RESUMO

Abstract Liupan Mountains are an important region in China in the context of forest cover and vegetation due to huge afforestation and plantation practices, which brought changes in soil physio-chemical properties, soil stocks, and soil stoichiometries are rarely been understood. The study aims to explore the distribution of soil nutrients at 1-m soil depth in the plantation forest region. The soil samples at five depth increments (0-20, 20-40, 40-60, 60-80, and 80-100 cm) were collected and analyzed for different soil physio-chemical characteristics. The results showed a significant variation in soil bulk density (BD), soil porosity, pH, cation exchange capacity (CEC), and electric conductivity (EC) values. More soil BD (1.41 g cm-3) and pH (6.97) were noticed in the deep soil layer (80-100 cm), while the highest values of porosity (60.6%), EC (0.09 mS cm-1), and CEC (32.9 c mol kg-1) were reflected in the uppermost soil layer (0-20 cm). Similarly, the highest contents of soil organic carbon (SOC), total phosphorus (TP), available phosphorus (AP), total nitrogen (TN), and available potassium (AK) were calculated in the surface soil layer (0-20 cm). With increasing soil depth increment a decreasing trend in the SOC and other nutrient concentration were found, whereas the soil total potassium (TK) produced a negative correlation with soil layer depth. The entire results produced the distribution of SOCs and TNs (stocks) at various soil depths in forestland patterns were 020cm > 2040cm > 4060cm 6080cm 80100 cm. Furthermore, the stoichiometric ratios of C, N, and P, the C/P, and N/P ratios showed maximum values (66.49 and 5.46) in 0-20 cm and lowest values (23.78 and 1.91) in 80-100 cm soil layer depth. Though the C/N ratio was statistically similar across the whole soil profile (0-100 cm). These results highlighted that the soil depth increments might largely be attributed to fluctuations in soil physio-chemical properties, soil stocks, and soil stoichiometries. Further study is needed to draw more conclusions on nutrient dynamics, soil stocks, and soil stoichiometry in these forests.

Resumo As montanhas de Liupan são uma região importante na China no contexto de cobertura florestal e vegetação devido às enormes práticas de florestamento e plantação, que trouxeram mudanças nas propriedades físico-químicas do solo, e estoques e estequiometrias do solo raramente são compreendidos. O estudo visa explorar a distribuição de nutrientes do solo a 1 m de profundidade do solo na região da floresta plantada. As amostras de solo em cinco incrementos de profundidade (0-20, 20-40, 40-60, 60-80 e 80-100 cm) foram coletadas e analisadas para diferentes características físico-químicas do solo. Os resultados mostraram uma variação significativa nos valores de densidade do solo (BD), porosidade do solo, pH, capacidade de troca catiônica (CEC) e condutividade elétrica (CE). Mais DB do solo (1,41 g cm-3) e pH (6,97) do solo foram observados na camada profunda do solo (80-100 cm), enquanto os maiores valores de porosidade (60,6%), CE (0,09 mS cm-1) e CEC (32,9 c mol kg-1) foram refletidos na camada superior do solo (0-20 cm). Da mesma forma, os maiores teores de carbono orgânico do solo (SOC), fósforo total (TP), fósforo disponível (AP), nitrogênio total (TN) e potássio disponível (AK) foram calculados na camada superficial do solo (0-20 cm). Com o aumento do incremento da profundidade do solo, uma tendência decrescente no SOC e na concentração de outros nutrientes foi encontrada, enquanto o potássio total do solo (TK) produziu uma correlação negativa com a profundidade da camada do solo. Todos os resultados produziram a distribuição de SOCs e TNs (estoques) em várias profundidades de solo em padrões de floresta 0 20cm> 20 40cm> 40 60cm 60 80cm 80 100 cm. Além disso, as relações estequiométricas de C, N e P, as relações C / P e N / P, apresentaram valores máximos (66,49 e 5,46) em 0-20 cm, e valores mais baixos (23,78 e 1,91) em solo de 80-100 cm profundidade da camada. Embora a relação C / N fosse estatisticamente semelhante em todo o perfil do solo (0-100 cm). Esses resultados destacaram que os incrementos de profundidade do solo podem ser amplamente atribuídos a flutuações nas propriedades físico-químicas do solo, estoques e estequiometrias do solo. Mais estudos são necessários para tirar conclusões adicionais sobre a dinâmica dos nutrientes, estoques de solo e estequiometria do solo nessas florestas.

