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1.
Sci Rep ; 11(1): 21247, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-34711886

RESUMO

Biodiversity conservation has faced many challenges, especially the conversion of natural areas that compete with use for agriculture, energy production and mineral extraction. This problem is further aggravated by lack of knowledge of the biodiversity that exists and the geographical distribution of different groups. The objectives of our study were to examine the distributional pattern of Gerromorpha diversity in Brazil, create a map of conservation priority areas, estimate the degree of protection that the current network of protected areas guarantees to this insect group, and identify the size thresholds in geographical distributions that would allow species to be protected. We used species occurrences from the Water Bugs Distributional Database, and we used 19 bioclimatic variables to build models of the potential distributions of species using the MaxEnt program. Using the potential model results, we calculated diversity metrics and overlapped them with the current state and federal "conservation units" (protected areas for biodiversity) in Brazil. Total beta diversity and turnover portions were separated into two faunistic groups, one in northern and the other in southern Brazil. The Amazon has higher beta diversity than what was predicted by the null models. We detected a positive relationship between species distribution area and occurrence in conservation units. Conservation units with less than 250 km2 do not protect Gerromorpha species. Our results reinforce the necessity of formulating new conservation strategies for this group, contemplating species with both restricted and ample distributions, because rare and specialist species are the most harmed by habitat reduction, given that they are more sensitive to environmental disturbance.


Assuntos
Biodiversidade , Conservação dos Recursos Naturais , Ecossistema , Água Doce , Insetos , Animais , Brasil , Meio Ambiente , Geografia , Modelos Teóricos , Dinâmica Populacional , Análise Espacial
2.
Environ Monit Assess ; 193(11): 752, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34709469

RESUMO

Building dams for hydroelectric use causes several negative effects on the aquatic fauna with special attention to fish communities. In fact, among other impacts, dams act as a barrier for migratory fish, causing discontinuities in rivers and not allowing fish to move to the headwaters to breed and back to the lower portions of rivers, to grow. For more than 300 years, fishways have been used to minimize the impact of dams. Here, we assess the worldwide knowledge about fishways, identifying the temporal and spatial pattern and the situation of Brazil in this global pattern. For this, we conducted scientometric research on the Web of Science repository with the following words: weir, fish, facilities, ladder, pass, dam, fish ladder, fish pass, fishway, hydropower, Petromyzon, and salmon between 1985 and 2019. Initially, we obtained 1282 articles. After a selection, 324 articles aimed to describe fishway efficiency and the relationship with the fish fauna remained. Most of the articles on dams, fishways, and fish are from North America and Europe. Among the articles in South America, most are from Brazil. Nonetheless, information on the topic is incipient in Brazil, since the country has one of the biggest hydropower in the world and 42 scientific articles about fishways published in the international scientific database. Ecology is the area of knowledge with most articles, with continuous growth in the last 10 years. Studies in the field of ecology are strategical, as this field can integrate different areas of knowledge to test the efficiency of fishways in fish conservation and may be able to answer the question: "Are fishways an ecological trap?" Research focusing on this question is important to understand the efficiency of fishways to better evaluate solutions to minimize the negative effects of dams on fish and increase the effectiveness of fishways.


Assuntos
Monitoramento Ambiental , Rios , Animais , Brasil , Europa (Continente) , Peixes
3.
Sci Total Environ ; 788: 147617, 2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34134352

RESUMO

The ongoing encroachment of agricultural activities into natural areas is a growing problem for the ecological condition of streams. Stream ecological condition is best measured using both biotic and abiotic parameters that reflect different channel, riparian zone and catchment aspects. Multiple physical-chemical measures of water quality have long been widely used to represent the environmental conditions of water bodies. More recently, physical habitat structure, catchment land use and land cover have been employed to better understand water body conditions. Both water quality and physical habitat structure metrics are usually measured in the field and often have strong predictive power to analyze biological assemblage conditions. On the other hand, remote sensing of catchment land use and land cover provide relatively low-cost environmental information at large spatial extents, minimizing the need for fieldwork and reducing analytical time. Given these considerations, our aim in the present study was to evaluate the degree to which stream environmental conditions could be measured reliably via remote sensing. In particular, we assessed whether a remote sensing index (Normalized Difference Vegetation Index) and land use can be used as reliable surrogates for site habitat condition, channel dimensions, and water quality. We found that our remote sensing variables were not sufficient for predicting stream water quality or habitat structure. Therefore, we recommend using remote sensing indicators only when it is impossible to measure water quality and habitat structure in the field directly.

