Landscape Function and Disturbance in Arctic Tundra

Transcription

1 James F. Reynolds John D. Tenhunen (Eds.) Landscape Function and Disturbance in Arctic Tundra With 109 Figures, 11 in color and 47 Tables Springer

2 Contents I Introduction 1 1 Ecosystem Response, Resistance, Resilience, and Recovery in Arctic Landscapes: Introduction J. F. REYNOLDS and J. D. TENHUNEN Introduction NRC Committee Report The R4D Program Objectives and Conceptual Framework Program Implementation Landscape Function Summary 14 References 16 2 Integrated Ecosystem Research in Northern Alaska, G. R. SHAVER Introduction Early Days at NARL The U. S. Tundra Biome Program The Meade River RATE Program Eagle Creek and Eagle Summit.', The Arctic LTER Program at Toolik Lake Other Studies In Alaska and Elsewhere Summary and Prospects 27 References 29 3 Disturbance and Recovery of Arctic Alaskan Vegetation D. A. WALKER Introduction Disturbance and Recovery Typical Disturbance and Recovery Patterns Small Disturbed Patches Contaminants Hydrocarbon Spills 43

3 VIII Contents Seawater and Reserve-Pit Spills Fire Transportation Corridors Bulldozed Tundra and Related Disturbances Off-Road Vehicle Trails Summer Travel Winter Travel Permanent Roads and Pads Gravel Mines Native Species in Revegetation of Gravel Pads and Mines Road Dust Roadside Impoundments Cumulative Impacts Conclusions 62 References 64 4 Terrain and Vegetation of the Imnavait Creek Watershed D. A. WALKER and M. D. WALKER Introduction Terrain Glacial Deposits Retransported Hillslope Deposits Colluvial Basin Deposits Floodplain Deposits Vegetation Flora Vegetation Types Lichen-Covered Rocks Dry Heath Exposed Sites Snowbeds Tussock Tundra Riparian Areas Mires Beaded Ponds West-Facing Toposequence Terrain Sensitivity to Disturbance Conclusions 98 Appendix A. List of Plants for Imnavait Creek, Alaska 99 References Vegetation Structure and Aboveground Carbon and Nutrient Pools in the Imnavait Creek Watershed S. C. HAHN, S. F. OBERBAUER, R. GEBAUER, N. E. GRULKE, O. L. LANGE, and J. D. TENHUNEN 109

4 Contents IX 5.1 Introduction Description of Vegetation Sampling Methods Cover Biomass and Nutrient Pools Cover Aboveground Biomass Live Biomass Photosynthetic Biomass Lichen Biomass Organic Litter Watershed Patterns Nutrient Pools N and P in Heath Cryptogams N and P in Communities Discussion and Conclusions 124 References 126 II Physical Environment, Hydrology, and Transport Energy Balance and Hydrological Processes in an Arctic Watershed L. HINZMAN, D. L. KANE, C. S. BENSON, and K. R. EVERETT Introduction Radiation and Thermal Regimes Surface Energy Balance Snow Cover and Soil Thermal Regime Hydrological Processes Snowmelt Plot and Basin Water Balance \ Runoff and Basin Discharge Precipitation, Evaporation, and Evapotranspiration Energy Balance and Hydrology Models Simulation of the Thermal Regime Simulation of Snowmelt v Simulation of Catchment Runoff Conclusions 152 References Shortwave Reflectance Properties of Arctic Tundra Landscapes A. S. HOPE and D. A. STOW Introduction Shortwave Reflectance Studies in Arctic Environments

5 X Contents Environmental Considerations Radiometric Data Image Data Spectral Reflectance ' Aboveground Biomass, Vegetation Composition Landscape Patterns Effects of Dust Deposition Albedo Undisturbed Tussock Tundra Effects of Dust Deposition Conclusions 162 References Isotopic Tracers for Investigating Hydrological Processes L. W. COOPER, I. L. LARSEN, C. SOUS, J. M. GREBMEIER, C. R. OLSEN, D. K. SOLOMON, and R. B. COOK Introduction Units Conservative vs Nonconservative Isotopes Nonconservative Tracers Sulfur Oxygen Oxygen-18 Content of Snowpack Oxygen-18 Content of Imnavait Creek Oxygen-18 Content of Soil Moisture Covariance of Oxygen-18 and Deuterium in Watershed Compartments Covariance of Oxygen-18 and Deuterium in Plant Water Long-Lived Radioisotopes: Lead-210 and Cesium Distribution of 137 Cs on Tundra and in Lake Sediments Cycling of 137 Cs in Annual Berries Distribution of 210 Pb in Tundra Conclusions 178 References 179 III Nutrient and Carbon Fluxes Surface Water Chemistry and Hydrology of a Small Arctic Drainage Basin K. R. EVERETT, D. L. KANE, and L. D. HINZMAN Introduction Watershed Instrumentation Snowmelt Period Snowmelt Hydrology 187

6 Contents XI Snowmelt Chemistry Overland Flow Water Track Flow Imnavait Creek Flow Post Snowmelt Period Atmospheric Inputs Rainfall Dry Deposition Rime Water Chemistry Overland Flow Active Layer Flow Imnavait Creek Flow Conclusions 198 References* Nutrient Availability and Uptake by Tundra Plants J. P. SCHIMEL, K. KIELLAND, and F. S. CHAPIN HI Introduction Controls on Mineralization and Nutrient Supply Patterns of Nutrient Supply in the Soil Patterns of Mineralization Controls on N and P Mineralization Controls on Decomposition and Mineralization Temperature Enzyme Activities Microbial Activity at Low Temperatures Freeze-Thaw Events Effects of Low Oxygen on Microbial Activity and Mineralization Substrate Quality ' Fate of Available Nutrients Microbial Nutrient Uptake and Competition with Plants Plant Uptake Soil Factors Controlling Nutrient Absorption Rooting Strategies Uptake Characteristics of Tundra Plants Retranslocation vs Current Uptake Disturbances Vehicle Tracks Road Dust Gray Water Climate Change 217 References 218

