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• 31. [Article] The Impact of Disturbance on Carbon Stores and Dynamics in Forests of Coastal Alaska

  Changes in climate caused by increased concentrations of carbon dioxide (CO₂) in the Earth’s atmosphere have led land and ocean surface temperatures to increase by 0.85°C and sea level to increase by 19 ...

  Citation × Citation Citation Abstract Copy Title: The Impact of Disturbance on Carbon Stores and Dynamics in Forests of Coastal Alaska Author: Yatskov, Mikhail A. Changes in climate caused by increased concentrations of carbon dioxide (CO₂) in the Earth’s atmosphere have led land and ocean surface temperatures to increase by 0.85°C and sea level to increase by 19 cm relative to preindustrial times. Global climate change will lead to further alterations in mean temperature and precipitation, as well as their extremes that are likely to influence disturbance regimes. Disturbance play an important role in forest dynamics and succession, by influencing forest ecosystems structure and function, reorganizing forests by reducing live and increasing dead matter, and thus affecting ecosystem carbon (C) balances. Under a changing climate disturbances are likely to cause widespread tree mortality across forested landscapes, creating vast amounts of coarse woody debris (CWD) that will emit C to the atmosphere to a degree that regional C balances and future C dynamics are likely to change. C balance of forested regions depends on inputs in form of C sequestered by live components during growth and outputs in form of C emitted from dead components through decomposition and combustion. Live trees in many forest ecosystems represent the largest aboveground C pool and the dynamics of this pool, as controlled by growth and mortality, have been extensively studied. In contrast, few have examined either the post-disturbance fate of CWD C or assessed C storage potential of salvaged biomass despite the occurrence of multiple recent large-scale disturbance events. Biomass and C stores and their uncertainty were estimated in the Temperate and the Boreal ecoregions of Coastal Alaska using the empirical data from the Forest Inventory and Analysis (FIA) program, literature data, and modeling using standard methods employed by the FIA program. The average aboveground woody live (218.9±4.6 Mg/ha) and log (28.1±1.8 Mg/ha) biomass in the Temperate ecoregion were among the lowest in the Pacific Northwest, whereas snag biomass (30.5±1.0 Mg/ha) was among the highest. In the Boreal ecoregion, CWD biomass comprised almost 50% of the regional aboveground woody store (76.7±3.8 Mg/ha) with bark beetle damaged stands containing 82% of the total CWD biomass. In contrast, in the Temperate ecoregion, CWD comprised 20% of the regional aboveground woody store (277.5 ±5.4 Mg/ha) with 76% of total CWD biomass in undisturbed stands. Total C stores estimates in Coastal Alaska ranged between 1523.6 and 1892.8 Tg with the highest contribution from soils and the largest potential reductions in uncertainty related to the tree and soils C pools. The impact of a large-scale spruce bark beetle (SBB) outbreak on aboveground dead wood C dynamics on the Kenai Peninsula was modeled utilizing data from the FIA program and CWD decomposition rate-constants from a chronosequence and decomposition-vectors analysis. Decomposition rate-constants from the chronosequence ranged between -0.015 yr⁻¹ and -0.022 yr⁻¹ for logs and -0.003 yr⁻¹ and +0.002 yr⁻¹ for snags. Decomposition rate-constants from the decomposition-vectors ranged between -0.045 yr⁻¹ and +0.003 yr⁻¹ among decomposition phases and -0.048 yr⁻¹ and +0.006 yr⁻¹ among decay classes. Relative to log generating disturbances those creating snags delayed C flux from CWD to the atmosphere, produced a smaller magnitude C flux, and had the potential to store 10% to 66% more C in a disturbed system over time. The effect of several management strategies ranging from "leave-as-is" to "salvage-and-utilization" on C stores and emissions following SBB outbreak on Kenai Peninsula, Alaska was evaluated. A forest with immediate post-disturbance regeneration reached pre-disturbance C stores faster than one with delayed regeneration. Lack of regeneration, representing a loss of tree cover on the disturbed portion of the landscape, caused a permanent decrease in wood C stores. Among the "salvage-and-utilization" scenarios considered, biomass fuel production with substitution for fossil fuels created the largest long-term C storage assuming the substitution was permanent. Given that reduction in near-term emissions may be a more robust strategy than long-term ones, the "leave-as-is" scenarios may represent the most feasible way to mitigate global climate change following disturbance. Title: The Impact of Disturbance on Carbon Stores and Dynamics in Forests of Coastal Alaska Author: Yatskov, Mikhail A. Changes in climate caused by increased concentrations of carbon dioxide (CO₂) in the Earth’s atmosphere have led land and ocean surface temperatures to increase by 0.85°C and sea level to increase by 19 cm relative to preindustrial times. Global climate change will lead to further alterations in mean temperature and precipitation, as well as their extremes that are likely to influence disturbance regimes. Disturbance play an important role in forest dynamics and succession, by influencing forest ecosystems structure and function, reorganizing forests by reducing live and increasing dead matter, and thus affecting ecosystem carbon (C) balances. Under a changing climate disturbances are likely to cause widespread tree mortality across forested landscapes, creating vast amounts of coarse woody debris (CWD) that will emit C to the atmosphere to a degree that regional C balances and future C dynamics are likely to change. C balance of forested regions depends on inputs in form of C sequestered by live components during growth and outputs in form of C emitted from dead components through decomposition and combustion. Live trees in many forest ecosystems represent the largest aboveground C pool and the dynamics of this pool, as controlled by growth and mortality, have been extensively studied. In contrast, few have examined either the post-disturbance fate of CWD C or assessed C storage potential of salvaged biomass despite the occurrence of multiple recent large-scale disturbance events. Biomass and C stores and their uncertainty were estimated in the Temperate and the Boreal ecoregions of Coastal Alaska using the empirical data from the Forest Inventory and Analysis (FIA) program, literature data, and modeling using standard methods employed by the FIA program. The average aboveground woody live (218.9±4.6 Mg/ha) and log (28.1±1.8 Mg/ha) biomass in the Temperate ecoregion were among the lowest in the Pacific Northwest, whereas snag biomass (30.5±1.0 Mg/ha) was among the highest. In the Boreal ecoregion, CWD biomass comprised almost 50% of the regional aboveground woody store (76.7±3.8 Mg/ha) with bark beetle damaged stands containing 82% of the total CWD biomass. In contrast, in the Temperate ecoregion, CWD comprised 20% of the regional aboveground woody store (277.5 ±5.4 Mg/ha) with 76% of total CWD biomass in undisturbed stands. Total C stores estimates in Coastal Alaska ranged between 1523.6 and 1892.8 Tg with the highest contribution from soils and the largest potential reductions in uncertainty related to the tree and soils C pools. The impact of a large-scale spruce bark beetle (SBB) outbreak on aboveground dead wood C dynamics on the Kenai Peninsula was modeled utilizing data from the FIA program and CWD decomposition rate-constants from a chronosequence and decomposition-vectors analysis. Decomposition rate-constants from the chronosequence ranged between -0.015 yr⁻¹ and -0.022 yr⁻¹ for logs and -0.003 yr⁻¹ and +0.002 yr⁻¹ for snags. Decomposition rate-constants from the decomposition-vectors ranged between -0.045 yr⁻¹ and +0.003 yr⁻¹ among decomposition phases and -0.048 yr⁻¹ and +0.006 yr⁻¹ among decay classes. Relative to log generating disturbances those creating snags delayed C flux from CWD to the atmosphere, produced a smaller magnitude C flux, and had the potential to store 10% to 66% more C in a disturbed system over time. The effect of several management strategies ranging from "leave-as-is" to "salvage-and-utilization" on C stores and emissions following SBB outbreak on Kenai Peninsula, Alaska was evaluated. A forest with immediate post-disturbance regeneration reached pre-disturbance C stores faster than one with delayed regeneration. Lack of regeneration, representing a loss of tree cover on the disturbed portion of the landscape, caused a permanent decrease in wood C stores. Among the "salvage-and-utilization" scenarios considered, biomass fuel production with substitution for fossil fuels created the largest long-term C storage assuming the substitution was permanent. Given that reduction in near-term emissions may be a more robust strategy than long-term ones, the "leave-as-is" scenarios may represent the most feasible way to mitigate global climate change following disturbance. Close

