948 resultados para Wildlife conservation
Resumo:
Lead is a highly toxic metal known to be an important cause of morbidity and mortality in waterbirds and terrestrial birds worldwide. The risk to birds of poisoning from lead has resulted in the introduction of legislation in many countries, such as UK restrictions on the use of lead in angling weights and lead gunshot. In this study, we examined data on current and historical trends in lead poisoning in British waterbirds and related these to the introduction of legislation restricting the use of lead. Our results indicate that lead poisoning has continued to affect a wide range of British waterbirds long after legal restrictions were introduced. Elevated levels of lead (i.e. > 20.0 mu g/dL) were found in the blood of 34 % (n = 285) of waterbirds tested at four sites in Britain during the 2010/2011 winter and accounted for the deaths of at least 10.6 % (n = 2,365) of waterbirds recovered across Britain between 1971 and 2010 and 8.1 % (n = 1,051) between 2000 and 2010, with lead gunshot being the most likely source of poisoning. The proportion of birds dying from lead poisoning in England did not vary significantly after the introduction of legislation, accounting for 13.7 % of non-infectious causes of death between 1971 and 1987 (n = 204), 20.8 % (n = 360) between 1988 and 1999 and 11.8 % (n = 423) between 2000 and 2010, despite a significant change in lead-related mortality in mute swans found during the same time period, 25 % (n = 12) between 1971 and 1987, 4.6 % (n = 65) between 1988 and 1999 and 2 % (n = 100) between 2000 and 2010. Existing legislation needs review and extension to ensure the delivery of international commitments and a broad-scale transition to the use of non-toxic shot and angling materials in all environments.
Resumo:
Global amphibian declines are a major element of the current biodiversity crisis. Monitoring changes in the distribution and abundance of target species is a basic component in conservation decision making and requires robust and repeatable sampling. For EU member states, surveillance of designated species, including the common frog Rana temporaria, is a formal requirement of the 'EC Habitats & Species Directive'. We deployed established methods for estimating frog population density at local water bodies and extrapolated these to the national and ecoregion scale. Spawn occurred at 49.4% of water bodies and 70.1% of independent 500-m survey squares. Using spawn mat area, we estimated the number of adult breeding females and subsequently the total population assuming a sex ratio of 1:1. A negative binomial model suggested that mean frog density was 23.5 frogsha [95% confidence interval (CI) 14.9-44.0] equating to 196M frogs (95%CI 124M-367M) throughout Ireland. A total of 86% of frogs bred in drainage ditches, which were a notably common feature of the landscape. The recorded distribution of the species did not change significantly between the last Article 17 reporting period (1993-2006) and the current period (2007-2011) throughout the Republic of Ireland. Recording effort was markedly lower in Northern Ireland, which led to an apparent decline in the recorded distribution. We highlight the need to coordinate biological surveys between adjacent political jurisdictions that share a common ecoregion to avoid apparent disparities in the quality of distributional information. Power analysis suggested that a reduced sample of 40-50 survey squares is sufficient to detect a 30% decline (consistent with the International Union for Conservation of Nature Category of 'Vulnerable') at 80% power providing guidance for minimizing future survey effort. Our results provin assessments for R. temporaria and other clump-spawning amphibians. 2013 The Zoological Society of London.
Resumo:
Aim: Retrospective genetic monitoring, comparing genetic diversity of extant populations with historical samples, can provide valuable and often unique insights into evolutionary processes informing conservation strategies. The Yellow marsh saxifrage (Saxifraga hirculus) is listed as ‘critically endangered’ in Ireland with only two extant populations. We quantified genetic changes over time and identified genotypes in extant populations that could be used as founders for reintroductions to sites where the species is extinct.
Location: Ireland.
Methods: Samples were obtained from both locations where the species is currently found, including the most threatened site at the Garron Plateau, Co. Antrim, which held only 13 individuals during 2011. Herbarium samples covering the period from 1886 to 1957 were obtained including plants from the same area as the most threatened population, as well as three extinct populations. In total, 422 individuals (319 present-day and 103 historical) were genotyped at six microsatellite loci. Species distribution modelling was used to identify areas of potentially suitable habitat for reintroductions.
Results: Level of phenotypic diversity within the most threatened population was significantly lower in the present-day compared with historical samples but levels of observed heterozygosity and number of alleles, whilst reduced, did not differ significantly. However, Bayesian clustering analysis suggested gradual lineage replacement over time. All three measures of genetic diversity were generally lower at the most threatened population compared with the more substantial extant populations in Co. Mayo. Species distribution modelling suggested that habitat at one site where the species is extinct may be suitable for reintroduction.
Main conclusions: The dominant genetic lineage in the most threatened population is rare elsewhere; thus, care needs to be taken when formulating any potential reintroduction programme. Our findings highlight both the need for genetic monitoring of threatened populations, but also for its swift implementation before levels of diversity become critically low.
