RESUMO
PREMISE: Agriculture expansion, livestock, and global change have transformed biological communities and altered, through aerosols and direct deposition, N:P balance in soils of inter-Andean valleys, potentially affecting flowering phenology of many species and thereby flowering synchrony and plant reproduction. METHODS: We evaluated the influence of variation in temperature and moisture along the local elevational gradient and treatments with the addition of N and P and grazing on flowering synchrony and reproduction of Croton, a dominant shrub of the inter-Andean dry scrub. Along the elevational gradient (300 m difference between the lowest and highest site), we set up plots with and without grazing nested with four nutrient treatments: control and addition of N or P alone or combined N + P. We recorded the number of female and male flowers in bloom monthly from September 2017 to August 2019 to calculate flowering synchrony. We assessed fruiting, seed mass, and pre-dispersal seed predation. RESULTS: Higher growing-season soil temperatures, which were negatively associated with local elevation and higher nitrogen availability promoted flowering synchrony of Croton, particularly among larger plants. Greater flowering synchrony, high soil temperatures, and addition of N + P resulted in production of more fruits of Croton, but also intensified pre-dispersal seed predation. CONCLUSIONS: Temperature, availability of moisture throughout the elevational gradient, and nutrient manipulation affected flowering synchrony, which subsequently affected production of fruits in Croton. These results emphasize the critical role of current anthropogenic changes in climate and nutrient availability on flowering synchrony and reproduction of Croton, a dominant plant of the inter-Andean scrub.
Assuntos
Flores , Nitrogênio , Reprodução , Flores/fisiologia , Nitrogênio/metabolismo , Temperatura , Solo/química , Estações do Ano , Fósforo , EcossistemaRESUMO
AIMS: The present study aimed to use a conventional and metagenomic approach to investigate the microbiological diversity of water bodies in a network of drainage channels and rivers located in the central area of the city of Belém, northern Brazil, which is considered one of the largest cities in the Brazilian Amazon. METHODS AND RESULTS: In eight of the analyzed points, both bacterial and viral microbiological indicators of environmental contamination-physical-chemical and metals-were assessed. The bacterial resistance genes, drug resistance mechanisms, and viral viability in the environment were also assessed. A total of 473 families of bacteria and 83 families of viruses were identified. Based on the analysis of metals, the levels of three metals (Cd, Fe, and Mn) were found to be above the recommended acceptable level by local legislation. The levels of the following three physicochemical parameters were also higher than recommended: biochemical oxygen demand, dissolved oxygen, and turbidity. Sixty-three bacterial resistance genes that conferred resistance to 13 different classes of antimicrobials were identified. Further, five mechanisms of antimicrobial resistance were identified and viral viability in the environment was confirmed. CONCLUSIONS: Intense human actions combined with a lack of public policies and poor environmental education of the population cause environmental degradation, especially in water bodies. Thus, urgent interventions are warranted to restore the quality of this precious and scarce asset worldwide.
Assuntos
Bactérias , Metagenômica , Microbiologia da Água , Brasil , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/classificação , Bactérias/efeitos dos fármacos , Saúde Ambiental , Rios/microbiologia , Rios/virologia , Vírus/genética , Vírus/isolamento & purificação , Monitoramento Ambiental , Farmacorresistência Bacteriana/genética , Humanos , Cidades , Metais/farmacologiaRESUMO
We investigate the effects of spatial changes in environmental conditions and anthropogenic influences on larval fish communities in two tropical estuaries with varying levels of human impact. Our findings revealed a distinct structure of larval fish assemblages between the two estuaries located in northeastern Brazil, and we observed that eutrophication, characterized by high concentrations of nutrients, had adverse effects on the abundance and richness of larval fish assemblages. Additionally, we observed that a decrease in rainfall had an impact on larval fish assemblages, particularly during the dry season, when intermittent upstream rivers lead to changes in salinity and species composition within the estuaries. This study contributed to evaluating the community descriptors of two tropical estuaries under different levels of human influence, providing insights into the vulnerability of larval fish assemblages to climate change, specifically in relation to human influences and hypersalinity and the effects of marinization in shallow tropical estuaries in this region.
