981 resultados para local populations


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The rapid expansion of the mineral and metal mining sector in the past decade was accompanied by an increase in social conflicts. What are the impacts of large-scale mining operations? What are the strategies used by transnational corporations to gain access to underground resources and legitimize their activities? And how do local and indigenous communities confronted with mining react to, negotiate with and resist these activities? This book covers 13 case studies of copper, gold, uranium and other mining operations, situated in Latin America, Africa, Asia, Australia and Switzerland. With an extensive introduction to the subject and a systematic comparison across mining operations in different phases of development and social contexts, it serves as a primer and reference book for activists, students and researchers alike.

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The benefits of protection of a small (4.3 km(2)) marine protected area (MPA) for Senegalese sole, Solea senegalensis, were investigated through experimental fishing trials and long-term (up to 293days) passive acoustic telemetry. A total of 106 trammel net sets were carried out between 2007 and 2011. Significant differences in abundance and biomass of sole between bottom types/depths (sandy bottoms between 12 and 20m deep vs muddy bottoms between 35 and 45m deep) were found, but no significant differences were attributable to the implementation of the no-take area. Passive acoustic telemetry revealed that most Senegalese sole spent a large part of their time between first and last detections (average residency index=69%) inside a relatively small area (average 95%=1.2km(2)), during which they preferred sandy bottoms, the most common habitat inside the MPA. Results also demonstrated that Senegalese sole do regular excursions beyond reserve boundaries, eventually emigrating from the MPA. The results suggest that small coastal MPAs providing adequate habitat may protect individuals of this species while allowing for moderate levels of adult spillover to neighbouring areas.

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1. Chrysophtharta bimaculata is a native chrysomelid species that can cause chronic defoliation of plantation and regrowth Eucalyptus forests in Tasmania, Australia. Knowledge of the dispersion pattern of C. bimaculata was needed in order to assess the efficiency of an integrated pest management (IPM) programme currently used for its control. 2. Using data from yellow flight traps, local populations of C. bimaculata adults were monitored over a season at spatial scales relevant to commercial forestry: within a 50-ha operational management unit (a forestry 'coupe') and between coupes. In addition, oviposition was monitored over a season at a subset of the between-coupe sites. 3. Dispersion indices (Taylor's Power Law and Iwao's Mean Crowding regression method) demonstrated that C. bimaculata adults were spatially aggregated within and between coupes, although the number of egg-batches laid at the between-coupe scale was uniform. Spatial autocorrelation analysis showed that trap-catches at the within-coupe level were similar (positively autocorrelated) to a radius distance of approximately 110 m, and then dissimilar (negatively autocorrelated) at approximately 250 m. At the between-coupe scale, no repeatable spatial autocorrelation patterns were observed. 4. For any individual site, rapid changes in beetle density were observed to be associated with loosely aggregated flights of beetles into and out of that site. Peak adult catches (> the weekly mean plus standard deviation trap-catch) for a site occurred for a period of 2.0 +/- 0.22 weeks at a time (n = 37), with normally only one or two peaks per site per season. Peak oviposition events for a site occurred on average 1.4 +/- 0.11 times per season and lasted 1.5 +/- 0.12 weeks. 5. Analysis of an extensive data set (n = 417) demonstrated that adult abundance at a site was positively correlated with egg density, but negatively correlated with tree damage (caused by conspecifics) and the presence of conspecific larvae. There was no relationship between adult abundance and a visual estimate of the amount of young foliage on trees. 6. Adults of C. bimaculata are show n to occur in relatively small, mobile aggregations. This means that pest surveys must be both regular (less than 2 weeks apart) and intensive (with sampling points no more than 150 m apart) if beetle populations are to be monitored with confidence. Further refinement of the current IPM strategy must recognize the problems posed by this temporal and spatial patchiness, particularly with regard to the use of biological insecticides, such as Bacillus thuringiensis, for which only a very short operational window exists.

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Considering that vernacular architecture may bear important lessons on hazard mitigation, this chapter focuses on the European Mediterranean countries and studies traditional seismic-resistant architectural elements and techniques that local populations developed to prevent or repair earthquake damage. This area was selected as a case study because, as a highly seismic region, it has suffered the effect of many earthquakes along the history and, thus, regions within this area are prone to have developed a Local Seismic Culture. After reviewing seismic resistant construction concepts, a wide range of traditional construction solutions that, in many cases, have shown to improve the seismic performance of vernacular constructions of these regions is presented, as a contribution to the general overview of retrofitting building systems provided in this book. The main motivation is that most of these techniques can be successfully applied to preserve and to retrofit surviving examples without prejudice for their identity.

