893 resultados para endangered
Resumo:
In the Tajik National Park (TNP) - a high-altitude area of nearly 26,000 km2 in Central Asia - past and present human activities visibly contrast with standard conservation requirements for protected areas worldwide. This paper focuses on resource management, and highlights three major processes that threaten both the sustainable use of natural resources and the preservation of nature per se: (i) intensified use of biomass as a fuel resource, (ii) inappropriate pasture management, and (iii) increased pressure on endangered wildlife. From analysis of these processes - their historical background, root causes, trends and interrelationships - options and needs to improve park management are proposed and discussed.
Resumo:
Between 1966 and 2003, the Golden-winged Warbler (Vermivora chrysoptera) experienced declines of 3.4% per year in large parts of the breeding range and has been identified by Partners in Flight as one of 28 land birds requiring expedient action to prevent its continued decline. It is currently being considered for listing under the Endangered Species Act. A major step in advancing our understanding of the status and habitat preferences of Golden-winged Warbler populations in the Upper Midwest was initiated by the publication of new predictive spatially explicit Golden-winged Warbler habitat models for the northern Midwest. Here, I use original data on observed Golden-winged Warbler abundances in Wisconsin and Minnesota to compare two population models: the hierarchical spatial count (HSC) model with the Habitat Suitability Index (HSI) model. I assessed how well the field data compared to the model predictions and found that within Wisconsin, the HSC model performed slightly better than the HSI model whereas both models performed relatively equally in Minnesota. For the HSC model, I found a 10% error of commission in Wisconsin and a 24.2% error of commission for Minnesota. Similarly, the HSI model has a 23% error of commission in Minnesota; in Wisconsin due to limited areas where the HSI model predicted absences, there was incomplete data and I was unable to determine the error of commission for the HSI model. These are sites where the model predicted presences and the Golden-winged Warbler did not occur. To compare predicted abundance from the two models, a 3x3 contingency table was used. I found that when overlapped, the models do not complement one another in identifying Golden-winged Warbler presences. To calculate discrepancy between the models, the error of commission shows that the HSI model has only a 6.8% chance of correctly classifying absences in the HSC model. The HSC model has only 3.3% chance of correctly classifying absences in the HSI model. These findings highlight the importance of grasses for nesting, shrubs used for cover and foraging, and trees for song perches and foraging as key habitat characteristics for breeding territory occupancy by singing males.
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BACKGROUND: Tissues are endowed with protective mechanisms to counteract chronic ischemia. Previous studies have demonstrated that endogenous heme oxygenase (HO)-1 may protect parenchymal tissue from inflammation- and reoxygenation-induced injury. Nothing is known, however, on whether endogenous HO-1 also plays a role in chronic ischemia to protect from development of tissue necrosis. The aim of this study is, therefore, to evaluate in vivo whether endogenous HO-1 exerts protection on chronically ischemic musculocutaneous tissue, and whether this protection is mediated by an attenuation of the microcirculatory dysfunction. MATERIALS AND METHODS: In C57BL/6-mice, a chronically ischemic flap was elevated and fixed into a dorsal skinfold chamber. In a second group, tin-protoporphyrin-IX was administrated to competitively block the action of HO-1. Animals without flap elevation served as controls. With the use of intravital fluorescence microscopy, microcirculation, apoptotic cell death, and tissue necrosis were analyzed over a 10-day observation period. The time course of HO-1 expression was determined by Western blotting. RESULTS: Chronic ischemia induced an increase of HO-1 expression, particularly at day 1 and 3. This was associated with arteriolar dilation and hyperperfusion, which was capable of maintaining an adequate capillary perfusion density in the critically perfused central part of the flap, demarcating the distal necrosis. Inhibition of endogenous HO-1 by tin-protoporphyrin-IX completely abrogated arteriolar dilation (44.6 +/- 6.2 microm versus untreated flaps: 71.3 +/- 7.3 microm; P < 0.05) and hyperperfusion (3.13 +/- 1.29 nL/s versus 8.55 +/- 3.56 nL/s; P < 0.05). This resulted in a dramatic decrease of functional capillary density (16 +/- 16 cm/cm(2)versus 84 +/- 31 cm/cm(2); P < 0.05) and a significant increase of apoptotic cell death (585 +/- 51 cells/mm(2)versus 365 +/- 53 cells/mm(2); P < 0.05), and tissue necrosis (73% +/- 5% versus 51% +/- 5%; P < 0.001). CONCLUSION: Thus, our results suggest that chronic ischemia-induced endogenous HO-1 protects ischemically endangered tissue, probably by the vasodilatory action of the HO-1-associated carbon monoxide.
