 2005 and 2015 PNADs (Pesquisa Nacional Por Amostra de Domicílios). Design/methodology/approach: The methodology is the decomposition approach proposed by Firpo et al. (2007, 2009). This method adopts estimates of unconditional quantile regressions, based on the concepts of influence function and recentered influence function (RIF). Findings: Among the main results, income differentials were shown to benefit the urban–urban worker when compared to the rural–urban worker, and income differences to the benefit of the rural–urban workers, when these were compared to the rural–rural workers. The educational variable was relevant in explaining the income disparity and expressing increasing effects in the higher quantiles. Originality/value: The methodology used in this work is considered recent in the literature as it is based on the RIF regression (Firpo et al., 2007, 2009). The main advantage of this method is the possibility of assigning a "composition effect" and a "wage structure effect" for each variable that determines the level of income at different points of the income distribution. [ABSTRACT FROM AUTHOR]

Avin et al (2005) showed that, in the presence of exposure-induced mediator-outcome confounding, decomposing the total causal effect (TCE) using standard conditional exchangeability assumptions is not possible even under a nonparametric structural equation model with all confounders observed. Subsequent research has investigated the assumptions required for such a decomposition to be identifiable and estimable from observed data. One approach was proposed by VanderWeele et al (2014). They decomposed the TCE under three different scenarios: (1) treating the mediator and the exposure-induced confounder as joint mediators; (2) generating path-specific effects albeit without distinguishing between multiple distinct paths through the exposure-induced confounder; and (3) using so-called randomised interventional analogues where sampling values from the distribution of the mediator within the levels of the exposure effectively marginalises over the exposure-induced confounder. In this paper, we extend their approach to the case where there are multiple mediators that do not influence each other directly but which are all influenced by an exposure-induced mediator-outcome confounder. We provide a motivating example and results from a simulation study based on from our work in dental epidemiology featuring the 1982 Pelotas Birth Cohort in Brazil. [ABSTRACT FROM AUTHOR]

Both N deposition and changes in precipitation amount are important components of global change and affect aquatic ecosystem functioning by altering the detrital quality and detrital processing rates by macroinvertebrates and microorganisms. Changes in precipitation pattern can also modify the physical structure of the ecosystem, determining habitat availability for aquatic organisms. Although these drivers can individually affect ecosystem structure and functioning, their interactive effects are poorly understood.To better understand the combined effects of detritus quality and precipitation regime on the structure and function of aquatic ecosystems we manipulated litter quality, by modifying N:P stoichiometry and rainfall amount on tropical natural aquatic microcosms (water‐holding epiphytic bromeliads). We performed an orthogonal manipulation of litter N:P ratio (natural N:P and high N:P) and rainfall levels (current level and predicted 40% increase for south‐eastern Brazil)Changes in litter quality affected the abundance of the aquatic organisms inhabiting bromeliads, including algae and bacteria. However, changes in litter quality combined with changes in precipitation levels affected only one group of macroinvertebrates, the Naididae worms (Oligochaeta) an important group of detritivores in the bromeliad systems. These combined drivers also affected the decomposition of organic matter by changing coloured organic matter concentrations, fine particulate matter biomass, and NH4+ concentrations in bromeliad tanks. The NH4+ concentration in bromeliad water was positively related with Naididae abundance, suggesting that these worms can act as ecosystem engineers by boosting N cycling. In both N:P treatments we observed a 50% decrease in N flux from litter to bromeliad leaves due to increases in nutrient leaching from the tanks caused by rainfall.The combined effects of litter quality and changes in precipitation regimes altered the decomposition process and nutrient cycling in tank bromeliads, probably through changes in the abundance of some keystone species (e.g. Naididae). Aquatic macroinvertebrate community structure remained similar after manipulating precipitation, despite changes in the abundance of some species. Although some microorganisms were washed out of the system, their abundance inside the bromeliads remained stable. We conclude that the abundance of individuals belonging to aquatic communities in bromeliad phytotelmata are generally stable and resistant to changes in rainfall levels, but are sensitive to changes in litter quality.This experiment showed that the interactive effects of increased precipitation and N concentrations differed from the effects of either factor alone. As responses to changes in these factors were complex rather than additive, caution is required in predicting the outcomes of changes in both factors in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to test associations between a municipal social development indicator and indicators of public dental services; examine differences in the achievement of public dental services goals between fluoridated and nonfluoridated municipalities; and, quantify contribution of a municipal social development indicator in estimated mean differences in the public dental services indicators between fluoridated and nonfluoridated municipalities. Methods: A secondary analysis of data from 293 municipal dental health services records from Southern Brazil between 2010 and 2015 was conducted. Multivariable log‐binomial regression models were fitted to test the associations between municipal Human Development Index (HDI) and multiple public dental services indicators (proportion of public dental health service coverage, the proportion of tooth extraction among all clinical procedures, and monthly participation in supervised tooth brushing). Cut‐off points for outcomes were based on state goals for public dental services. Blinder‐Oaxaca decomposition analyses were performed to quantify the relative contribution of HDI in the differences in outcomes according to the municipal water fluoridation status. Results: Municipalities within the lowest tertile of HDI had 66% lower prevalence of having insufficient public dental health service coverage (less than state goals)than those in the highest tertile of HDI (PR: 0.44; 95% CI: 0.24, 0.50). Municipalities with lowest HDI had nearly 30% higher prevalence of failing the state goals regarding the proportion of extraction and supervised tooth brushing (PR: 1.30; 95% CI: 1.20, 1.40 and PR: 1.34; 95% CI: 1.23, 1.45, respectively). Mean public dental health service coverage was higher in nonfluoridated municipalities than fluoridated municipalities, and municipal HDI explained 36% of the total estimated mean difference. Conclusions: This study found associations between municipal social development and public dental services indicators in Southern Brazil. However, higher HDI was associated with lower public dental health service coverage, lower proportion of extraction and higher coverage of supervised tooth brushing [Correction added on 2 April 2019, after first online publication: In the preceding sentence, the text "but with a higher proportion of extraction and supervised tooth brushing" was changed to "lower proportion of extraction and higher coverage of supervised tooth brushing"]. Municipal HDI contributed significantly towards the gap in public dental coverage between fluoridated and nonfluoridated municipalities, favoring nonfluoridated municipalities. These findings have important policy implications for reducing oral health inequalities as it highlights the interplay between key oral health policies and their distribution according to municipal social development. [ABSTRACT FROM AUTHOR]

