The Experts below are selected from a list of 4470 Experts worldwide ranked by ideXlab platform
James W Kirchner - One of the best experts on this subject based on the ideXlab platform.
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effects of Wet Meadow riparian vegetation on streambank erosion 2 measurements of vegetated bank strength and consequences for failure mechanics
Earth Surface Processes and Landforms, 2002Co-Authors: E R Micheli, James W KirchnerAbstract:We measured the effect of Wet Meadow vegetation on the bank strength and failure mechanics of a meandering montane Meadow stream, the South Fork of the Kern River at Monache Meadow, in California's Sierra Nevada. Streambanks colonized by ‘Wet’ graminoid Meadow vegetation were on average five times stronger than those colonized by ‘dry’ xeric Meadow and scrub vegetation. Our measurements show that strength is correlated with vegetation density indicators, including stem counts, standing biomass per unit area, and the ratio of root mass to soil mass. Rushes appear better than sedges at stabilizing coarse bar surfaces, while sedges are far more effective at stabilizing actively eroding cut banks. Wet Meadow floodplain vegetation creates a composite cut bank configuration (a cohesive layer overlying cohesionless materials) that erodes via cantilever failure. Field measurements and a geotechnical model of cantilever stability show that by increasing bank strength, Wet Meadow vegetation increases the thickness, width, and cohesiveness of a bank cantilever, which, in turn, increases the amount of time required to undermine, detach, and remove bank failure blocks. At Monache Meadow, it takes approximately four years to produce and remove a 1 m wide Wet Meadow bank block. Wet Meadow vegetation limits bank migration rates by increasing bank strength, altering bank failure modes, and reducing bank failure frequency. Copyright © 2002 John Wiley & Sons, Ltd.
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effects of Wet Meadow riparian vegetation on streambank erosion 1 remote sensing measurements of streambank migration and erodibility
Earth Surface Processes and Landforms, 2002Co-Authors: E R Micheli, James W KirchnerAbstract:We quantified how rates of stream channel migration in a montane Meadow vary as a function of the riparian vegetation community. The South Fork of the Kern River at Monache Meadow, located in California's southern Sierra Nevada range, supports two distinct types of vegetation: a dry Meadow community dominated by sagebrush and non-native grasses (xeric scrub and Meadow), and a Wet Meadow community dominated by rushes and sedges (hydric graminoids). We measured rates of lateral stream migration for dry versus Wet Meadow reaches from aerial photographs spanning a 40-year period (1955–1995). While stream migration rates averaged only 0·24 ± 0·02 m a−1 in the Wet Meadow, the dry Meadow channel migrated an average of 1·4 ± 0·3 m a−1. We used a linear model of meander migration to calculate coefficients that characterize bank migration potential, or bank erodibility, independent of channel curvature. These calculations demonstrate that, at Monache Meadow, banks without Wet Meadow vegetation are roughly ten times more susceptible to erosion than banks with Wet Meadow vegetation. Where stream bank heights consistently exceed 1 m, low water availability creates riparian habitats dominated by dry Meadow vegetation. Thus, channel incision may reduce bank stability not only by increasing bank height, but also by converting banks from Wet Meadow to dry Meadow vegetation. Copyright © 2002 John Wiley & Sons, Ltd.
Hana Šantrůčková - One of the best experts on this subject based on the ideXlab platform.
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Soil CO 2 efflux in three Wet Meadow ecosystems with different C and N status
Community Ecology, 2008Co-Authors: K. Zemanová, Hana Čížková, Keith R. Edwards, Hana ŠantrůčkováAbstract:Data on soil respiration of three Wet Meadow ecosystems in the Czech Republic are presented. There were three study sites: two sites with peaty soil, one of them aneutrophic (nitrogen rich) and second of them oligotrophic. Third site was mesotrophic with mineral soil. Soil respiration was measured in situ as CO 2 efflux using a Licor 6400 equipped with a soil chamber during the vegetation seasons, since June until October 2006. Soil respiration rates were significantly affected by soil temperature, although they differed among the sites, just as nutrient availability differed on each site. Despite of seasonal variation, the nutrient rich site on organic soil consistently yielded the highest respiration rates, and nutrient poor site yielded the lowest respiration rates. The highest CO 2 emissions rates in situ were measured in June, when the soil temperature was 19°C. The rates reached up to 10.31 μmol CO 2 m −2 s −1 at eutrophic site, at peaty oligotrophic site 7.03 μmol CO 2 m −2 s −1 , and 8.38 μmol CO ...
