729 resultados para COMMUNITIES ACARI
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In 2000 the European Statistical Office published the guidelines for developing theHarmonized European Time Use Surveys system. Under such a unified framework,the first Time Use Survey of national scope was conducted in Spain during 2002–03. The aim of these surveys is to understand human behavior and the lifestyle ofpeople. Time allocation data are of compositional nature in origin, that is, they aresubject to non-negativity and constant-sum constraints. Thus, standard multivariatetechniques cannot be directly applied to analyze them. The goal of this work is toidentify homogeneous Spanish Autonomous Communities with regard to the typicalactivity pattern of their respective populations. To this end, fuzzy clustering approachis followed. Rather than the hard partitioning of classical clustering, where objects areallocated to only a single group, fuzzy method identify overlapping groups of objectsby allowing them to belong to more than one group. Concretely, the probabilistic fuzzyc-means algorithm is conveniently adapted to deal with the Spanish Time Use Surveymicrodata. As a result, a map distinguishing Autonomous Communities with similaractivity pattern is drawn.Key words: Time use data, Fuzzy clustering; FCM; simplex space; Aitchison distance
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A key issue in the implementation of the Water Framework Directive is the classification of streams and rivers using biological quality parameters and type-specific reference conditions. Four groups of stream types were defined in NE Spain on the basis of 152 diatom samples by means of detrended correspondence analysis and classification techniques. Diatom analysis was restricted to epilithic taxa, and the sites included gradients ranging from near-natural streams to sites with poor ecological quality. The main gradient shows a clear separation of sites in relation to the degree of human influence: polluted streams (mainly located in the lowlands) differ from streams in mountainous areas and in the Pyrenees. A second gradient is related to physiographical features. Headwater streams can be distinguished by their catchment geology. The type-specific diatom taxa for the stream types studied were determined by using indicator species analysis (IndVal). The type-specific taxa from near-natural streams are coincident with the indicator taxa for high ecological status. Human impact reduced the typological heterogeneity of the diatom community composition. Overall, the diatom communities in NE Spain exhibit a regional distribution pattern that closely corresponds with that observed in river systems elsewhere. Physiographical differences are only evident in undisturbed sites, while nutrient enrichment and other human disturbances may mask the regional differences in the distribution of diatom communities
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The importance of competition between similar species in driving community assembly is much debated. Recently, phylogenetic patterns in species composition have been investigated to help resolve this question: phylogenetic clustering is taken to imply environmental filtering, and phylogenetic overdispersion to indicate limiting similarity between species. We used experimental plant communities with random species compositions and initially even abundance distributions to examine the development of phylogenetic pattern in species abundance distributions. Where composition was held constant by weeding, abundance distributions became overdispersed through time, but only in communities that contained distantly related clades, some with several species (i.e., a mix of closely and distantly related species). Phylogenetic pattern in composition therefore constrained the development of overdispersed abundance distributions, and this might indicate limiting similarity between close relatives and facilitation/complementarity between distant relatives. Comparing the phylogenetic patterns in these communities with those expected from the monoculture abundances of the constituent species revealed that interspecific competition caused the phylogenetic patterns. Opening experimental communities to colonization by all species in the species pool led to convergence in phylogenetic diversity. At convergence, communities were composed of several distantly related but species-rich clades and had overdispersed abundance distributions. This suggests that limiting similarity processes determine which species dominate a community but not which species occur in a community. Crucially, as our study was carried out in experimental communities, we could rule out local evolutionary or dispersal explanations for the patterns and identify ecological processes as the driving force, underlining the advantages of studying these processes in experimental communities. Our results show that phylogenetic relations between species provide a good guide to understanding community structure and add a new perspective to the evidence that niche complementarity is critical in driving community assembly.
