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961.
Will climate change increase hybridization risk between potential plant invaders and their congeners in Europe? 下载免费PDF全文
Günther Klonner Iwona Dullinger Johannes Wessely Oliver Bossdorf Marta Carboni Wayne Dawson Franz Essl Andreas Gattringer Emily Haeuser Mark van Kleunen Holger Kreft Dietmar Moser Jan Pergl Petr Pyšek Wilfried Thuiller Patrick Weigelt Marten Winter Stefan Dullinger 《Diversity & distributions》2017,23(8):934-943
962.
Mitch?D.?WeegmanEmail author Todd?W.?Arnold Russell?D.?Dawson David?W.?Winkler Robert?G.?Clark 《Oecologia》2017,185(1):119-130
Changes to weather patterns under a warming climate are complex: while warmer temperatures are expected virtually worldwide, decreased mean precipitation is expected at mid-latitudes. Migratory birds depend on broad-scale weather patterns to inform timing of movements, but may be more susceptible to local weather patterns during sedentary periods. We constructed Bayesian integrated population models (IPMs) to assess whether continental or local weather effects best explained population dynamics in an environmentally sensitive aerial insectivorous bird, the tree swallow (Tachycineta bicolor), along a transcontinental gradient from British Columbia to Saskatchewan to New York, and tested whether population dynamics were synchronous among sites. Little consistency existed among sites in the demographic rates most affecting population growth rate or in correlations among rates. Juvenile apparent survival at all sites was stable over time and greatest in New York, whereas adult apparent survival was more variable among years and sites, and greatest in British Columbia and Saskatchewan. Fledging success was greatest in Saskatchewan. Local weather conditions explained significant variation in adult survival in Saskatchewan and fledging success in New York, corroborating the hypothesis that local more than continental weather drives the population dynamics of this species and, therefore, demographic synchrony measured at three sites was limited. Nonetheless, multi-population IPMs can be a powerful tool for identifying correlated population trajectories caused by synchronous demographic rates, and can pinpoint the scale at which environmental drivers are responsible for changes. We caution against applying uniform conservation actions for populations where synchrony does not occur or is not fully understood. 相似文献
963.
Nutrient sulfate is essential for numerous physiological functions in mammalian growth and development. Accordingly, disruptions to any of the molecular processes that maintain the required biological ratio of sulfonated and unconjugated substrates are likely to have detrimental consequences for mammalian physiology. Molecular processes of sulfate biology can be broadly grouped into four categories: firstly, intracellular sulfate levels are maintained by intermediary metabolism and sulfate transporters that mediate the transfer of sulfate across the plasma membrane; secondly, sulfate is converted to 3′-phosphoadenosine 5′-phosphosulfate (PAPS), which is the universal sulfonate donor for all sulfonation reactions; thirdly, sulfotransferases mediate the intracellular sulfonation of endogenous and exogenous substrates; fourthly, sulfate is removed from substrates via sulfatases. From the literature, we curated 91 human genes that encode all known sulfate transporters, enzymes in pathways of sulfate generation, PAPS synthetases and transporters, sulfotransferases and sulfatases, with a focus on genes that are linked to human and animal pathophysiology. The predominant clinical features linked to these genes include neurological dysfunction, skeletal dysplasias, reduced fecundity and reproduction, and cardiovascular pathologies. Collectively, this review provides reference information for genetic investigations of perturbed mammalian sulfate biology. 相似文献
964.
Seasonal patterns in reproductive success of temperate‐breeding birds: Experimental tests of the date and quality hypotheses 下载免费PDF全文
Vanessa B. Harriman Russell D. Dawson Lauren E. Bortolotti Robert G. Clark 《Ecology and evolution》2017,7(7):2122-2132
For organisms in seasonal environments, individuals that breed earlier in the season regularly attain higher fitness than their late‐breeding counterparts. Two primary hypotheses have been proposed to explain these patterns: The quality hypothesis contends that early breeders are of better phenotypic quality or breed on higher quality territories, whereas the date hypothesis predicts that seasonally declining reproductive success is a response to a seasonal deterioration in environmental quality. In birds, food availability is thought to drive deteriorating environmental conditions, but few experimental studies have demonstrated its importance while also controlling for parental quality. We tested predictions of the date hypothesis in tree swallows (Tachycineta bicolor) over two breeding seasons and in two locations within their breeding range in Canada. Nests were paired by clutch initiation date to control for parental quality, and we delayed the hatching date of one nest within each pair. Subsequently, brood sizes were manipulated to mimic changes in per capita food abundance, and we examined the effects of manipulations, as well as indices of environmental and parental quality, on nestling quality, fledging success, and return rates. Reduced reproductive success of late‐breeding individuals was causally related to a seasonal decline in environmental quality. Declining insect biomass and enlarged brood sizes resulted in nestlings that were lighter, in poorer body condition, structurally smaller, had shorter and slower growing flight feathers and were less likely to survive to fledge. Our results provide evidence for the importance of food resources in mediating seasonal declines in offspring quality and survival. 相似文献
965.
Yun Heacock‐Kang Zhenxin Sun Jan Zarzycki‐Siek Ian A. McMillan Michael H. Norris Andrew P. Bluhm Darlene Cabanas Dawson Fogen Hung Vo Stuart P. Donachie Bradley R. Borlee Christopher D. Sibley Shawn Lewenza Michael J. Schurr Herbert P. Schweizer Tung T. Hoang 《Molecular microbiology》2017,106(6):976-985
966.
