Filters: Tags: monitoring 1-Changes in Plant and Animal Distribution: Fauna (X) > partyWithName: Krebs, Charles J. (X)
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The insulative value of early and deep winter snow is thought to enhance winter reproduction and survival by arctic lemmings (Lemmus and Dicrostonyx spp). This leads to the general hypothesis that landscapes with persistently low lemming population densities, or low amplitude population fluctuations, have a low proportion of the land base with deep snow. We experimentally tested a component of this hypothesis, that snow depth influences habitat choice, at three Canadian Arctic sites: Bylot Island, Nunavut; Herschel Island, Yukon; Komakuk Beach, Yukon. We used snow fencing to enhance snow depth on 9-ha tundra habitats, and measured the intensity of winter use of these and control areas by counting rodent winter nests...
Categories: Publication;
Types: Citation;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Categories: Publication;
Types: Citation;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Categories: Data,
Publication;
Types: Citation,
Downloadable,
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Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
The insulative value of early and deep winter snow is thought to enhance winter reproduction and survival by arctic lemmings (Lemmus and Dicrostonyx spp). This leads to the general hypothesis that landscapes with persistently low lemming population densities, or low amplitude population fluctuations, have a low proportion of the land base with deep snow. We experimentally tested a component of this hypothesis, that snow depth influences habitat choice, at three Canadian Arctic sites: Bylot Island, Nunavut; Herschel Island, Yukon; Komakuk Beach, Yukon. We used snow fencing to enhance snow depth on 9-ha tundra habitats, and measured the intensity of winter use of these and control areas by counting rodent winter nests...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
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: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
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: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Categories: Publication;
Types: Citation;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
at publisher site.]
Categories: Publication;
Types: Citation;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Categories: Publication;
Types: Citation;
Tags: Birds,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Categories: Publication;
Types: Citation;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
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...
Neonatal reproductive failure should occur when energetic costs of parental investment outweigh fitness benefits. However, little is known about the drivers of neonatal reproductive failure in free-ranging species experiencing continuous natural variation in predator abundance and in the energetic and fitness costs and benefits associated with parental investment., Long-term comprehensive studies are required to better understand how biotic, abiotic and life-history conditions interact to drive occurrences of reproductive failure in the wild., Using 24 years (1987-2011) of reproductive data from a northern boreal population of North American red squirrels in south-western Yukon, we examined the effects of predator...
Categories: Publication;
Types: Citation;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Body condition of animals influences the likelihood of surviving harsh environmental conditions, successfully reproducing, and resisting disease. The sum of these individual components of fitness, in turn, have consequences for the growth and persistence of wildlife populations. Here we compared the body mass and condition of adult female arctic ground squirrels ( Urocitellus parryii plesius (Osgood, 1900)), an obligate hibernator, in source and sink habitats. We tested the hypothesis that adult females would be in poorer condition in the boreal forest than in adjacent meadows. We found that, during spring, postpartum females in forests weighed less (405 ± 7 vs. 437 ± 11 g; mean ± SE) and were in poorer condition...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Birds,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Neonatal reproductive failure should occur when energetic costs of parental investment outweigh fitness benefits. However, little is known about the drivers of neonatal reproductive failure in free-ranging species experiencing continuous natural variation in predator abundance and in the energetic and fitness costs and benefits associated with parental investment., Long-term comprehensive studies are required to better understand how biotic, abiotic and life-history conditions interact to drive occurrences of reproductive failure in the wild., Using 24 years (1987-2011) of reproductive data from a northern boreal population of North American red squirrels in south-western Yukon, we examined the effects of predator...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
Chapter 12
Categories: Data,
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Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
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...
Categories: Data,
Publication;
Types: Citation,
Downloadable,
Map Service,
OGC WFS Layer,
OGC WMS Layer,
Shapefile;
Tags: Mammals,
Monitoring 1-Changes in Plant and Animal Distribution: Fauna
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