775 resultados para School and community
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The significance of recruitment systems for community structure of epigaeic ants in a tropical upland forest in southern Brazil was evaluated by examining patterns of spatial occurrence at fixed points. Normal exploratory activity was evaluated with pitfall traps, while the effect of recruitment and diet was evaluated by using honey and sardine baits at the same points. Through techniques developed for environmental impact assessment, the significance of recruitment was evaluated following perturbation, or the placement of bait. Of the 46 species encountered, 15 were sufficiently frequent to study. Of these, only 6 showed significant spatial frequency changes at baits when compared with pitfall trap collections. In one analysis, monthly differences were important for a few smaller species, suggesting thermic limitations, while bait types either increased or decreased spatial point usage. The magnitude of spatial point variation is an index for the strength of recruitment in community organization. Bait types suggest nutritional possibilities of each species. Both recruitment and diet are probably functions of the species composition of the ant community.
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Incluye Bibliografía
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Good afternoon. I am so pleased to be here with you today. I welcome this opportunity to talk with you about how University of Nebraska Cooperative Extension, part of the Institute of Agriculture and Natural Resources at the University of Nebraska – Lincoln, works with Nebraska’s at-risk families. I’m extremely proud of our work to help families meet their needs and develop and strengthen skills they can use to better share in Nebraska’s good life.
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Sunken parcels of macroalgae and wood provide important oases of organic enrichment at the deep-sea floor, yet sediment community structure and succession around these habitat islands are poorly evaluated. We experimentally implanted 100-kg kelp falls and 200 kg wood falls at 1670 m depth in the Santa Cruz Basin to investigate (1) macrofaunal succession and (2) species overlap with nearby whale-fall and cold-seep communities over time scales of 0.25-5.5 yr. The abundance of infaunal macrobenthos was highly elevated after 0.25 and 0.5 yr near kelp parcels with decreased macrofaunal diversity and evenness within 0.5 m of the falls. Apparently opportunistic species (e.g., two new species of cumaceans) and sulfide tolerant microbial grazers (dorvilleid polychaetes) abounded after 0.25-0.5 yr. At wood falls, opportunistic cumaceans become abundant after 0.5 yr, but sulfide tolerant species only became abundant after 1.8-5.5 yr, in accordance with the much slower buildup of porewater sulfides at wood parcels compared with kelp falls. Species diversity decreased significantly over time in sediments adjacent to the wood parcels, most likely due to stress resulting from intense organic loading of nearby sediments (up to 20-30% organic carbon). Dorvilleid and ampharetid polychaetes were among the top-ranked fauna at wood parcels after 3.0-5.5 yr. Sediments around kelp and wood parcels provided low-intensity reducing conditions that sustain a limited chemoautrotrophically-based fauna. As a result, macrobenthic species overlap among kelp, wood, and other chemosynthetic habitats in the deep NE Pacific are primarily restricted to apparently sulfide tolerant species such as dorvilleid polychaetes, opportunistic cumaceans, and juvenile stages of chemosymbiont containing vesicomyid bivalves. We conclude that organically enriched sediments around wood falls may provide important habitat islands for the persistence and evolution of species dependent on organic- and sulfide-rich conditions at the deep-sea floor and contribute to beta and gamma diversity in deep-sea ecosystems. (C) 2010 Elsevier Ltd. All rights reserved.
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We present a new approach to determine the number and composition of guilds, using the hyperdiverse leaf-litter ant fauna as a model, based on appropriate morphological variables and species co-occurrence null models to describe the complex assemblages of interacting Species Community structure at the 1-m(2) scale. We obtained 18 linear morphometric measures from 949 workers of 171 leaf-litter ant species (18762 measurements) surveyed in four Atlantic Forest localities to test whether the assemblages are morphologically structured; the morphological characters were selected to indicate diet and foraging habits. Principal components analysis was used to characterize the morphospace and to describe the guild structure (number of species and composition). The guild proportionality assembly rule (significant tendency toward constant proportion of species in guilds) was assessed at the 1-m(2) scale. Our analysis indicates that the division of leaf-litter ants into guilds is based mainly on microhabitat distribution in the leaf-litter, body size and shape, eye size, and phylogeny. The same guild scheme applied to four more sites shows that different Atlantic Forest areas have the same leaf-fitter ant guilds. The guild proportionality assembly rule was confirmed for most guilds, Suggesting that there are guild-specific limitations on species coexistence within assemblages; on the other hand, in a few cases the variance in guild proportion was greater than expected under the null assumptions. Other studies on ant functional group classification are partially supported by our quantitative morphological analysis. Our results, however, imply that there are more compartments than indicated in previous models, particularly among cryptic species (confined to soil and litter) and tropical climate specialists. We argue that a general null model for the analysis of species association based oil morphology can reveal objectively defined groups and may thus contribute to a robust theory to explain community structure in general and have important consequences on studies of litter ant community ecology in particular.