• 32. [Article] Relationships among juvenile anadromous salmonids, their freshwater habitat, and landscape characteristics over multiple years and spatial scales in the Elk River, Oregon

  Research on the distribution of juvenile salmonids in streams has been dominated by studies examining small areas over short periods. However, information relevant to freshwater influences on population ...

  Citation × Citation Citation Abstract Copy Title: Relationships among juvenile anadromous salmonids, their freshwater habitat, and landscape characteristics over multiple years and spatial scales in the Elk River, Oregon Author: Burnett, Kelly M. Research on the distribution of juvenile salmonids in streams has been dominated by studies examining small areas over short periods. However, information relevant to freshwater influences on population persistence is likely to derive from longer-term, multi-scale studies. Relationships were examined among juvenile anadromous salmonids, their freshwater habitat, and landscape characteristics throughout the Elk River, Oregon over 7 years at multiple spatial scales. Ocean-type chinook salmon (Oncorhynchus tshawytscha), coho salmon (0. kisutch), coastal cutthroat trout (0. clarki) and winter-run steelhead (0. mykiss) comprised the salmonid assemblage. Habitat selection was quantified at stream system, valley segment, and channel unit scales by selection ratios estimated with bootstrapping methods. Unconstrained valleys in tributaries and pools in the mainstem were typically selected by each species except steelhead, which often avoided these. Valley segment types generally did not differ for characteristics routinely assessed in stream surveys. Thus, fish probably perceived other biotic or abiotic differences among valley segment types. Evidence suggested competition may have influenced selection by coho and chinook salmon. Discriminant analysis indicated that level of use by juvenile chinook salmon appeared related to valley segment type and spatial position. Unconstrained valleys, nearby valley segments, and valley segments with larger, deeper pools, containing more wood were most highly used by chinook salmon. Mean volume and maximum depth of pools were each directly related to catchment area, which explained more variation than landscape characteristics summarized at any of five spatial scales. At each scale except the most spatially extensive, wood density in valley segments was negatively related to the percent area in resistant rock types and positively related to the percent area in mature to old forests. The most variation was explained with these landscape variables summarized at an intermediate spatial scale (i.e., sub-catchment). Although spatial scales appeared similar in processes affecting wood density, finer scales omitted key source areas for wood delivery, and coarser scales included source areas less tightly coupled to wood dynamics in surveyed channels. If only 1 or 2 years of data or one spatial scale had been examined, as commonly occurs, conclusions may have differed substantially from those in this study. Title: Relationships among juvenile anadromous salmonids, their freshwater habitat, and landscape characteristics over multiple years and spatial scales in the Elk River, Oregon Author: Burnett, Kelly M. Research on the distribution of juvenile salmonids in streams has been dominated by studies examining small areas over short periods. However, information relevant to freshwater influences on population persistence is likely to derive from longer-term, multi-scale studies. Relationships were examined among juvenile anadromous salmonids, their freshwater habitat, and landscape characteristics throughout the Elk River, Oregon over 7 years at multiple spatial scales. Ocean-type chinook salmon (Oncorhynchus tshawytscha), coho salmon (0. kisutch), coastal cutthroat trout (0. clarki) and winter-run steelhead (0. mykiss) comprised the salmonid assemblage. Habitat selection was quantified at stream system, valley segment, and channel unit scales by selection ratios estimated with bootstrapping methods. Unconstrained valleys in tributaries and pools in the mainstem were typically selected by each species except steelhead, which often avoided these. Valley segment types generally did not differ for characteristics routinely assessed in stream surveys. Thus, fish probably perceived other biotic or abiotic differences among valley segment types. Evidence suggested competition may have influenced selection by coho and chinook salmon. Discriminant analysis indicated that level of use by juvenile chinook salmon appeared related to valley segment type and spatial position. Unconstrained valleys, nearby valley segments, and valley segments with larger, deeper pools, containing more wood were most highly used by chinook salmon. Mean volume and maximum depth of pools were each directly related to catchment area, which explained more variation than landscape characteristics summarized at any of five spatial scales. At each scale except the most spatially extensive, wood density in valley segments was negatively related to the percent area in resistant rock types and positively related to the percent area in mature to old forests. The most variation was explained with these landscape variables summarized at an intermediate spatial scale (i.e., sub-catchment). Although spatial scales appeared similar in processes affecting wood density, finer scales omitted key source areas for wood delivery, and coarser scales included source areas less tightly coupled to wood dynamics in surveyed channels. If only 1 or 2 years of data or one spatial scale had been examined, as commonly occurs, conclusions may have differed substantially from those in this study. Close

