The Experts below are selected from a list of 21894 Experts worldwide ranked by ideXlab platform

M J Trlica - One of the best experts on this subject based on the ideXlab platform.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology an isotopic study using δ13c and δ18o
    Oecologia, 1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quantified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water potentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (Δ), leaf nitrogen content and Water sources using stable isotopes of Water (δ18O). The carbon and Water relations of Salix were significantly affected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk significantly increased summer plant Water potentials and integrative measures of gas exchange (Δ), though browsing did not consistently affect instantaneous rates of photosynthesis, leaf nitrogen or the sources of Water used by Salix. No effect of experimental manipulations of Surface Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from δ18O values we calculated that Salix appears to rely on streams for approximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas exchange, while experimental damming had in general no effect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly different, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive effect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology
    1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quan- tified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water po- tentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (D), leaf nitrogen content and Water sources using stable isotopes of Water (d 18 O). The carbon and Water relations of Salix were signifi- cantly aAected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk signifi- cantly increased summer plant Water potentials and in- tegrative measures of gas exchange (D), though browsing did not consistently aAect instantaneous rates of pho- tosynthesis, leaf nitrogen or the sources of Water used by Salix. No eAect of experimental manipulations of sur- face Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from d 18 O values we calculated that Salix appears to rely on streams for ap- proximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas ex- change, while experimental damming had in general no eAect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly diAerent, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive eAect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

K P Alstad - One of the best experts on this subject based on the ideXlab platform.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology an isotopic study using δ13c and δ18o
    Oecologia, 1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quantified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water potentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (Δ), leaf nitrogen content and Water sources using stable isotopes of Water (δ18O). The carbon and Water relations of Salix were significantly affected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk significantly increased summer plant Water potentials and integrative measures of gas exchange (Δ), though browsing did not consistently affect instantaneous rates of photosynthesis, leaf nitrogen or the sources of Water used by Salix. No effect of experimental manipulations of Surface Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from δ18O values we calculated that Salix appears to rely on streams for approximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas exchange, while experimental damming had in general no effect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly different, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive effect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology
    1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quan- tified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water po- tentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (D), leaf nitrogen content and Water sources using stable isotopes of Water (d 18 O). The carbon and Water relations of Salix were signifi- cantly aAected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk signifi- cantly increased summer plant Water potentials and in- tegrative measures of gas exchange (D), though browsing did not consistently aAect instantaneous rates of pho- tosynthesis, leaf nitrogen or the sources of Water used by Salix. No eAect of experimental manipulations of sur- face Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from d 18 O values we calculated that Salix appears to rely on streams for ap- proximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas ex- change, while experimental damming had in general no eAect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly diAerent, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive eAect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

S A Williams - One of the best experts on this subject based on the ideXlab platform.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology an isotopic study using δ13c and δ18o
    Oecologia, 1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quantified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water potentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (Δ), leaf nitrogen content and Water sources using stable isotopes of Water (δ18O). The carbon and Water relations of Salix were significantly affected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk significantly increased summer plant Water potentials and integrative measures of gas exchange (Δ), though browsing did not consistently affect instantaneous rates of photosynthesis, leaf nitrogen or the sources of Water used by Salix. No effect of experimental manipulations of Surface Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from δ18O values we calculated that Salix appears to rely on streams for approximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas exchange, while experimental damming had in general no effect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly different, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive effect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology
    1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quan- tified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water po- tentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (D), leaf nitrogen content and Water sources using stable isotopes of Water (d 18 O). The carbon and Water relations of Salix were signifi- cantly aAected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk signifi- cantly increased summer plant Water potentials and in- tegrative measures of gas exchange (D), though browsing did not consistently aAect instantaneous rates of pho- tosynthesis, leaf nitrogen or the sources of Water used by Salix. No eAect of experimental manipulations of sur- face Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from d 18 O values we calculated that Salix appears to rely on streams for ap- proximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas ex- change, while experimental damming had in general no eAect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly diAerent, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive eAect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

Jeffrey M Welker - One of the best experts on this subject based on the ideXlab platform.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology an isotopic study using δ13c and δ18o
    Oecologia, 1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quantified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water potentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (Δ), leaf nitrogen content and Water sources using stable isotopes of Water (δ18O). The carbon and Water relations of Salix were significantly affected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk significantly increased summer plant Water potentials and integrative measures of gas exchange (Δ), though browsing did not consistently affect instantaneous rates of photosynthesis, leaf nitrogen or the sources of Water used by Salix. No effect of experimental manipulations of Surface Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from δ18O values we calculated that Salix appears to rely on streams for approximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas exchange, while experimental damming had in general no effect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly different, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive effect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