RESUMO

Liupan Mountains are an important region in China in the context of forest cover and vegetation due to huge afforestation and plantation practices, which brought changes in soil physio-chemical properties, soil stocks, and soil stoichiometries are rarely been understood. The study aims to explore the distribution of soil nutrients at 1-m soil depth in the plantation forest region. The soil samples at five depth increments (0-20, 20-40, 40-60, 60-80, and 80-100 cm) were collected and analyzed for different soil physio-chemical characteristics. The results showed a significant variation in soil bulk density (BD), soil porosity, pH, cation exchange capacity (CEC), and electric conductivity (EC) values. More soil BD (1.41 g cm-3) and pH (6.97) were noticed in the deep soil layer (80-100 cm), while the highest values of porosity (60.6%), EC (0.09 mS cm-1), and CEC (32.9 c mol kg-1) were reflected in the uppermost soil layer (0-20 cm). Similarly, the highest contents of soil organic carbon (SOC), total phosphorus (TP), available phosphorus (AP), total nitrogen (TN), and available potassium (AK) were calculated in the surface soil layer (0-20 cm). With increasing soil depth increment a decreasing trend in the SOC and other nutrient concentration were found, whereas the soil total potassium (TK) produced a negative correlation with soil layer depth. The entire results produced the distribution of SOCs and TNs (stocks) at various soil depths in forestland patterns were 0→20cm > 20→40cm > 40→60cm ≥ 60→80cm ≥ 80→100 cm. Furthermore, the stoichiometric ratios of C, N, and P, the C/P, and N/P ratios showed maximum values (66.49 and 5.46) in 0-20 cm and lowest values (23.78 and 1.91) in 80-100 cm soil layer depth. Though the C/N ratio was statistically similar across the whole soil profile (0-100 cm). These results highlighted that the soil depth increments might largely be attributed to fluctuations in soil physio-chemical properties, soil stocks, and soil stoichiometries. Further study is needed to draw more conclusions on nutrient dynamics, soil stocks, and soil stoichiometry in these forests.

As montanhas de Liupan são uma região importante na China no contexto de cobertura florestal e vegetação devido às enormes práticas de florestamento e plantação, que trouxeram mudanças nas propriedades físico-químicas do solo, e estoques e estequiometrias do solo raramente são compreendidos. O estudo visa explorar a distribuição de nutrientes do solo a 1 m de profundidade do solo na região da floresta plantada. As amostras de solo em cinco incrementos de profundidade (0-20, 20-40, 40-60, 60-80 e 80-100 cm) foram coletadas e analisadas para diferentes características físico-químicas do solo. Os resultados mostraram uma variação significativa nos valores de densidade do solo (BD), porosidade do solo, pH, capacidade de troca catiônica (CEC) e condutividade elétrica (CE). Mais DB do solo (1,41 g cm-3) e pH (6,97) do solo foram observados na camada profunda do solo (80-100 cm), enquanto os maiores valores de porosidade (60,6%), CE (0,09 mS cm-1) e CEC (32,9 c mol kg-1) foram refletidos na camada superior do solo (0-20 cm). Da mesma forma, os maiores teores de carbono orgânico do solo (SOC), fósforo total (TP), fósforo disponível (AP), nitrogênio total (TN) e potássio disponível (AK) foram calculados na camada superficial do solo (0-20 cm). Com o aumento do incremento da profundidade do solo, uma tendência decrescente no SOC e na concentração de outros nutrientes foi encontrada, enquanto o potássio total do solo (TK) produziu uma correlação negativa com a profundidade da camada do solo. Todos os resultados produziram a distribuição de SOCs e TNs (estoques) em várias profundidades de solo em padrões de floresta 0 → 20cm> 20 → 40cm> 40 → 60cm ≥ 60 → 80cm ≥ 80 → 100 cm. Além disso, as relações estequiométricas de C, N e P, as relações C / P e N / P, apresentaram valores máximos (66,49 e 5,46) em 0-20 cm, e valores mais baixos (23,78 e 1,91) em solo de 80-100 cm profundidade da camada. Embora a relação C / N fosse estatisticamente semelhante em todo o perfil do solo (0-100 cm). Esses resultados destacaram que os incrementos de profundidade do solo podem ser amplamente atribuídos a flutuações nas propriedades físico-químicas do solo, estoques e estequiometrias do solo. Mais estudos são necessários para tirar conclusões adicionais sobre a dinâmica dos nutrientes, estoques de solo e estequiometria do solo nessas florestas.

