897 resultados para Socio-ecological systems


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Ecological models written in a mathematical language L(M) or model language, with a given style or methodology can be considered as a text. It is possible to apply statistical linguistic laws and the experimental results demonstrate that the behaviour of a mathematical model is the same of any literary text of any natural language. A text has the following characteristics: (a) the variables, its transformed functions and parameters are the lexic units or LUN of ecological models; (b) the syllables are constituted by a LUN, or a chain of them, separated by operating or ordering LUNs; (c) the flow equations are words; and (d) the distribution of words (LUM and CLUN) according to their lengths is based on a Poisson distribution, the Chebanov's law. It is founded on Vakar's formula, that is calculated likewise the linguistic entropy for L(M). We will apply these ideas over practical examples using MARIOLA model. In this paper it will be studied the problem of the lengths of the simple lexic units composed lexic units and words of text models, expressing these lengths in number of the primitive symbols, and syllables. The use of these linguistic laws renders it possible to indicate the degree of information given by an ecological model.

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Seascape ecology provides a useful framework from which to understand the processes governing spatial variability in ecological patterns. Seascape context, or the composition and pattern of habitat surrounding a focal patch, has the potential to impact resource availability, predator-prey interactions, and connectivity with other habitats. For my dissertation research, I combined a variety of approaches to examine how habitat quality for fishes is influenced by a diverse range of seascape factors in sub-tropical, back-reef ecosystems. In the first part of my dissertation, I examined how seascape context can affect reef fish communities on an experimental array of artificial reefs created in various seascape contexts in Abaco, Bahamas. I found that the amount of seagrass at large spatial scales was an important predictor of community assembly on these reefs. Additionally, seascape context had differing effects on various aspects of habitat quality for the most common reef species, White grunt Haemulon plumierii. The amount of seagrass at large spatial scales had positive effects on fish abundance and secondary production, but not on metrics of condition and growth. The second part of my dissertation focused on how foraging conditions for fish varied across a linear seascape gradient in the Loxahatchee River estuary in Florida, USA. Gray snapper, Lutjanus griseus, traded food quality for quantity along this estuarine gradient, maintaining similar growth rates and condition among sites. Additional work focused on identifying major energy flow pathways to two consumers in oyster-reef food webs in the Loxahatchee. Algal and microphytobenthos resource pools supported most of the production to these consumers, and body size for one of the consumers mediated food web linkages with surrounding mangrove habitats. All of these studies examined a different facet of the importance of seascape context in governing ecological processes occurring in focal habitats and underscore the role of connectivity among habitats in back-reef systems. The results suggest that management approaches consider the surrounding seascape when prioritizing areas for conservation or attempting to understand the impacts of seascape change on focal habitat patches. For this reason, spatially-based management approaches are recommended to most effectively manage back-reef systems.

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Introduction: Food availability and access are strongly affected by seasonality in Ethiopia. However, there are little data on seasonal variation in Infant and Young Child Feeding (IYCF) practices and malnutrition among 6-23 months old children in different agro-ecological zones of rural Ethiopia. Methods: Socio-demographic, anthropometry and IYCF indicators were assessed in post- and pre-harvest seasons among children aged 6–23 months of age randomly selected from rural villages of lowland and midland agro-ecological zones. Results: Child stunting and underweight increased from prevalence of 39.8% and 26.9% in post-harvest to 46.0% and 31.8% in pre-harvest seasons, respectively. The biggest increase in prevalence of stunting and underweight between post- and pre-harvest seasons was noted in the midland zone. Wasting decreased from 11.6% post-harvest to 8.5% pre-harvest, with the biggest decline recorded in the lowland zone. Minimum meal frequency, minimum acceptable diet and poor dietary diversity increased considerably in pre-harvest compared to post-harvest season in the lowland zone. Feeding practices and maternal age were predictors of wasting, while women’s dietary diversity and children age was predictor of child dietary diversity in both seasons. Conclusion: There is seasonal variation in malnutrition and IYCF practices among children 6-23 months of age with more pronounced effect in midland agro-ecological zone. A major contributing factor for child malnutrition may be poor feeding practices. Health information strategies focused on both IYCF practices and dietary diversity of mothers could be a sensible approach to reduce the burden of child malnutrition in rural Ethiopia.

