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Contributors | |
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Introduction | |
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General Introduction | |
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The Kluane Region | |
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Geography and Geology | |
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Weather and Climate | |
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Temperature | |
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Precipitation | |
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Study Area and Vegetation | |
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Vertebrate Food Web | |
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History of Hare Cycles | |
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Large Mammals | |
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Human Impacts | |
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Trophic Interactions, Community Organization, and the Kluane Ecosystem | |
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Trophic-level Theory | |
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Community Structure | |
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Control of Trophic-level Biomass | |
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Case Studies in Mammalian Communities | |
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Interactions of Trophic Levels | |
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Bottom-up Models | |
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Top-down Models | |
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Herbivore-dominated Models | |
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Vegetation-dominated Models | |
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Dilution Models | |
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Reciprocal Models | |
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Experimental Perturbations in the Boreal Forest | |
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Experiment 1: Application of Fertilizer | |
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Experiment 2: Addition of Rabbit Chow | |
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Experiment 3: Exclusion of Carnivores | |
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Experiment 4: Exclusion of Carnivores and the Addition of Rabbit Chow | |
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Experiment 5: Exclusion of Hares | |
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Experiment 6: Exclusion of Hares and the Addition of Fertilizer | |
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Experiment 7: Removal of Vegetation | |
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Discussion | |
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Limitations of the Models | |
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Models of Trophic-level Interactions in Different Ecosystems | |
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Summary | |
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Experimental Design and Practical Problems of Implementation | |
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Experimental Design | |
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Choice of Treatments | |
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Size and Spatial Location of Treatments | |
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To Replicate or Not to Replicate | |
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Practical Problems of Implementation | |
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The Evolution of a Predator-proof Fence | |
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Food Supplementation | |
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Fertilizer | |
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Hare Exclosures | |
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Organization, Personnel, and Equipment | |
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Organizational Structure | |
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The Problem of Training and Protocols | |
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Seen Sheets | |
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Winter Work at Kluane | |
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Equipment | |
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Summary | |
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Plant Dynamics | |
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Herbs and Grasses | |
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Hypotheses Regarding Vegetation | |
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Study Area | |
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Tests of Predictions from Three Models | |
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Donor Control Model | |
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Herbivore Control Model | |
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Combined Top-down Bottom-up Model | |
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Which Model Best Describes Boreal Forest Herbs and Grasses? | |
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Transient Dynamics and Stability | |
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Impacts of Climatic Warming | |
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Summary | |
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Shrubs | |
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The Shrub Community at Kluane | |
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Species Composition | |
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Pattern Changes and Succession | |
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Secondary Chemicals in Kluane Shrubs | |
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Biomass Dynamics | |
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Methods of Estimation | |
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Impacts of Treatments | |
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Growth Rates of Shrubs | |
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Methods of Estimation | |
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Impacts of Treatments | |
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Losses of Twigs to Browsing and Natural Mortality | |
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Methods of Estimation | |
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Impacts of Treatments | |
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What Limits Primary Production of Shrubs? | |
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Succession in Boreal Forest Shrubs | |
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Impact of Hare and Moose Browsing | |
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Role of Secondary Chemicals | |
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Summary | |
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Trees | |
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Tree Community at Kluane | |
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Tree Abundance on the Study Area | |
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Tree Growth | |
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White Spruce Cone and Seed Production | |
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Vegetation Mapping | |
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Fire History of the Study Area | |
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Other Forms of Disturbance | |
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Succession in the Boreal Forest | |
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Fertilizer Effects on Trees | |
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Summary | |
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Herbivores | |
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Snowshoe Hare Demography | |
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The Snowshoe Hare Cycle | |
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Methods | |
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Demographic Parameters | |
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Density and Rates of Change | |
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Sex and Age Structure | |
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Reproduction | |
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Survival Rates | |
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Causes of Death | |
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Immigration and Emigration | |
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Impacts of Experimental Treatments | |
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Impacts on Hare Demography | |
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Causation of the Hare Cycle | |
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Efficacy of the Experimental Treatments | |
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Experimental Scale and Methodological Concerns | |
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Interactions with Other Species | |
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Conclusions | |
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The Role of Red Squirrels and Arctic Ground Squirrels | |
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Natural History | |
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Red Squirrels | |
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Arctic Ground Squirrels | |
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Community Interactions and Factors Affecting Population Dynamics | |
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Methods | |
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Red Squirrels | |