4.
Ecol Evol ; 10(21): 12024-12035, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33209267

RESUMO

The identification of the mechanisms underlying patterns of species co-occurrence is a way to identify which process(es) (niche, neutral, or both) structure metacommunities. The current paper had the goal of identifying patterns of co-occurrence in Neotropical stream fish and determining which processes structure the fish metacommunity, and identifying any gradients underlying this structure. Results indicated that the metacommunity formed by the species pool was structured by a pattern of nested co-occurrence (hyperdispersed species loss) and a mass-effect mechanism. However, a set of core species, displaying a Clementsian pattern, was structured by a species-sorting mechanism. Both, hyperdispersed species loss and the Clementsian patterns point to a discrete set of communities within the metacommunity. These communities could be isolated by the water physicochemical conditions or morphological characteristics of the stream channel.

5.
Sci Rep ; 10(1): 19777, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33188230

RESUMO

In community ecology, it is important to understand the distribution of communities along environmental and spatial gradients. However, it is common for the residuals of models investigating those relationships to be very high (> 50%). It is believed that species' intrinsic characteristics such as rarity can contribute to large residuals. The objective of this study is to test the relationship among communities and environmental and spatial predictors by evaluating the relative contribution of common and rare species to the explanatory power of models. Our hypothesis is that the residual of partition the variation of community matrix (varpart) models will decrease as rare species get removed. We used several environmental variables and spatial filters as varpart model predictors of fish and Zygoptera (Insecta: Odonata) communities in 109 and 141 Amazonian streams, respectively. We built a repetition structure, in which we gradually removed common and rare species independently. After the repetitions and removal of species, our hypothesis was not corroborated. In all scenarios, removing up to 50% of rare species did not reduce model residuals. Common species are important and rare species are irrelevant for understanding the relationships among communities and environmental and spatial gradients using varpart. Therefore, our findings suggest that studies using varpart with single sampling events that do not detect rare species can efficiently assess general distributional patterns of communities along environmental and spatial gradients. However, when the objectives concern conservation of biodiversity and functional diversity, rare species must be carefully assessed by other complementary methods, since they are not well represented in varpart models.


Assuntos
Biodiversidade , Odonatos/classificação , Odonatos/genética , Animais , Rios
6.
Sci Rep ; 10(1): 2174, 2020 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-32034267

RESUMO

Riparian vegetation plays an important role in providing energy to small watercourses and maintaining ecological processes through organic matter input and together with hydrological and geomorphological watercourse characteristics influence on fish assemblages. The goal of this paper was partitioning and quantifying the influence of riparian zone (type of riverbank substrate, bank slope, type of riparian vegetation cover and percentage of riparian vegetation cover on the main channel), physical habitat (stream channel width and depth, type of substrate and aquatic habitat in channel, water velocity and organic matter), water quality (turbidity, temperature, conductivity, pH, dissolved oxygen and chlorophyll concentration) and spatial variables (linear distances between sampled points) on fish assemblages (richness and abundance per species) in headwater streams of the Upper Paraná River basin, Central Brazil. For this purpose, it was performed a variation partitioning analysis between riparian, physical habitat, water and spatial variables sets and a Redundancy Analysis to quantify the influence of variables on the fish assemblages. Only the physical habitat and water quality variables influenced the fish assemblages (richness and abundance per species).


Assuntos
Biodiversidade , Peixes/fisiologia , Pradaria , Rios , Animais , Peixes/classificação , Clima Tropical
7.
Bull Environ Contam Toxicol ; 104(4): 393-399, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31993678

RESUMO

Bats are sensitive to contaminants generated by agricultural activities, mining, and urbanization. In this review, we update the status of bat toxicology in Brazil. Agriculture, for example, in addition to habitat fragmentation and loss, undoubtedly affects non-target organisms through the use of pesticides. Other factors such as trace metals are a neglected problem in the country, as they can deposit on insects and plants reaching bats through the ingestion of these foods. Of the 184 species of bats in the country, only 4.9% have been investigated. The frugivorous species, Artibeus lituratus, has frequently been studied for the effects of pesticide exposure, and impacts at the cellular level on metabolism and reproduction have been observed. Given the scarcity of studies on bat ecotoxicology, we encourage national researchers and scientists elsewhere to increase knowledge of the effects of chemical contaminants on bats in Brazil.


