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Filters: partyWithName: Boonstra, Rudy (X) > partyWithName: Krebs, Charles J. (X) > Extensions: Citation (X)

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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
The following is a book review found at http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v416/n6882/full/416679a_fs.html in the journal Nature. Just as every picture tells a story, so too does every scientific project. This book is the story of the Kluane Boreal Forest Ecosystem Project, told brilliantly by the researchers who toiled for ten years from 1986 to uncover the drama and complexity of this Canadian ecosystem. Whoever wants to learn about the boreal forest of North America, one of the largest ecosystems of the world, and the stage on which a classic ecological drama — the ten-year population cycle of the snowshoe hare — is played out repeatedly, should definitely read this book. Equally...
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....
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...
Small mammals in boreal forest ecosystems fluctuate dramatically in abundance and 1 possible mechanism to explain these changes is the bottom-up hypothesis of variation in food supplies. Here we ask if variation in berry crops produced by 6 major species of dwarf shrubs and herbs, epigeous mushroom crops, and white spruce seeds allow us to predict changes in the abundance of the red-backed vole (Myodes [= Clethrionomys] rutilus), the deer mouse (Peromyscus maniculatus), and field voles (Microtus oeconomus and M. pennsylvanicus combined) over 13 years (1997-2009) in the Kluane Lake region of the southwestern Yukon, Canada. M. rutilus is the dominant rodent in these forests, comprising 64% of the catch. Overwinter...
Chapter 5
Categories: Publication; Types: Citation; Tags: M1-Ecosystems


map background search result map search result map 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 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