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The purpose of this research is to assess public values and perceptions concerning industrial heritage in the Keweenaw by studying visitors at an endangered mining site tour. This research presents and analyzes feedback collected directly from participants in the Cliff Mine (Michigan) archaeological field school public tour surveys in June 2011, gathers semi-structured interview data from survey participants and local experts, and synthesizes and collates both survey and interview data. As those who study heritage site visitors have found, in all outreach there is a necessity for deeper understanding of visitors for the outreach to be effective. An appropriate metric for collecting public values and opinions was created and used at the Cliff Mine archaeological field school public tours. To accomplish research goals, an opinion survey was created to collect demographic information and qualitative feedback from visitors at the Cliff Mine field school. The survey, a pre-tour and post-tour question list, found that all visitors who filled out a survey supported preservation and most were adults over 46 years of age. Most visitors were white-collar professionals, identified as local residents, and found out about the tour through the newspaper. Interview questions were constructed to supplement and expand on the visitor survey results. In addition, local experts involved in Keweenaw heritage were interviewed. All interviewees supported heritage preservation but often had conflicting views when activities such as mineral collecting were factored into the preservation question. By analyzing responses to the survey and interviews, improvements to outreach efforts at the Cliff Mine are recommended. Future research should further explore perceptions of social class and identity, and should seek out stakeholders not contacted through this research, in order to improve outreach and include all community groups.
Resumo:
Blood perfusion to the femoral head might be endangered during the surgical approach or the preparation of the femoral head or both in hip resurfacing arthroplasty. The contribution of the intramedullary blood supply to the femoral head in osteoarthritis is questionable. Therefore, the contribution of the extraosseous blood supply to osteoarthritic femoral heads was measured intraoperatively to question if there is measurable blood flow between the epiphysis and metaphysis in osteoarthritic hips in case of extraosseus vessel damage. At defined points during surgery we acquired the epiphyseal and metaphyseal femoral head perfusion by high-energy laser Doppler flowmetry. Complete femoral neck osteotomy sparing the retinacular vessels to simulate intraosseous blood disruption showed unchanged epiphyseal blood flow compared to initial measurement after capsulotomy. The pulsatile signal disappeared after transection of the retinacular vessels. Based on these acute measurements, we conclude intramedullary blood vessels to the femoral head do not provide measurable blood supply to the epiphysis once the medial femoral circumflex artery or the retinacular vessels have been damaged. We recommend the use of a safe surgical approach for hip resurfacing and careful implantation of the femoral component to respect blood supply to the femoral head and neck region in hip resurfacing arthroplasty.
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The International Society for Mobile Youth Work (ISMO) and the National Council of Churches in Kenya (NCCK) organised from the 27th to 30th October 2003 at the Jumuia Conference and Country Home in Limuru/Kenya with 198 participants from 35 countries around the world the 8th International Symposium on Mobile Youth Work with special focus on children at risk (street children and youth) in Africa. For this purpose there were invited field workers, scientists and stakeholders engaged as advocates for the rights and well being of endangered children and youths. The participants came mainly from African countries and of course especially from Kenya, but also from Asia, Latin America and from Europe.