Resumo:
Rapid in situ diagnosis of damage is a key issue in the preservation of stone-built cultural heritage. This is evident in the increasing number of congresses, workshops and publications dealing with this issue. With this increased activity has come, however, the realisation that for many culturally significant artefacts it is not possible either to remove samples for analysis or to affix surface markers for measurement. It is for this reason that there has been a growth of interest in non-destructive and minimally invasive techniques for characterising internal and external stone condition. With this interest has come the realisation that no single technique can adequately encompass the wide variety of parameters to be assessed or provide the range of information required to identify appropriate conservation. In this paper we describe a strategy to address these problems through the development of an integrated `tool kit' of measurement and analytical techniques aimed specifically at linking object-specific research to appropriate intervention. The strategy is based initially upon the acquisition of accurate three-dimensional models of stone-built heritage at different scales using a combination of millimetre accurate LiDAR and sub-millimetre accurate Object Scanning that can be exported into a GIS or directly into CAD. These are currently used to overlay information on stone characteristics obtained through a combination of Ground Penetrating Radar, Surface Permeametry, Colorimetry and X-ray Fluorescence, but the possibility exists for adding to this array of techniques as appropriate. In addition to the integrated three-dimensional data array provided by superimposition upon Digital Terrain Models, there is the capability of accurate re-measurement to show patterns of surface loss and changes in material condition over time. Thus it is possible to both record and base-line condition and to identify areas that require either preventive maintenance or more significant pre-emptive intervention. In pursuit of these goals the authors are developing, through a UK Government supported collaboration between University Researchers and Conservation Architects, commercially viable protocols for damage diagnosis, condition monitoring and eventually mechanisms for prioritizing repairs to stone-built heritage. The understanding is, however, that such strategies are not age-constrained and can ultimately be applied to structures of any age.
Resumo:
Throughout the European Union, the EC Habitats Directive requires that member states undertake national surveillance of designated species. Despite biological connections between-populations across-borders, national assessments need not be co-ordinated in any way. We conducted a trans-boundary assessment of the status of Eurasian otters (Lutra lutra) aimed at providing consistency across a single biogeographical unit, i.e. the island of Ireland, comprising two states, i.e. the Republic of Ireland and the United Kingdom (Northern Ireland). Our aim was to ensure consistency with previous assessments conducted separately in each state, and permit each Government to fulfil their separate statutory reporting commitments. The species range increased by 23% from 1996–2006 and 2007–11. The population estimate of 9400 [95%CI 8700–12,200] breeding females during 2010/11 was not significantly different from 8300 [95%CI 7600–9800] breeding females established as a baseline during 1981–82. Modelling of species-habitat associations suggested that available habitat was not limiting and no putative pressures recorded at sites surveyed negatively affected species occurrence. Thus, under the statutory parameters for assessing a species’ conservation status, i.e. range, population, habitat and future prospects, the otter was judged to be in ‘Favourable’ status throughout Ireland and in both discrete political jurisdictions. Thus, we provide a trans-boundary test case for EU member states that share habitats and species across ecoregions, ensuring conservation assessment data are standardised, synchronised, spatially consistent and, therefore, biologically relevant without compromising legal and administrative autonomy within separate jurisdictions.
Resumo:
Oyster populations around the world have seen catastrophic decline which has been largely attributed to overexploitation, disease and pollution. While considerable effort and resources have been implemented into restoring these important environmental engineers, the success of oyster populations is often limited by poor understanding of site-specific dispersal patterns of propagules. Water-borne transport is a key factor controlling or regulating the dispersal of the larval stage of benthic marine invertebrates which have limited mobility. The distribution of the native oyster Ostrea edulis in Strangford Lough, Northern Ireland, together with their densities and population structure at subtidal and intertidal sites has been documented at irregular intervals between 1997 and 2013. This paper revisits this historical data and considers whether different prevailing environmental conditions can be used to explain the distribution, densities and population structure of O. edulis in Strangford Lough. The approach adopted involved comparing predictive 2D hydrodynamic models coupled with particle tracking to simulate the dispersal of oyster larvae with historical and recent field records of the distribution of both subtidal and intertidal, populations since 1995. Results from the models support the hypothesis that commercial stocks of O. edulis introduced into Strangford Lough in the 1990s resulted in the re-establishment of wild populations of oysters in the Northern Basin which in turn provided a potential source of propagules for subtidal populations. These results highlight that strategic site selection (while inadvertent in the case of the introduced population in 1995) for the re-introduction of important shellfish species can significantly accelerate their recovery and restoration.