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Genetic diversity among three field populations of Lutzomyia longipalpis in Colombia was studied using isozyme analysis. Study sites were as much as 598 km apart and included populations separated by the eastern Cordillera of the Andes. Genetic variability among populations, estimated by heterozygosity, was within values typical for insects in general (8.1%). Heterozygosity for field populations were compared with a laboratory colony from Colombia (Melgar colony) and were only slightly lower. These results suggest that establishment and long term maintenance of the Melgar colony has had little effect on the level of isozyme variability it carries. Genetic divergences between populations was evaluated using estimates of genetic distance. Genetic divergence among the three field populations was low (D=0.021), suggesting they represent local populations within a single species. Genetic distance between field populations and the Melgar colony was also low (D=0.016), suggesting that this colony population does not depart significantly from natural populations. Finally, comparisons were made between Colombian populations and colonies from Brazil and Costa Rica. Genetic distance values were high between Colombian and both Brazil and Costa Rica colony populations (D=0.199 and 0.098 respectively) providing additional support for our earlier report that populations from the three countries represent distinct species

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The Local Tobacco Control Profiles for England provides a snapshot of the extent of tobacco use, tobacco related harm, and measures being taken to reduce this harm at a local level. These profiles have been designed to help local government and health services to assess the effect of tobacco use on their local populations. They will inform commissioning and planning decisions to tackle tobacco use and improve the health of local communities. The tool allows you to compare your local authority against other local authorities in the region and benchmark your local authority against the England average.

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A variety of behavioural traits have substantial effects on the gene dynamics and genetic structure of local populations. The mating system is a plastic trait that varies with environmental conditions in the domestic cat (Felis catus) allowing an intraspecific comparison of the impact of this feature on genetic characteristics of the population. To assess the potential effect of the heterogenity of males' contribution to the next generation on variance effective size, we applied the ecological approach of Nunney & Elam (1994) based upon a demographic and behavioural study, and the genetic 'temporal methods' of Waples (1989) and Berthier et al. (2002) using microsatellite markers. The two cat populations studied were nearly closed, similar in size and survival parameters, but differed in their mating system. Immigration appeared extremely restricted in both cases due to environmental and social constraints. As expected, the ratio of effective size to census number (Ne/N) was higher in the promiscuous cat population (harmonic mean = 42%) than in the polygynous one (33%), when Ne was calculated from the ecological method. Only the genetic results based on Waples' estimator were consistent with the ecological results, but failed to evidence an effect of the mating system. Results based on the estimation of Berthier et al. (2002) were extremely variable, with Ne sometimes exceeding census size. Such low reliability in the genetic results should retain attention for conservation purposes.

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A recent study suggests that sex-specific dispersal rates can be quantitatively estimated on the basis of sex- and state-specific (pre- vs. postdispersal) F-statistics. In the present paper, we extend this approach to account for the hierarchical structure of natural populations, and we validate it through individual-based simulations. The model is applied to an empirical data set consisting of 536 individuals (males, females, and predispersal juveniles) of greater white-toothed shrews (Crocidura russula), sampled according to a hierarchical design and typed for seven autosomal microsatellite loci. From this dataset, dispersal is significantly female biased at the local scale (breeding-group level), but not at the larger scale (among local populations). We argue that selective pressures on dispersal are likely to depend on the spatial scale considered, and that short-distance dispersal should mainly respond to kin interactions (inbreeding or kin competition avoidance), which exert differential pressure on males and females.