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Arctic Ground Squirrels | |
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Results | |
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Red Squirrels | |
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Arctic Ground Squirrels | |
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Discussion | |
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Role of Stochastic Events | |
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Treatment Effects | |
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Role of Squirrels in the Boreal Forest Community | |
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Conclusions | |
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Voles and Mice | |
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Natural History and Food Web Links | |
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Community Interactions and Factors Affecting Population Dynamics | |
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Methods | |
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Small Mammal Trapping | |
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Data Analysis | |
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Robustness of Data | |
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Impacts of the Manipulations | |
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Northern Red-Backed Vole | |
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Microtus Voles | |
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What Limits Mice and Vole Populations at Kluane? | |
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Northern Red-Backed Vole | |
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Microtus Species | |
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Summary | |
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Forest Grouse and Ptarmigan | |
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The Ecological Role of Forest and Alpine Grouse | |
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Trophic Position | |
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Life History | |
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Habitats | |
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Current Understanding of Population Dynamics | |
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Predicted Responses to Experimental Treatments | |
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Methods | |
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Duration of Grouse Studies | |
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Shakwak Valley Population Trends | |
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Numerical and Reproductive Parameters on Treatment Grids | |
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Data Robustness and Limitations | |
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Demography of Grouse | |
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Population Trends in the Shakwak Valley | |
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Reproductive Parameters | |
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Population Trends on Control Plots | |
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Relationship of Changes to the Snowshoe Hare Cycle | |
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Response of Forest Grouse to Experimental Treatments | |
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Fertilizer Addition | |
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Food Addition | |
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Predator Exclosure | |
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Predator Exclosure + Food | |
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Discussion | |
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Hypotheses Related to Grouse Population Trends | |
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Did the Experiments Change the Dynamics for Grouse? | |
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Linkages on the Same Trophic Level | |
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Linkages to Other Trophic Levels | |
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Conclusions | |
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Comparison with Other Studies | |
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Unexpected Results | |
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Unanswered Questions | |
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Other Herbivores and Small Predators: Arthropods, Birds, and Mammals | |
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Methods | |
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Arthropods | |
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Songbirds and Woodpeckers | |
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Other Herbivores | |
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Predicted Responses to Experimental Treatments | |
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Responses by Species Groups | |
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Arthropods | |
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Birds | |
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Other Herbivores | |
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Discussion | |
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Links to the 10-Year Cycle | |
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Effects of Fertilization | |
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Other Patterns in the Food Web | |
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Summary | |
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Mammalian Predators | |
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Coyotes and Lynx | |
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Methods | |
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Population Monitoring | |
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Foraging Behavior | |
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Functional Responses | |
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Numerical Responses | |
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Density | |
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Adult Survival | |
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Emigration | |
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Recruitment | |
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Social Organization | |
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Home Ranges | |
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Social Groups | |
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Foraging Behavior | |
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Diets | |
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Scavenging Behavior | |
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Hunting Tactics | |
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Group Hunting | |
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Use of Trails | |
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Habitat Use | |
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Functional Responses | |
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Components of Functional Responses | |
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Prey Switching | |
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Synthesis and Conclusions | |
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Numerical Responses | |
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Functional Responses | |
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Total Impact of Predation by Coyotes and Lynx on Hares | |
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Impact of Predation by Coyotes and Lynx on Alternative Prey | |
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Coexistence of Coyotes and Lynx | |
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The Specialist-Generalist Contrast | |
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Other Mammalian Predators | |
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Methods | |
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Red Fox | |
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Wolf | |
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Weasel | |
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Wolverine | |
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Marten | |
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Mink and Otter | |
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Synthesis and Conclusions | |
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Avian Predators | |
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Great Horned Owls | |
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Methods | |
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Population Census | |
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Monitoring Diets | |
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Radio Telemetry | |
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Analysis of Telemetry Data | |
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Statistical Analyses | |
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Demography | |
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Reproduction and Population Productivity | |
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Survival and Emigration | |
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Estimating Numerical Responses | |
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Foraging Behavior | |
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Diet | |
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Prey Preferences | |
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Estimating Functional Responses and Predation Impact | |
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Social Organization | |