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The effects of habitat configuration on species persistence are predicted to be most apparent when remaining habitat cover is below 30%. We tested this prediction by comparing vertebrate communities in 21 landscapes located in the southern Amazonia, including 7 control landscapes (similar to 100% of forest cover) and 14 fragmented landscapes (4 x 4 km). The fragmented landscapes retained similar proportions of forest (similar to 25%), but had contrasting configurations, resulting from two different deforestation patterns: the "fish-bone pattern" common in small properties, and the large-property pattern generally used by large ranchers. Vertebrates were surveyed in all landscapes in February-July 2009 with interviews (n = 150). We found a significant difference in reported species richness among the fish-bone, large-property, and control areas (mean = 29.3, 38.8 and 43.5 respectively). Control areas and large-properties tended to have a higher number of specialist species (mean = 13.7, and 11.7, respectively), when compared with the fish-bone pattern (5.1). Vertebrate community composition in the control and large-properties was more similar to one another than to those of the fish-bone landscapes. The number of fragments was the main factor affecting the persistence of species, being negatively associated with specialist species richness. Species richness was also positively related with the size of the largest fragment structurally connected to the studied landscapes (i.e., a regional scale effect). Our results demonstrated that the large-property pattern, which results in less fragmented landscapes, can maintain a more diverse community of large vertebrates, including top predators, which are considered fundamental for maintaining ecosystem integrity. These results support the hypothesis that landscape configuration contributes to the persistence and/or extirpation of species.
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We investigated the effects of the habitat-modifying green algae Caulerpa taxifolia on meiobenthic communities along the coast of New South Wales, Australia. Samples were taken from unvegetated sediments, sediments underneath the native seagrass Zostera capricorni, and sediments invaded by C. taxifolia at 3 sites along the coast. Meiofaunal responses to invasion varied in type and magnitude depending on the site, ranging from a slight increase to a substantial reduction in meiofauna and nematode abundances and diversity. The multivariate structure of meiofauna communities and nematode assemblages, in particular, differed significantly in sediments invaded by C. taxifolia when compared to native habitats, but the magnitude of this dissimilarity differed between the sites. These differential responses of meiofauna to C. taxifolia were explained by different sediment redox potentials. Sediments with low redox potential showed significantly lower fauna abundances, lower numbers of meiofaunal taxa and nematode species and more distinct assemblages. The response of meiofauna to C. taxifolia also depended on spatial scale. Whereas significant loss of benthic biodiversity was observed locally at one of the sites, at the larger scale C. taxifolia promoted an overall increase in nematode species richness by favouring species that were absent from the native environments. Finally, we suggest there might be some time-lags associated with the impacts of C. taxifolia and point to the importance of considering the time since invasion when evaluating the impact of invasive species.
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Is there a psychological basis for teaching and learning in the context of a liberal education, and if so, what might such a psychological basis look like? Traditional teaching and assessment often emphasize remembering facts and, to some extent, analyzing ideas. Such skills are important, but they leave out of the aspects of thinking that are most important not only in liberal education, but in life, in general. In this article, I propose a theory called WICS, which is an acronym for wisdom, intelligence, and creativity, synthesized. The basic idea underlying this theory is that, through liberal education, students need to acquire creative skills and attitudes to generate new ideas about how to adapt flexibly to a rapidly changing world, analytical skills and attitudes to ascertain whether these new ideas are good ones, practical skills and attitudes to implement the new ideas and convince others of their value, and wisdom-based skills and attitudes in order to ensure that the new ideas help to achieve a common good through the infusion of positive ethical values.
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In his compelling case study of local governance and community safety in the UK Thames Valley, Kevin Stenson makes several important contributions to the field of governmentality studies. While the paper’s merits are far-reaching, to this reader’s assessment they can be summarized in the following key areas: 1) Empirically, the article enhances our knowledge of the political economic transformation of a region otherwise overlooked in social science research ; 2) Conceptually, Stenson offers several theoretical and analytical refrains that, while becoming increasingly commonplace, are nonetheless still germane and rightly oriented to offer push back against otherwise totalizing, reified accounts of roll back/roll out neoliberalism. A welcomed new approach is offered as a corrective, The Realist Governmentality perspective, which emphasizes the interrelated and co-constitutive nature of politics, local culture, and habitus in processes related to the restructuring of social governance; 3) Methodologically, the paper makes a pitch for the ways in which finely grained, nuanced, mixed-method/ethnographic analyses have the potential to further problematize and recast a field of governmentality studies far too often dominated by discursive and textual approaches.
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There has been much commentary about the re-ordering of the relations between nation state government, geographical territory, and populations in the advanced liberal democracies. This is seen as a product of: increasing demographic and cultural diversity due to legal and illegal migration; economic, cultural, and political global interdependence; footloose mobility of capital and the outsourcing of jobs to poorer countries; the growing power of international corporations and financial markets; and the growth of supra-national bodies like the European Union and The North Atlantic Free Trade Association, the World Trade Organisation, and (debatably), the UN. These developments are held to be associated with the gradual demise of the model of the increasingly secular nation state first crystallised by the Treaty of Westphalia in 1648. This conception provided a mutual, guarantee of states’ jurisdiction over territory and populations through their legitimated attempts to monopolise the use of force. Though, the relations between these states have always been asymmetrical and often challenged (Hunter 1998).
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It is a challenging time to be a social scientist. Many of the concepts and categories we took for granted have been revealed as temporally and geographically specific. It is now widely accepted that the nation-state is no longer the sole container for economic, political and social processes, if indeed it ever was. This is where Kevin Stenson begins his paper. He traces the re-ordering of both state and nation, highlighting recent discussions about the unbundling and rescaling of the state and outlining how increasing ethnic and cultural diversity challenge homogeneous conceptions of the nation. In Stenson’s account these are largely empirical processes that are the basis for the important questions he raises about changing understandings of publics and social order, and their implications for the local governance of community safety. He contrasts two alternative positions; the ‘universal human rights position’ which refuses to privilege the interests of majority populations, and a more ‘communitarian and nationalistic position’ which he argues is most likely to be deployed by right wing politicians and interests groups. Drawing from extensive research in the Thames Valley region of the United Kingdom, he shows how these two understandings have both shaped the local policy response to crime and disorder.