Assuntos

RESUMO

The Argentine shortfin squid, Illex argentinus, inhabits in the southwest Atlantic; it is a semelparous species which grows rapidly along its 1 year lifespan. The identification of its stocks is critical for sustainable fishery exploitation. Parasites have been used as biological indicators in a lower number of studies dealing with squids, therefore a validation of this methodology is necessary. The intra- and inter-cohort variability of parasite assemblages in the summer-spawning stock of I. argentinus was analysed to assess their value as indicators of stock structure. Four squid samples from the continental shelf of central Patagonia, corresponding to 3 consecutive cohorts, were examined for metazoan parasites. Results evidenced heterogeneity in terms of parasite assemblage composition and structure, dominated by short-lived gastrointestinal parasites, with a strong influence of host size, but no effect of squid sex. These changes are related to their recent habitats and diets, which change with ontogeny and migrations, clouding any interpretation of patterns when samples spatially or temporally separated are compared. Many squid species share these characteristics; therefore, it is recommended that the use of parasites as biological tags should be restricted to simultaneous sampling, while size or age must be considered for deriving proper conclusions.

Assuntos

RESUMO

Functional traits are morphological and physiological characteristics that determine growth, reproduction, and survival strategies. The leaf economics spectrum proposes two opposing life history strategies: species with an "acquisitive" strategy grow fast and exploit high-resource environments, while species with a "conservative" strategy emphasize survival and slow growth under low resource conditions. We analyzed intra and interspecific variation in nine functional traits related to biomass allocation and tissue quality in seven Neotropical palm species from understory and canopy strata. We expected that the level of resources of a stratum that a species typically exploits would determine the dominance of either the exploitative or conservative strategy, as well as degree of divergence in functional traits between species. If this is correct, then canopy species will show an acquisitive strategy emphasizing traits targeting a larger size, whereas understory species will show a conservative strategy with traits promoting efficient biomass allocation and survival in the shade. Two principal components (57.22% of the variation) separated palm species into: (a) canopy species whose traits were congruent with the acquisitive strategy and emphasized large size (i.e., diameter, height, carbon content, and leaf area), and (b) understory species whose traits were associated with efficient biomass allocation (i.e., dry mass fraction -DMF- and tissue density). As we unravel the variation in functional traits in palms, which make up a substantial proportion of the tropical flora, we gain a deeper understanding of how plants adapt to environmental gradients.

Assuntos

RESUMO

Deforestation accounts for the majority of greenhouse gas emissions in developing countries. In Brazil, deforestation represents ~ 70% of the nation's greenhouse gas emissions. Among the main deforested vegetation, Cerrado (Brazilian savanna) occupies a prominent position as it is the second biggest biome in Brazil. Despite its importance, there are still few estimates of above and belowground biomass of Cerrado vegetation encompassing its structural and spatial complexity. Also, Cerrado holds a specific biodiversity that is normally undervalued and which is being lost in the fires of agricultural fronts. In this context, this study aimed to verify the relationship of the existing flora biodiversity in a cerrado stricto sensu with its aboveground biomass and carbon stocks. The possibility of a relationship between fine root mass and soil organic carbon content was also verified. The study area presented a total of 67 species and 798 trees (average: 1596 trees ha-1). The mean total aboveground biomass and carbon stocks were 77.08 Mg ha-1 and 38.54 Mg ha-1 respectively. Soil organic carbon stock (0-30 cm) was 8.51 Mg ha-1 whereas fine roots were 1.637 Mg ha-1. Total aboveground biomass presented a highly significant asymptotic relationship with biodiversity demonstrating its importance in reaching high biomass accumulation. A significant relationship between soil organic carbon content and fine root biomass was found making easier belowground biomass estimates.

Assuntos

RESUMO

Fragmented tropical forest landscapes preserve much of the remaining biodiversity and carbon stocks. Climate change is expected to intensify droughts and increase fire hazard and fire intensities, thereby causing habitat deterioration, and losses of biodiversity and carbon stock losses. Understanding the trajectories that these landscapes may follow under increased climate pressure is imperative for establishing strategies for conservation of biodiversity and ecosystem services. Here, we used a quantitative predictive modelling approach to project the spatial distribution of the aboveground biomass density (AGB) by the end of the 21st century across the Brazilian Atlantic Forest (AF) domain. To develop the models, we used the maximum entropy method with projected climate data to 2100, based on the Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) 4.5 from the fifth Assessment Report. Our AGB models had a satisfactory performance (area under the curve > 0.75 and p value < .05). The models projected a significant increase of 8.5% in the total carbon stock. Overall, the projections indicated that 76.9% of the AF domain would have suitable climatic conditions for increasing biomass by 2100 considering the RCP 4.5 scenario, in the absence of deforestation. Of the existing forest fragments, 34.7% are projected to increase their AGB, while 2.6% are projected to have their AGB reduced by 2100. The regions likely to lose most AGB-up to 40% compared to the baseline-are found between latitudes 13° and 20° south. Overall, although climate change effects on AGB vary latitudinally for the 2071-2100 period under the RCP 4.5 scenario, our model indicates that AGB stocks can potentially increase across a large fraction of the AF. The patterns found here are recommended to be taken into consideration during the planning of restoration efforts, as part of climate change mitigation strategies in the AF and elsewhere in Brazil.