• 33. [Article] Simulated response of ecosystem processes to climate change in northern California and western Nevada

  In order to investigate potential climate impacts on landscape-scale ecosystem processes, I implemented a dynamic general vegetation model (DGVM) over a large domain in northern California and western ...

  Citation × Citation Citation Abstract Copy Title: Simulated response of ecosystem processes to climate change in northern California and western Nevada Author: McGlinchy, Maureen C. In order to investigate potential climate impacts on landscape-scale ecosystem processes, I implemented a dynamic general vegetation model (DGVM) over a large domain in northern California and western Nevada on a rectangular grid of ca. 800-meter spatial resolution. I used 100 years of observed, monthly climate and nine future climate projections in an attempt to explore the range of possible climate futures in the region. I selected three general circulation models (MIROC3.2(medres), UKMO-HadCM3 and CSIRO-Mk3.0), incorporating a range of 2xCO₂ temperature sensitivity. Each GCM was run through three carbon dioxide emissions scenarios (SRES A2, A1B and B1). For this analysis, I focused the study on the simulated ecological impacts under the three A2 scenarios. Historical observations and future climate scenarios were interpolated to the 800-meter grid by the PRISM model. MC1, a systems-based DGVM, compared favorably to observed data for simulations of vegetation distribution and annual streamflow. MC1 slightly overestimated annual production in the Sierra Nevada and Klamath Mountains and underestimated it in the Coast Range and Eastern Cascades. MC1 displayed a low bias for annual area burned and high bias for pyrogenic emissions. Validation of simulated model output was complicated because MC1 does not consider the effects of land management on ecosystems and the study region is heavily-impacted by development, logging, fire suppression, grazing and pre-European, indigenous land-use and burning. Under all future climate projections, an increase in growing season length and temperature led to the replacement of tundra and subalpine vegetation types with temperate conifer forest. Increased winter minimum temperatures promoted the expansion of mixed needleleaf-broadleaf forest, particularly in the mid-elevations of the Sierra Nevada and in coastal forests. In the MIROC3.2 and HadCM3 scenarios, ecosystem-level net primary productivity (NPP) did not increase with enhanced CO₂ fertilization because production remained limited by water, even though both NPP and water-use-efficiency were increased at the leaf level in proportion to CO₂ concentration. Increases in NPP were projected in CSIRO-Mk3, but increased precipitation and warmer temperatures also increased rates of heterotrophic respiration for no net gain in net ecosystem productivity (NEP). Fire extent and severity increased in all scenarios, mostly driven by significant decreases in mountainous snowpack and earlier snowmelt. Thus, a relatively constant NEP and increased fire emissions produced decreases in total ecosystem carbon across all future scenarios. Projected annual streamflow varied between future climate scenarios and was highly influenced by projected precipitation. In all future simulations, high-elevation mountainous landscapes were highly sensitive to projected changes in climate, largely attributable to an increased growing season and temperature, decreased snowpack and reduced fire return interval. Coastal forests were also highly susceptible to changes in vegetation type and increases in fire. Several sources contribute to uncertainty in MC1, including input datasets, model assumptions, uncertainties in ecosystem science, and questions of scale. Therefore, these results should be considered preliminary, but useful in suggesting a range of plausible ecological futures as we continue to refine model capabilities. Title: Simulated response of ecosystem processes to climate change in northern California and western Nevada Author: McGlinchy, Maureen C. In order to investigate potential climate impacts on landscape-scale ecosystem processes, I implemented a dynamic general vegetation model (DGVM) over a large domain in northern California and western Nevada on a rectangular grid of ca. 800-meter spatial resolution. I used 100 years of observed, monthly climate and nine future climate projections in an attempt to explore the range of possible climate futures in the region. I selected three general circulation models (MIROC3.2(medres), UKMO-HadCM3 and CSIRO-Mk3.0), incorporating a range of 2xCO₂ temperature sensitivity. Each GCM was run through three carbon dioxide emissions scenarios (SRES A2, A1B and B1). For this analysis, I focused the study on the simulated ecological impacts under the three A2 scenarios. Historical observations and future climate scenarios were interpolated to the 800-meter grid by the PRISM model. MC1, a systems-based DGVM, compared favorably to observed data for simulations of vegetation distribution and annual streamflow. MC1 slightly overestimated annual production in the Sierra Nevada and Klamath Mountains and underestimated it in the Coast Range and Eastern Cascades. MC1 displayed a low bias for annual area burned and high bias for pyrogenic emissions. Validation of simulated model output was complicated because MC1 does not consider the effects of land management on ecosystems and the study region is heavily-impacted by development, logging, fire suppression, grazing and pre-European, indigenous land-use and burning. Under all future climate projections, an increase in growing season length and temperature led to the replacement of tundra and subalpine vegetation types with temperate conifer forest. Increased winter minimum temperatures promoted the expansion of mixed needleleaf-broadleaf forest, particularly in the mid-elevations of the Sierra Nevada and in coastal forests. In the MIROC3.2 and HadCM3 scenarios, ecosystem-level net primary productivity (NPP) did not increase with enhanced CO₂ fertilization because production remained limited by water, even though both NPP and water-use-efficiency were increased at the leaf level in proportion to CO₂ concentration. Increases in NPP were projected in CSIRO-Mk3, but increased precipitation and warmer temperatures also increased rates of heterotrophic respiration for no net gain in net ecosystem productivity (NEP). Fire extent and severity increased in all scenarios, mostly driven by significant decreases in mountainous snowpack and earlier snowmelt. Thus, a relatively constant NEP and increased fire emissions produced decreases in total ecosystem carbon across all future scenarios. Projected annual streamflow varied between future climate scenarios and was highly influenced by projected precipitation. In all future simulations, high-elevation mountainous landscapes were highly sensitive to projected changes in climate, largely attributable to an increased growing season and temperature, decreased snowpack and reduced fire return interval. Coastal forests were also highly susceptible to changes in vegetation type and increases in fire. Several sources contribute to uncertainty in MC1, including input datasets, model assumptions, uncertainties in ecosystem science, and questions of scale. Therefore, these results should be considered preliminary, but useful in suggesting a range of plausible ecological futures as we continue to refine model capabilities. Close