Kerstin Wilhelm Deborah A. Dawson Louise K. Gentle Giles F. Horsfield Christian Schltterer Carolsyn Greig Marion East Heribert Hofer Diethard Tautz Terry Burke 《Molecular ecology resources》2003,3(3):360-362
We have isolated 10 polymorphic microsatellite loci in the spotted hyena, Crocuta crocuta. The loci displayed between eight and 14 alleles in a minimum of 12 individuals tested. These loci will be used to investigate relatedness within social groups, the genetic structure of populations, sexual selection, and mate choice in spotted hyenas. 相似文献
967.
Modelling potential impacts of climate change on the bioclimatic envelope of species in Britain and Ireland 总被引:8,自引:0,他引:8
P. M. Berry T. P. Dawson P. A. Harrison R. G. Pearson 《Global Ecology and Biogeography》2002,11(6):453-462
Aim Climate change has the potential to have significant impacts on the distribution of species and on the composition of habitats. This paper identifies the potential changes in the future distribution of species under the UKCIP98 climate change scenarios, in order that such changes can be taken into account in conservation management. Location The model was applied to Britain and Ireland. Methods A model based on an artificial neural network was used to predict the changing bioclimate envelopes of species in Britain and Ireland. Fifty‐four species representing 15 habitats were modelled. Results The modelled species could be placed into three categories: those losing suitable climate space, those gaining it, and those showing little or no change. When the species were associated with habitats it was found that Arctic–Alpine/montane heath communities were the most sensitive to climate change, followed by pine woodland and beech woodland in southern England. In lowland heath, wet heath, cereal field margins, coastal grazing marsh, drought‐prone acid grassland and calcareous grassland, the species either showed little change or an increase in suitable climate space. The other eight habitats showed a mixed response. Conclusions The species show a variety of responses to climate change and thus their current habitat associations may alter. The uncertain future of some species and habitats is highlighted. Conservation policy and practice will need to be revised in the face of climate change. 相似文献
968.
The distributions and effects of nutrients in the sediments of a shallow eutrophic Chinese lake 总被引:8,自引:2,他引:6
The temporal and spatial distribution of total nitrogen and total phosphate in the sediments of a shallow eutrophic Chinese lake (Lake Chao), and their relationships with the physical and chemical features of sediments, and their effects on the lake water quality and trophic state, are presented in this paper. The following results were obtained: (1) higher concentration of Tot-N and Tot-P in the sediments occurred in the summer and the autumn seasons; (2) higher annual average Tot-N and Tot-P concentrations were observed in the sediments near the various river mouths and in the western part of the lake; (3) Tot-N and Tot-P concentration in the lake sediments generally increased with increase in lake sediment Eh, pH, and Al2O3, and declined with decrease in lake sediment size diameters and SiO2; and, (4) correlations were observed in both the temporal and spatial distributions between the trophic state, Tot-N and Tot-P concentration in the lake water, and the Tot-N and Tot-P concentration found in the lake sediments. 相似文献
969.
Does diet in Celtic Sea fishes reflect prey availability? 总被引:1,自引:0,他引:1
J. K. Pinnegar† V. M. Trenkel‡ A. N. Tidd W. A. Dawson M. H. Du buit§ 《Journal of fish biology》2003,63(S1):197-212
Feeding preferences of Celtic Sea fishes were investigated using a database of stomach content records, collected between 1977 and 1994. The diet of cod Gadus morhua , hake Merluccius merluccius , megrim Lepidorhombus whiffiagonis , whiting Merlangius merlangus and saithe Pollachius virens changed markedly as the animals grew larger, and although large predators generally chose larger bodied prey, the variability of prey sizes consumed also increased. Large predators continued to select small, low value, benthic prey ( e.g . Callionymus spp. and Trisopterus spp.) which were easier to catch, rather than larger, more energy lucrative pelagic prey ( e.g . mackerel Scomber scombrus ), even though these pelagic prey‐fishes were nearly always available and were often very abundant. Stock estimates of the International Council for the Exploration of the Sea and U.K. groundfish survey catches were used as indices of prey abundance. Blue‐whiting Micromesistius poutassou and other small pelagic fishes ( Argentina spp. and clupeoids) were identified as being particularly important, and were consumed by some predators more often than would be expected given the abundance of these prey in the environment. There was no evidence for density‐dependent feeding by predators on mackerel and only hake exhibited density‐dependent feeding on horse‐mackerel. Hake, cod and megrim consumed more blue‐whiting when this prey was at higher abundance in the environment. In choosing what prey to consume, predators must balance costs and benefits, considering the quality of prey and the energy expended during search, capture and handling. 相似文献
970.
Fiona E Shaw John Bond David A Richardson Pamela Dawson I Nicholas Steen Ian G McKeith Rose Anne Kenny 《BMJ (Clinical research ed.)》2003,326(7380):73
ObjectiveTo determine the effectiveness of multifactorial intervention after a fall in older patients with cognitive impairment and dementia attending the accident and emergency department.DesignRandomised controlled trial.Participants274 cognitively impaired older people (aged 65 or over) presenting to the accident and emergency department after a fall: 130 were randomised to assessment and intervention and 144 were randomised to assessment followed by conventional care (control group).SettingTwo accident and emergency departments, Newcastle upon Tyne.ResultsIntention to treat analysis showed no significant difference between intervention and control groups in proportion of patients who fell during 1 year''s follow up (74% (96/130) and 80% (115/144), relative risk ratio 0.92, 95% confidence interval 0.81 to 1.05). No significant differences were found between groups for secondary outcome measures.ConclusionsMultifactorial intervention was not effective in preventing falls in older people with cognitive impairment and dementia presenting to the accident and emergency department after a fall.