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Reciprocal selection between interacting species is a major driver of biodiversity at both the genetic and the species level. This reciprocal selection, or coevolution, has led to the diversification of two highly diverse and abundant groups of organisms, flowering plants and their insect herbivores. In heterogeneous environments, the outcome of coevolved species interactions is influenced by the surrounding community and/or the abiotic environment. The process of adaptation allows species to adapt to their local conditions and to local populations of interacting species. However, adaptation can be disrupted or slowed down by an absence of genetic variation or by increased inbreeding, together with the following inbreeding depression, both of which are common in small and isolated populations that occur in fragmented environments. I studied the interaction between a long-lived plant Vincetoxicum hirundinaria and its specialist herbivore Abrostola asclepiadis in the southwestern archipelago of Finland. I focused on mutual local adaptation of plants and herbivores, which is a demonstration of reciprocal selection between species, a prerequisite for coevolution. I then proceeded to investigate the processes that could potentially hamper local adaptation, or species interaction in general, when the population size is small. I did this by examining how inbreeding of both plants and herbivores affects traits that are important for interaction, as well as among-population variation in the effects of inbreeding. In addition to bi-parental inbreeding, in plants inbreeding can arise from self-fertilization which has important implications for mating system evolution. I found that local adaptation of the plant to its herbivores varied among populations. Local adaptation of the herbivore varied among populations and years, being weaker in populations that were most connected. Inbreeding caused inbreeding depression in both plants and herbivores. In some populations inbreeding depression in herbivore biomass was stronger in herbivores feeding on inbred plants than in those feeding on outbred ones. For plants it was the other way around: inbreeding depression in anti-herbivore resistance decreased when the herbivores were inbred. Underlying some of the among-population variation in the effects of inbreeding is variation in plant phenolic compounds. However, variation in the modification of phenolic compounds in the digestive tract of the herbivore did not explain the inbreeding depression in herbivore biomass. Finally, adult herbivores had a preference for outbred host plants for egg deposition, and herbivore inbreeding had a positive effect on egg survival when the eggs were exposed to predators and parasitoids. These results suggest that plants and herbivores indeed exert reciprocal selection, as demonstrated by the significant local adaptation of V. hirundinaria and A. asclepiadis to one another. The most significant cause of disruption of the local adaptation of herbivore populations was population connectivity, and thus probably gene flow. In plants local adaptation tended to increase with increasing genetic variation. Whether or not inbreeding depression occurred varied according to the life-history stage of the herbivore and/or the plant trait in question. In addition, the effects of inbreeding strongly depended on the population. Taken together, inbreeding modified plant-herbivore interactions at several different levels, and can thus affect the strength of reciprocal selection between species. Thus inbreeding has the potential to affect the outcome of coevolution.

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Notre thèse étudie les liens entre les « redevances forestières annuelles » (RFA) et le « développement local » dans deux communes du Cameroun. Ce travail anthropologique s’inscrit dans le débat qui se fait à l’échelle internationale relativement au rôle et au devenir des populations locales dans la gestion des ressources naturelles. Dans le passé, la gestion des redevances forestières annuelles (RFA) a été, dans les pays d’Afrique centrale et au Cameroun en particulier, sous la seule responsabilité de l’État central. Une telle politique n’offrait pas la garantie nécessaire à l’utilisation durable de ces ressources qui sont indispensables à la vie des populations villageoises riveraines et à l’équilibre de l’environnement. Profitant de la crise des années 1980 et 1990 en Afrique, le FMI et la Banque mondiale ont exercé une pression sur les États africains pour qu’ils revoient, en conformité avec la Conférence de Rio (1992), leurs politiques en matière de gestion et de conservation des ressources forestières. Dans le bassin du Congo, le Cameroun a été le tout premier pays à réviser, en 1994, ses lois forestières par le biais d’une décentralisation de la fiscalité forestière : les taxes perçues furent réparties entre l’État, les collectivités territoriales décentralisées et les populations villageoises riveraines. Les fonds transférés aux communes et aux populations riveraines devaient servir au développement local en contribuant notamment à l’amélioration des conditions générales de vie des populations à travers la réalisation d’œuvres sociales, l’adduction d’eau, la construction et l’entretien des routes, des écoles, des cases de santé, etc. Dans les faits, l’impact de la fiscalité forestière décentralisée reste à ce jour encore peu visible sur la dynamique du développement local des communes. Notre projet de recherche doctorale prend place dans le domaine d’une anthropologie du développement centrée sur l’étude des solutions que les populations locales apportent aux problèmes auxquels elles sont confrontées dans leur vie de tous les jours. L’analyse des impacts que les politiques de développement économique exercent sur les populations villageoises d’Afrique est ici à l’avant-plan, pas seulement au sens d’une critique des politiques étatiques en matière d’exploitation forestière, mais aussi au sens d’une meilleure compréhension des conditions de mise en œuvre de ces politiques et de l’impact de celles-ci sur les populations villageoises, tant sur le plan des avantages financiers directs que des transformations écologiques que les activités forestières introduisent dans les pratiques agricoles des villageois. Sur le plan méthodologique, il faut noter que ce fut très difficile d’obtenir les informations nécessaires, notre sujet d’étude se révélant être très sensible quant à sa portée politique. Nous avons néanmoins pu recueillir un solide ensemble de données par le biais d’une démarche de proximité de type qualitatif qui a été conduite dans deux communes forestières qui représentent deux réalités différentes en matière de gestion des RFA. La collecte des données a été faite, de manière intensive, dans sept villages qui répondaient à nos critères : nous avons ainsi pu étudier, de manière approfondie, la situation des groupes sociaux les plus défavorisés qui sont exclus dans le partage des revenus forestiers. Pour construire notre cadre théorique, nous avons combiné des éléments empruntés aux théories environnementales, à l’anthropologie économique et à l’analyse des modes de gestion. Il faut noter, par ailleurs, que l’anthropologue n’est ni un aménagiste, ni un environnementaliste, ni un spécialiste des études managériales. Nous avons conduit notre étude comparative dans les communes concernées en nous fixant pour objectif de comprendre les mécanismes de gestion des RFA mis en place par les leaders locaux et d’évaluer leur impact sur l’amélioration des conditions de vie des populations villageoises et sur leur écosystème. Notre préoccupation était de savoir si les RFA constituent des vecteurs de développement socioéconomique pour des populations vivant dans et de la forêt.

