251 research outputs found

    Effects of intrapopulation phenotypic traits of invasive crayfish on leaf litter processing

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    The impact of invasive alien species (IAS) on an ecosystem is primarily studied at the species level, whereas the functional impacts of their genetic and phenotypic traits are poorly investigated. We used two laboratory based experiments to assess how intrapopulation phenotypic traits (size, sex, and number of claws) of the invasive red swamp crayfish Procambarus clarkii affect invertebrate shredders and leaf processing. Leaf consumption was significantly affected by the size and number of claws but not by the sex of the crayfish. Bigger animals presented a higher overall consumption but, in contrast, the mass of leaves consumed per unit crayfish body mass decreased with size. Indeed, the production of particulate organic matter followed the same trend, suggesting that the higher metabolic needs of smaller animals are responsible for their higher feeding activity on leaf litter. Claw loss in P. clarkii also led to increased leaf consumption and may be related to increased energy requirements for claw regeneration. Our results highlight the importance of also considering the phenotypic traits within populations for better understanding the impacts of IAS on ecosystem processes.This work was supported by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) and the FreshBioFun project (PTDC/AAC-AMB/117068/2010) funded by the Portuguese Foundation for Science and Technology (FCT), by the Ministerio da Ciencia, Tecnologia e Ensino Superior (MCTES) and by the European Regional Development Fund (ERDF) through the COMPETE2020 - Programa Operacional Competitividade e Internacionalizacao (POCI). We acknowledge the anonymous referees and the editor for their constructive suggestions and our colleague Tony Collins for the English revision

    Remote sensing depicts riparian vegetation responses to water stress in a humid Atlantic region

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    Riparian areas in the Cantabrian Atlantic ecoregion (northwest Portugal) play a key role in soil formation and conservation, regulation of nutrient and water cycle, creation of landscape aesthetic value and the preservation of biodiversity. The maintenance of their ecological integrity is crucial given the ever increase in multiple anthropogenic (water demand and agriculture) and climatic pressures (droughts and extreme events). We developed a transferable remote sensing approach, taking advantage of the latest freely available technologies (Sentinel-2 and Copernicus Land products), to detect intra-annual and inter-annual changes in riparian vegetation productivity at the river basin scale related to water stress. This study has used the normalized difference vegetation index (NDVI) to investigate riparian vegetation productivity dynamics on three different vegetation types (coniferous, broadleaved and grassland) over the past 5 years (2015-2019). Our results indicated that inter-annual seasonality differed between drier (2017) and wetter (2016) years. We found that intra-annual dynamics of NDVI were influenced by the longitudinal river zonation. Our model ranked first (r2m = 0.73) showed that the productivity of riparian vegetation during the dry season was positively influenced by annual rainfall and by the type of riparian vegetation. The emergent long lags between climatic variation and riparian plant productivity provides opportunities to forecast early warnings of climatically-driven impacts. In addition, the different average productivity levels among vegetation types should be considered when assessing climatic impacts on riparian vegetation. Future applications of Sentinel 2 products could seek to distinguish riparian areas that are likely to be more vulnerable to changes in the annual water balance from those that are more resistant under longer-term changes in climate.Contrato-Programa UIDB/04050/2020. ERA4CS/0004/2016. CLIMALERT: Climate Alert Smart System for Sustainable Water and Agriculture, an ERA-NET initiated by JPI Climate (ERA4CS programme) co-funded by the EU commission (Grant Agreement 690462) and FCT (ERA4CS/0004/2016). This work was supported by the “Contrato-Programa” UIDB/04050/2020 funded by national funds through the FCT I.P. (GP

    Non-interactive effects drive multiple stressor impacts on the taxonomic and functional diversity of atlantic stream macroinvertebrates

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    Freshwaters are considered among the most endangered ecosystems globally due to multiple stressors, which coincide in time and space. These local stressors typically result from land-use intensification or hydroclimatic alterations, among others. Despite recent advances on multiple stressor effects, current knowledge is still limited to manipulative approaches minimizing biological and abiotic variability. Thus, the assessment of multiple stressor effects in real-world ecosystems is required. Using an extensive survey of 50 stream reaches across North Portugal, we evaluated taxonomic and functional macroinvertebrate responses to multiple stressors, including marked gradients of nutrient enrichment, flow reduction, riparian vegetation structure, thermal stress and dissolved oxygen depletion. We analyzed multiple stressor effects on two taxonomic (taxon richness, Shannon-diversity) and two trait-based diversity indices (functional richness, functional dispersion), as well as changes in trait composition. We found that multiple stressors had additive effects on all diversity metrics, with nutrient enrichment identified as the most important stressor in three out of four metrics, followed by dissolved oxygen depletion and thermal stress. Taxon richness, Shannon-diversity and functional richness responded similarly, whereas functional dispersion was driven by changes in flow velocity and thermal stress. Functional trait composition changed along a major stress gradient determined by nutrient enrichment and oxygen depletion, which was positively correlated with organisms possessing fast-living strategies, aerial respiration, adult phases, and gathering-collector feeding habits. Overall, our results reinforce the need to consider complementary facets of biodiversity to better identify assembly processes in response to multiple stressors. Our data suggest that stressor interactions may be less frequent in real-word streams than predicted by manipulative experiments, which can facilitate mitigation strategies. By combining an extensive field survey with an integrative consideration of multiple biodiversity facets, our study provides new insights that can help to better assess and manage rivers in a global change context.This work was supported by the project STREAMECO: Biodiversity and ecosystem functioning under climate change: from the gene to the stream (PTDC/CTA-AMB/31245/2017), funded by the Portuguese Foundation for Science and Technology (FCT) and the European Regional Development Fund (ERDF) through the COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI). This work was also supported by the River2Ocean project (NORTE-01-0145- FEDER-000068), co-financed by the European Regional Development Fund (ERDF), through Programa Operacional Regional do Norte (NORTE2020); by CCDR-N (Norte Portugal Regional Coordination and Development Commission) and European Funds (FEDER/POCI/COMPETE2020) through the project AgriFoodXXI (NORTE-01-0145-FEDER-000041); and by the “ContratoPrograma” UIDB/04050/2020 funded by national funds through the FCT I.P., the Centre of Molecular and Environmental Biology (CBMA). This work had the support of national funds through Portuguese Foundation for Science and Technology (FCT), under the project LA/P/0069/ 2020 granted to the Associate Laboratory ARNET. CG-C was funded by ”la Caixa” Foundation (ID 100010434), by means of a Junior Leader Fellowship contract (LCF/BQ/PR22/11920005)