Assuntos
Estuários , Peixes , Animais , Humanos , Larva , Brasil , Rios , EcossistemaRESUMO
This study brings information on the dynamics of C and N in urban forests in a subtropical region. We tested the hypothesis that C and N isotopic sign of leaves and soil and physiological traits of trees would vary from center to periphery in a megacity, considering land uses, intensity of automotive fleet and microclimatic conditions. 800 trees from four fragments were randomly chosen. Soil samples were collected at every 10 cm in trenches up to 1 m depth to analyze C and N contents. Both, plants and soil were assessed for δ13C, δ15N, %C and %N. Physiological traits [carbon assimilation (A)], CO2 internal and external pressure ratio (Pi/Pa) and intrinsic water use efficiency iWUE were estimated from δ13C and Δ Î´13C in leaves and soil ranged from -27.42 to -35.39 and from -21.22 to -28.18 , respectively, and did not vary along the areas. Center-periphery gradient was not evidenced by C. Emissions derived from fossil fuel and distinct land uses interfered at different levels in δ13C signature. δ15N in the canopy and soil varied clearly among urban forests, following center-periphery gradient. Leaf δ15N decreased from the nearest forest to the city center to the farthest, ranging from <3 to <-3 . δ15N was a good indicator of atmospheric contamination by NOx emitted by vehicular fleet and a reliable predictor of land use change. %N followed the same trend of δ15N either for soils or leaves. Forest fragments located at the edges of the center-periphery gradient presented significantly lower A and Pi/Pa ratio and higher iWUE. These distinct physiological traits were attributed to successional stage and microclimatic conditions. Results suggest that ecosystem processes related to C and N and ecophysiological responses of urban forests vary according to land use and vehicular fleet.
Assuntos
Ecossistema , Solo , Carbono , Dióxido de Carbono , Florestas , Combustíveis Fósseis , Plantas , Árvores , ÁguaRESUMO
The construction of dams causes several impacts on aquatic environments, altering the flow of rivers, environmental variables, and all biota present, including parasites. Little is known about how the parasitic community can be influenced in the long term by environmental changes. In this study, it was expected that the impacts caused by environmental disturbances will be directly reflected by the composition of the parasite populations. We evaluated the change in the structure of the Prochilodus lineatus endoparasite community between two periods sampled 15 years apart in the upper Paraná River floodplain. There was a significant difference in the weight-length relationship of P. lineatus between these periods and a total of 15 species of parasites were found: 11 species in Period 1 and nine species in Period 2 and five species occurred in both periods. The species richness and diversity were higher in Period 1, and we observed that the correlation of descriptors (richness, diversity and evenness) increased with fish length in this period. In both periods, digeneans numerically dominated the parasitic community, and we verified changes in the composition of parasites between periods. Both the host and the parasites were possibly affected by the environmental impacts resulting from the construction of dams over time, and it is noteworthy that complex life cycle parasites such as Digenea and Acanthocephala require intermediate hosts to complete their life cycle, and the population responds to fluctuations in the face of modified environments.
Assuntos
Acantocéfalos , Caraciformes , Parasitos , Trematódeos , Animais , Brasil , RiosRESUMO
In this study, through a rapid assessment, we evaluated differences in richness, abundance, species composition and beta diversity of Euglossini bees in preserved areas and areas altered by riverine human populations in the Caxiuanã National Forest (northern Amazon). Our hypotheses were: i) the species richness, diversity, abundance and composition of Euglossini bees differ between the preserved and altered areas because many species are intolerant to small anthropic disturbances; and ii) areas altered by riverine populations have higher values ââof beta diversity (species dissimilarity between sites) than preserved areas, due to local changes in habitat and increased heterogeneity between sites. We sampled two areas (preserved and altered) and, in each area, four transects were sampled with odorous baits. We used a Student's t test to evaluate differences in richness, abundance, and Shannon-Wiener diversity index. We also evaluated differences in composition and differences in beta diversity between areas. We collected 102 specimens, identified in 18 species and three genera, 63 individuals (61.8% of the total) in preserved areas and 39 individuals (38.2%) in altered areas. Euglossa liopoda (Dressler, 1982) was the most abundant in altered areas and Euglossa imperialis (Cockerell, 1922) the most abundant in preserved areas. Species richness was 2.5 times greater in the transects of preserved areas, and species composition also differed between the sampled areas. In contrast, species abundance did not differ between transects of both areas. Despite our small sample size, this study demonstrated that the richness, composition and beta diversity of Euglossini bees can be potentially affected by local changes in habitat caused by small-scale activities provided by traditional Amazonian groups. Our results indicate the urgency for more comprehensive studies aimed to investigate these relationships.
