46 research outputs found

    Relative contribution of decreased productivity and survival to recent changes in the demographic trend of the RiviĂšre George Caribou Herd

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    The Rivière George caribou herd (RGCH) was numerically low during the middle part of the century but apparently erupted in the sixties and the seventies. Puberty was early and pregnancy rate was high among RGCH females from 1973 until the mid-eighties when fecundity decreased significantly, in particular among sub-adults; productivity remained low in 1992. Autumn calf:female ratios reflected this trend in pregnancy, exceeding 50 calves: 100 cows between 1973 and 1983, but dropping thereafter progressively to a low of 24 in 1992. In 1993, this ratio rebounded back to 42. Annual adult survival rate of radio-collared females was high (0.95) at the beginning of the monitoring in 1984, but exhibited a variable but declining trend until 1992. Simulations were conducted to estimate the demographic trend of the RGCH between 1984 and 1992, using annual survival rates of radio-collared animals and annual autumn calffemale ratios to estimate calf production. Age structure played a minor role in estimating the finite rate of increase (Lamda). According to the simulations, the RGCH increased in size until 1987, and showed a slight decrease thereafter. The herd should have decreased by 12-15% between 1988 and 1993, according to the simulations. Productivity first caused a decline in Lamda, but in recent years decreased survival contributed slightly more than productivity to the reduction in Lamda. Estimation of the herd size by means of aerial censuses in 1976, 1984, 1988 and 1993 suggested a similar pattern in demographic trend, differences being statistically meaningless. We speculated on the future of the RGCH, that could have erupted after many decades of unfavourable weather. The herd will exhibit a rapid descent to low numbers if wolves show a numerical response to current caribou abundance, or if lichen availability on the winter range decreases due to competition with the adjacent and increasing Rivière aux Feuilles herd; otherwise it will exhibit dampened oscillations, whose amplitude will depend on the time-lag of vegetation reaction to decrease grazing pressure on the summer range

    Management of indigenous North American deer at the end of the 20th century in relation to large predators and primary production

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    Five deer species occupy North America: caribou (3.6 × 106individuals), moose (1.1 × 106), white-tailed deer (28.5 × 106), mule deer (5.0 × 106) and wapiti (1.1 × 106). Caribou characterise the north of the boreal forest and the tundra, whereas moose dominate in coniferous and mixed forests growing further south. White-tailed deer are typical of the deciduous forests of the east while mule deer replace them in the mountainous terrain of the west. Wapiti possess the smallest range, mostly adjacent to the prairies to the west. The two large obligate carnivores preying on deer show a reduced distribution: wolves are almost restricted to Canada, and cougar to the mule deer range. We determined the current status of each species with the help of a questionnaire mailed to all jurisdictions harbouring deer. Most reports of threatened populations concerned caribou whereas many jurisdictions declared overabundance of white-tailed deer and wapiti. Hunting was allowed for all species when they abounded in a jurisdiction. Hunters harvested annually 7.0 × 106deer on the continent, 87% being white-tailed deer. The two species that caused most conflicts with humans had the highest harvest rate: 16-17%. In terms of biomass, white-tailed deer and wapiti yielded the highest harvests, with 55 and 39 kg × km-2of range, respectively. The average standing biomass of deer in winter ranged between 28 kg × km-2in Nevada to 901 kg × km-2in Indiana. The lowest standing biomasses occurred in the boreal forest (predators), in the prairies (agriculture) and in the south-west (aridity), and the highest ones in the south-east, where only white-tailed deer is present. The current abundance of deer in North America parallels, in general, the primary production of the landscape (r2= 0.38; P < 0.0001), but predators and human activity modify this pattern

    Targeted sequencing for high-resolution evolutionary analyses following genome duplication in salmonid fish:Proof of concept for key components of the insulin-like growth factor axis

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    Acknowledgements This study was funded by a Natural Environment Research Council grant (NERC, project code: NBAF704). FML is funded by a NERC Doctoral Training Grant (Project Reference: NE/L50175X/1). RLS was an undergraduate student at the University of Aberdeen and benefitted from financial support from the School of Biological Sciences. DJM is indebted to Dr. Steven Weiss (University of Graz, Austria), Dr. Takashi Yada (National Research Institute of Fisheries Science, Japan), Dr. Robert Devlin (Fisheries and Oceans Canada, Canada), Prof. Samuel Martin (University of Aberdeen, UK), Mr. Neil Lincoln (Environment Agency, UK) and Prof. Colin Adams/Mr. Stuart Wilson (University of Glasgow, UK) for providing salmonid material or assisting with its sampling. We are grateful to staff at the Centre for Genomics Research (University of Liverpool, UK) (i.e. NERC Biomolecular Analysis Facility – Liverpool; NBAF-Liverpool) for performing sequence capture/Illumina sequencing and providing us with details on associated methods that were incorporated into the manuscript. Finally, we are grateful to the organizers of the Society of Experimental Biology Satellite meeting 'Genome-powered perspectives in integrative physiology and evolutionary biology' (held in Prague, July 2015) for inviting us to contribute to this special edition of Marine Genomics and hosting a really stimulating meeting.Peer reviewedPublisher PD