Assuntos

RESUMO

Every year more than 150,000 tons of resin used in a myriad of industrial applications are produced by Brazilian plantations of Pinus elliottii Engelm. (slash pine), which are also used for timber. A pine tree can be tapped for resin over a period of several years. Resin is a complex mixture of terpenes, which are carbon-rich molecules, presumably influencing pine plantation carbon budgets. A total of 270 trees (overall mean DBH of 22.93 ± 0.11 cm) of 14-, 24-, and 26-year-old stands had their C content measured. Three different treatments (intact, wounded panels, and wounded + chemically stimulated panels, 30 trees each) were applied per site. Above- and belowground biomass, as well as resin yield, were quantified for two consecutive years. Data were statistically evaluated using normality distribution tests, analyses of variance, and mean comparison tests (p ≤ 0.05). The highest resin production per tree was recorded in the chemically stimulated 14-year-old stand. Tree dry wood biomass, a major stock of carbon retained in cell wall polysaccharides, ranged from 245.69 ± 11.73 to 349.99 ± 16.73 kg among the plantations. Variations in carbon concentration ranged from 43% to 50% with the lowest percentages in underground biomass. There was no significant difference in lignin concentrations. Soils were acidic (pH 4.3 ± 0.10-5.83 ± 0.06) with low C (from 0.05% to 1.4%). Significantly higher C stock values were recorded in pine biomass compared to those reported for temperate zones. Resin-tapping biomass yielded considerable annual increments in C stocks and should be included as a relevant component in C sequestration assessments of planted pine forests.

RESUMO

Soil microbial communities regulate a myriad of critical biogeochemical functions in forest ecosystems. Anthropogenic disturbances in natural forests could drive major shifts in plant and microbial communities resulting in substantial biogeochemical alterations. We evaluated the effect of anthropogenic disturbances in the soils of Andean temperate forests with different levels of degradation: i) mature forest (MF), ii) secondary forest (SF), iii) degraded forest (DF), and iv) deforested site converted into a prairie (DP). We quantified total soil carbon, nitrogen and phosphorous (TC, TN, and TP), and available nutrient stocks. The soil microbial community structure (i.e., composition, diversity, and abundance) was assessed under each condition from amplicon sequence variants (ASVs) obtained via NGS-Illumina sequencing and subsequent microbiome analysis. There were no significant differences in TC, TN, and TP across the forested states (MF, SF, DF). The deforested site condition presented significantly higher soil TC, TN, and TP and the lowest C:N, C:P, and N:P ratios. The DP soil microbiome was significantly more diverse in bacteria (D' = 0.47 ± 0.04); and fungi (H' = 5.11 ± 0.33). The bacterial microbiome was dominated by Proteobacteria (45.35 ± 0.89 %), Acidobacteria (20.73 ± 1.48 %), Actinobacteria (12.59 ± 0.34 %), and Bacteroidetes (7.32 ± 0.36 %) phyla in all sites. The soil fungal community was dominated by the phyla Ascomycota (42.11 ± 0.95 %), Mortierellomycota (28.74 ± 2.25 %), Basidiomycota (24.61 ± 0.52), and Mucoromycota (2.06 ± 0.43 %). Yet, there were significant differences at the genus level across conditions. Forest to prairie conversion facilitated the introduction of exotic bacterial and fungal taxa associated with agricultural activities and livestock grazing (∼50 % of DP core microbiome composed of unique ASVs). For example, the ammonia-oxidizing bacteria community emerged as a dominant group in the DP soils, along with a reduction in the ectomycorrhizal fungi community. The surface soil microbial community was surprisingly resistant to forest degradation and did not show a clear succession along the degradation gradient, but it was strongly altered after deforestation.

Assuntos

RESUMO

Fish stocking is a common management strategy in Brazil, yet no assessment has examined its real extent and features. The present work investigated fish stocking practices in Brazil between 2010 and 2019 to characterize propagule pressure, species composition, the use of non-native species, geographical and temporal trends, environment types, and responsible agencies. Based on information disseminated on the internet, the study detected 1,155 stocking events (ca. 115 events/year). In total, ca. 56.4 million fish were stocked, with an average of ca. 90 thousand fish/event. We found events in all Brazilian regions involving 436 municipalities and 21 states. Most events occurred in the Northeast region (66.3%), which received alone ca. 41 million fish. Reservoirs were the primary target environment, and the public sector conducted most events. Fish stocking involved 63 taxa, including 14 non-native taxa and three hybrids. Considering the events that informed composition, 62.4% released non-native species, which summed 19.7 million fish. These results provide a broad overview of fish stocking practices in Brazil, and reveal that this action is widely disseminated. Its frequent use, associated with the lack of proper criteria and the illegal stocking of non-native species, raise concerns about technical aspects, outcomes, and potential environmental impacts.