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Many terrestrial and marine systems are experiencing accelerating decline due to the effects of global change. This situation has raised concern about the consequences of biodiversity losses for ecosystem function, ecosystem service provision, and human well-being. Coastal marine habitats are a main focus of attention because they harbour a high biological diversity, are among the most productive systems of the world and present high anthropogenic interaction levels. The accelerating degradation of many terrestrial and marine systems highlights the urgent need to evaluate the consequence of biodiversity loss. Because marine biodiversity is a dynamic entity and this study was interested global change impacts, this study focused on benthic biodiversity trends over large spatial and long temporal scales. The main aim of this project was to investigate the current extent of biodiversity of the high diverse benthic coralligenous community in the Mediterranean Sea, detect its changes, and predict its future changes over broad spatial and long temporal scales. These marine communities are characterized by structural species with low growth rates and long life spans; therefore they are considered particularly sensitive to disturbances. For this purpose, this project analyzed permanent photographic plots over time at four locations in the NW Mediterranean Sea. The spatial scale of this study provided information on the level of species similarity between these locations, thus offering a solid background on the amount of large scale variability in coralligenous communities; whereas the temporal scale was fundamental to determine the natural variability in order to discriminate between changes observed due to natural factors and those related to the impact of disturbances (e.g. mass mortality events related to positive thermal temperatures, extreme catastrophic events). This study directly addressed the challenging task of analyzing quantitative biodiversity data of these high diverse marine benthic communities. Overall, the scientific knowledge gained with this research project will improve our understanding in the function of marine ecosystems and their trajectories related to global change.
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The soy expansion model in Argentina generates structural changes in traditional lifestyles that can be associated with different biophysical and socioeconomic impacts. To explore this issue, we apply an innovative method for integrated assessment - the Multi Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM) framework - to characterize two communities in the Chaco Region, Province of Formosa, North of Argentina. These communities have recently experienced the expansion of soy production, altering their economic activity, energy consumption patterns, land use, and human time allocation. The integrated characterization presented in the paper illustrates the differences (biophysical, socioeconomic, and historical) between the two communities that can be associated with different responses. The analysis of the factors behind these differences has important policy implications for the sustainable development of local communities in the area.
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1. As trees in a given cohort progress through ontogeny, many individuals die. This risk of mortality is unevenly distributed across species because of many processes such as habitat filtering, interspecific competition and negative density dependence. Here, we predict and test the patterns that such ecological processes should inscribe on both species and phylogenetic diversity as plants recruit from saplings to the canopy. 2. We compared species and phylogenetic diversity of sapling and tree communities at two sites in French Guiana. We surveyed 2084 adult trees in four 1-ha tree plots and 943 saplings in sixteen 16-m2 subplots nested within the tree plots. Species diversity was measured using Fisher's alpha (species richness) and Simpson's index (species evenness). Phylogenetic diversity was measured using Faith's phylogenetic diversity (phylogenetic richness) and Rao's quadratic entropy index (phylogenetic evenness). The phylogenetic diversity indices were inferred using four phylogenetic hypotheses: two based on rbcLa plastid DNA sequences obtained from the inventoried individuals with different branch lengths, a global phylogeny available from the Angiosperm Phylogeny Group, and a combination of both. 3. Taxonomic identification of the saplings was performed by combining morphological and DNA barcoding techniques using three plant DNA barcodes (psbA-trnH, rpoC1 and rbcLa). DNA barcoding enabled us to increase species assignment and to assign unidentified saplings to molecular operational taxonomic units. 4. Species richness was similar between saplings and trees, but in about half of our comparisons, species evenness was higher in trees than in saplings. This suggests that negative density dependence plays an important role during the sapling-to-tree transition. 5. Phylogenetic richness increased between saplings and trees in about half of the comparisons. Phylogenetic evenness increased significantly between saplings and trees in a few cases (4 out of 16) and only with the most resolved phylogeny. These results suggest that negative density dependence operates largely independently of the phylogenetic structure of communities. 6. Synthesis. By contrasting species richness and evenness across size classes, we suggest that negative density dependence drives shifts in composition during the sapling-to-tree transition. In addition, we found little evidence for a change in phylogenetic diversity across age classes, suggesting that the observed patterns are not phylogenetically constrained.
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This FY2007 budget will continue progress toward growing Iowa’s economy, improving student achievement and expanding health care security. With your cooperation last year we enacted the Strong Start program, the Watershed Improvement Review Board, the Iowa Values Fund, Iowa Cares, the Meth Control Act, a balanced budget and other initiatives which made for a very productive session. In a spirit of cooperation we deliver the FY2007 budget at the start of the session to allow more time for your consideration.