There is a vast literature that estimates the effect of the minimum wage on wage inequality in various countries. However, as the minimum wage directly affects nonlabor income of families in some countries (in the Brazilian case via the benefits of the pension system and of certain social programs), this article extends the empirical analysis by studying the effects of the minimum wage on the level of inequality of household income as a whole. To accomplish that we employ a decomposition method that gauges the contribution of the increases in the minimum wage that occurred in recent decades in Brazil through the labor and nonlabor sources of household income. The results show that the minimum wage had a contribution of 64 percent to the observed fall in income inequality between 1995 and 2014 and that pensions were the most relevant channel over this period. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising fuel, can be obtained from different sources of raw materials, including water. This is a renewable and sustainable source, which can obtain a high hydrogen purity via electrolysis. Among the processes for obtaining hydrogen from the water, the electrolytic conversion is the best known, in which two electrodes are responsible for conducting electricity and production of this gas. However, to promote this segregation, some technological challenges must be overcome, as the efficiency of electrolyzers, efficiency and durability of the main fuel cells and the integration of the electrolysis systems for supply and energy, aiming to reduce production costs. The Brazil stands out worldwide with production of fuels obtained from renewable sources and also seeks to develop the hydrogen production through water electrolysis. [ABSTRACT FROM AUTHOR]