Assuntos
Quirópteros/metabolismo , Poluentes Ambientais/toxicidade , Praguicidas/toxicidade , Reprodução/efeitos dos fármacos , Animais , Brasil , Quirópteros/fisiologia , Ecossistema , Ecotoxicologia , Insetos/metabolismo , Oligoelementos/metabolismo
8.
PLoS One ; 13(9): e0204114, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30231064

RESUMO

Several hypotheses are used to explain species richness patterns. Some of them (e.g. species-area, species-energy, environment-energy, water-energy, terrestrial primary productivity, environmental spatial heterogeneity, and climatic heterogeneity) are known to explain species richness patterns of terrestrial organisms, especially when they are combined. For aquatic organisms, however, it is unclear if these hypotheses can be useful to explain for these purposes. Therefore, we used a selection model approach to assess the predictive capacity of such hypotheses, and to determine which of them (combined or not) would be the most appropriate to explain the fish species distribution in small Brazilian streams. We perform the Akaike's information criteria for models selections and the eigenvector analysis to control the special autocorrelation. The spatial structure was equal to 0.453, Moran's I, and require 11 spatial filters. All models were significant and had adjustments ranging from 0.370 to 0.416 with strong spatial component (ranging from 0.226 to 0.369) and low adjustments for environmental data (ranging from 0.001 to 0.119) We obtained two groups of hypothesis are able to explain the richness pattern (1) water-energy, temporal productivity-heterogeneity (AIC = 4498.800) and (2) water-energy, temporal productivity-heterogeneity and area (AIC = 4500.400). We conclude that the fish richness patterns in small Brazilian streams are better explained by a combination of Water-Energy + Productivity + Temporal Heterogeneity hypotheses and not by just one.


Assuntos
Biodiversidade , Peixes/fisiologia , Modelos Teóricos , Rios , Clima Tropical , Animais , Brasil , Geografia , Análise de Regressão , Especificidade da Espécie , Estatística como Assunto
9.
Ecol Evol ; 7(9): 3190-3200, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28480018

RESUMO

An important aspect of conservation is to understand the founding elements and characteristics of metacommunities in natural environments, and the consequences of anthropogenic disturbance on these patterns. In natural Amazonian environments, the interfluves of the major rivers play an important role in the formation of areas of endemism through the historical isolation of species and the speciation process. We evaluated elements of metacommunity structure for Zygoptera (Insecta: Odonata) sampled in 93 Amazonian streams distributed in two distinct biogeographic regions (areas of endemism). Of sampled streams, 43 were considered to have experienced negligible anthropogenic impacts, and 50 were considered impacted by anthropogenic activities. Our hypothesis was that preserved ("negligible impact") streams would present a Clementsian pattern, forming clusters of distinct species, reflecting the biogeographic pattern of the two regions, and that anthropogenic streams would present random patterns of metacommunity, due to the loss of more sensitive species and dominance of more tolerant species, which have higher dispersal ability and environmental tolerance. In negligible impact streams, the Clementsian pattern reflected a strong biogeographic pattern, which we discuss considering the areas of endemism of Amazonian rivers. As for communities in human-impacted streams, a biotic homogenization was evident, in which rare species were suppressed and the most common species had become hyper-dominant. Understanding the mechanisms that trigger changes in metacommunities is an important issue for conservation, because they can help create mitigation measures for the impacts of anthropogenic activities on biological communities, and so should be expanded to studies using other taxonomic groups in both tropical and temperate systems, and, wherever possible, at multiple spatial scales.

