共查询到20条相似文献,搜索用时 15 毫秒
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Ian Fraser 《BMJ (Clinical research ed.)》1953,2(4843):987-988
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M. Garel J. -M. Cugnasse A. Loison J. -M. Gaillard C. Vuiton D. Maillard 《European Journal of Wildlife Research》2005,51(2):69-76
Monitoring change in the population size of mouflon (Ovis gmelini musimon × Ovis sp.) in rugged areas is an important yet difficult task for wildlife ecologists. To assess population change of mouflon inhabiting the Caroux-Espinouse massif, France, we compared a pedestrian and helicopter survey, using counts of animals as indices of abundance. Environmental factors such as date of survey and temperature affected the detection of mouflons from the ground and the air. Both indices were sensitive to observed changes in population size. A decrease in the pedestrian index was recorded in 1994, the year following an epizootic of keratoconjunctivitis, which markedly reduced the survival rate of mouflon. Variations in pedestrian index accounted for variations in harvests when excluding epizootic events. Both surveys detected a decrease in population size, which accounted for the recent increase of harvest. Helicopter and pedestrian surveys are reliable tools to monitor annually mouflons in mountainous areas. Simulations indicated that helicopter surveys should be preferred by managers because they provide the best trade-off between cost and precision. 相似文献
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George A. Hawkins-Ambler 《BMJ (Clinical research ed.)》1900,2(2076):1140-1141
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G. Arbour Stephens 《BMJ (Clinical research ed.)》1926,2(3436):906-907
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T. M. Allison 《BMJ (Clinical research ed.)》1926,2(3442):1243-1244
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F. G. Bushnell 《BMJ (Clinical research ed.)》1926,2(3440):1145-1146
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Michel Lepley Michel Thevenot Claude-P. Guillaume Philippe Ponel Patrick Bayle 《Bird Study》2013,60(2):156-162
Capsule In this region the diet is mainly cold-blooded prey, mostly insects such as beetles. Aims To describe the diet of this newly separated, poorly documented and endangered species. Method Diet was inferred from pellet analysis, collected during a single breeding and winter period in the steppe of the Crau. Results A total of 5409 prey were identified from 257 pellets. Vertebrates were seldom taken, except by adults (small passerines) during the fledgling period. High seasonal differences were found. Hymenoptera were largely consumed in autumn, Arachnida in autumn and winter, Orthoptera in summer and autumn and Lepidoptera larvae in winter and spring and by fledglings. Nevertheless, Coleoptera were ingested in large proportions all year round. Carabidae were the main prey in winter and Melolonthidae were especially important for adults during the nestling period, as were Cetoniidae for the fledglings. Conclusion Small mammals and small birds were less exploited in France and Spain (L. m. meridionalis) than in Israel (L. m. elegans or L. m. aucheri), whereas the opposite might be expected, following a north–south climatic gradient. Thus, the nominate subspecies L. m. meridionalis differed in diet from L. m. elegans or L. m. aucheri. 相似文献