We described the effects of fire ants (Solenopsis saevissima) (Hymenoptera: Formicidae) on and in a big-eared opossum (Mammalia: Marsupialia: Dedelphidae) carcass. The observations were made in southeastern Brazil beside of a public highway. We documented the competitive ability of the fire ants, which sought to reduce competition with necrophagous flies by constructing a soil structure over the natural orifices of the carcass. After we removed the structure, the ants changed their physical and ecological behavior on the carcass until the end of decomposition. This ant behavior of blocking access to the carcass delays the decomposition process due to the fact that other necrophagous insects cannot forage there. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Brazilian cerrado occurs interspersed with the semi-deciduous seasonal forest, and soil fertility is considered as the main determinant of the abrupt transitions between both vegetation types. We aimed to study patterns across chemical traits of green leaves in 121 cerrado and seasonal forest woody species from southeastern Brazil, their response to soil nutrient status, and their effects on decomposition rates. We compared leaf traits of both cerrado and forest species and constructed multilevel models to account for partitioning of variance in each trait. We calculated the community-weighted mean of each trait to assess their response to soil nutrient status and their effects on decomposition rates of standard plant material. Most of the traits were significantly correlated among themselves, with cerrado species having lower nutrient concentrations than the seasonal forest. Taxonomy accounted for 52 % of the total variance in leaf traits, whereas vegetation type accounted for 19 %. All leaf traits but leaf manganese and aluminium concentrations were significantly related to soil properties. Decomposition rates were affected indirectly by soil features through its effects on leaf traits. Contrary to the expected, the higher the leaf nitrogen concentration in the surrounding litter, the lower the decomposition rate. Even with a large effect of taxonomy on leaf nutrient-related traits, soil exerted an important role on the chemical traits. Strategies of both cerrado and seasonal forest species were carried out through multi-element control of soil on leaf nutrient composition. The effect of such different strategies on functioning was, however, less prominent. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Applied Economics / Economía Aplicada is the property of FEA-RP, Universidade de Sao Paulo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Experiments using litter monocultures have indicated that litter decomposes faster on its home site owing to specialised decomposers leading to a home-field advantage (HFA). However, most natural forests, in particular tropical rainforests, harbour more than one species of trees, all of which contribute to the local litter layer. Since interactions among different litter types that cause non-additive decomposition dynamics may prevent HFA, the occurrence of HFA in such multispecies ecosystems is still a matter of debate. Here we studied whether there is an HFA in a highly diverse forest ecosystem in the Atlantic Rainforest of Brazil. We used a litter decomposition experiment using natural litter mixtures with reciprocal transfers among three forest successional stages that differed in their tree species composition and general litter quality. We also investigated the role of soil macro- and meso-invertebrates for HFA and their relative importance along a successional gradient. Results of various statistical procedures failed to demonstrate HFA. A reason for this lack of a HFA may be rapid shifts in the composition of local microbial communities in response to local litter quality. Our experiments indicate a rapid resilience of the microbial decomposition during forest regeneration. [Copyright &y& Elsevier]

In this study we evaluated the uptake, decomposition and nutrient release of the deciduous material in summer in areas of secondary forest and eucalyptus plantations in Redenção da Serra, SP. Were installed ten collectors in each area to evaluate the contribution of deciduous material (litter). It was collected every 15 days from December 2003 for 75 days. Part of the litter was placed in decomposition bags and distributed in surface areas, being collected every 15 days for evaluation. The area under eucalyptus showed greater intake of dry matter, lower decomposition constant and longer half life. There was a higher proportion of the fraction in the forest leaves and branches on the fraction area of eucalyptus. At time zero, the area of secondary forest showed higher accumulation of N, K, Ca, Mg and P. As for the area of eucalyptus, there was a sequence of N, Ca, K, Mg and P. At the end of 75 days, the area of eucalypt in plantation showed higher percentages of N, P, K and Ca. For the climatic conditions of Redenção da Serra, in summer, the area with eucalyptus showed greater intake of dry matter and nutrient content remaining compared with the area of forest. [ABSTRACT FROM AUTHOR]

The article discusses a study on evaluation of the participation of Nasutitermes corniger, N. ephratae and N. macrocephalus in the consumption of the wood litter in a remnant area of Coastal Forest in Brazil. These species are the principal termites that construct their nests in trees. It was found in the study area that wood consumption by three species was estimated to be 66.9 kilo grams of dry mass, corresponding to approximately 2.9 percent of the annual production of wood-litter.