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This contribution addresses the substantial tax privilege for businesses introduced by the German Inheritance Tax Act 2009. Advocates of the vast or even entire tax exemption for businesses stress the potential damage of the inheritance tax on businesses, as those often lack liquidity to meet tax liability. This submission tackles this issue empirically based on data of the German Inheritance Tax Statistics and the SOEP. The results indicate that former German inheritance tax law has not endangered transferred businesses. Hence, there is no need for the tremendous tax privilege for businesses in current German inheritance tax law. An alternative flat inheritance tax without tax privileges, which meets revenue neutrality per tax class according to current tax law, provokes in some cases relative high tax loads which might trouble businesses.
Resumo:
This paper examines the impact of disastrous and ‘ordinary’ floods on human societies in what is now Austria. The focus is on urban areas and their neighbourhoods. Examining institutional sources such as accounts of the bridge masters, charters, statutes and official petitions, it can be shown that city communities were well acquainted with this permanent risk: in fact, an office was established for the restoration of bridges and the maintenance of water defences and large depots for timber and water pipes ensured that the reconstruction of bridges and the system of water supply could start immediately after the floods had subsided. Carpenters and similar groups gained 10 to 20 per cent of their income from the repair of bridges and other flood damage. The construction of houses in endangered zones was adapted in order to survive the worst case experiences. Thus, we may describe those communities living along the central European rivers as ‘cultures of flood management’. This special knowledge vanished, however, from the mid-nineteenth century onwards, when river regulations gave the people a false feeling of security.
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There is a lively debate on whether biodiversity conservation and agricultural production could be better reconciled by land sparing (strictly separating production fields and conservation areas) or by land sharing (combining both, agricultural production and biodiversity conservation on the same land). The debate originates from tropical countries, where agricultural land use continues to increase at the expense of natural ecosystems. But is it also relevant for Europe, where agriculture is withdrawing from marginal regions whilst farming of fertile lands continues to be intensified? Based on recent research on farmland biodiversity we conclude that the land sharing – land sparing dichotomy is too simplistic for Europe. Instead we differentiate between productive and marginal farmland. On productive farmland, semi-natural habitats are required to yield ecosystem services relevant for agriculture, to promote endangered farmland species which society wants to conserve even in intensively farmed regions, and to allow migration of non-farmland species through the agricultural matrix. On marginal farmland, high-nature value farming is a traditional way of land sharing, yielding high quality agricultural products and conserving specialized species. To conserve highly disturbance-sensitive species, there is a need for nature reserves. In conclusion, land sparing is not a viable olution for Europe in both productive and marginal farmland but because of different reasons in each type of farmland.
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Members of the Mycobacterium tuberculosis complex (MTBC) cause a serious disease with similar pathology, tuberculosis; in this review, bovine tuberculosis will be considered as disease caused by any member of the MTBC in bovids. Bovine tuberculosis is responsible for significant economic loss due to costly eradication programs and trade limitations and poses a threat to both endangered and protected species as well as to public health. We here give an overview on all members of the MTBC, focusing on their isolation from different animal hosts. We also review the recent advances made in elucidating the evolutionary and phylogenetic relationships of members of the MTBC. Because the nomenclature of the MTBC is controversial, its members have been considered species, subspecies or ecotypes, this review discusses the possible implications for diagnostics and the legal consequences of naming of new species.
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Detecting and quantifying threats and researching and implementing management actions are key to improving the conservation status of endangered species. Bibliometric analysis can constitute a useful tool for the evaluation of such questions from a long-term perspective. Taking as a case study the Cinereous Vulture Aegypius monachus in Spain, we tested relationships between population dynamics, research efforts, existing threats and conservation milestones. The population growth of the species (from 206 pairs in 1976 to 2,068 in 2011) was parallelled by the increase in the total number of publications, the number of articles in SCI journals and the number of published works dealing with aspects of conservation, threats and management. These results are discussed in terms of cause-effect relationships taking into account that the influence of other non-mutually exclusive factors could also probably explain such associations. Similarly, we analysed the trend of the Cinereous Vulture breeding population with respect to different threats and indices of food availability, obtaining a positive correlation with the increase in big-game hunting bags in Spain. With respect to conservation milestones, we concluded that the current situation is positive in terms of the protection of the species and its habitat, with the situation in relation to food availability being unclear. Finally, we reviewed the main conservation actions that have been taken for the species in Spain and how these have been progressively modified based on new scientific and technical evidence, as an example of adaptive management applied to conservation.