• 34. [Article] Where's the ground surface? Elevation bias in LIDAR-derived digital elevation models due to dense vegetation in Oregon tidal marshes

  Light Detection and Ranging (LIDAR) is a powerful resource for coastal and wetland managers and its use is increasing. Vegetation density and other land cover characteristics influence the accuracy of ...

  Citation × Citation Citation Abstract Copy Title: Where's the ground surface? Elevation bias in LIDAR-derived digital elevation models due to dense vegetation in Oregon tidal marshes Author: Ewald, Michael J. Light Detection and Ranging (LIDAR) is a powerful resource for coastal and wetland managers and its use is increasing. Vegetation density and other land cover characteristics influence the accuracy of LIDAR-derived ground surface digital elevation models; however, the degree to which wetland land cover biases LIDAR estimates of the ground surface is largely unknown. The minimum-bin LIDAR gridding technique has been proposed as a way to mitigate dense vegetation interference to generate LIDAR-derived digital elevation models (DEM). Past research has focused on the ability to resolve the marsh plain elevation and only limited research has investigated the overall DEM accuracy across the landscape using a wide range of cell sizes and land cover classes. I compared LIDAR-derived DEM accuracy across a 174 ha tidal wetland restoration site with a mix of native wetland and non-native agricultural pasture species. I found an optimum cell size of 1.4 m (1.96 m²) with a mean positive bias of 4.5 cm and a mean absolute error of 24.3 cm. At cell sizes smaller than the optimum, vegetation interferes with the LIDAR sensor and positively biases DEM models. At cell sizes larger than 1.4 m, the DEM captures and favors low features within the landscape, such as channels and ditches, which thereby degrade overall DEM performance. In addition, I investigated LIDAR interference by twelve common tidal wetland vegetation associations across six Oregon estuaries, using survey-grade Global Positioning System (GPS) measurements of the wetland surface and quantitative vegetation data (percent cover by species) for each measurement location. The fundamental vertical accuracy (FVA) of the LIDAR datasets was 4.5 cm root mean square error (RMSE) and had no consistent positive or negative bias in open landcover. Within wetland vegetation communities, my results suggest that LIDAR estimates of the ground surface in tidal wetlands are typically 10 cm to 30 cm above GPS measurements. Plant associations dominated by Carex obnupta and Carex lyngbyei exhibited the largest discrepancy between LIDAR and GPS measurements (mean discrepancies 36.6 cm and 48.8 cm respectively). The smallest errors observed in the study were about 10 cm to 11 cm and occurred in several different plant associations, including two low tidal marsh associations dominated by a mixture of Deschampsia cespitosa, Distichlis spicata, Sarcocornia perennis and Jaumea carnosa. These results suggest that the minimum-bin gridding technique for LIDAR may mitigate vegetation interference by densely vegetated land covers within LIDAR-derived DEM. However, care should be taken to select an appropriate cell size and validate the results before relying on the DEM for analysis. My research yields new information for coastal LIDAR users and increases our understanding of uncertainty in LIDAR-derived datasets to improve the ability to accurately evaluate and manage coastal environments. Title: Where's the ground surface? Elevation bias in LIDAR-derived digital elevation models due to dense vegetation in Oregon tidal marshes Author: Ewald, Michael J. Light Detection and Ranging (LIDAR) is a powerful resource for coastal and wetland managers and its use is increasing. Vegetation density and other land cover characteristics influence the accuracy of LIDAR-derived ground surface digital elevation models; however, the degree to which wetland land cover biases LIDAR estimates of the ground surface is largely unknown. The minimum-bin LIDAR gridding technique has been proposed as a way to mitigate dense vegetation interference to generate LIDAR-derived digital elevation models (DEM). Past research has focused on the ability to resolve the marsh plain elevation and only limited research has investigated the overall DEM accuracy across the landscape using a wide range of cell sizes and land cover classes. I compared LIDAR-derived DEM accuracy across a 174 ha tidal wetland restoration site with a mix of native wetland and non-native agricultural pasture species. I found an optimum cell size of 1.4 m (1.96 m²) with a mean positive bias of 4.5 cm and a mean absolute error of 24.3 cm. At cell sizes smaller than the optimum, vegetation interferes with the LIDAR sensor and positively biases DEM models. At cell sizes larger than 1.4 m, the DEM captures and favors low features within the landscape, such as channels and ditches, which thereby degrade overall DEM performance. In addition, I investigated LIDAR interference by twelve common tidal wetland vegetation associations across six Oregon estuaries, using survey-grade Global Positioning System (GPS) measurements of the wetland surface and quantitative vegetation data (percent cover by species) for each measurement location. The fundamental vertical accuracy (FVA) of the LIDAR datasets was 4.5 cm root mean square error (RMSE) and had no consistent positive or negative bias in open landcover. Within wetland vegetation communities, my results suggest that LIDAR estimates of the ground surface in tidal wetlands are typically 10 cm to 30 cm above GPS measurements. Plant associations dominated by Carex obnupta and Carex lyngbyei exhibited the largest discrepancy between LIDAR and GPS measurements (mean discrepancies 36.6 cm and 48.8 cm respectively). The smallest errors observed in the study were about 10 cm to 11 cm and occurred in several different plant associations, including two low tidal marsh associations dominated by a mixture of Deschampsia cespitosa, Distichlis spicata, Sarcocornia perennis and Jaumea carnosa. These results suggest that the minimum-bin gridding technique for LIDAR may mitigate vegetation interference by densely vegetated land covers within LIDAR-derived DEM. However, care should be taken to select an appropriate cell size and validate the results before relying on the DEM for analysis. My research yields new information for coastal LIDAR users and increases our understanding of uncertainty in LIDAR-derived datasets to improve the ability to accurately evaluate and manage coastal environments. Close