Neste estudo, por meio de uma avaliação rápida, investigamos diferenças na riqueza, abundância, composição de espécies e diversidade beta de abelhas Euglossini em áreas preservadas e áreas alteradas por populações ribeirinhas na Floresta Nacional de Caxiuanã (norte da Amazônia). Nossas hipóteses foram: i) a riqueza de espécies, diversidade, abundância e composição das abelhas Euglossini diferem entre as áreas preservadas e alteradas, uma vez que muitas espécies são intolerantes a pequenos distúrbios antrópicos; e ii) áreas alteradas por populações ribeirinhas apresentam maiores valores de diversidade beta (dissimilaridade de espécies entre locais) do que áreas preservadas, devido às mudanças locais no habitat e aumento da heterogeneidade entre locais. Amostramos duas áreas (preservadas e alteradas) e, em cada área, foram amostrados quatro transectos com iscas odoríferas. Nós utilizamos testes t de Student, para avaliar diferenças de riqueza, abundância e índice de diversidade de Shannon-Wiener. Também avaliamos as diferenças na composição e as diferenças na diversidade beta entre as áreas. Foram coletados 102 espécimes, em 18 espécies e três gêneros, 63 deles (61,8%) em áreas preservadas e 39 (38,2%) em áreas alteradas. Euglossa liopoda (Dressler, 1982) foi a mais abundante nas áreas alteradas e Euglossa imperialis (Cockerell, 1922) nas áreas preservadas. A riqueza foi 2,5 vezes maior nos transectos de áreas preservadas, e a composição de espécies também diferiu entre as áreas amostradas. Em contraste, a abundância de espécies não foi diferente entre os transectos das duas áreas. Apesar de nosso esforço amostral reduzido, nossos resultados demonstram que a riqueza, composição e diversidade beta das abelhas Euglossini podem potencialmente ser afetadas por mudanças locais no habitat causadas por atividades de pequena escala fornecidas por grupos tradicionais da Amazônia. Esses resultados indicam a urgência por estudos mais extensos no sentido de investigar as relações aqui estudadas.
Assuntos
Animais , Abelhas/classificação , Alteração Ambiental , Meio AmbienteRESUMO
To evaluate the physiological state of the wild fish inhabiting the Biobío River in South-Central Chile, susceptible to the chemical contamination from different sources, biochemical and physiological biomarkers were applied to wild fish Percilia irwini and Trichomycterus areolatus in situ. Fish caught in the Biobío river in low, medium, and high anthropic impacts areas, with different pollution degrees along the river. Ethoxyresorufin O-O deethylase (EROD) activity was evaluated in fish liver. Length, weight, Gonad weight and Liver weight, Physiological Index, and gill and liver histopathology were conducted. Physicochemical parameters (pH, Temperature, Conductivity, and TDS) were measured at each sampling site. The results indicated a deteriorating condition in the biological parameters of both species in a high anthropic zone. Fishes show an increase in physiological indices and EROD liver activity, agreeing with previous studies supporting evidence of reproductive change development as we move downstream the river. Also, an increase in histopathological lesions towards the lower third stretch of the Biobío River. The Integrated Index of Physiological Biomarkers (IPBR) indicated that sites located in the high impact area (P. irwini: BC: 4.09; RC: 3.38; PC: 3.50; SJ: 2.34 and T. areolatus BC: 6.06, PC: 5.37; SJ: 5.42) have the most detrimental environmental quality, compared to reference area. The integrated biomarker analysis demonstrates that the alterations observed are related to the high anthropic activity levels downstream from the sites with the least intervention, demonstrating that the IPBR used is a complementary tool for studies of the Environmental Effects Monitoring approach.
Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água , Animais , Biomarcadores , Chile , Peixes , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidadeRESUMO
Between 2003 and 2005, vertebrae of 151 Xingu River Potamotrygon leopoldi (Potamotrygonidae) (75 males and 76 females) were analysed to derive a growth curve for this species. The disc width (WD ) was significantly different between sexes, with females measuring 149-700 mm WD and males 109-500 mm WD . The average percentage error for vertebrae readings of the whole sample was 2·7%. The marginal increment ratio (RMI ) showed an increasing trend with the highest value in November, decreasing from December on. The majority of vertebrae displaying RMI zero, occurred in September, but the annual periodicity of ring deposition throughout the year was not conclusive. Tetracycline (TCN) injected specimens were held in captivity for 13 months and displayed a fluorescent mark in vertebrae confirming a yearly periodicity of band pair formation with the translucent ring deposited in September-October. The Akaike information criterion (AIC) showed that, among the seven models considered, the best fit was obtained for the von Bertalanffy modified with W0 (where W0 = WD at birth) for both sexes. Growth parameters for females were: W0 = 149 mm; W∞ = 763·06 mm; k = 0·12 year- 1 , whereas for males: W0 = 109 mm; W∞ = 536·4 and k = 0·22 year-1 . Maximal ages were 7·2 years in males and 14·3 years in females. The species shows sexual dimorphism expressed in the growth pattern, size at maturity, longevity and asymptotic sizes. Concern for sustainability is raised due to the construction of the Belo Monte Hydroelectric Power Plant (2015 and 2016) in the State of Pará causing changes to the habitat of this species, which is endemic to the Xingu River and two of its tributaries.
