944 resultados para Semiarid grassland ecosystem
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Drastic biodiversity declines have raised concerns about the deterioration of ecosystem functions and have motivated much recent research on the relationship between species diversity and ecosystem functioning. A functional trait framework has been proposed to improve the mechanistic understanding of this relationship, but this has rarely been tested for organisms other than plants. We analysed eight datasets, including five animal groups, to examine how well a trait-based approach, compared with a more traditional taxonomic approach, predicts seven ecosystem functions below- and above-ground. Trait-based indices consistently provided greater explanatory power than species richness or abundance. The frequency distributions of single or multiple traits in the community were the best predictors of ecosystem functioning. This implies that the ecosystem functions we investigated were underpinned by the combination of trait identities (i.e. single-trait indices) and trait complementarity (i.e. multi-trait indices) in the communities. Our study provides new insights into the general mechanisms that link biodiversity to ecosystem functioning in natural animal communities and suggests that the observed responses were due to the identity and dominance patterns of the trait composition rather than the number or abundance of species per se.
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International policy frameworks such as the Common Fisheries Policy and the European Marine Strategy Framework Directive define high-level strategic goals for marine ecosystems. Strategic goals are addressed via general and operational management objectives. To add credibility and legitimacy to the development of objectives, for this study stakeholders explored intermediate level ecological, economic and social management objectives for Northeast Atlantic pelagic ecosystems. Stakeholder workshops were undertaken with participants being free to identify objectives based on their own insights and needs. Overall 26 objectives were proposed, with 58% agreement in proposed objectives between two workshops. Based on published evidence for pressure-state links, examples of operational objectives and suitable indicators for each of the 26 objectives were then selected. It is argued that given the strong species-specific links of pelagic species with the environment and the large geographic scale of their life cycles, which contrast to demersal systems, pelagic indicators are needed at the level of species (or stocks) independent of legislative region. Pelagic community indicators may be set at regional scale in some cases. In the evidence-based approach used in this study, the selection of species or region specific operational objectives and indicators was based on demonstrated pressure-state links. Hence observed changes in indicators can reliably inform on appropriate management measures
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We consider the problem of regulating the rate of harvesting a natural resource, taking account of the wider system represented by a set of ecological and economic indicators, given differing stakeholder priorities. This requires objective and transparent decision making to show how indicators impinge on the resulting regulation decision. We offer a new scheme for combining indicators, derived from assessing the suitability of lowering versus not lowering the harvest rate based on indicator values relative to their predefined reference levels. Using the practical example of fisheries management under an “ecosystem approach,” we demonstrate how different stakeholder views can be quantitatively represented by weighting sets applied to these comparisons. Using the scheme in an analysis of historical data from the Celtic Sea fisheries, we find great scope for negotiating agreement among disparate stakeholders.
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O presente trabalho aborda aspectos da Ecologia e serviços ambientais prestados pelas salinas solares tropicais. Estes importantes ecossistemas artificiais adquirem uma relevância ecológica, económica e cultural nestas zonas do globo por se manterem produtivos durante todo o ano. O estudo foi realizado em 02 salinas da região Nordeste do Brasil, no Estado do Rio Grande do Norte, produtor de 97% o sal marinho nacional. Nestas salinas, verificou-se que existe uma lacuna de conhecimento acerca do histórico de exploração no Brasil, assim como da sua caracterização ambiental. Foi ainda aplicada uma abordagem sistêmica integrando os serviços ecossistêmicos aplicados à conservação das salinas solares. Portanto, teve-se como objetivo central desta investigação realizar a caracterização das salinas solares no litoral semiárido do Brasil, analisando os serviços ambientais prestados por estes importantes ecossistemas, assim como as potencialidades alternativas para a sua gestão. Através de análises de parâmetros físico-químicos da salmoura e dos sedimentos foram caracterizados os diferentes tipos de habitats identificados ao longo do gradiente espacial da salinidade. Concomitantemente, também foram identificados os principais serviços ambientais prestados pelas salinas solares tropicais, os quais permitiram a realização de uma análise sobre quais desses serviços poderiam ser interrompidos em função das diferentes pressões antrópicas. A partir desta análise, verificou-se que as salinas são sistemas integrados, representando ecossistemas com dinâmicas biogeoquímicas diferenciadas, as quais estão associados ao manejo para a atividade econômica de produção de sal. Essa afirmativa é observada pois, de um lado tem-se o ecossistema hipersalino, composto por um mosaico de habitats, cuja salinidade é um dos principais agentes reguladores da biodiversidade encontrada em cada habitat. Por sua vez, é exatamente a logística da produção de sal marinho que determina o gradiente espacial da salinidade, o qual influencia na segmentação dos diferentes habitas encontrados nas salinas. Assim, percebe-se que quando corretamente manejado, um sistema biológico típico de uma salina é uma ferramenta de auxílio à produção de sal, configurando-se neste caso como o principal serviço ecossistêmico voltado exclusivamente ao importante mercado do Brasil: a produção de sal marinho por evaporação solar.
