99 resultados para connectivity conservation

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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Selection of sites for successful restoration of impacted shellfish populations depends on understanding the dispersion capability and habitat requirements of the species involved. In Strangford Lough, Northern Ireland, the horse mussel (Modiolus modiolus) biogenic reefs cover only a fraction of their historical range with the remaining reefs badly damaged and requiring restoration. Previous experimental trials suggest that translocation of horse mussels accelerates reef recovery and has therefore been proposed as a suitable restoration technique. We used a series of coupled hydrodynamic and particle dispersal models to assess larval dispersion from remnant and translocated populations to identify suitable areas for adult live M. modiolus translocation in Strangford Lough, Northern Ireland. A maximum entropy model (MAXENT) was used to identify if dispersing larvae could reach habitat suitable for adult M. modiolus. From these we predicted if translocated mussels will reseed themselves or be able to act as larval sources for nearby reefs. The dispersal models showed that the remnant M. modiolus populations are largely self-recruiting with little connectivity between them. The majority of larvae settled near the sources and movement was largely dependent on the tides and not influenced by wind or waves. Higher reef elevation resulted in larvae being able to disperse further away from the release point. However, larval numbers away from the source population are likely to be too low for successful recruitment. There was also little connectivity between the Irish Sea and Strangford Lough as any larvae entering the Lough remained predominantly in the Strangford Narrows. The areas covered by these self-seeding populations are suitable for M. modiolus translocation according to the MAXENT model. As a result of this work and in conjunction with other field work we propose a combination of total protection of all remaining larval sources and small scale translocations onto suitable substrata in each of the identified self-recruiting areas.

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There is growing interest in the mating systems of sharks and their relatives (Class Chondrichthyes) because these ancient fishes occupy a key position in vertebrate phylogeny and are increasingly in need of conservation due to widespread overexploitation. Based on precious few genetic and field observational studies, current speculation is that polyandrous mating strategies and multiple paternity may be common in sharks as they are in most other vertebrates. Here, we test this hypothesis by examining the genetic mating system of the bonnethead shark, Sphyrna tiburo, using microsatellite DNA profiling of 22 litters (22 mothers, 188 embryos genotyped at four polymorphic loci) obtained from multiple locations along the west coast of Florida. Contrary to expectations based on the ability of female S. tiburo to store sperm, the social nature of this species and the 100% multiple paternity observed in two other coastal shark species, over 81% of sampled bonnethead females produced litters sired by a single male (i.e. genetic monogamy). When multiple paternity occurred in S. tiburo, there was an indication of increased incidence in larger mothers with bigger litters. Our data suggest that sharks may exhibit complex genetic mating systems with a high degree of interspecific variability, and as a result some species may be more susceptible to loss of genetic variation in the face of escalating fishing pressure. Based on these findings, we suggest that knowledge of elasmobranch mating systems should be an important component of conservation and management programmes for these heavily exploited species.

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Patients with coxarthrosis (cOA) have a reduced incidence of intracapsular femoral neck fracture, suggesting that cOA offers protection. The distribution of bone in the femoral neck was compared in cases of coxarthrosis and postmortem controls to assess the possibility that disease-associated changes might contribute to reduced fragility. Whole cross-section femoral neck biopsies were obtained from 17 patients with cOA and 22 age- and sex-matched cadaveric controls. Densitometry was performed using peripheral quantitated computed tomography (pQCT) and histomorphometry on 10-µm plastic-embedded sections. Cortical bone mass was not different between cases and controls (P > 0.23), but cancellous bone mass was increased by 75% in cOA (P = 0.014) and histomorphometric cancellous bone area by 71% (P <0.0001). This was principally the result of an increase of apparent density (mass/vol) of cancellous bone (+45%, P = 0.001). Whereas cortical porosity was increased in the cases (P <0.0001), trabecular width was also increased overall in the cases by 52% (P <0.001), as was cancellous connectivity measured by strut analysis (P <0.01). Where osteophytic bone was present (n = 9) there was a positive relationship between the amount of osteophyte and the percentage of cancellous area (P <0.05). Since cancellous bone buttresses and stiffens the cortex so reducing the risk of buckling, the increased cancellous bone mass and connectivity seen in cases of cOA probably explain, at least in part, the ability of patients with cOA to resist intracapsular fracture of the femoral neck during a fall.