• 35. [Article] Resource Selection by the California Condor (Gymnogyps californianus) Relative to Terrestrial-Based Habitats and Meteorological Conditions

  This is the publisher’s final pdf. The article was published by the Public Library of Science and is in the public domain.

  Citation × Citation Citation Abstract Copy Title: Resource Selection by the California Condor (Gymnogyps californianus) Relative to Terrestrial-Based Habitats and Meteorological Conditions Author: Schwarz, Carl J., George, Daniel, Burnett, L. Joseph, Rivers, James W., Johnson, J. Matthew, Haig, Susan M., Glendening, John W., Grantham, Jesse This is the publisher’s final pdf. The article was published by the Public Library of Science and is in the public domain. Title: Resource Selection by the California Condor (Gymnogyps californianus) Relative to Terrestrial-Based Habitats and Meteorological Conditions Author: Schwarz, Carl J., George, Daniel, Burnett, L. Joseph, Rivers, James W., Johnson, J. Matthew, Haig, Susan M., Glendening, John W., Grantham, Jesse This is the publisher’s final pdf. The article was published by the Public Library of Science and is in the public domain. Close

• 36. [Article] Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the author(s) ...

  Citation × Citation Citation Abstract Copy Title: Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs Author: Pelletier, Jon D., Ruggiero, Peter, Murray, A. Brad, Pierce, Jennifer L., et al. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by John Wiley & Sons Ltd. on behalf of the American Geophysical Union. The published article can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%292328-4277/issues Title: Forecasting the response of Earth's surface to future climatic and land use changes: A review of methods and research needs Author: Pelletier, Jon D., Ruggiero, Peter, Murray, A. Brad, Pierce, Jennifer L., et al. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by John Wiley & Sons Ltd. on behalf of the American Geophysical Union. The published article can be found at: http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%292328-4277/issues Close

• 37. [Article] The role of rock resistance and rock uplift on topographic relief and river longitudinal profiles in the coastal mountains of Oregon and a landscape-scale test for steady-state conditions

  Analysis of topographic and river morphometric parameters was conducted using digital elevation models (DEMs) and field observations in order to determine the role of variable rock resistance on topographic ...