A estocagem de peixes é uma estratégia de manejo comum no Brasil, mas nenhum estudo investigou sua real extensão e características. O presente trabalho investigou práticas de estocagem de peixes realizadas no Brasil entre 2010 e 2019, para caracterizar a pressão de propágulos, composição de espécies, participação de espécies não-nativas, variação espaço-temporal, ambientes e órgãos responsáveis. Com base em informações divulgadas na internet, o estudo detectou 1155 eventos de estocagem (ca. 115 eventos/ano). No total, ca. 56,4 milhões de peixes foram liberados, com média de ca. 90 mil peixes/evento. Encontramos eventos em todas as regiões brasileiras, envolvendo 436 municípios e 21 estados. A região nordeste somou a maioria dos casos (66,3%), e sozinha recebeu cerca de 41 milhões de peixes. Os reservatórios foram o principal ambiente alvo, sendo o setor público o principal responsável pelas ações. A estocagem de peixes envolveu 63 táxons, incluindo 14 táxons não-nativos e três híbridos. Considerando os eventos que informaram a composição das espécies, 62,4% liberaram espécies não-nativas, que somaram 19,7 milhões de peixes. Estes resultados fornecem um amplo panorama das práticas de estocagem de peixes no Brasil, e revelam que essa ação de manejo é amplamente disseminada. Seu uso frequente, associado com a falta de critérios apropriados e a soltura ilegal de espécies não-nativas, suscita preocupações quanto a aspectos técnicos, resultados, e potenciais impactos ambientais.

Assuntos

RESUMO

Climate change is a major constraint on the sustainability of the humid tropics, maintaining ecosystem services, food production, and social functioning. Humid tropics play an essential role in C storage and greenhouse gas (GHG) emission reduction. Unfortunately, unplanned economic exploration, human occupation, and lack of knowledge of techniques to maintain ecosystem services negatively affect the humid tropics. In this study, we focused on the mechanisms of GHG emissions, C storage, and their mitigation strategies. This review indicated technologies that can be adopted by farmers in humid tropics to maintain or increase their capacity to store C stocks and reduce GHG emissions. The adoption of climate-smart agriculture technologies and the regulation of ecosystem services markets will accelerate the progress of preserving the humid tropics. Improved management practices, such as proper N fertilizer management and the introduction of N2-fixing legumes, can increase soil C sequestration, providing economic and environmental trade-offs associated with these management strategies. Public and private investments toward knowledge dissemination and technology adoption regarding GHG emissions reduction and soil C storage are needed to allow humid tropics to maintain their critical function of generating environmental and societal benefits.

Assuntos

RESUMO

Trace elements bioaccumulation patterns can be an important tool to assess differences among cetaceans' populations. In this work, their use as potential chemical markers to differentiate franciscanas (Pontoporia blainvillei) populations was evaluated. Franciscanas were collected from three states in southeastern Brazil, which comprise three different Franciscana Management Areas (FMAs): Espírito Santo (FMA Ia), southern Rio de Janeiro (FMA IIa), and central São Paulo (FMA IIb). The concentrations of As, Cd, Cu, Fe, Hg, Mn and Zn were determined in the muscle, liver and kidney of the animals. Cadmium was the most valuable chemical marker to differentiate stocks, separating at least FMA IIa from the others. The higher Cd levels in FMA IIa, along with dietary information, indicate that the predominant consumption of cephalopods by this population is the main reason for the differences found. Additionally, environmental characteristics of the areas should also be considered as divergent sources of trace elements. Our findings suggest that non-essential trace elements, such as Cd, can be successful markers to differentiate populations. The Mn concentrations in FMA Ia raised concern and must be carefully monitored, as well as other elements that compose the iron ore tailings that have impacted the Espírito Santo coastal area. Additionally, this is the first study to report trace element concentration in the franciscanas from FMA IIa (southern Rio de Janeiro). Trace element concentrations found in franciscanas may represent different contamination levels in their preys and environments, which might pose specific threats to distinct populations. Therefore, our findings are important to characterize and differentiate franciscana populations and to guide precise management and conservation actions for the distinct stocks of this endangered species.