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The sense of place that relates human beings to their environment is under threat from the rising tide of placelessness which can result from potentially positive forces such as urban regeneration as well as negative ones such as incremental degradation. The concept of sense of place, and the need to protect and enhance special places, has underpinned UK conservation legislation and policy in the post-war era. In Northern Ireland, due to its distinctive settlement tradition, its troubled political circumstances and its centralised administrative system, a unique hierarchy of special places has evolved, involving areas of townscape and village character as well as conventional conservation areas. For the first time a comprehensive comparative survey of the townscape quality of most of these areas has been carried out in order to test the hypothesis that too many conservation area designations may devalue the conservation coinage. It also assesses the contribution that areas of townscape character can make in this situation, as potential conservation areas or as second-level local amenity designations. Its findings support the initial hypothesis: assessment of townscape quality on the basis of consistent criteria demonstrates a decline in the quality of more recent conservation area designations, and hence some devaluation of the coinage. However, the need for local discretion in the protection of local amenity supports the concept of areas of townscape and village character as an additional and distinct designation. This contradicts recent policy recommendations from the Northern Ireland Planning Commission and contains valuable lessons for conservation policy and practice in other parts of the UK.

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1. The freshwater pearl mussel Margaritifera margaritifera L. is globally endangered and is threatened by commercial exploitation, pollution and habitat loss throughout its range. Captive breeding would be a valuable tool in enhancing the status of M. margaritifera in the UK. 2. We have developed a semi-natural system for successfully infecting juvenile brown trout with glochidial M. margaritifera, and culturing juvenile mussels in experimental tanks where glochidial M. margaritifera can excyst from fish gills and settle into sediment. 3. Infected fish had less than 1% mortality. Levels of infection varied among fish. Two yearly cohorts of juvenile M. margaritifera were identified from samples of sediment taken from each experimental tank. Individuals range in size from 1.4 mm (2000 cohort) to >3 mm in length (1999 cohort). 4. The number of juvenile M. margaritifera present in the two experimental tanks are estimated to be between 3600 (tank A) and 0 (tank B) for the putative 1999 cohort and between 6000 (tank A) and 13 000 (tank B) for the putative 2000 cohort. 5. This pioneering method for large-scale cultivation of juvenile M. margaritifera is intermediate between the release of infected fish into rivers and the intensive cultivation systems developed in continental Europe and the USA for other species of unionid. This is the first time that large numbers of M. margaritifera have been cultured and represents a significant breakthrough in the conservation of this globally endangered Red Data List species. The method is straightforward and is most cost-effective when undertaken alongside established hatchery processes.

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The key enzyme in coronavirus replicase polyprotein processing is the coronavirus main protease, 3CL(pro). The substrate specificities of five coronavirus main proteases, including the prototypic enzymes from the coronavirus groups I, II and III, were characterized. Recombinant main proteases of human coronavirus (HCoV), transmissible gastroenteritis virus (TGEV), feline infectious peritonitis virus, avian infectious bronchitis virus and mouse hepatitis virus (MHV) were tested in peptide-based trans-cleavage assays. The determination of relative rate constants for a set of corresponding HCoV, TGEV and MHV 3CL(pro) cleavage sites revealed a conserved ranking of these sites. Furthermore, a synthetic peptide representing the N-terminal HCoV 3CL(pro) cleavage site was shown to be effectively hydrolysed by noncognate main proteases. The data show that the differential cleavage kinetics of sites within pp1a/pp1ab are a conserved feature of coronavirus main proteases and lead us to predict similar processing kinetics for the replicase polyproteins of all coronaviruses.

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This paper evaluates how long-term records could and should be utilized in conservation policy and practice. Traditionally, there has been an extremely limited use of long-term ecological records (greater than 50 years) in biodiversity conservation. There are a number of reasons why such records tend to be discounted, including a perception of poor scale of resolution in both time and space, and the lack of accessibility of long temporal records to non-specialists. Probably more important, however, is the perception that even if suitable temporal records are available, their roles are purely descriptive, simply demonstrating what has occurred before in Earth’s history, and are of little use in the actual practice of conservation. This paper asks why this is the case and whether there is a place for the temporal record in conservation management. Key conservation initiatives related to extinctions, identification of regions of greatest diversity/threat, climate change and biological invasions are addressed. Examples of how a temporal record can add information that is of direct practicable applicability to these issues are highlighted. These include (i) the identification of species at the end of their evolutionary lifespan and therefore most at risk from extinction, (ii) the setting of realistic goals and targets for conservation ‘hotspots’, and (iii) the identification of various management tools for the maintenance/restoration of a desired biological state. For climate change conservation strategies, the use of long-term ecological records in testing the predictive power of species envelope models is highlighted, along with the potential of fossil records to examine the impact of sea-level rise. It is also argued that a long-term perspective is essential for the management of biological invasions, not least in determining when an invasive is not an invasive. The paper concludes that often inclusion of a long-term ecological perspective can provide a more scientifically defensible basis for conservation decisions than the one based only on contemporary records. The pivotal issue of this paper is not whether long-term records are of interest to conservation biologists, but how they can actually be utilized in conservation practice and policy.