  Citation × Citation Citation Abstract Copy Title: The role of rock resistance and rock uplift on topographic relief and river longitudinal profiles in the coastal mountains of Oregon and a landscape-scale test for steady-state conditions Author: VanLaningham, Sam J. Analysis of topographic and river morphometric parameters was conducted using digital elevation models (DEMs) and field observations in order to determine the role of variable rock resistance on topographic relief, to examine how spatially and temporally variable rock uplift rates relate to river morphology, and to address the degree to which uplift and erosion are in steady-state in the actively uplifting region of the Coast Ranges and Klamath Mountains in Oregon. Four domains were differentiated based on mapped geology and topography - the northern (~45° - 46° N), central (-44° - 45° N), south-central (-43° - 44° N) and southern regions (-42° - 43° N). Bedrock control, on the range scale, is indicated through the association of higher topography with exposures of more resistant volcanic and metamorphic rocks. Lithologic changes coincide with knickpoints on river longitudinal profiles between the latitudes of 43° - 45° N, where rock uplift appears to be low. Rock type seems to be a strong control on topographic relief in these regions. However, in the southern region and less somewhat in the north, where rock uplift rates are highest, changes in lithology along river profiles do not display significant knickpoints. Uplift likely controls river profile form in the northern and southern regions. Basin hypsometric integrals and drainage density values are relatively constant in the study area except in the central region. Rivers in this region are almost exclusively alluvial - whereas most rivers in the Coast Ranges are bedrock or mixed bedrock-alluvial types. These low values in the central region, coupled with the presence of alluvial channels, suggests that the topography is expressing signals of low to no rock uplift in this region. The correspondence seen between low uplift rates and bedrock control and high uplift rates and a transparent bedrock signal suggests that an uplift rate threshold may exist. This has implications for modeling topographic evolution in tectonically-active mountain belts. Title: The role of rock resistance and rock uplift on topographic relief and river longitudinal profiles in the coastal mountains of Oregon and a landscape-scale test for steady-state conditions Author: VanLaningham, Sam J. Analysis of topographic and river morphometric parameters was conducted using digital elevation models (DEMs) and field observations in order to determine the role of variable rock resistance on topographic relief, to examine how spatially and temporally variable rock uplift rates relate to river morphology, and to address the degree to which uplift and erosion are in steady-state in the actively uplifting region of the Coast Ranges and Klamath Mountains in Oregon. Four domains were differentiated based on mapped geology and topography - the northern (~45° - 46° N), central (-44° - 45° N), south-central (-43° - 44° N) and southern regions (-42° - 43° N). Bedrock control, on the range scale, is indicated through the association of higher topography with exposures of more resistant volcanic and metamorphic rocks. Lithologic changes coincide with knickpoints on river longitudinal profiles between the latitudes of 43° - 45° N, where rock uplift appears to be low. Rock type seems to be a strong control on topographic relief in these regions. However, in the southern region and less somewhat in the north, where rock uplift rates are highest, changes in lithology along river profiles do not display significant knickpoints. Uplift likely controls river profile form in the northern and southern regions. Basin hypsometric integrals and drainage density values are relatively constant in the study area except in the central region. Rivers in this region are almost exclusively alluvial - whereas most rivers in the Coast Ranges are bedrock or mixed bedrock-alluvial types. These low values in the central region, coupled with the presence of alluvial channels, suggests that the topography is expressing signals of low to no rock uplift in this region. The correspondence seen between low uplift rates and bedrock control and high uplift rates and a transparent bedrock signal suggests that an uplift rate threshold may exist. This has implications for modeling topographic evolution in tectonically-active mountain belts. Close

• 38. [Article] Beaver ecology on the west Copper River Delta, Alaska

  Since the 1964 earthquake and geologic uplift, beavers (Castor canadensis) have expanded their historic range from the inland (outwash plain) Copper River Delta, Alaska to the once tidally influenced ...

  Citation × Citation Citation Abstract Copy Title: Beaver ecology on the west Copper River Delta, Alaska Author: Cooper, Erin E. Since the 1964 earthquake and geologic uplift, beavers (Castor canadensis) have expanded their historic range from the inland (outwash plain) Copper River Delta, Alaska to the once tidally influenced areas of the outer area (uplifted marsh). The uplift presents a unique opportunity to observe beaver expansion, habitat selection and influence on hydrologic structure of a coastal wetland ecosystem after a major disturbance. First, I examined the relationship between the sites of active beaver lodges and associated water and vegetative features (Chapter 2). I hypothesized that active lodge sites would be associated with distinct water features and woody vegetation types in each landscape. I used aerial photographic and ground survey methods to compare sightability and to determine habitat associations. I developed an a priori set of models to determine active beaver lodge occurrence using logistic regression with presence and absence as the response variables and water features and vegetation cover as the dependent variables. My results were similar between survey methods but differed between the two major landscape types. In the uplifted marsh, odds of an active lodge occurrance increased with the presence of former tidal sloughs and an increase in mixed shrub coverage. The odds of an active lodge occurrence increased with the presence of streams and decreased with increasing closed cottonwood-alder-willow coverage in the outwash plain. Post earthquake uplift, beaver now exploit a unique topographic setting through the use and modification of former tidal sloughs and a transitioning mixed shrub vegetation community. Second, I quantified the influence of beaver on the surface water of the West Copper River Delta using remote sensing (Chapter 3). Water features were documented from digitized aerial photographs from 1959, 1974, 1986, 1992/1993, and 1996. My results showed that surface water area in beaver influenced water impoundments increased from 0 to 20% from 1959 to 1996, concurrent with beaver colonization of the uplifted marsh. These results suggest that beavers may have altered the trajectory of wetland change on the West Copper River Delta by raising the water table within open water basins and flooding those areas that would have otherwise drained. Beaver may be used an effective management tool in wetland restoration where key habitat features are available. Title: Beaver ecology on the west Copper River Delta, Alaska Author: Cooper, Erin E. Since the 1964 earthquake and geologic uplift, beavers (Castor canadensis) have expanded their historic range from the inland (outwash plain) Copper River Delta, Alaska to the once tidally influenced areas of the outer area (uplifted marsh). The uplift presents a unique opportunity to observe beaver expansion, habitat selection and influence on hydrologic structure of a coastal wetland ecosystem after a major disturbance. First, I examined the relationship between the sites of active beaver lodges and associated water and vegetative features (Chapter 2). I hypothesized that active lodge sites would be associated with distinct water features and woody vegetation types in each landscape. I used aerial photographic and ground survey methods to compare sightability and to determine habitat associations. I developed an a priori set of models to determine active beaver lodge occurrence using logistic regression with presence and absence as the response variables and water features and vegetation cover as the dependent variables. My results were similar between survey methods but differed between the two major landscape types. In the uplifted marsh, odds of an active lodge occurrance increased with the presence of former tidal sloughs and an increase in mixed shrub coverage. The odds of an active lodge occurrence increased with the presence of streams and decreased with increasing closed cottonwood-alder-willow coverage in the outwash plain. Post earthquake uplift, beaver now exploit a unique topographic setting through the use and modification of former tidal sloughs and a transitioning mixed shrub vegetation community. Second, I quantified the influence of beaver on the surface water of the West Copper River Delta using remote sensing (Chapter 3). Water features were documented from digitized aerial photographs from 1959, 1974, 1986, 1992/1993, and 1996. My results showed that surface water area in beaver influenced water impoundments increased from 0 to 20% from 1959 to 1996, concurrent with beaver colonization of the uplifted marsh. These results suggest that beavers may have altered the trajectory of wetland change on the West Copper River Delta by raising the water table within open water basins and flooding those areas that would have otherwise drained. Beaver may be used an effective management tool in wetland restoration where key habitat features are available. Close

• 39. [Article] Cumulative effects of land use on salmon habitat in southwest Oregon coastal streams

  As part of a hierarchical approach to classifying watersheds and stream habitats based on geomorphic and geologic criteria, we defined ten classes of fluvial and lacustrine habitats at the scale of valley ...