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Cape Verde is a tropical oceanic ecosystem, highly fragmented and dispersed, with islands physically isolated by distance and depth. To understand how isolation affects the ecological variability in this archipelago, we conducted a research project on the community structure of the 18 commercially most important demersal fishes. An index of ecological distance based on species relative dominance (Di) is developed from Catch Per Unit Effort, derived from an extensive database of artisanal fisheries. Two ecological measures of distance between islands are calculated: at the species level, DDi, and at the community level, DD (sum of DDi). A physical isolation factor (Idb) combining distance (d) and bathymetry (b) is proposed. Covariance analysis shows that isolation factor is positively correlated with both DDi and DD, suggesting that Idb can be considered as an ecological isolation factor. The effect of Idb varies with season and species. This effect is stronger in summer (May to November), than in winter (December to April), which appears to be more unstable. Species react differently to Idb, independently of season. A principal component analysis on the monthly (DDi) for the 12 islands and the 18 species, complemented by an agglomerative hierarchical clustering, shows a geographic pattern of island organization, according to Idb. Results indicate that the ecological structure of demersal fish communities of Cape Verde archipelago, both in time and space, can be explained by a geographic isolation factor. The analytical approach used here is promising and could be tested in other archipelago systems.
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Calacarus heveae Feres, 1992 is an Eriophyidae mite described from rubber tree (Hevea brasiliensis Muell. Arg.) in the northwest region of the State of São Paulo. This mite prefers the adaxial face of the folioles and it can reduce the brightness of the leaves, turning them progressively yellow and brownish, and consequently premature fall. The aim of this work was to study the biology of C. heveae in laboratory, on detached rubber tree folioles. The study was conducted at 28±1 ºC in the photophase (12h), 25±1 ºC in the dark phase (12h), and 90±5% relative humidity. The study was initiated with a total of 59 eggs. The average duration of egg, larva and nymph stages was 5.8, 2.0 and 1.4 days, respectively. The period from egg to adult lasted 9.3 days, and the average periods of pre-oviposition, oviposition and post-oviposition, 1.8, 6.1 and 1.2 days, respectively. The average longevity of the adult male was ca. 4.0 days, while the longevity adult female was about 8.4 days. The average daily oviposition rate was 2.3 egg per female while the average fecundity was 16.2 eggs per female.
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The Convention on Biological Diversity (CBD) aims at the conservation of all three levels of biodiversity, that is, ecosystems, species and genes. Genetic diversity represents evolutionary potential and is important for ecosystem functioning. Unfortunately, genetic diversity in natural populations is hardly considered in conservation strategies because it is difficult to measure and has been hypothesised to co-vary with species richness. This means that species richness is taken as a surrogate of genetic diversity in conservation planning, though their relationship has not been properly evaluated. We tested whether the genetic and species levels of biodiversity co-vary, using a large-scale and multi-species approach. We chose the high-mountain flora of the Alps and the Carpathians as study systems and demonstrate that species richness and genetic diversity are not correlated. Species richness thus cannot act as a surrogate for genetic diversity. Our results have important consequences for implementing the CBD when designing conservation strategies.
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Are differences in local banking development long-lasting? Do they affect long-term economic performance?I answer these questions by relying on an historical development that occurred in Italian cities during the 15thcentury. A sudden change in the Catholic doctrine had driven the Jews toward money lending. Cities thatwere hosting Jewish communities developed complex banking institutions for two reasons: first, the Jews werethe only people in Italy who were allowed to lend for a profit and, second, the Franciscan reaction to Jewishusury led to the creation of charity lending institutions, the Monti di Pietà, that have survived until today andhave become the basis of the Italian banking system. Using Jewish demography in 1500 as an instrument, Iprovide evidence of (1) an extraordinary persistence in the level of banking development across Italian cities (2)large effects of current local banking development on per-capita income. Additional firm-level analyses suggestthat well-functioning local banks exert large effects on aggregate productivity by reallocating resources towardmore efficient firms. I exploit the expulsion of the Jews from the Spanish territories in Italy in 1541 to arguethat my results are not driven by omitted institutional, cultural and geographical characteristics. In particular,I show that, in Central Italy, the difference in current income between cities that hosted Jewish communitiesand cities that did not exists only in those regions that were not Spanish territories in the 16th century.
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A partir de teleógina de Amblyomma nodosum Neumann, 1899, removida de Tamandua tetradactyla (Linnaeus, 1758) foram obtidas posturas que originaram larvas, em condições de laboratório. Um total de 219 larvas foi examinado em microscopia de luz, com objetiva de imersão e microscopia de confocal com varredura a laser. Buscou-se analisar a variação do número das cerdas internas dos lados direito e esquerdo, no fundo da cápsula do Órgão de Haller, com intuito de utilizá-las como um parâmetro quetotáxico na diagnose específica. A média do número de cerdas foi 5,06±0, 71, com valores limites da amplitude de 4-11.