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We tested the general predictions of increased use of nest boxes and positive trends in local populations of Common Goldeneye (Bucephala clangula) and Bufflehead (Bucephala albeola) following the large-scale provision of nest boxes in a study area of central Alberta over a 16-year period. Nest boxes were rapidly occupied, primarily by Common Goldeneye and Bufflehead, but also by European Starling (Sturnus vulgaris). After 5 years of deployment, occupancy of large boxes by Common Goldeneye was 82% to 90% and occupancy of small boxes by Bufflehead was 37% to 58%. Based on a single-stage cluster design, experimental closure of nest boxes resulted in significant reductions in numbers of broods and brood sizes produced by Common Goldeneye and Bufflehead. Occurrence and densities of Common Goldeneye and Bufflehead increased significantly across years following nest box deployment at the local scale, but not at the larger regional scale. Provision of nest boxes may represent a viable strategy for increasing breeding populations of these two waterfowl species on landscapes where large trees and natural cavities are uncommon but wetland density is high.

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Considerable attention has been given to the impact of climate change on avian populations over the last decade. In this paper we examine two issues with respect to coastal bird populations in the UK: (1) is there any evidence that current populations are declining due to climate change, and (2) how might we predict the response of populations in the future? We review the cause of population decline in two species associated with saltmarsh habitats. The abundance of Common Redshank Tringa totanus breeding on saltmarsh declined by about 23% between the mid-1980s and mid-1990s, but the decline appears to have been caused by an increase in grazing pressure. The number of Twite Carduelis flavirostris wintering on the coast of East Anglia has declined dramatically over recent decades; there is evidence linking this decline with habitat loss but a causal role for climate change is unclear. These examples illustrate that climate change could be having population-level impacts now, but also show that it is dangerous to become too narrowly focused on single issues affecting coastal birds. Making predictions about how populations might respond to future climate change depends on an adequate understanding of important ecological processes at an appropriate spatial scale. We illustrate this with recent work conducted on the Icelandic population of Black-tailed Godwits Limosa limosa islandica that shows large-scale regulatory processes. Most predictive models to date have focused on local populations (single estuary or a group of neighbouring estuaries). We discuss the role such models might play in risk assessment, and the need for them to be linked to larger-scale ecological processes. We argue that future work needs to focus on spatial scale issues and on linking physical models of coastal environments with important ecological processes.

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Considerable attention has been given to the impact of climate change on avian populations over the last decade. In this paper we examine two issues with respect to coastal bird populations in the UK: (1) is there any evidence that current populations are declining due to climate change, and (2) how might we predict the response of populations in the future? We review the cause of population decline in two species associated with saltmarsh habitats. The abundance of Common Redshank Tringa totanus breeding on saltmarsh declined by about 23% between the mid-1980s and mid-1990s, but the decline appears to have been caused by an increase in grazing pressure. The number of Twite Carduelis flavirostris wintering on the coast of East Anglia has declined dramatically over recent decades; there is evidence linking this decline with habitat loss but a causal role for climate change is unclear. These examples illustrate that climate change could be having population-level impacts now, but also show that it is dangerous to become too narrowly focused on single issues affecting coastal birds. Making predictions about how populations might respond to future climate change depends on an adequate understanding of important ecological processes at an appropriate spatial scale. We illustrate this with recent work conducted on the Icelandic population of Black-tailed Godwits Limosa limosa islandica that shows large-scale regulatory processes. Most predictive models to date have focused on local populations (single estuary or a group of neighbouring estuaries). We discuss the role such models might play in risk assessment, and the need for them to be linked to larger-scale ecological processes. We argue that future work needs to focus on spatial scale issues and on linking physical models of coastal environments with important ecological processes.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)