Assuntos

RESUMO

Coastal eutrophication is an issue of serious global concern and although nutrient subsidies can enhance primary productivity of coastal wetlands, they can be detrimental to their long-term maintenance. By supplying nutrients to coastal ecosystems at levels comparable to intensive agriculture practices, roosting colonial waterbirds provide a natural experimental design to examine the impacts of anthropogenic nutrient enrichment in these systems. We tested the hypothesis that long-term nutrient enrichment from bird guano deposition is linked to declines in island size, which may subsequently decrease the stability and resilience of mangrove cays in Belize. We combined remote sensing analysis with field- and lab-based measurements of forest structure, sediment nutrients, and porewater nutrients on three pairs of rookery and control cays in northern, central, and southern Belize. Our results indicate that rookery cays are disappearing approximately 13 times faster than cays without seasonal or resident seabird populations. Rookery cays were associated with a significantly higher concentration of nitrogen (N) in mangrove leaves and greater aboveground biomass, suggesting that eutrophication from bird guano contributes to increased aboveground productivity. Sediments of rookery cays also had lower percentages of soil organic matter and total N and carbon (C) than control islands, which suggests that eutrophication accelerates organic matter decomposition resulting in lower total C stocks on rookery cays. Our results indicate that coastal eutrophication can reduce ecosystem stability by contributing to accelerated cay loss, with potential consequences for mangrove resilience to environmental variability under contemporary and future climatic scenarios.

Assuntos

RESUMO

OBJECTIVES: Tree legume species play an important role in forest restoration in the tropics. Understanding how different species adjust carbohydrate allocation and growth under distinct nutrient availability will enhance the success of restoring degraded areas. DATA DESCRIPTION: A 2-year tropical forest plantation of the Forest Restoration Program of the Balbina Hydropower Dam was evaluated. Three non-N-fixing (Cenostigma tocantinum, Dipteryx odorata and Senna reticulata) and three N-fixing (Clitoria fairchildiana, Inga edulis and Acacia spp.) tree legume species were either fertilized or not fertilized. Growth rates and biomass allocation were calculated, and carbon (C) fractions and nitrogen (N), phosphorus (P) and nonstructural carbohydrate (NSC) concentrations were determined. Multiple nutrient additions increased the growth rates and aboveground biomass production of fertilized plants. According to the results presented, different species and N- fixers respond differently to fertilization regimes. The authors encourage the use of the presented data in meta-analysis studies that consider the fertilization or nutrient deficiency effects on growth, carbohydrate and nutrient responses. N-fixing species with high biomass growth and foliar N are important for restoring N and C cycles in nutrient-limited soils. Fertilization treatments are fundamental during the early stages of forest plantation development.

Assuntos

RESUMO

Billfishes are considered important fishery resources and the identification of aggregation sites is imperative for proper management. Here we present evidence of a seasonal aggregation site for juvenile istiophorid billfishes in southern Brazil. We discuss the results as they relate with the need for management at a local scale and participatory monitoring with artisanal fishing communities as a way to ensure access to data on the occurrence and population status in the long term.

RESUMO

Tropical forests vary widely in biomass carbon (C) stocks and fluxes even after controlling for forest age. A mechanistic understanding of this variation is critical to accurately predicting responses to global change. We review empirical studies of spatial variation in tropical forest biomass, productivity and woody residence time, focusing on mature forests. Woody productivity and biomass decrease from wet to dry forests and with elevation. Within lowland forests, productivity and biomass increase with temperature in wet forests, but decrease with temperature where water becomes limiting. Woody productivity increases with soil fertility, whereas residence time decreases, and biomass responses are variable, consistent with an overall unimodal relationship. Areas with higher disturbance rates and intensities have lower woody residence time and biomass. These environmental gradients all involve both direct effects of changing environments on forest C fluxes and shifts in functional composition - including changing abundances of lianas - that substantially mitigate or exacerbate direct effects. Biogeographic realms differ significantly and importantly in productivity and biomass, even after controlling for climate and biogeochemistry, further demonstrating the importance of plant species composition. Capturing these patterns in global vegetation models requires better mechanistic representation of water and nutrient limitation, plant compositional shifts and tree mortality.

Assuntos

RESUMO

Abstract: The Spiny Red Lobster has an important commercial role in Brazil. However, a downward trend in the production of lobsters due to overfishing has been observed and there is also a devaluation of the product in the international market due to the instability in the size pattern of lobsters commercialized. Here in Brazil we detected two issues regarding the Spiny Red Lobster: (1) According to recent studies, there are genetic and morphological differences between Caribbean and Brazilian populations, which may be considered different species and; (2) Current legislation, such as seasonal closures, does not consider the multiple probable stocks of the species, which have direct implications in management and conservation. Thus, the recognition of the Spiny Red Lobster from Brazil as Panulirus meripurpuratus and investments on population and biological research are essential to improve its management considering regional stock differences.

