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261.
Abstract: Wildlife population models are potentially valuable for conservation planning. Validation is necessary to ensure that models are sufficiently robust for predicting management outcomes consistent with conservation objectives. Sorensen et al. (2008) produced a model of woodland caribou (Rangifer tarandus) population growth rate that was recently modified and used as a predictive tool at several scales. We computed confidence intervals and evaluated the performance of this model using novel data. Confidence intervals were wide, and results suggested that the model may have a positive bias, resulting in over-estimation of population growth rates, as well as low predictive power. Wide confidence intervals mean that current understanding of factors governing woodland caribou herd dynamics is not sufficient for wildlife managers to make reliable projections of responses to management. 相似文献
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CRAIG M. YOUNG 《Austral ecology》1990,15(4):413-426
Benthic suspension feeders often occur at high densities on temperate reefs and other hard bottoms. Beeause many such organisms hayc prodigious feeding rates in the laboratory, it has often been predicted that established epifauna would deplete larval populations, thereby influencing density, spatial distribution and species eomposition at settlement. Most field manipulations of filter-feeder density have not controlled for faetors other than larval predation that could produce the same pattern. In controlled experiments, larval predation effects are seldom observed. Intermittent feeding and small radii of predator influenee present many more opportunities for settlement than has generally been assumed. Two important faetors often foil attempts to measure predation effeets: low statistieal power due to small effect sizes, and choice of spatial scales larger than thdse where predation effeets oeeur. 相似文献
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CRAIG W. BENKMAN 《Ibis》1988,130(2):288-293
The importance of the crossed mandibles to crossbills for foraging on conifer cones was studied by removing most of the crossed portion of the mandibles of two Red Crossbills L. curvirostra. The foraging rate of these two bill-altered crossbills on the cones of three species of conifers was compared to their rates prior to bill alteration and to two controls. The mandible crossing proved essential for extracting seeds from closed cones. However, as cones open the bill crossing becomes less critical. The mandible crossing appears to be one of several adaptations of crossbills that have extended the period during which conifer seeds can be exploited effectively. 相似文献
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PATRICK K. DEVERS DEAN F. STAUFFER GARY W. NORMAN DAVE E. STEFFEN DARROCH M. WHITAKER JEFFREY D. SOLE TOM J. ALLEN STEVE L. BITTNER DAVID A. BUEHLER JOHN W. EDWARDS DANIEL E. FIGERT SCOTT T. FRIEDHOFF WILLIAM W. GIULIANO CRAIG A. HARPER WILLIAM K. IGO ROY L. KIRKPATRICK MICHAEL H. SEAMSTER HARRY A. SPIKER Jr. DAVID A. SWANSON BRIAN C. TEFFT 《野生动植物专论》2007,168(1):1-36