    Re: Lack of association between Matrix Metalloproteinase-1 (MMP-1) promoter polymorphism and risk of renal cell carcinoma

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    Federal University of São Paulo Section of NephrologyFederal University of São Paulo Section of UrologyInstitute of Energetic and Nuclear ResearchUNIFESP, Section of NephrologyUNIFESP, Section of UrologySciEL

    Evaluation of the lactic acid consumption in yeast cultures by voltammetric means

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    Abstract The voltammetric study of the lactic acid reduction was performed in media suitable for yeast growth, using platinum microelectrodes. The decrease of the voltammetric peak current from square wave voltammetry, ∆I p , in cultures of the yeasts Candida utilis and Saccharomyces cerevisiae was related to both the growth time and cellular biomass. Either the imposed variations of medium composition or those resulting from cellular growth did not significantly affect the ∆I p values. For both yeast species, similar specific growth rates were estimated from the variation of I p and absorbance at 640 nm

    Historical experiments simulations in physics education: a computational approach of the historical and empirical dimensions of science in classroom

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    Neste trabalho propomos a utilização de simulações computacionais de experimentos históricos no ensino de física como estratégia de resgate e articulação das dimensões histórica e empírica da física na sala de aula. Como exemplo, apresentamos uma classe de simulação computacional didática, caracterizada aqui como Simulação Didática Interativa (SDI), utilizando o software Modellus para apresentar a experiência do plano inclinado proposta por Galileu Galilei(1564-1642) em sua obra Discursos e Demonstrações Matemáticas em Torno de Duas Novas Ciências (1638), onde a lei da queda dos corpos é investigada.In this paper we propose the use of computer simulations of historical experiments in physics education as a strategy to recover and articulate the historical and empirical dimensions of scientific knowledge in the classroom. Particularly, we present a Didactic Interactive Simulation (DIS) using the software Modellus to rescue the experiment of the inclined plane described by Galileo Galilei in his work Discourse and Mathematical Demonstrations Concerning Two New Sciences (1638), in which he investigates the law of falling bodies

    Small reserve but high diversity: butterfly community across an altitudinal gradient in the Brazilian Atlantic Forest

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    The present study aimed to describe the composition of the butterfly community in relation to the altitudinal gradient in the Reserva Particular do Patrimônio Natural (RPPN) Alto-Montana, Serra da Mantiqueira, Minas Gerais, Brazil, and to provide a list of species for the area. We collected samples in the RPPN Alto-Montana along an altitudinal gradient from 1400 to 2100 m, between the dry and rainy seasons of 2018 and 2019. During this period, the sampling method utilizing Van-Someren Rydon traps totaled 3,936 hours and the effort using sweep nets totaled 246 hours. A total of 1,253 butterflies distributed across 124 species and six families of diurnal butterflies were observed (Hesperiidae, Lycaenidae, Nymphalidae, Papilionidae, Pieridae, and Riodinidae). Nymphalidae was the most representative family, followed by Hesperiidae, Pieridade, Lycaenidae, Papilionidae and Riodinidae. Moreover, we recorded 37 species with only one individual (singletons) and 20 species with only two individuals (doubletons), totalling 57 species, which corresponds to 46% of all sampled richness. The rarefaction curve did not reveal a tendency toward stabilization. However, the indices showed slightly higher values for the 124 species sampled. The analysis performed using the Bootstrap estimator predicted a total of 143.22 species (± 10.87 SE), with a further 19 additional species than observed. Chao 1 predicted 153.42 (± 11.82 SE), and Jackknife 1 predicted 164.00 (± 16.29 SE) species, with 29 and 40 additional species than the observed, respectively. Our study contributes to the knowledge of butterfly biodiversity in Serra da Mantiqueira and reveals a high species richness for the RPPN Alto Montana, especially considering the relatively small area. In addition, our study provides the first inventory of butterflies for the RPPN Alto Montana, thus supporting further studies investigating the butterfly richness in the Serra da Mantiqueira region. Finally, our findings of endemic, rare, and endangered butterfly species highlight the relevance of further conservation strategies to be considered for the Protected Area’s Management Plan
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