Resumo:
Epixylic bryophytes are important components of forest vegetation but are currently endangered by increment of wood harvest and intensive forest management. In this paper we present a study about the relationship between forest management, deadwood abundance, deadwood attributes and species richness of epixylic bryophytes on 30 plots comprising three forest types (managed coniferous, managed deciduous and unmanaged deciduous forests) in three regions in Germany. Additionally we analyzed the relations between deadwood attributes (wood species, decay, deadwood type, size) and bryophytes on deadwood items (n = 799) and calculated species interaction networks of wood species and bryophytes. Overall, species richness of epixylic bryophytes was positively related to deadwood abundance and diversity. The mean deadwood abundance was lowest in unmanaged forests (9.7 m<sup>3</sup> ha<sup>-1</sup>) compared with 15.0 m<sup>3</sup> ha<sup>-1</sup> in managed deciduous and 25.1 m<sup>3</sup> ha<sup>-1</sup> in managed coniferous forests. Accordingly, epixylic bryophyte species richness per plot increased from 7 species per 400 m 2 in unmanaged, 10 in managed deciduous and 16 in managed coniferous forests. The interaction network provided evidence of importance of tree-species diversity for bryophyte diversity and the relevance of particular wood species for rare bryophytes.<br></br> Generally, the results demonstrate a considerable lack of deadwood in all forest types, even in unmanaged forests. Species richness of epixylic bryophytes was strongly limited by available substrates within the observed deadwood abundance ranging up to only 60 m<sup>3</sup> ha<sup>-1</sup>. Altogether, this suggests a high demand to increase both abundance and diversity of deadwood in forests.
Resumo:
1. Positive interactions among plants can increase species richness by relaxing environmental filters and providing more heterogeneous environments. However, it is not known if facilitation could affect coexistence through other mechanisms. Most studies on plant coexistence focus on negative frequency-dependent mechanisms (decreasing the abundance of common species); here, we test if facilitation can enhance coexistence by giving species an advantage when rare. 2. To test our hypothesis, we used a global data set from drylands and alpine environments and measured the intensity of facilitation (based on co-occurrences with nurse plants) for 48 species present in at least 4 different sites and with a range of abundances in the field. We compared these results with the degree of facilitation experienced by species which are globally rare or common (according to the IUCN Red List), and with a larger data base including over 1200 co-occurrences of target species with their nurses. 3. Facilitation was stronger for rare species (i.e. those having lower local abundances or considered endangered by the IUCN) than for common species, and strongly decreased with the abundance of the facilitated species. These results hold after accounting for the distance of each species from its ecological optimum (i.e. the degree of functional stress it experiences). 4. Synthesis. Our results highlight that nurse plants not only increase the number of species able to colonize a given site, but may also promote species coexistence by preventing the local extinction of rare species. Our findings illustrate the role that nurse plants play in conserving endangered species and link the relationship between facilitation and diversity with coexistence theory. As such, they provide further mechanistic understanding on how facilitation maintains plant diversity.
Resumo:
Recent studies on the avalanche risk in alpine settlements suggested a strong dependency of the development of risk on variations in damage potential. Based on these findings, analyses on probable maximum losses in avalanche-prone areas of the municipality of Davos (CH) were used as an indicator for the long-term development of values at risk. Even if the results were subject to significant uncertainties, they underlined the dependency of today's risk on the historical development of land-use: Small changes in the lateral extent of endangered areas had a considerable impact on the exposure of values. In a second step, temporal variations in damage potential between 1950 and 2000 were compared in two different study areas representing typical alpine socio-economic development patterns: Davos (CH) and Galtür (A). The resulting trends were found to be similar; the damage potential increased significantly in number and value. Thus, the development of natural risk in settlements can for a major part be attributed to long-term shifts in damage potential.