10.
PLoS One ; 11(11): e0165706, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27806085

RESUMO

Commonly used guidelines for the management of human immunodeficiency virus (HIV) infection (highly active antiretroviral therapy, HAART) include drug combinations such as tenofovir disoproxil fumarate (TDF) + lamivudine (3TC) and combivir [zidovudine (AZT) + 3TC] + efavirenz (EFV). These combinations may enhance the genotoxic effects induced by such drugs individually, since the therapy requires lifelong adherence and the drugs have unknown effects during treatment. Thus, the evaluation of the benefits and risks of HAART is of great importance. In order to assess the cytotoxic and genotoxic potential of three concentrations of each of the antiretroviral combinations TDF + 3TC (800 + 400, 1600 + 800, and 3200 + 1600 mg/kg body weight, BW) and combivir + EFV (200 + 100 + 400, 400 + 200 + 800, and 800 + 400 + 1600 mg/kg BW) after two exposure periods (24 h and 48 h), in the present study the in vivo comet assay (single-cell gel electrophoresis) and the mouse bone marrow micronucleus test were used. Neither TDF + 3TC nor combivir + EFV induced DNA damage at any concentrations tested after 24 h or 48 h using the comet assay. After 24 h, both combinations increased the micronucleus frequency at all concentrations tested. After 48 h, combivir + EFV increased the micronucleated polychromatic erythrocyte (MNPCE) frequency at the two highest concentrations tested. Polychromatic erythrocytes (PCE)/normochromatic erythrocytes (NCE) ratio was high for both combinations, suggesting that they can be mitogenic. Since genotoxicity may be related to carcinogenesis, it is necessary to conduct further studies to verify the long-term mutagenic effects of these drugs.


Assuntos
Quimioterapia Combinada/efeitos adversos , Lamivudina/administração & dosagem , Tenofovir/administração & dosagem , Zidovudina/administração & dosagem , Animais , Terapia Antirretroviral de Alta Atividade , Medula Óssea/efeitos dos fármacos , Ensaio Cometa , Relação Dose-Resposta a Droga , Combinação de Medicamentos , Lamivudina/efeitos adversos , Camundongos , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Tenofovir/efeitos adversos , Zidovudina/efeitos adversos
11.
Artigo em Inglês | LILACS | ID: lil-468017

RESUMO

Bats of the genus Artibeus are among the most important seed dispersers in early successional forests. We report observations on the foraging behavior of Artibeus lituratus in Pedra da Cebola Municipal Park, an urban park in the city of Vitória, Espírito Santo, southeastern Brazil. Observations were made during six consecutive days (April 1st to April 6th, 2006). Three mist-nets were opened each night close to a Maclura tinctoria tree (Moraceae), remaining open from 18:00 to 22:00, totaling four hours per night, and 24 hours of sampling effort. We observed two peaks of feeding activity at the tree, one between 18:20 and 19:30, and a second one at 21:00. This is the first observation of Artibeus lituratus feeding on M. tinctoria fruits, therefore adding a new item to the known diet of the species. M. tinctoria fruits have large seeds that are not swallowed by bats, they consume the fruit pulp and discard the seeds. A diet of fruits with large seeds may indicate an important resource not detected in dietary studies based on fecal samples, but better detected by direct observation or by studying feeding roosts. It is important to use different sampling techniques in dietary studies since they complement each other and, together, provide a better knowledge on the diet of bats.


Morcegos do gênero Artibeus estão entre os mais importantes dispersores de sementes em florestas em estágios iniciais de sucessão. Aqui descrevemos observações sobre o comportamento de forrageio de Artibeus lituratus no Parque Municipal da Pedra da Cebola, um parque urbano na cidade de Vitória, Espírito Santo, sudeste do Brasil. As observações foram feitas durante seis dias consecutivos (01 a 06 de Abril de 2006). Três redes de neblina foram abertas cada noite, próximas a uma árvore de Maclura tinctoria, Moraceae, permanecendo abertas das 18:00 às 22:00 horas, totalizando quatro horas por noite, e 24 horas de esforço amostral. Foram observados dois picos de atividade de forrageio, o primeiro entre 18:20 e 19:30 horas, e o segundo às 21:00 horas. Este é o primeiro registro de consumo de frutos de M. tinctoria por A. lituratus, adicionando mais um ítem para a dieta conhecida desta espécie. Os frutos de M. tinctoria possuem sementes de tamanho relativamente grande, que não são ingeridas pelos morcegos. Eles consomem a polpa dos frutos e descartam as sementes. Uma dieta de frutos com sementes grandes pode indicar um recurso importante que não é detectado em estudos de dieta baseados apenas na análise de fezes, e que será detectado apenas por observação direta ou através do estudo de sítios de alimentação. O uso de técnicas de amostragem variadas em estudos de dieta é de extrema importância, pois elas complementam umas às outras, e em conjunto nos fornecem informações melhores e mais precisas sobre a dieta de morcegos do que qualquer uma delas forneceria isoladamente.


Assuntos
Comportamento Alimentar/classificação , Ecologia , Ecossistema , Frutas/efeitos adversos , Quirópteros/classificação , Sementes , Árvores
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