  • carbon and Water relations of salix monticola in response to winter browsing and changes in Surface Water Hydrology
    1999
    Co-Authors: K P Alstad, Jeffrey M Welker, S A Williams, M J Trlica
    Abstract:

    To ascertain whether browsing or hydrologic conditions influence the physiological performance of Salix and whether Salix and graminoids (Carex) use and possibly compete for similar Water resources, we quan- tified the in situ seasonal patterns of plant Water and carbon relations over three growing seasons. Our studies were designed to address the physiological factors which may be responsible for poor woody plant regeneration in montane riparian habitats of Rocky Mountain National Park, Colo. As these systems act to insure the delivery of fresh Water to downstream users, the maintenance of their integrity is critical. We quantified plant Water po- tentials, instantaneous rates of carbon fixation, leaf carbon isotope discrimination (D), leaf nitrogen content and Water sources using stable isotopes of Water (d 18 O). The carbon and Water relations of Salix were signifi- cantly aAected by winter browsing by elk and in some cases by landscape position with regard to proximity to active streams. Winter browsing of Salix by elk signifi- cantly increased summer plant Water potentials and in- tegrative measures of gas exchange (D), though browsing did not consistently aAect instantaneous rates of pho- tosynthesis, leaf nitrogen or the sources of Water used by Salix. No eAect of experimental manipulations of sur- face Water conditions on Salix physiology was observed, likely due to the mesic nature of our study period. Using a two-member linear mixing model, from d 18 O values we calculated that Salix appears to rely on streams for ap- proximately 80% of its Water. In contrast, the graminoid Carex derives almost 50% of its Water from rainfall, indicating divergent Water source use by these two life forms. Based on these findings, winter browsing by elk improved Salix Water balance possibly by altering the shoot to root ratio which in turn leads to higher Water potentials and higher degrees of season-long gas ex- change, while experimental damming had in general no eAect on the physiological performance of Salix plants. In addition, as the Water sources of Salix and Carex were significantly diAerent, competition for Water may not influence the growth, development, and regeneration of Salix. Thus, under the conditions of our study, herbivory had a positive eAect on the physiological performance of Salix, but it is still unclear whether these changes in physiology transcend into improved Salix regeneration and survivorship. However, under drier environmental conditions such as lower snowpacks and lower stream flows, the browsing resistance of Salix and ecosystem regeneration may be greatly hindered because the reliance of Salix on stream Water makes it vulnerable to changes in Surface Water and hydrological conditions.

Donald W Sada - One of the best experts on this subject based on the ideXlab platform.

  • Surface Water Hydrology and geomorphic characterization of a playa lake system implications for monitoring the effects of climate change
    Journal of Hydrology, 2014
    Co-Authors: Kenneth D Adams, Donald W Sada
    Abstract:

    Summary Playa lakes are sensitive recorders of subtle climatic perturbations because these ephemeral Water bodies respond to the flux of diffuse and channelized flow from their Watersheds as well as from direct precipitation. The Black Rock Playa in northwestern Nevada is one of the largest playas in North America and is noted for its extreme flatness, varying less than one meter across a Surface area of 310 km 2 . Geo-referenced Landsat imagery was used to map Surface-area fluctuations of ephemeral lakes on the playa from 1972 to 2013 to provide baseline data on Surface Water Hydrology of this system to compare to future hydrologic conditions caused by climate change. The area measurements were transformed into depth and volumetric estimates using results of detailed topographic global positioning system (GPS) surveys and correlated with available Surface hydrological and meteorological monitoring data. Playa lakes reach their maximum size ( 2 ) in spring, fed by melting snows from high mountains on the periphery of the drainage basin, and usually desiccate by early- to mid-summer. The combination of a shallow groundWater table, sediment deposition, and hydro-aeolian planation probably are largely responsible for the flatness of the playa. When lakes do not form for a period of several years, the clay- and silt-rich playa Surface transforms from one that is hard and durable into one that is soft and puffy, probably from upward capillary movement of Water and resultant evaporation. Subsequent flooding restores the hard and durable Surface. The near-global availability of Landsat imagery for the last 41 years should allow the documentation of baseline Surface hydrologic characteristics for a large number of widely-distributed playa lake systems that can be used to assess the hydrologic effects of future climate changes.