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Soil CO2efflux in three Wet Meadow ecosystems with different C and N status
Community Ecology, 2008Co-Authors: K. Zemanová, Hana Čížková, K. Edwards, Hana ŠantrůčkováAbstract:Data on soil respiration of three Wet Meadow ecosystems in the Czech Republic are presented. There were three study sites: two sites with peaty soil, one of them aneutrophic (nitrogen rich) and second of them oligotrophic. Third site was mesotrophic with mineral soil. Soil respiration was measured \ud in situ\ud as CO2\ud efflux using a Licor 6400 equipped with a soil chamber during the vegetation seasons, since June until October 2006. Soil respiration rates were significantly affected by soil temperature, although they differed among the sites, just as nutrient availability differed on each site. Despite of seasonal variation, the nutrient rich site on organic soil consistently yielded the highest respiration rates, and nutrient poor site yielded the lowest respiration rates. The highest CO2\ud emissions rates \ud in situ\ud were measured in June, when the soil temperature was 19°C. The rates reached up to 10.31 μmol CO2 m-2\ud s-1\ud at eutrophic site, at peaty oligotrophic site 7.03 μmol CO2\ud m-2\ud s-1 , and 8.38 μmol CO2\ud m-2\ud at mineral mesotrophic site, respectively. When we used a temperature dependency exponential model to avoid the effect of different soil temperature, the pattern observed in the field was even clearer. The peaty eutrophic soil was more sensitive to temperature then the mineral and peaty oligotrophic soil and C mineralization was more enhanced there
E R Micheli - One of the best experts on this subject based on the ideXlab platform.
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effects of Wet Meadow riparian vegetation on streambank erosion 2 measurements of vegetated bank strength and consequences for failure mechanics
Earth Surface Processes and Landforms, 2002Co-Authors: E R Micheli, James W KirchnerAbstract:We measured the effect of Wet Meadow vegetation on the bank strength and failure mechanics of a meandering montane Meadow stream, the South Fork of the Kern River at Monache Meadow, in California's Sierra Nevada. Streambanks colonized by ‘Wet’ graminoid Meadow vegetation were on average five times stronger than those colonized by ‘dry’ xeric Meadow and scrub vegetation. Our measurements show that strength is correlated with vegetation density indicators, including stem counts, standing biomass per unit area, and the ratio of root mass to soil mass. Rushes appear better than sedges at stabilizing coarse bar surfaces, while sedges are far more effective at stabilizing actively eroding cut banks. Wet Meadow floodplain vegetation creates a composite cut bank configuration (a cohesive layer overlying cohesionless materials) that erodes via cantilever failure. Field measurements and a geotechnical model of cantilever stability show that by increasing bank strength, Wet Meadow vegetation increases the thickness, width, and cohesiveness of a bank cantilever, which, in turn, increases the amount of time required to undermine, detach, and remove bank failure blocks. At Monache Meadow, it takes approximately four years to produce and remove a 1 m wide Wet Meadow bank block. Wet Meadow vegetation limits bank migration rates by increasing bank strength, altering bank failure modes, and reducing bank failure frequency. Copyright © 2002 John Wiley & Sons, Ltd.