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Dissertação de Mestrado, Gestão da Água e da Costa, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2010
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Tese de dout., Ciências e Tecnologia das Pescas, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2005
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The decoupling of CAP payments leads production decisions and resources allocation to be more dependent on market prices and competitive advantages. The objective of this paper is to assess the effects of CAP trends on the montado/dehesa traditional ecosystem of Mediterranean regions in terms of farm income, land, labour and capital. A positive mathematical supply model disaggregated by the montado agro-forestry production systems of the Alentejo region in southern Portugal is developed. The results show that decoupling payments of CAP have negative economic effects on agricultural activities and resource use. Agricultural income increases with single farm payments but the foreseen increases in prices do not compensate the loss of the Agenda 2000 area payments in terms of competitiveness. These results reinforce the need to promote alternative agricultural and non-agricultural activities and policies in Mediterranean rural European areas and regions. (C) 2011 Society for Policy Modeling. Published by Elsevier Inc. All rights reserved.
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Thesis (Master's)--University of Washington, 2013
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Dissertação de Mestrado, Estudos Integrados dos Oceanos, 25 de Julho 2013, Universidade dos Açores.
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Learning and teaching processes, like all human activities, can be mediated through the use of tools. Information and communication technologies are now widespread within education. Their use in the daily life of teachers and learners affords engagement with educational activities at any place and time and not necessarily linked to an institution or a certificate. In the absence of formal certification, learning under these circumstances is known as informal learning. Despite the lack of certification, learning with technology in this way presents opportunities to gather information about and present new ways of exploiting an individual’s learning. Cloud technologies provide ways to achieve this through new architectures, methodologies, and workflows that facilitate semantic tagging, recognition, and acknowledgment of informal learning activities. The transparency and accessibility of cloud services mean that institutions and learners can exploit existing knowledge to their mutual benefit. The TRAILER project facilitates this aim by providing a technological framework using cloud services, a workflow, and a methodology. The services facilitate the exchange of information and knowledge associated with informal learning activities ranging from the use of social software through widgets, computer gaming, and remote laboratory experiments. Data from these activities are shared among institutions, learners, and workers. The project demonstrates the possibility of gathering information related to informal learning activities independently of the context or tools used to carry them out.
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Dissertation presented to obtain the degree of Doctor in Electrical and Computer Engineering, specialization on Collaborative Enterprise Networks
Using life strategies to explore the vulnerability of ecosystem services to invasion by alien plants
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Invasive plants can have different effects of ecosystem functioning and on the provision of ecosystem services, from strongly deleterious impacts to positive effects. The nature and intensity of such effects will depend on the service and ecosystem being considered, but also on features of life strategies of invaders that influence their invasiveness as well as their influence of key processes of receiving ecosystems. To address the combined effect of these various factors we developed a robust and efficient methodological framework that allows to identify areas of possible conflict between ecosystem services and alien invasive plants, considering interactions between landscape invasibility and species invasiveness. Our framework combines the statistical robustness of multi-model inference, efficient techniques to map ecosystem services, and life strategies as a functional link between invasion, functional changes and potential provision of services by invaded ecosystems. The framework was applied to a test region in Portugal, for which we could successfully predict the current patterns of plant invasion, of ecosystem service provision, and finally of probable conflict (expressing concern for negative impacts, and value for positive impacts on services) between alien species richness (total and per plant life strategy) and the potential provision of selected services. Potential conflicts were identified for all combinations of plant strategy and ecosystem service, with an emphasis for those concerning conflicts with carbon sequestration, water regulation and wood production. Lower levels of conflict were obtained between invasive plant strategies and the habitat for biodiversity supporting service. The added value of the proposed framework in the context of landscape management and planning is discussed in perspective of anticipation of conflicts, mitigation of negative impacts, and potentiation of positive effects of plant invasions on ecosystems and their services.
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446 p.