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Food security is a global and regional concern of rapidly increasing consequence. It is at risk of inattention because of competing crises, because of its theoretical amenability to previously effective, if temporary measures, most impressively with the so-called Green Revolution and because of the recourse to the global trade paradigm as a putative solution. We identify some missing or under-emphasised dimensions in this analysis, with particular reference to Asia, which in spite of recent growth-or in some cases because of it-faces particularly daunting food problems. Greater emphasis needs to be given to population size and distribution through more concerted family planning and enlightened migration policy; public policy to retain or encourage plant-based diets; integration of food, health and environmental approaches to create resilient regional food systems; and the incorporation of food into the broader human security agenda. While regional organisations, along with their NGO counterparts and nation states, have an over-arching role to strategise in this way, substantial progress could still be made at the community and household levels, especially with current technologies which can marshal their collective and coherent action.

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The evolution of a secondary terrestrial lifestyle in diving beetles (Coleoptera: Dytiscidae) has never been analysed in a phylogenetic framework before. Here we study Terradessus caecus Watts, a terrestrial species of the subfamily Hydroporinae endemic to Australia. We infer its phylogenetic placement using Bayesian inference and maximum-likelihood methods based on a multilocus molecular dataset. We also investigate the divergence time estimates of this lineage using a Bayesian relaxed clock approach. Finally, we infer ancestral ecological preferences using a likelihood approach. We recover T. caecus nested in the genus Paroster Sharp with strong support. Therefore, we establish a synonymy for both species of Terradessus with Paroster: Paroster caecus (Watts) n.comb. and Paroster anophthalmus (Brancucci & Monteith) n.comb. Paroster is an endemic Australian genus that has a remarkable number of subterranean species in underground aquifers with highly derived morphologies. Our results highlight one of the most remarkable radiations of aquatic beetles with independent ecological pathways likely linked to palaeoclimatic disruptions in the Neogene. Paroster caecus (Watts) n.comb. originated from a mid-Miocene split following the onset of an aridification episode that has been ongoing to the present day. The deep changes in ecological communities in association with the drying-out of palaeodrainage systems might have pushed this lineage to colonize a new niche in terrestrial habitats.

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The assessment of water quality has changed markedly worldwide over the last years, especially in Europe due to the implementation of the Water Framework Directive. Fish was considered a key-element in this context and several fish-based multi-metric indices have been proposed. In this study, we propose a multi-metric index, the Estuarine Fish Assessment Index (EFAI), developed for Portuguese estuaries, designed for the overall assessment of transitional waters, which could also be applied at the water body level within an estuary. The EFAI integrates seven metrics: species richness, percentage of marine migrants, number of species and abundance of estuarine resident species, number of species and abundance of piscivorous species, status of diadromous species, status of introduced species and status of disturbance sensitive species. Fish sampling surveys were conducted in 2006, 2009 and 2010, using beam trawl, in 13 estuarine systems along the Portuguese coast. Most of the metrics presented a high variability among the transitional systems surveyed. According to the EFAI values, Portuguese estuaries presented a "Good" water quality status (except the Douro in a particular year). The assessments in different years were generally concordant, with a few exceptions. The relationship between the EFAI and the Anthropogenic Pressure Index (API) was not significant, but a negative and significant correlation was registered between the EFAI and the expert judgement pressure index, at both estuary and water body level. The ordination analysis performed to evaluate similarities among North-East Atlantic Geographical Intercalibration Group (NEAGIG) fish-based indices put in evidence four main groups: the French index, since it is substantially different from all the other indices (uses only four metrics based on densities); indices from Ireland, United Kingdom and Spain (Asturias and Cantabria); the Dutch and German indices; and the indices of Belgium. Portugal and Spain (Basque country). The need for detailed studies, including comparative approaches, on several aspects of these assessment tools, especially in what regards their response to anthropogenic pressures was stressed. (C) 2011 Elsevier Ltd. All rights reserved.