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effects of Wet Meadow riparian vegetation on streambank erosion 1 remote sensing measurements of streambank migration and erodibility
Earth Surface Processes and Landforms, 2002Co-Authors: E R Micheli, James W KirchnerAbstract:We quantified how rates of stream channel migration in a montane Meadow vary as a function of the riparian vegetation community. The South Fork of the Kern River at Monache Meadow, located in California's southern Sierra Nevada range, supports two distinct types of vegetation: a dry Meadow community dominated by sagebrush and non-native grasses (xeric scrub and Meadow), and a Wet Meadow community dominated by rushes and sedges (hydric graminoids). We measured rates of lateral stream migration for dry versus Wet Meadow reaches from aerial photographs spanning a 40-year period (1955–1995). While stream migration rates averaged only 0·24 ± 0·02 m a−1 in the Wet Meadow, the dry Meadow channel migrated an average of 1·4 ± 0·3 m a−1. We used a linear model of meander migration to calculate coefficients that characterize bank migration potential, or bank erodibility, independent of channel curvature. These calculations demonstrate that, at Monache Meadow, banks without Wet Meadow vegetation are roughly ten times more susceptible to erosion than banks with Wet Meadow vegetation. Where stream bank heights consistently exceed 1 m, low water availability creates riparian habitats dominated by dry Meadow vegetation. Thus, channel incision may reduce bank stability not only by increasing bank height, but also by converting banks from Wet Meadow to dry Meadow vegetation. Copyright © 2002 John Wiley & Sons, Ltd.
K. Zemanová - One of the best experts on this subject based on the ideXlab platform.
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Soil CO 2 efflux in three Wet Meadow ecosystems with different C and N status
Community Ecology, 2008Co-Authors: K. Zemanová, Hana Čížková, Keith R. Edwards, Hana ŠantrůčkováAbstract:Data on soil respiration of three Wet Meadow ecosystems in the Czech Republic are presented. There were three study sites: two sites with peaty soil, one of them aneutrophic (nitrogen rich) and second of them oligotrophic. Third site was mesotrophic with mineral soil. Soil respiration was measured in situ as CO 2 efflux using a Licor 6400 equipped with a soil chamber during the vegetation seasons, since June until October 2006. Soil respiration rates were significantly affected by soil temperature, although they differed among the sites, just as nutrient availability differed on each site. Despite of seasonal variation, the nutrient rich site on organic soil consistently yielded the highest respiration rates, and nutrient poor site yielded the lowest respiration rates. The highest CO 2 emissions rates in situ were measured in June, when the soil temperature was 19°C. The rates reached up to 10.31 μmol CO 2 m −2 s −1 at eutrophic site, at peaty oligotrophic site 7.03 μmol CO 2 m −2 s −1 , and 8.38 μmol CO ...
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Soil CO2efflux in three Wet Meadow ecosystems with different C and N status
Community Ecology, 2008Co-Authors: K. Zemanová, Hana Čížková, K. Edwards, Hana ŠantrůčkováAbstract:Data on soil respiration of three Wet Meadow ecosystems in the Czech Republic are presented. There were three study sites: two sites with peaty soil, one of them aneutrophic (nitrogen rich) and second of them oligotrophic. Third site was mesotrophic with mineral soil. Soil respiration was measured \ud in situ\ud as CO2\ud efflux using a Licor 6400 equipped with a soil chamber during the vegetation seasons, since June until October 2006. Soil respiration rates were significantly affected by soil temperature, although they differed among the sites, just as nutrient availability differed on each site. Despite of seasonal variation, the nutrient rich site on organic soil consistently yielded the highest respiration rates, and nutrient poor site yielded the lowest respiration rates. The highest CO2\ud emissions rates \ud in situ\ud were measured in June, when the soil temperature was 19°C. The rates reached up to 10.31 μmol CO2 m-2\ud s-1\ud at eutrophic site, at peaty oligotrophic site 7.03 μmol CO2\ud m-2\ud s-1 , and 8.38 μmol CO2\ud m-2\ud at mineral mesotrophic site, respectively. When we used a temperature dependency exponential model to avoid the effect of different soil temperature, the pattern observed in the field was even clearer. The peaty eutrophic soil was more sensitive to temperature then the mineral and peaty oligotrophic soil and C mineralization was more enhanced there
James D Harwood - One of the best experts on this subject based on the ideXlab platform.