Resumo: A lagosta vermelha tem um importante papel comercial no Brasil, porém, uma tendência de queda na produção de lagostas devido a sobrepesca tem sido observada e há também uma desvalorização do produto no mercado internacional devido à instabilidade no comprimento das lagostas comercializadas. Aqui no Brasil, detectamos dois problemas em relação à lagosta vermelha: (1) De acordo com estudos recentes, existem diferenças genéticas e morfológicas entre as populações caribenha e brasileira e; (2) Atualmente a legislação não considera os múltiplos estoques prováveis da espécie. Desta forma, os períodos de defeso sazonais não consideram os diferentes estoques, o que tem implicações diretas no manejo e na conservação. Logo, o reconhecimento da lagosta vermelha do Brasil como Panulirus meripurpuratus e investimentos em pesquisas biológicas e populacionais são fundamentais pra facilitar seu manejo considerando diferenças regionais nos seus estoques.

RESUMO

Mine reclamation has long relied on reusing topsoil to mitigate mining impacts but recently constructed soils (i.e., Technosols) have emerged as novel technologies for restoring post mining landscapes. However, their success depends on their ability to sustain soil functions. To assess the efficiency of a limestone mine reclamation, we measured the soil quality (SQ) of a three- (SC3) and seven-year-old (SC7) Technosol under sugarcane, and one 20-year-old (P20) Technosol under pasture, constructed with limestone spoil in southeastern Brazil. Soil chemical, physical, and biological attributes were evaluated and compared with those of an adjacent natural soil (NS; Rhodic Lixisol). We also tested the Soil Management Assessment Framework (SMAF) for assessing the SQ of the studied soils. SMAF was suitable to detect SQ changes over the years of reclamation. After three and seven years under sugarcane cultivation, the Technosols showed similar SQ indexes (= 0.70 and 0.67) to that of the native soil (SQ = 0.69), whereas after 20 years under pasture the SQ (= 0.88) of P20 was superior to that of NS. Overall, the Technosols recovered most of the ecosystem services expected for healthy soils, especially in P20, where carbon stocks were 2.7 times higher than in NS (82.1 vs 30.35 Mg C ha-1). We highlight the importance of using soil quality assessment tools, such as SMAF, in mine reclamation. In summary, Technosols from limestone wastes could restore basic soil functions under tropical environmental conditions within only 20 years.

Assuntos

RESUMO

The biogeographic origin of species may help to explain differences in average tree height and aboveground biomass (AGB) of tropical mountain forests. After the Andean uplift, small-statured trees should have been among the initial colonizers of the highlands (new cold environment) from the lowland tropics, since these species are pre-adapted to cold conditions with narrow vessels that are relatively resistant to freezing. If the descendants of these small-statured clades continue to dominate tropical highland forests, there will be a high co-occurrence of close relatives at high elevations. In other words, this scenario predicts a systematic decline in tree size, AGB, and phylogenetic diversity with elevation. In contrast, the colonization of Andean forests by some large-statured clades that originated in temperate regions may modify this expectation and promote a mixing of tropical and temperate clades, thereby increasing the phylogenetic diversity in tropical highland forests. This latter scenario predicts an increase or no change of tree size, AGB, and phylogenetic diversity with elevation. We assessed how the historical immigration of large-statured temperate-affiliated tree lineages adapted to cold conditions may have influenced the composition and structure of Andean forests. Specifically, we used 92 0.25-ha forest inventory plots distributed in the tropical Andes Mountains of Colombia to assess the relationship between the phylogenetic diversity and AGB along elevational gradients. We classified tree species as being either "tropical affiliated" or "temperate affiliated" and estimated their independent contribution to forest AGB. We used structural equation modeling to separate the direct and indirect effect of elevation on AGB. We found a hump-shaped relationship of phylogenetic diversity, AGB, and tree size with elevation. The high phylogenetic diversity found between 1,800-2,200 m above sea level (asl) was due to the mixing of highland floras containing many temperate-affiliated species, and lowland floras containing mostly tropical-affiliated species. The high AGB in highland forests, which contrasted with the expected decline of AGB with elevation, was likely due to the significant contribution of temperate-affiliated species. Our findings highlight the lasting importance of biogeographic history on the composition and structure of Andean mountain forests.