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The rise in population growth, as well as nutrient mining, has contributed to low agricultural productivity in Sub-Saharan Africa (SSA). A plethora of technologies to boost agricultural production have been developed but the dissemination of these agricultural innovations and subsequent uptake by smallholder farmers has remained a challenge. Scientists and philanthropists have adopted the Integrated Soil Fertility Management (ISFM) paradigm as a means to promote sustainable intensification of African farming systems. This comparative study aimed: 1) To assess the efficacy of Agricultural Knowledge and Innovation Systems (AKIS) in East (Kenya) and West (Ghana) Africa in the communication and dissemination of ISFM (Study I); 2) To investigate how specifically soil quality, and more broadly socio-economic status and institutional factors, influence farmer adoption of ISFM (Study II); and 3) To assess the effect of ISFM on maize yield and total household income of smallholder farmers (Study III). To address these aims, a mixed methodology approach was employed for study I. AKIS actors were subjected to social network analysis methods and in-depth interviews. Structured questionnaires were administered to 285 farming households in Tamale and 300 households in Kakamega selected using a stratified random sampling approach. There was a positive relationship between complete ISFM awareness among farmers and weak knowledge ties to both formal and informal actors at both research locations. The Kakamega AKIS revealed a relationship between complete ISFM awareness among farmers and them having strong knowledge ties to formal actors implying that further integration of formal actors with farmers’ local knowledge is crucial for the agricultural development progress. The structured questionnaire was also utilized to answer the query pertaining to study II. Soil samples (0-20 cm depth) were drawn from 322 (Tamale, Ghana) and 459 (Kakamega, Kenya) maize plots and analysed non-destructively for various soil fertility indicators. Ordinal regression modeling was applied to assess the cumulative adoption of ISFM. According to model estimates, soil carbon seemed to preclude farmers from intensifying input use in Tamale, whereas in Kakamega it spurred complete adoption. This varied response by farmers to soil quality conditions is multifaceted. From the Tamale perspective, it is consistent with farmers’ tendency to judiciously allocate scarce resources. Viewed from the Kakamega perspective, it points to a need for farmers here to intensify agricultural production in order to foster food security. In Kakamega, farmers with more acidic soils were more likely to adopt ISFM. Other household and farm-level factors necessary for ISFM adoption included off-farm income, livestock ownership, farmer associations, and market inter-linkages. Finally, in study III a counterfactual model was used to calculate the difference in outcomes (yield and household income) of the treatment (ISFM adoption) in order to estimate causal effects of ISFM adoption. Adoption of ISFM contributed to a yield increase of 16% in both Tamale and Kakamega. The innovation affected total household income only in Tamale, where ISFM adopters had an income gain of 20%. This may be attributable to the different policy contexts under which the two sets of farmers operate. The main recommendations underscored the need to: (1) improve the functioning of AKIS, (2) enhance farmer access to hybrid maize seed and credit, (3) and conduct additional multi-locational studies as farmers operate under varying contexts.

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As the world population and food production demands rise, keeping agricultural soils and landscapes healthy and productive are of paramount importance to sustaining local and global food security and the flow of ecosystem services to society. The global population, expected to reach 9.7 billion people by 2050, will put additional pressure on the available land area and resources for agricultural production. Sustainable production intensification for food security is a major challenge to both industrialized and developing countries. The paper focuses on the results from long-term multi-factorial experiments involving tillage practices, crop rotations and fertilization to study the interactions amongst the treatments in the context of sustainable production intensification. The paper discusses the results in relation to reported performance of crops and soil quality in Conservation Agriculture systems that are based on no or minimum soil disturbance (no-till seeding and weeding), maintenance of soil mulch cover with crop biomass and cover crops, and diversified cropping systems involving annuals and perennials. Conservation Agriculture also emphasizes the necessity of an agro-ecosystems approach to the management of agricultural land for sustainable production intensification, as well as to the site-specificity of agricultural production. Arguments in favor of avoiding the use of soil tillage are discussed together with agro-ecological principles for sustainable intensification of agriculture. More interdisciplinary systems research is required to support the transformation of agriculture from the conventional tillage agriculture to a more sustainable agriculture based on the principles and practices of Conservation Agriculture, along with other complementary practices of integrated crop, nutrient, water, pest, energy and farm power management.