Leaf breakdown in streams is affected by several factors, such as leaf characteristics, water chemistry, microbial activity, and abundance of shredders. In turn, shredders may be resource-controlled. We hypothesized that the size of litter patches affects leaf breakdown, because large patches should be stable over time and therefore harbor high densities of shredders. We selected litter patches (area 0.25–10 m2) in 10 pools of three first-order streams (Manaus, Brazil). We installed 10 leaf packs of Mabea speciosa (Euphorbiaceae) in each patch, and sampled one after 1 day and three after 5, 19, and 28 days. The leaf packs were quickly colonized by the shredding caddisflies Triplectides and Phylloicus. The leaf breakdown rate (mean k = 0.026 ± 0.0015 SE) was high and similar to values reported for other tropical and temperate streams, although much higher than values reported for the adjacent Cerrado biome. Assemblage composition varied over time, but was not related to the size of litter patches. Contrary to our hypothesis, litter patch area did not affect breakdown rates ( r2 = 0.012, P = 0.766) or abundance of shredders after 5, 19, and 28 days ( r2 < 0.243, P > 0.147). We found, however, a positive relationship between the abundance of tropical shredders and leaf breakdown after 19 days ( r2 = 0.572, P = 0.011), suggesting that shredders play an important role in leaf breakdown in these headwater streams. Our study indicates that leaf breakdown rates in tropical streams are variable and can be as high as those of temperate streams. [ABSTRACT FROM AUTHOR]

We have studied the production of polysaccharides by bacterioplankton in an eutrophic tropical reservoir (Barra Bonita, SP–Brazil) through a decay experiment using glucose as carbon source. The temporal evolution was monitored by measuring the total organic carbon and the contents of monosaccharides. The glucose added to the reservoir sample water was consumed at higher rates within the first hours of incubation, and after 30 days 94.4% of the carbon contents were mineralized; 4.2% remained as particulate organic carbon (POC) form and 1.5% as dissolved organic carbon (DOC) form. The production of polysaccharides occurred in two stages: within the first 48 h, there was intense glucose consumption with small POC increment (ca. 16%) and release of small quantities of dissolved polysaccharide. In the second, more intense stage production was accelerated after the 9th day of incubation, with the highest polysaccharide concentration measured on the 20th day. Such formation of polysaccharides was related to the excretion of capsules and sheaths by bacterioplankton, mainly in the senescence of heterotrophic populations, with release of reserve and structural intracellular materials. [ABSTRACT FROM AUTHOR]

Along-channel velocity, salinity, and total suspended sediment concentration profiles were measured during 15 complete neap and spring tidal cycles in the dry and rainy seasons in four cross-sections in a tropical estuary, Itamaracá, Pernambuco, Brazil. The net longitudinal fluxes of salt and sediments were decomposed into advective, tidal, and cross-sectional shear transports. The advective transport of both salt and suspended sediments were for most parts export-directed and greater than the combined river discharge, suggesting a non-steady state. The dispersive tidal transport was decomposed into four separate mechanisms of which tidal pumping transport and tidal wave transport (similar to transport by Stokes' drift) are the main transport mechanisms. The cross-sectional shear transport was negligibly small, and thus, vertical nor lateral effects are significant with respect to longitudinal dispersion in the case of Itamaracá. [ABSTRACT FROM AUTHOR]

Principle factors which influence mangrove leaf litter turnover, in particular the role of leaf-removing crabs, were evaluated in a riverine mangrove site near Bragança (Pará, North Brazil). Our special interest was focussed on the role of the leaf-removing crab Ucides cordatus. Leaf litter fluxes between the mangrove forest and the adjacent estuary were investigated by estimating the biomass and fate of leaf litter material and propagules. Vegetation is dominated by Rhizophora mangle, with Avicennia germinans trees, both up to 25 m high, found intermittently. During 1997, Rhizophora trees produced around 1.40 g DW m-2 d-1 of leave fall and 0.75 g DW m-2 d-1 of propagules. Leaf decomposition rates on the ground were about 0.06 g DW m-2 d-1, irrespective of species, habitat or site exposure. This amount accounts for <3% of total leaf fall. Average leaf litter biomass present on the ground was 0.01 g DW m-2 d-1. When the mangrove forest was flooded (on average 10 days per month) the quantity of leaf litter and propagules washed out with the spring tide was 10 and 17 times greater than during neap tide. Nevertheless, tidal export and decomposition together made up less than 39 percent of annual leaf litter fall. The bulk of the remaining amount is apparently removed by Ucides. Each crab consumed about 1.30 g DW of leaf litter material and propagules per day. Since the average density of these crabs was 1.38 crabs m-2, it is proposed that Ucides is a keystone species in Bragantinian mangroves. [ABSTRACT FROM AUTHOR]