7 XII Contents 11 Landscape Patterns of Carbon Dioxide Exchange in Tundra Ecosytems S. F. OBERBAUER, W. CHENG, C. T. GILLESPIE, B. OSTENDORF, A. SALA, R. GEBAUER, R. A. VIRGINIA, and J. D. TENHUNEN Introduction Methods Community Types Leaf Photosynthesis Ecosystem Efflux Ecosystem Net CO 2 Exchange CO 2 Uptake Factors Affecting CO 2 Uptake Light Temperature Phenology Water Availability Nutrition Landscape Patterns in Leaf Photosynthesis CO 2 Efflux Factors Affecting CO 2 Efflux Live Plant Biomass Soil Quality Thaw Depth and Depth to Water Table Soil Moisture Soil Temperature Landscape Patterns of CO 2 Efflux Daily and Seasonal Patterns of CO 2 Efflux Dust Deposition Effects on CO 2 Efflux Landscape Patterns in Net CO 2 Exchange Conclusions 250 References Control of Tundra Methane Emission by Microbial Oxidation S. C. WHALEN, W. S. REEBURGH, and C. E. REIMERS Introduction Sampling Procedure Results and Discussion Methane Flux and Environmental Variables in Tundra and Taiga Physiology, Controls, and Potential for Microbial CH 4 Oxidation 265

8 Contents, XIII Methane Oxidation by Tundra Soils in a Warmer Climate Conclusions 271 References Dynamics of Dissolved and Particulate Carbon in an Arctic Stream M. W. OSWOOD, J. G. IRONS III, and D. M. SCHELL Introduction Site Description Imnavait Creek Watershed Description of Imnavait Creek Field and Laboratory Procedures Physical Regime Carbon in Imnavait Creek Concentrations Transport Spatial Variability Seasonal Dynamics Conclusions 285 References 287 IV Modeling Landscape Function Patch and Landscape Models of Arctic Tundra: Potentials and Limitations J. F. REYNOLDS, J. D. TENHUNEN, P. W. LEADLEY, H. Li, D. L. MOORHEAD, B. OSTENDORF, and F. S. CHAPIN III Introduction Modeling Framework ' ; _ Spatial Simulation Units \ Types of Models Bottom-Up Models Ecosystem Gas Exchange Motivation Description Potentials and Limitations Plant Growth Motivation Description Potentials and Limitations Nitrogen Uptake Motivation Description 306

9 XIV.. Contents Potentials and Limitations Decomposition Motivation Description Potentials and Limitations Top-Down Models Hydrologic Transport Motivation Description Potentials and Limitations Topographically Derived Vegetation Model Motivation Description Potentials and Limitations Conclusions 318 References Modeling Dry Deposition of Dust Along the Dalton Highway R. LAMPRECHT and W. GRABER Introduction Model Fundamentals Modeling Heavy Particle Dispersion Estimation of Atmospheric Boundary Layer Parameters Dust Characterization and Mass Transfer Through the Atmosphere Theory of Particle Dry Deposition into Vegetation Numerical Results Conclusions 343 References Modeling Decomposition in Arctic Ecosystems D. L. MOORHEAD and J. F. REYNOLDS Introduction Controls on Decomposition Arctic Decomposition Models ABISKO ARTUS BARK GENDEC General Description Validation Model Comparisons Effects of Environmental Changes 359

10 Contents. XV Climate Change Effects of Elevated CO Impacts of Road Dust Deposition Tussock Phosphorus Dynamics Conclusions 362 References Hydrological Controls on Ecosystem Gas Exchange in an Arctic Landscape B. OSTENDORF, P. QUINN, K. BEVEN, and J. D. TENHUNEN Introduction Description of Models Community Gas Exchange Spatial Variation in Water Availability Coupling of Hydrology and Ecosystem Gas Exchange Vegetation Distribution Spatial Variation in Water Table Water Balance and Seasonal Changes in Water Fluxes Evapotranspiration Discharge Interception and Surface Water Retention Carbon Balance and Seasonal Changes in Carbon Fluxes Predicted Water Table and Soil Respiration Predicted Watershed Level Net CO 2 Balance Discussion and Conclusions 382 References Road-Related Disturbances in an Arctic Watershed: Analyses by a Spatially Explicit Model of Vegetation and Ecosystem Processes P. W. LEADLEY, H. LI, B. OSTENDORF, andj. F. REYNOLDS Introduction Environmental Gradients and Vegetation Distribution Vegetation and Topography Role of Water and Light Role of Nutrients Description of Model Overview T-HYDRO T-VEG T-NUT T-PLT 394

11 XVI Contents Disturbance Scenarios Effects of Altering Discharge Effects of Road Dust Model Validation and Limitations Model Predictions for Undisturbed Watershed Vegetation Discharge N Availability and NPP Model Evaluation Model Predictions for Disturbed Watershed Discharge Disturbance Road#l Road # Roads #3 and # Dust and Discharge Disturbance Effect of Disturbance on Spatial Patterns Discussion Model Comparisons Patterns of N Availability Extrapolation Potential: Some Cautionary Notes Conclusions 412 References 413 V Summary Ecosystem Response, Resistance, Resilience, and Recovery in Arctic Landscapes: Progress and Prospects J. D. TENHUNEN and }. F. REYNOLDS The NRC Tasks and R4D Accomplishments Conclusion 425 References 426 Subject Index ': 429