    Re-evaluation of blood mercury, lead and cadmium concentrations in the Inuit population of Nunavik (Québec): a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Arctic populations are exposed to mercury, lead and cadmium through their traditional diet. Studies have however shown that cadmium exposure is most often attributable to tobacco smoking. The aim of this study is to examine the trends in mercury, lead and cadmium exposure between 1992 and 2004 in the Inuit population of Nunavik (Northern QuĂ©bec, Canada) using the data obtained from two broad scale health surveys, and to identify sources of exposure in 2004.</p> <p>Methods</p> <p>In 2004, 917 adults aged between 18 and 74 were recruited in the 14 communities of Nunavik to participate to a broad scale health survey. Blood samples were collected and analysed for metals by inductively coupled plasma mass spectrometry, and dietary and life-style characteristics were documented by questionnaires. Results were compared with data obtained in 1992, where 492 people were recruited for a similar survey in the same population.</p> <p>Results</p> <p>Mean blood concentration of mercury was 51.2 nmol/L, which represent a 32% decrease (p < 0.001) between 1992 and 2004. Mercury blood concentrations were mainly explained by age (partial r<sup>2 </sup>= 0.20; p < 0.0001), and the most important source of exposure to mercury was marine mammal meat consumption (partial r<sup>2 </sup>= 0.04; p < 0.0001). In 2004, mean blood concentration of lead was 0.19 ÎŒmol/L and showed a 55% decrease since 1992. No strong associations were observed with any dietary source, and lead concentrations were mainly explained by age (partial r<sup>2 </sup>= 0.20.; p < 0.001). Blood cadmium concentrations showed a 22% decrease (p < 0.001) between 1992 and 2004. Once stratified according to tobacco use, means varied between 5.3 nmol/L in never-smokers and 40.4 nmol/L in smokers. Blood cadmium concentrations were mainly associated with tobacco smoking (partial r<sup>2 </sup>= 0.56; p < 0.0001), while consumption of caribou liver and kidney remain a minor source of cadmium exposure among never-smokers.</p> <p>Conclusion</p> <p>Important decreases in mercury, lead and cadmium exposure were observed. Mercury decrease could be explained by dietary changes and the ban of lead cartridges use likely contributed to the decrease in lead exposure. Blood cadmium concentrations remain high and, underscoring the need for intensive tobacco smoking prevention campaigns in the Nunavik population.</p

    RÉSULTATS DES DEUX PREMIÈRES ANNÉES D'UN PLAN QUINQUENNAL D'INVENTAIRE AÉRIEN POUR LA GESTON DE L'ORIGNAL AU QUÉBEC

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    Un plan quiquennal visant le suivi de la densité de l'orignal (Alces alces) a débuté au Québec en 1980. Environ 120 parcelels de 60 km2 chacune ont été couvertes annuellement entre le 46e et 50e degré latitude. Les Zones d'Aménagement et de Conservation (Z.A.C.), couvrant en moyenne 10 000 km2, ont servi de base à la stratification de l'aire à l'étude. L'échantillonnage a suivi une allocation optimale des parcelles basée sur l'intensité de la récolte d'orignaux depuis cinq ans. Seuls des avions monomoteurs ont servi à l'exécution des inventaires. Le densité de l'orignal a été estimée à l'aide d'un modÚle à trois variables explicatives présidant la densité qu'aurait trouvée une équipe à bord d'un hélicoptÚre si elle avait fait un décompte total des animaux occupant les parcelles. Ce modÚle tient compte du nombre d'orignaux vus d'un avion monomoteur en vol rectiligne, du pourcentage de la parcelle occupé par les réseaux de pistes et de l'abondance des peuplements forestiers ouverts. Les résultats des deux premiÚres années ont révélé des densités moyennes de 0,12 et 0,14 orignal km-2. Deux problÚmes ont surgi lors de la réalisation de ce programme: 1) dans donné milieux trÚs ouverts, la droite d'estimation a donné à l'occasion des prédictions négatives; 2) un méthode correcte de calcul des intervalles de confiance n'est pas encore déterminée. Le premier problÚme a été en grade partie résolu par le calcul d'un nouveau modÚle basé sur un plus grand éventail de degré d'ou venture des peuplements forestiers; le second problÚme est encore à l'étude

    Life History and Ecology of Coyotes in the Mid-Atlantic States: A Summary of the Scientifi c Literature

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    Relatively little information has been published on Coyotes in the eastern United States, particularly in the mid-Atlantic region, the last area of the contiguous US to be colonized by Coyotes. Increases in eastern Coyote distribution and abundance have been documented, and concerns about their impact on wildlife and livestock are growing. Information from published and unpublished manuscripts, theses, dissertations, and state wildlife agency records in the mid-Atlantic region were examined and synthesized. This review provides a comprehensive summary of Coyote ecology in the mid-Atlantic for natural resource managers and researchers
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