  Citation × Citation Citation Abstract Copy Title: Cumulative effects of land use on salmon habitat in southwest Oregon coastal streams Author: Frissell, Christopher Andrew, 1960- As part of a hierarchical approach to classifying watersheds and stream habitats based on geomorphic and geologic criteria, we defined ten classes of fluvial and lacustrine habitats at the scale of valley segments. Valley segments are landscape units which encompass surface waters and the adjacent floodplains and hillslopes with which they interact over time frames of thousands of years. They form a large-scale template that constrains the character of aquatic habitat, controls the effects of disturbances in riparian areas, and mediates responses of streams to upland and upstream events. The regional distribution of valley segment types in southwest Oregon reflects bedrock geology and tectonic history of the landscape. Fluvial segment types differ in stream adjacent landforms, slope erosion processes, floodplain and valley morphology, channel slope, riparian vegetation, streambank texture, gravel bar morphology, and pool-forming features. Studies that do not carefully account for inherent differences between valley segment types could fail to detect critical changes in stream habitat caused by human disturbance. Alluvial valley and alluviated canyon segment types, which have extensive floodplains, low channel slopes, abundant woody debris, and ample gravel beds, are of greatest direct importance for salmon and other native fishes. Virtually all alluvial valleys in the study area have been heavily disturbed by logging, agriculture, and residential development. Alluviated canyon segments located in the few drainage basins where human activity has been limited probably serve as habitat refugia for the last diverse assemblages and productive populations of salmon in the region. Alluviated canyons in extensively-fogged basins exhibit increased abundance of large woody debris, fewer cross-channel debris jams, more extensive bank erosion, reduced pool area and increased riffle area, shallower riffles, and increased surface concentration of fine sediments in pools and other habitats, compared to similar segments in lesser-disturbed basins. These changes in channel morphology and stability appear to be driven by increased sediment load, caused by logging-related landslides and other erosion sources. Field studies in Sixes River basin indicated that abundance and diversity of salmonid fishes declines as maximum stream temperature increases. Changes in summer distribution of juvenile chinook and coho salmon since 1970 are related to changes In water temperature. Although some tributaries have cooled, a decline in rearing distribution in mainstem areas could be caused by long-term loss of channel complexity and associated coolwater refugia. Analysis of fish habitat structures constructed by federal and state agencies indicated that failure rates are high. Recovery of anadromous fish runs in southwest Oregon will require protection of remaining habitat refugia and reduction of sediment yield from disturbed watersheds. Title: Cumulative effects of land use on salmon habitat in southwest Oregon coastal streams Author: Frissell, Christopher Andrew, 1960- As part of a hierarchical approach to classifying watersheds and stream habitats based on geomorphic and geologic criteria, we defined ten classes of fluvial and lacustrine habitats at the scale of valley segments. Valley segments are landscape units which encompass surface waters and the adjacent floodplains and hillslopes with which they interact over time frames of thousands of years. They form a large-scale template that constrains the character of aquatic habitat, controls the effects of disturbances in riparian areas, and mediates responses of streams to upland and upstream events. The regional distribution of valley segment types in southwest Oregon reflects bedrock geology and tectonic history of the landscape. Fluvial segment types differ in stream adjacent landforms, slope erosion processes, floodplain and valley morphology, channel slope, riparian vegetation, streambank texture, gravel bar morphology, and pool-forming features. Studies that do not carefully account for inherent differences between valley segment types could fail to detect critical changes in stream habitat caused by human disturbance. Alluvial valley and alluviated canyon segment types, which have extensive floodplains, low channel slopes, abundant woody debris, and ample gravel beds, are of greatest direct importance for salmon and other native fishes. Virtually all alluvial valleys in the study area have been heavily disturbed by logging, agriculture, and residential development. Alluviated canyon segments located in the few drainage basins where human activity has been limited probably serve as habitat refugia for the last diverse assemblages and productive populations of salmon in the region. Alluviated canyons in extensively-fogged basins exhibit increased abundance of large woody debris, fewer cross-channel debris jams, more extensive bank erosion, reduced pool area and increased riffle area, shallower riffles, and increased surface concentration of fine sediments in pools and other habitats, compared to similar segments in lesser-disturbed basins. These changes in channel morphology and stability appear to be driven by increased sediment load, caused by logging-related landslides and other erosion sources. Field studies in Sixes River basin indicated that abundance and diversity of salmonid fishes declines as maximum stream temperature increases. Changes in summer distribution of juvenile chinook and coho salmon since 1970 are related to changes In water temperature. Although some tributaries have cooled, a decline in rearing distribution in mainstem areas could be caused by long-term loss of channel complexity and associated coolwater refugia. Analysis of fish habitat structures constructed by federal and state agencies indicated that failure rates are high. Recovery of anadromous fish runs in southwest Oregon will require protection of remaining habitat refugia and reduction of sediment yield from disturbed watersheds. Close

• 40. [Article] Road networks, timber harvest, and the spread of Phytophthora root rot infestations of Port-Orford-­cedar in southwest Oregon

  Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree ...