Assuntos

RESUMO

Resumo Introdução: As empresas dos canais de distribuição têm como principal função intermediar transações entre os fornecedores e revendas. Além disso, elas servem como agentes entre as revendas e os usuários finais comissionando à revenda. Este artigo foi desenvolvido em uma distribuidora nacional de automação, com 20 anos neste mercado que apresenta problemas no estoque como: rupturas e excessos, buscando ações para minimizar estes principais problemas. Objetivo: O objetivo da pesquisa foi analisar e contextualizar estas variáveis, podendo assim identificar sugestões de ações de melhorias de como evitar problemas em gestão de estoques. Materiais e métodos: A metodologia utilizada foi a análise qualitativa, tendo como método de pesquisa o estudo de caso único. Foi aplicado um questionário estruturado e avaliadas as informações do banco de dados da empresa. Foi elaborado um fluxograma do setor de compras e estoque para mapear o funcionamento do setor. Resultados: Os resultados da pesquisa evidenciaram a empresa acredita que tem um controle de estoque adequado, mas identificou a necessidade de melhorias, devido às frequentes rupturas no estoque, assim como os excessos de itens com baixo giro de vendas. Conclusões: Foram determinados ferramentas e indicadores de gestão de estoques para controlar os problemas de distribuição logística.

Resumen Introducción: Las empresas de los canales de distribución tienen como principal función intermediar transacciones entre los proveedores y reventas. Además, ellos sirven como agentes entre los revendedores y los usuarios finales comisionando a la reventa. Este artículo fue desarrollado en una distribuidora nacional de automatización, con 20 años en este mercado y que presenta problemas en el stock como rupturas y excesos, buscando acciones para minimizar estés problemas principales. Objetivo: El objetivo de la investigación fue analizar y contextualizar estas variables, pudiendo así identificar sugerencias de acciones de mejoras de cómo evitar problemas en la gestión de inventarios. Materiales y métodos: La metodología utilizada fue el análisis cualitativo, teniendo como método de investigación el estudio de caso. Se aplicó un cuestionario estructurado y evaluado la información de la base de datos de la empresa. Se elaboró un diagrama de flujo del sector de compras y stock para mapear el funcionamiento del sector. Resultados: Los resultados de la investigación evidenciaron que la empresa cree que tiene un control de inventario adecuado, pero identificó la necesidad de mejoras, debido a las frecuentes rupturas en el stock, así como los excesos de ítems con bajo giro de ventas. Conclusiones: Se han determinado herramientas e indicadores de gestión de stocks para controlar los problemas de distribución logística.

Abstract Introduction. Companies of distribution channels are mainly responsible broker transactions between suppliers and resellers. Additionally, they serve as agents between resellers and end-users commissioning resale. This article was developed in a national distributor of automation, with 20 years in this market that presents problems in stock as ruptures and excesses, actions seeking to minimize these core problems. Objective. The objective of the research was to analyze and contextualize these variables and thus identify suggestions for actions to improve how to avoid problems in inventory management. Materials and methods. The methodology was qualitative analysis, and as a research method, the single case study was analyzed. A structured questionnaire and evaluated information from the database of the company was applied. A flowchart of the purchasing and storage area was designed to map the functioning of the sector. Results. The results showed the company believes it has adequate inventory control, but identified the need for improvements due to frequent disruptions in stock, as well as the excess items with low sales turnover. Conclusions. Tools and inventory management indicators were determined to control the distribution logistics problems.

RESUMO

Non-legume bioenergy crops can be fertilized with animal manures instead of mineral fertilizers, but the simultaneous application of carbon (C) and nitrogen (N) with manures can increase nitrous oxide (N2O) emissions. On the other hand, manure could increase soil organic C stocks and partly offset greenhouse gas (GHG) emissions and global warming potential (GWP) of crop systems. We performed a two-year study in a biofuel cropping system with sunflower and canola to examine the effects of manure fertilization on grain yields and N use efficiency of crops, and on GWP and GHG intensity (GHGI) in no-till soils under subtropical conditions. The GWP and GHGI were calculated from measured methane (CH4) and N2O emissions and soil organic C stock change, and from estimated carbon dioxide emissions associated with agricultural inputs and farm operations. The following treatments were tested: (i) mineral fertilizer (MF); (ii) poultry manure (PM); (iii) pig deep-litter (PDL); and (iv) no-N control. The application rate of each treatment was adjusted to provide 60 kg available N ha-1 to crops. Grain yield and N accumulated by sunflower and canola were greater in fertilized treatments than in the control, and did not differ among N sources. However, crop N use efficiency was on average 50% lower with manures than MF. CH4 emissions were not affected by N sources, but N2O emissions increased as follows: control (1.37) < MF (2.04) < PDL (4.12) < PM (4.95 kg N ha-1). On the other hand, soil organic C stocks increased more rapidly with manures than MF, resulting in significantly lower GWP and GHGI with manures than MF after two years. These results indicate that animal manures can replace MF as the main source of N to non-legume oil crops and reduce net GHG emissions in biofuel cropping systems under subtropical conditions.

Assuntos