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plant animal interactions between carnivorous plants sheet web spiders and ground running spiders as guild predators in a Wet Meadow community
Ecology and Evolution, 2020Co-Authors: James J Krupa, Kevin R Hopper, Samuel B Gruber, Jason M Schmidt, James D HarwoodAbstract:Plant-animal interactions are diverse and widespread shaping ecology, evolution, and biodiversity of most ecological communities. Carnivorous plants are unusual in that they can be simultaneously engaged with animals in multiple mutualistic and antagonistic interactions including reversed plant-animal interactions where they are the predator. Competition with animals is a potential antagonistic plant-animal interaction unique to carnivorous plants when they and animal predators consume the same prey.The goal of this field study was to test the hypothesis that under natural conditions, sundews and spiders are predators consuming the same prey thus creating an environment where interkingdom competition can occur.Over 12 months, we collected data on 15 dates in the only protected Highland Rim Wet Meadow Ecosystem in Kentucky where sundews, sheet-web spiders, and ground-running spiders co-exist. One each sampling day, we attempted to locate fifteen sites with: (a) both sheet-web spiders and sundews; (b) sundews only; and (c) where neither occurred. Sticky traps were set at each of these sites to determine prey (springtails) activity-density. Ground-running spiders were collected on sampling days. DNA extraction was performed on all spiders to determine which individuals had eaten springtails and comparing this to the density of sundews where the spiders were captured.Sundews and spiders consumed springtails. Springtail activity-densities were lower, the higher the density of sundews. Both sheet-web and ground-running spiders were found less often where sundew densities were high. Sheet-web size was smaller where sundew densities were high.The results of this study suggest that asymmetrical exploitative competition occurs between sundews and spiders. Sundews appear to have a greater negative impact on spiders, where spiders probably have little impact on sundews. In this example of interkingdom competition where the asymmetry should be most extreme, amensalism where one competitor experiences no cost of interaction may be occurring.
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Plant–animal interactions between carnivorous plants, sheet‐web spiders, and ground‐running spiders as guild predators in a Wet Meadow community
Ecology and evolution, 2020Co-Authors: James J Krupa, Kevin R Hopper, Samuel B Gruber, Jason M Schmidt, James D HarwoodAbstract:Plant-animal interactions are diverse and widespread shaping ecology, evolution, and biodiversity of most ecological communities. Carnivorous plants are unusual in that they can be simultaneously engaged with animals in multiple mutualistic and antagonistic interactions including reversed plant-animal interactions where they are the predator. Competition with animals is a potential antagonistic plant-animal interaction unique to carnivorous plants when they and animal predators consume the same prey.The goal of this field study was to test the hypothesis that under natural conditions, sundews and spiders are predators consuming the same prey thus creating an environment where interkingdom competition can occur.Over 12 months, we collected data on 15 dates in the only protected Highland Rim Wet Meadow Ecosystem in Kentucky where sundews, sheet-web spiders, and ground-running spiders co-exist. One each sampling day, we attempted to locate fifteen sites with: (a) both sheet-web spiders and sundews; (b) sundews only; and (c) where neither occurred. Sticky traps were set at each of these sites to determine prey (springtails) activity-density. Ground-running spiders were collected on sampling days. DNA extraction was performed on all spiders to determine which individuals had eaten springtails and comparing this to the density of sundews where the spiders were captured.Sundews and spiders consumed springtails. Springtail activity-densities were lower, the higher the density of sundews. Both sheet-web and ground-running spiders were found less often where sundew densities were high. Sheet-web size was smaller where sundew densities were high.The results of this study suggest that asymmetrical exploitative competition occurs between sundews and spiders. Sundews appear to have a greater negative impact on spiders, where spiders probably have little impact on sundews. In this example of interkingdom competition where the asymmetry should be most extreme, amensalism where one competitor experiences no cost of interaction may be occurring.