Assuntos
Determinação da Idade pelo Esqueleto/métodos , Rajidae/crescimento & desenvolvimento , Distribuição por Idade , Animais , Brasil , Ecossistema , Feminino , Corantes Fluorescentes , Masculino , Periodicidade , Rios , TetraciclinaRESUMO
Studies on fish assemblages in streams point out, that understanding the relationship between species and their environment is crucial for conservation. The present study aimed at evaluating the effects of changes in abiotic variables on the composition and structure of fish assemblages in Neotropical urban streams from southern Brazil with different levels of urbanization. The composition and structure of fish assemblages showed significant differences along the urbanization gradient observed in the streams. Tolerant and non-native species were found in more urbanized sites. A matrix correlation revealed a relationship between abiotic variables and the spatial pattern of structure and composition of fish assemblages. Abiotic variables, such as total phosphorus, dissolved oxygen, and conductivity, determined the distribution of fish assemblages. Streams without urban influence exhibited intrinsically low species richness, suggesting that they are highly susceptible to species loss and diversity reduction. Thus, changes in water quality or hydrological conditions induced by urbanization may intensify these impacts.
Estudos sobre as assembleias de peixes em riachos têm enfatizado que a compreensão da relação entre as espécies e seu ambiente é crucial para a conservação das espécies. O objetivo deste estudo foi avaliar os efeitos de alterações nas variáveis abióticas sobre a composição e estrutura das assembleias de peixes em riachos urbanos com diferentes percentuais de urbanização no Brasil. A composição e estrutura das assembleias de peixes mostraram diferenças significativas ao longo do gradiente de urbanização dos riachos. Espécies tolerantes e não-nativas foram encontradas em locais mais urbanizados. A análise de correlação de matrizes indicou uma relação entre as variáveis abióticas e do arranjo espacial da estrutura e composição nas assembleias de peixes. Variáveis abióticas, tais como fósforo total, oxigênio dissolvido e condutividade, determinaram a distribuição das assembleias de peixes. Riachos sem influência urbana exibem naturalmente baixa riqueza específica, sugerindo ser suscetíveis à perda de espécies e redução da diversidade. Assim, mudanças induzidas pela urbanização na qualidade da água ou no regime hidrológico podem exacerbar esses impactos.
Assuntos
Animais , Alteração Ambiental , Fatores Abióticos/análise , Peixes/crescimento & desenvolvimento , Urbanização/tendênciasRESUMO
Studies on fish assemblages in streams point out, that understanding the relationship between species and their environment is crucial for conservation. The present study aimed at evaluating the effects of changes in abiotic variables on the composition and structure of fish assemblages in Neotropical urban streams from southern Brazil with different levels of urbanization. The composition and structure of fish assemblages showed significant differences along the urbanization gradient observed in the streams. Tolerant and non-native species were found in more urbanized sites. A matrix correlation revealed a relationship between abiotic variables and the spatial pattern of structure and composition of fish assemblages. Abiotic variables, such as total phosphorus, dissolved oxygen, and conductivity, determined the distribution of fish assemblages. Streams without urban influence exhibited intrinsically low species richness, suggesting that they are highly susceptible to species loss and diversity reduction. Thus, changes in water quality or hydrological conditions induced by urbanization may intensify these impacts.(AU)
Estudos sobre as assembleias de peixes em riachos têm enfatizado que a compreensão da relação entre as espécies e seu ambiente é crucial para a conservação das espécies. O objetivo deste estudo foi avaliar os efeitos de alterações nas variáveis abióticas sobre a composição e estrutura das assembleias de peixes em riachos urbanos com diferentes percentuais de urbanização no Brasil. A composição e estrutura das assembleias de peixes mostraram diferenças significativas ao longo do gradiente de urbanização dos riachos. Espécies tolerantes e não-nativas foram encontradas em locais mais urbanizados. A análise de correlação de matrizes indicou uma relação entre as variáveis abióticas e do arranjo espacial da estrutura e composição nas assembleias de peixes. Variáveis abióticas, tais como fósforo total, oxigênio dissolvido e condutividade, determinaram a distribuição das assembleias de peixes. Riachos sem influência urbana exibem naturalmente baixa riqueza específica, sugerindo ser suscetíveis à perda de espécies e redução da diversidade. Assim, mudanças induzidas pela urbanização na qualidade da água ou no regime hidrológico podem exacerbar esses impactos.(AU)