  Citation × Citation Citation Abstract Copy Title: Road networks, timber harvest, and the spread of Phytophthora root rot infestations of Port-Orford-­cedar in southwest Oregon Author: Clark, William C. Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree species of ecological, economical, and cultural importance to coastal Oregon and California. Local scale distribution of P. lateralis is thought to be associated with timber harvest and road-building disturbances. However, knowledge of the landscape-scale factors that contribute to successful invasions of P. lateralis is also important for effective land management of Port-Orford-cedar. P. lateralis is able to infest in wet conditions via stream networks (zoospore) and dry conditions via road networks (resting spore). This study tested the hypothesis that vehicles spread P. lateralis by relating its distribution to traffic intensive, anthropogenic disturbances (i.e. a road network, timber harvest) over a 31-yr period in a 3,910-km² portion of the Rogue River-Siskiyou National Forest in the Siskiyou Mountains of Oregon. Indices of road disturbance (presence/absence, configuration, length, density, road-stream network connectivity) and timber harvest (presence/absence, area, density, frequency) were related to locations of infested cedar populations from a USFS survey dataset using a geographic information system (GIS). About 40% of 934 7th-field catchments were infested with the pathogen. Total road length of the study site was 5,070 km; maximum road density was 8.2 km/km2 and averaged 1.6 km/km² in roaded catchments (n = 766). Timber activities extracted 17,370 ha (2,338 cutting units) of forest across 509 catchments; 345 catchments were cut ≥ twice. Maximum harvest density was 0.92 km²/km² ([mean] = 0.04). Both road networks and timber harvest patchworks were significantly related to cedar root rot heterogeneity. Chi-squared contingency tables showed that infestation rates were 2.2 times higher in catchments with roads compared to roadless catchments and 1.4 times higher in catchments with road-stream intersections compared to those that were unconnected. Infestation was twice as likely in catchments with both harvest and road presence than road presence alone. Single-variable logistic regression showed that a one percent increase in harvest density increased infestation odds 25% and a one-unit (km/km²) increase in road density increased infestation odds 80%. Road and stream network configuration was also important to pathogen distribution: 1) uninfested catchments are most likely to be spatially removed from infested, roaded catchments, 2) only 11% of 287 roaded catchments downstream of infested, roaded catchments were uninfested, and 3) only 12% of 319 catchments downstream of infested catchments were uninfested. Road networks and timber harvest patchworks appear to reduce landscape heterogeneity by providing up-catchment and down-catchment access to host populations by linking pathogenic materials to the stream network. Timber harvest data suggest that while infestation risk to Port-Orford-cedar populations remains high, management policies may have curbed infestation risk in timber-harvested catchments; if this is a result of specific P. lateralis mitigation policies adopted in the late 1980's or broader, region-wide conservation policies (i.e. the Northwest Forest Plan) is yet unclear. Title: Road networks, timber harvest, and the spread of Phytophthora root rot infestations of Port-Orford-­cedar in southwest Oregon Author: Clark, William C. Phytophthora lateralis is the causal agent of cedar root rot, a fatal forest pathogen whose principal host is Chamaecyparis lawsoniana (Port-Orford-cedar), a predominantly riparian-restricted endemic tree species of ecological, economical, and cultural importance to coastal Oregon and California. Local scale distribution of P. lateralis is thought to be associated with timber harvest and road-building disturbances. However, knowledge of the landscape-scale factors that contribute to successful invasions of P. lateralis is also important for effective land management of Port-Orford-cedar. P. lateralis is able to infest in wet conditions via stream networks (zoospore) and dry conditions via road networks (resting spore). This study tested the hypothesis that vehicles spread P. lateralis by relating its distribution to traffic intensive, anthropogenic disturbances (i.e. a road network, timber harvest) over a 31-yr period in a 3,910-km² portion of the Rogue River-Siskiyou National Forest in the Siskiyou Mountains of Oregon. Indices of road disturbance (presence/absence, configuration, length, density, road-stream network connectivity) and timber harvest (presence/absence, area, density, frequency) were related to locations of infested cedar populations from a USFS survey dataset using a geographic information system (GIS). About 40% of 934 7th-field catchments were infested with the pathogen. Total road length of the study site was 5,070 km; maximum road density was 8.2 km/km2 and averaged 1.6 km/km² in roaded catchments (n = 766). Timber activities extracted 17,370 ha (2,338 cutting units) of forest across 509 catchments; 345 catchments were cut ≥ twice. Maximum harvest density was 0.92 km²/km² ([mean] = 0.04). Both road networks and timber harvest patchworks were significantly related to cedar root rot heterogeneity. Chi-squared contingency tables showed that infestation rates were 2.2 times higher in catchments with roads compared to roadless catchments and 1.4 times higher in catchments with road-stream intersections compared to those that were unconnected. Infestation was twice as likely in catchments with both harvest and road presence than road presence alone. Single-variable logistic regression showed that a one percent increase in harvest density increased infestation odds 25% and a one-unit (km/km²) increase in road density increased infestation odds 80%. Road and stream network configuration was also important to pathogen distribution: 1) uninfested catchments are most likely to be spatially removed from infested, roaded catchments, 2) only 11% of 287 roaded catchments downstream of infested, roaded catchments were uninfested, and 3) only 12% of 319 catchments downstream of infested catchments were uninfested. Road networks and timber harvest patchworks appear to reduce landscape heterogeneity by providing up-catchment and down-catchment access to host populations by linking pathogenic materials to the stream network. Timber harvest data suggest that while infestation risk to Port-Orford-cedar populations remains high, management policies may have curbed infestation risk in timber-harvested catchments; if this is a result of specific P. lateralis mitigation policies adopted in the late 1980's or broader, region-wide conservation policies (i.e. the Northwest Forest Plan) is yet unclear. Close