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Categories: Publication; Types: Citation; Tags: M1-Birds
Predation is a central organizing process affecting populations and communities. Traditionally, ecologists have focused on the direct effects of predation--the killing of prey. However, predators also have significant sublethal effects on prey populations. We investigated how fluctuating predation risk affected the stress physiology of a cyclic population of snowshoe hares (Lepus americanus) in the Yukon, finding that they are extremely sensitive to the fluctuating risk of predation. In years of high predator numbers, hares had greater plasma cortisol levels at capture, greater fecal cortisol metabolite levels, a greater plasma cortisol response to a hormone challenge, a greater ability to mobilize energy and poorer...
Estimating population densities of small mammals (< 100 g) has typically been carried out by intensive livetrapping, but this technique may be stressful to animals and the effort required is considerable. Here, we used camera traps to detect small mammal presence and assessed if this provided a feasible alternative to livetrapping for density estimation. During 2010-2012, we used camera trapping in conjunction with mark-recapture livetrapping to estimate the density of northern red-backed voles (Myodes rutilus) and deer mice (Peromyscus maniculatus) in the boreal forest of Yukon, Canada. Densities for these 2 species ranged from 0.29 to 9.21 animals/ha and 0 to 5.90 animals/ha, respectively, over the course of this...
Categories: Publication; Types: Citation; Tags: M1-Birds
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The boreal forests of North America are undergoing major changes because of the direct effects of global warming and increased CO sub(2) levels. Plant production in the boreal forest is nutrient limited, and we examined how long-term fertilization affected growth of white spruce Picea glauca in the face of these major changes. We conducted a large-scale experiment by fertilizing two 1 km super(2) stands of white spruce in the southwestern Yukon with commercial NPK fertilizer from 1987 to 1994. Tree growth was measured by the width of annual increments in 60 trees from each of 2 control and of 2 matched fertilized 1 km super(2) sites for the period from 1977 to 1997 in a before, during, and after experimental design....


map background search result map search result map Population limitation of the northern red-backed vole in the boreal forests of northern Canada Climate and nutrient influences on the growth of white spruce trees in the boreal forests of the Yukon Seasonal changes in glucocorticoid and testosterone concentrations in free-living arctic ground squirrels from the boreal forest of the Yukon Estimating snowshoe hare population density from pellet plots: a further evaluation Experimental design and practical problems of implementation Herbivores - Forest grouse and ptarmigan Arctic ground squirrel population collapse in the boreal forests of the Southern Yukon Ecosystem Dynamics of the Boreal Forest: the Kluane Project Why Do the Boreal Forest Ecosystems of Northwestern Europe Differ from Those of Western North America? Why Do the Boreal Forest Ecosystems of Northwestern Europe Differ from Those of Western North America? Climate and nutrient influences on the growth of white spruce trees in the boreal forests of the Yukon Herbivores - Forest grouse and ptarmigan Experimental design and practical problems of implementation Arctic ground squirrel population collapse in the boreal forests of the Southern Yukon Seasonal changes in glucocorticoid and testosterone concentrations in free-living arctic ground squirrels from the boreal forest of the Yukon Estimating snowshoe hare population density from pellet plots: a further evaluation Ecosystem Dynamics of the Boreal Forest: the Kluane Project Population limitation of the northern red-backed vole in the boreal forests of northern Canada