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Foi estudada a dinâmica populacional de Calacarus heveae Feres, 1992, Phyllocoptruta seringueirae Feres, 1998 (Eriophyidae) e Tenuipalpus heveae Baker, 1945 (Tenuipalpidae) em seis clones de seringueira (Hevea brasiliensis Muell. Arg.), com o intuito de conhecer a sazonalidade e as possíveis diferenças nos níveis de infestação dessas espécies sobre os diferentes clones, em seringal localizado no sul do Estado de Mato Grosso. Para isso, no período de março de 2004 a março de 2005, foram realizadas coletas num intervalo médio de catorze dias em seis parcelas clonais. Em cada amostragem, foram analisados 100 folíolos de cada parcela, registrando-se o número total de ácaros encontrados em ambas as faces. Os níveis de infestação das espécies variaram entre os diferentes clones. O clone RRIM 600 apresentou maior abundância de T. heveae, enquanto que PB 235 e PB 260 de P. seringueira e C. heveae, respectivamente. Por outro lado, esse último clone apresentou menor número de indivíduos de T. heveae e P. seringueirae, e PB 235 de C. heveae. O primeiro semestre foi o período crítico de infestação, porém a duração da ocorrência e o pico de abundância dos fitófagos variaram nos diferentes clones.
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Aim This study used data from temperate forest communities to assess: (1) five different stepwise selection methods with generalized additive models, (2) the effect of weighting absences to ensure a prevalence of 0.5, (3) the effect of limiting absences beyond the environmental envelope defined by presences, (4) four different methods for incorporating spatial autocorrelation, and (5) the effect of integrating an interaction factor defined by a regression tree on the residuals of an initial environmental model. Location State of Vaud, western Switzerland. Methods Generalized additive models (GAMs) were fitted using the grasp package (generalized regression analysis and spatial predictions, http://www.cscf.ch/grasp). Results Model selection based on cross-validation appeared to be the best compromise between model stability and performance (parsimony) among the five methods tested. Weighting absences returned models that perform better than models fitted with the original sample prevalence. This appeared to be mainly due to the impact of very low prevalence values on evaluation statistics. Removing zeroes beyond the range of presences on main environmental gradients changed the set of selected predictors, and potentially their response curve shape. Moreover, removing zeroes slightly improved model performance and stability when compared with the baseline model on the same data set. Incorporating a spatial trend predictor improved model performance and stability significantly. Even better models were obtained when including local spatial autocorrelation. A novel approach to include interactions proved to be an efficient way to account for interactions between all predictors at once. Main conclusions Models and spatial predictions of 18 forest communities were significantly improved by using either: (1) cross-validation as a model selection method, (2) weighted absences, (3) limited absences, (4) predictors accounting for spatial autocorrelation, or (5) a factor variable accounting for interactions between all predictors. The final choice of model strategy should depend on the nature of the available data and the specific study aims. Statistical evaluation is useful in searching for the best modelling practice. However, one should not neglect to consider the shapes and interpretability of response curves, as well as the resulting spatial predictions in the final assessment.
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No presente trabalho foram estudados os ácaros associados a plantas ornamentais de praças, ruas e jardins residenciais, no município de Ilha Solteira, SP. Foram amostradas folhas de 20 espécies de plantas e alguns representantes das morfoespécies de ácaros encontrados foram montados em lâminas de microscopia com o meio de Hoyer, para posterior identificação sob microscópio óptico com contraste de fases. Foram registradas 23 espécies pertencentes a 15 gêneros de oito famílias. Dessas espécies, 13 são fitófagas, nove predadoras e uma de hábito alimentar não determinado. A família com maior riqueza de ácaros foi Tetranychidae, com nove espécies, sendo uma delas registrada pela primeira vez após a descrição original e outra pela primeira vez no Brasil. Lorryia formosa Cooremann, 1958 (Tydeidae) foi a que ocorreu em maior número de hospedeiros. As plantas com as maiores riquezas de ácaros foram Lagerstroemia indica L., Mussaenda alicia Hort. e Tabebuia sp., com seis espécies registradas em cada uma.