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Social Status and Vocal Activity | |
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Stability and Size of Home Ranges | |
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Effect of Territoriality on Spacing of Owls | |
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Territorial Behavior and Limitation of Population Increase | |
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Social Behavior and the Time Lag in the Numerical Response | |
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Responses to Large-Scale Experiments | |
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Space Use in Territories with Experimental Hot Spots of Prey | |
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Predator Movements from Poor Patches to Rich Patches | |
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Discussion | |
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Large Floating Population When Resources Are Abundant | |
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Factors Affecting Functional Responses and Predation Impact | |
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Limitation of Population Growth at Peaks of Cyclic Prey | |
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Time Lag in the Numerical Response of a Predator of Cyclic Prey | |
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Factors Limiting Spatial Aggregation of Predators | |
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Raptors and Scavengers | |
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Methods | |
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General Approach | |
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Population Surveys: The Intensive Search Area | |
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Reproductive Success | |
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Diets | |
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Data Analysis | |
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Predicted Responses of Raptors and Corvids | |
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Responses by Groups and Individual Species | |
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Large Resident Raptors | |
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Large Migratory Raptors | |
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Small Migratory Raptors | |
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Small Owls | |
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Corvids | |
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Other Raptors | |
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Intraguild Predation | |
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Discussion | |
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Functional, Numerical, and Reproductive Responses to Hare Densities | |
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Resource Partitioning and Diet Width | |
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Intraguild Predation | |
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Methodology and Limitations | |
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Summary | |
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Community and Ecosystem Organization | |
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Testing Hypotheses of Community Organization for the Kluane Ecosystem | |
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Experimental Perturbations of the Boreal Forest | |
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Direct and Indirect Effects | |
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The Experiments | |
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Methods | |
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Soil Nitrogen | |
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Vegetation | |
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Plant Secondary Chemicals | |
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Herbivore Biomass | |
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Predator Activity | |
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Direct Effects of Trophic-level Perturbations | |
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Fertilizer Addition | |
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Addition of Hare Food | |
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Predator Exclosure | |
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Predator Exclosure and Food Addition | |
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Hare Exclosure | |
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Hare Exclosure Plus Fertilizer | |
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Vegetation Removal | |
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Indirect Effects of Trophic-level Perturbations | |
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Fertilizer Addition | |
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Food Addition | |
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Predator Exclosure | |
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Food Addition and Predator Exclosure | |
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Hare Exclosure | |
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Discussion | |
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Direct Effects | |
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Indirect Effects | |
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Top-down versus Bottom-up | |
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Productivity and Biomass Responses | |
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Other Indirect Effects | |
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The Role of Secondary Chemicals | |
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The Dominant Pathways in the Vertebrate Community | |
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Conclusion | |
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Summary | |
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Vertebrate Community Structure in the Boreal Forest: Modeling the Effects of Trophic Interaction | |
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Trophic Interaction and Species Coexistence | |
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Interaction between Vegetation and Herbivores | |
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Interaction between Herbivores and Predators | |
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Modeling | |
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Interaction between Vegetation and Herbivores | |
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Equilibrium Conditions for Snowshoe Hares and Ground Squirrels | |
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Adding Predation to Models of Interaction between Herbivores and Vegetation | |
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The Effect of Herbivore Cycles on Predators | |
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Discussion | |
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Unresolved Modeling Issues | |
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Mechanisms of Coexistence | |
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Top-down and Bottom-up Influences on Community Structure | |
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Trophic Mass Flow Models of the Kluane Boreal Forest Ecosystem | |
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Questions about the Ecosystem Dynamics of the Boreal Forest | |
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Modeling the Kluane System | |
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Methods for Constructing Mass Balance Models | |
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Parameterization of Mass Balance Models | |
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Results from Mass Balance Models | |
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Consumption of Plant Biomass by Herbivores | |
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Phase of Cycle Models | |
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Seasonal Models | |
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Food Addition and Predator Reduction Models | |
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Partial Food Web Models | |
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Discussion | |
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Do Predator-Prey Dynamics Structure the Boreal Forest Ecosystem? | |
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Potential for Other Ecopath Models | |
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Synthesis and Implications | |
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Summary | |
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Conclusions and Future Directions | |
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Primary Findings | |
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Predator Trophic Level | |
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Herbivore Trophic Level | |
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Plant Trophic Level | |
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Secondary Findings | |
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Predator Trophic Level | |
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Herbivore Trophic Level | |
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Plant Trophic Level | |
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Opportunities for Further Work | |
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Unsolved Problems | |
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Future Boreal Forest Research | |
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How to Use the Enclosed Kluane CD-ROM | |
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Table of Contents for the Kluane CD-ROM | |
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Index | |