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The Charter of European Planning 2013 presents a Vision for the future of European cities and regions, highlighting the sustainability of cities and the preservation of urban ecosystems, integrating the man-made environment with the natural ecosystems and contribute to the well-being and quality of life of their inhabitants and other stakeholders. Thus, urban public policies are crucial to the improvement of the landscape ecological system, achievable by city planning and design. The paper aims to analyse if public urban policies in Portugal have been integrating strategies and/or guidelines to enhance the ecological system of the landscape. Then, which new perspectives are possible, framed by the recently approved law Bases of Public Policy of Soils, Land Management and Urban Planning (2014). This new law, in contrast with the previous ones, don’t allow reserving land to urbanize, in municipal master plans. Moreover, it is possible to revert land classified for urban purposes in those plans into rustic soils (when it is not yet infra-structured or built). It allows creating new planning and design dynamics, convert several areas and including them in the urban ecological structure, essential to the enhancement of landscape ecological system. This is a filed of work where landscape architecture has huge responsibilities, by associating and harmonize man-made environment with natural systems, enlightening sustainability consistent with conservation and improvement of Nature while contributing to the well-being and quality of life of Man. A sustainability that is ethical, aesthetic, ecological and cultural. The study is supported by a case study – the city of Évora. The ultimate goal is to propose measures to promote larger and better integration of ecological component in urban public policies, framed by the new territorial management law, taking into account and highlighting the specificities of the landscape system – Man and Nature – at the local level.

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Adherent deposits are very aggressive towards ancient heritage paintings since they affect the varnish and the painting’s layers, sometimes reaching the preparative layers. The biggest problem to the restorer is their removal without affecting the patina, the transparent varnish (well preserved) and fine colour glazes made during painting. Therefore, their removal requires preliminary cleaning tests that allow the optimization of the cleaning system composition that is going to be used. The study was focused on organic natural systems, as colourless supernatants, some of them used during ages, but insufficiently studied. The paper presents an evaluation of the effectiveness of cleaning varnished icons of the nineteenth century, with complex conservation cases using supernatants derived from aqueous dispersions extracted from vegetables and dry indigenous herbal infusions. Best results, after six consecutive cleaning steps, on tempera old icon was obtained for a mixture made of mature white onion juice + extract of Soapwort flowers + corn silk tea + acacia tea. As a best result after just one cleaning step was obtained for a quaternary mixture composed from mature white onion juice + mature carrot juice + corn silk tea + aqueous extract of Soapwort flowers.

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This paper presents the results of a research on the way which shows the role of the farmer women to contribute to overcome the life hindrances in the Amazonian agroforest environment, for food safety and familiar income. The sample was the women of the Associação de Produtores Alternativos - APA, Ouro Preto do Oeste, Rondônia, Brazil. Questionnaires were applied to 50 women of this community, in 2004/2005, with additional interviews in 2006, taking into account their role in the farms, and their several invisible activities. The role of APA?s women was compared to that of other Amazonian women, like rubber tappers and riverine people. The APA?s women perform tasks as field manpower - 78.0% of them, making decisions about what to plant - 18.0%, harvest destination - 32.0%, which animals to raise -14.0% and animal products destination -34.0%. Traditionally, in rural zone, the women with their children play a role as non-paid manpower, getting some monetary income with occasional commercialization of on-farm processed products as cheese, pickles, jellies and fruit liqueurs. They are responsible for the cultures practiced around the house. All these Amazonian women edaphoclimatic conditions, greatly contributing to the biodiversity, conservation, and to ecological, social and economic stability.are guardians, perpetuators and disseminators of a rich germplasm adapted to local.