In order to describe the humus forms present in different ecosystems of the Atlantic Forest (Brazil), a morpho-functional criterium was adopted. Samples were collected from eight sites: three sites in the Tabuleiro Forest, four sites in the Restinga, and one site in Tijuca Forest. Soil samples were sorted in L, F, and H horizon and the A horizon. A horizon was analysed for pH, total C and N, available P, and exchangeable bases. Our results include the recognition of an Ainterface horizon beneath the holorganic layer as well as aggregates 2–10 mm in diameter in the A horizon. Accumulation of organic matter was found to be related to both nitrogen content in litterfall and soil type. In the Tabuleiro Forest Tropical Mesotrophic Mull, Tropical Oligotrophic mull and Eumoder humus forms were found. Here the soil types, Ultisol and a Spodosol, explained in part the variation in humus form. In the Restinga, a wide range of humus forms was also observed including Moder–Mull, Dysmoder, Mesotrophic Mull and Eumoder; humus form was found to be related to the C:N ratio of the litterfall or to the soil substrate. At the Tijuca Forest, beneath an holorganic layer typical of a Moder (presence of the H horizon), an A horizon with a low C:N ratio typical of Mull was encountered. From the eight sites described, the Atlantic Forest biome can be said to be characterised by a great diversity of humus forms, which is a reflection of the complex environmental conditions found there. [Copyright &y& Elsevier]

Wind energy is one of the sources which is still in development in Brazil. However, it already represents 17% of the National Interconnected System. Due to the high level of uncertainty and fluctuations in wind speed, predicting wind energy with high accuracy is challenging. In this context, this paper proposes a novel decomposition-ensemble learning approach that combines Complete Ensemble Empirical Mode Decomposition (CEEMD) and Stacking-ensemble learning (STACK) based on Machine Learning algorithms to forecast the wind energy of a turbine in a wind farm at Parazinho city, Brazil, using multi-step-ahead forecasting strategy. The approached forecasting models were k -Nearest Neighbors, Partial Least Squares Regression, Ridge Regression, Support Vector Regression, and Cubist Regression. Additionally, Box-Cox transformation, correlation matrix, and principal component analysis were used to pre-process the data. The performance of the proposed forecasting models was evaluated by using three performance metrics: mean absolute error, mean absolute percentage error, and root mean square error, and the Diebold-Mariano statistical test to evaluate the forecasting error signals. The proposed models outperform the CEEMD, STACK, and single models in all forecasting horizons, with a performance improvement that ranges 0.06%–97.53%. Indeed, the decomposition-ensemble learning model is an efficient and accurate model for wind energy forecasting. Image 1 • A novel decomposition-ensemble learning model is proposed for wind energy forecasting. • CEEMD method deal with the non-linearity and non-stationarity of the time series. • Different preprocessing approaches are employed to deal with the high-correlation of the system's inputs. • STACK approach by divide-and-conquer scheme takes advantages of the models. • Proposed model improves the accuracy of wind energy forecasting multi-step ahead. [ABSTRACT FROM AUTHOR]

Ecosystem functions and the biomass of lower trophic levels are frequently controlled by predators. The strength of top‐down control in these trophic cascades can be affected by the identity and diversity of predators, prey, and resources, as well as environmental conditions such as temperature, moisture, and nutrient loading, which can all impact interaction strength between trophic levels. Few studies have been able to replicate a complete community over a large geographic area to compare the full trophic cascade in a manipulative experiment. Here, we identify geographic dependency in trophic cascade strength, and the driving factors and specific mechanisms behind it, by combining geographically replicated experiments with a novel approach of community analogues of common garden and transplant experiments. We studied a predator–detritivore–detritus food web in bromeliads in Puerto Rico, Costa Rica, and Brazil. We found that interaction strengths between resources, consumers, and predators were strongly site‐specific, but the exact mechanism differed between trophic levels. Large bodied predators created strong interaction strengths between predator and consumer trophic levels, reducing consumer abundance regardless of the geographic location, whereas small‐bodied predators created weak interactions with no impact on consumer abundances in any site. In contrast, the interaction strength between consumers and resources varied among sites, depending on the dominant species of leaf detritus. More labile leaf species in Costa Rica created a strong consumer–resource interaction and therefore strong trophic cascade, whereas tougher leaf species in Brazil created a weak consumer–resource interaction, and an overall weaker trophic cascade. Our study highlights the importance of replicating experiments over geographic scales to understand general patterns of ecological processes. [ABSTRACT FROM AUTHOR]