Resumo:
The growing accessibility to genomic resources using next-generation sequencing (NGS) technologies has revolutionized the application of molecular genetic tools to ecology and evolutionary studies in non-model organisms. Here we present the case study of the European hake (Merluccius merluccius), one of the most important demersal resources of European fisheries. Two sequencing platforms, the Roche 454 FLX (454) and the Illumina Genome Analyzer (GAII), were used for Single Nucleotide Polymorphisms (SNPs) discovery in the hake muscle transcriptome. De novo transcriptome assembly into unique contigs, annotation, and in silico SNP detection were carried out in parallel for 454 and GAII sequence data. High-throughput genotyping using the Illumina GoldenGate assay was performed for validating 1,536 putative SNPs. Validation results were analysed to compare the performances of 454 and GAII methods and to evaluate the role of several variables (e.g. sequencing depth, intron-exon structure, sequence quality and annotation). Despite well-known differences in sequence length and throughput, the two approaches showed similar assay conversion rates (approximately 43%) and percentages of polymorphic loci (67.5% and 63.3% for GAII and 454, respectively). Both NGS platforms therefore demonstrated to be suitable for large scale identification of SNPs in transcribed regions of non-model species, although the lack of a reference genome profoundly affects the genotyping success rate. The overall efficiency, however, can be improved using strict quality and filtering criteria for SNP selection (sequence quality, intron-exon structure, target region score).
Resumo:
It is often assumed that in order to avoid the most severe consequences of global anthropogenic climate change we have to preserve our existing carbon sinks, such as for instance tropical forests. Global carbon sink conservation raises a host of normative issues, though, since it is debatable who should pay the costs of carbon sink conservation, who has the duty to protect which sinks, and how far the duty to conserve one’s carbon sinks actually extends, especially if it conflicts with other duties one might have. According to some, forested states like Ecuador have a duty to preserve their tropical forests while the rich states of the global North have a duty of fairness to compensate states like Ecuador for the costs they incur. My aim in this paper is to critically analyse this standard line of argument and to criticise its validity both internally (i.e. with regard to its normative conclusion based on its premises) and externally (i.e. with regard to the argument’s underlying assumptions and its lack of contextualisation). As I will argue, the duty to conserve one’s forests is only a particular instantiation of a wider, more general duty to contribute towards global climate justice for which the context in which one operates (e.g. whether other agents are complying with their duties of global climate justice or not) matters significantly.
Resumo:
A conservação da biodiversidade nunca foi uma assunto tão popular como nas últimas décadas, mas esta popularidade crescente é devida à pior das razões: o passo acelerado da extinção de espécies e habitats. Os ecossistemas tropicais são, ao mesmo tempo, os mais diversos e os mais ameaçados, em parte porque muitos países destas regiões emergem ainda de situações de instabilidade social, económica e política. O Brasil é o maior país Neotropical, onde se encontram alguns dos biomas com maior diversidade e mais ameaçados do planeta. Actualmente, é também um país líder ao nível da planificação e implementação de medidas de conservação da biodiversidade. Vários dos biomas tropicais mais diversos e ameaçados encontram-se em território brasileiro. Dois destes biomas, a Amazónia e o Cerrado, convergem numa região ecotonal sujeita a uma elevada pressão humana, conhecida como o arco do desmatamento. O Araguaia, um dos maiores rios do Brasil, corre ao longo desta paisagem e os efeitos do desmatamento são já evidentes em toda a sua bacia. Por causa do acelerado ritmo de degradação deste ecossistema, torna-se urgente obter uma imagem clara da biodiversidade regional e compreender como e se a estratégia de conservação para esta região é capaz de lidar com as correntes ameaças e alcançar o seu objectivo a longo prazo: conservar a biota regional. Tendo a herpetofauna como grupo-alvo, os nossos objectivos principais foram: aumentar o conhecimento das comunidades de anfíbios e répteis squamata da região do curso médio do Rio Araguaia; compreender a importância deste rio nos padrões intraespecíficos de estrutura e diversidade genética para diferentes espécies com diferentes características ecológicas; avaliar o potencial de diferentes metodologias para o estudo e monitorização da herpetofauna regional. Os nossos resultados revelam que a amostragem continuada e o uso de diferentes técnicas são essenciais para a obtenção de uma imagem precisa da diversidade da herpetofauna local. As comunidades locais de anfíbios e lagartos apresentaram maior riqueza específica na Área de Protecção Ambiental Bananal/Cantão (APABC), uma área tampão, do no Parque Estadual do Cantão (PEC), uma área de conservação estrita. A APABC é caracterizada por uma maior heterogeneidade de habitats e os nosso resultados corroboram a teoria da heterogeneidade espacial e resultados recentes que revelam uma maior diversidade de lagartos nas zonas interfluviais do Cerrado, do que nas matas de galeria. Os resultados aqui apresentados não corroboram a hipótese de que os ecótonos apresentam maior diversidade do que os biomas em redor. Os nossos resultados revelaram ainda que o Rio Araguaia afecta de forma diferente a estrutura genética de várias espécies de anfíbios e lagartos. Estas diferenças poderão estar relacionadas com a ecologia das espécies, nomeadamente com o uso de diferentes habitats, a vagilidade, ou a estratégia alimentar. Sugerimos que a gestão integração de diferentes unidades de conservação, com diferentes estatutos, podem ajudar a preservar melhor a biota regional.