Inter‐regional comparison of land‐use effects on stream metabolism |
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| Authors: | MELODY J. BERNOT DANIEL J. SOBOTA ROBERT O. HALL JR PATRICK J. MULHOLLAND WALTER K. DODDS JACKSON R. WEBSTER JENNIFER L. TANK LINDA R. ASHKENAS LEE W. COOPER CLIFFORD N. DAHM STANLEY V. GREGORY NANCY B. GRIMM STEPHEN K. HAMILTON SHERRI L. JOHNSON WILLIAM H. MCDOWELL JUDITH L. MEYER BRUCE PETERSON GEOFFREY C. POOLE H. MAURICE VALETT CLAY ARANGO JAKE J. BEAULIEU AMY J. BURGIN CHELSEA CRENSHAW ASHLEY M. HELTON LAURA JOHNSON JEFF MERRIAM B. R. NIEDERLEHNER JONATHAN M. O’BRIEN JODY D. POTTER RICHARD W. SHEIBLEY SUZANNE M. THOMAS KYM WILSON |
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| Affiliation: | 1. Department of Biology, Ball State University, Muncie, IN 47306, U.S.A.;2. Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR 97331, U.S.A.;3. School of Earth and Environmental Sciences, Washington State University‐Vancouver Campus, Vancouver, WA 98686, U.S.A.;4. Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, U.S.A.;5. Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A.;6. Division of Biology, Kansas State University, Manhattan, KS 66506, U.S.A.;7. Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, U.S.A.;8. Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, U.S.A.;9. Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, U.S.A.;10. Department of Biology, University of New Mexico, Albuquerque, NM 87131, U.S.A.;11. School of Life Sciences, Arizona State University, Tempe, AZ 85287, U.S.A.;12. Kellogg Biological Station, Michigan State University, Hickory Corners, MI 49060, U.S.A.;13. Pacific NW Research Station, US Forest Service, Corvallis, OR 97331, U.S.A.;14. Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, U.S.A.;15. Institute of Ecology, University of Georgia, Athens, GA 30602, U.S.A.;16. Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, U.S.A.;17. Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, U.S.A.;18. USGS Washington Water Science Center, Tacoma, WA 98402, U.S.A. |
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| Abstract: | ![]()
1. Rates of whole‐system metabolism (production and respiration) are fundamental indicators of ecosystem structure and function. Although first‐order, proximal controls are well understood, assessments of the interactions between proximal controls and distal controls, such as land use and geographic region, are lacking. Thus, the influence of land use on stream metabolism across geographic regions is unknown. Further, there is limited understanding of how land use may alter variability in ecosystem metabolism across regions. 2. Stream metabolism was measured in nine streams in each of eight regions (n = 72) across the United States and Puerto Rico. In each region, three streams were selected from a range of three land uses: agriculturally influenced, urban‐influenced, and reference streams. Stream metabolism was estimated from diel changes in dissolved oxygen concentrations in each stream reach with correction for reaeration and groundwater input. 3. Gross primary production (GPP) was highest in regions with little riparian vegetation (sagebrush steppe in Wyoming, desert shrub in Arizona/New Mexico) and lowest in forested regions (North Carolina, Oregon). In contrast, ecosystem respiration (ER) varied both within and among regions. Reference streams had significantly lower rates of GPP than urban or agriculturally influenced streams. 4. GPP was positively correlated with photosynthetically active radiation and autotrophic biomass. Multiple regression models compared using Akaike’s information criterion (AIC) indicated GPP increased with water column ammonium and the fraction of the catchment in urban and reference land‐use categories. Multiple regression models also identified velocity, temperature, nitrate, ammonium, dissolved organic carbon, GPP, coarse benthic organic matter, fine benthic organic matter and the fraction of all land‐use categories in the catchment as regulators of ER. 5. Structural equation modelling indicated significant distal as well as proximal control pathways including a direct effect of land‐use on GPP as well as SRP, DIN, and PAR effects on GPP; GPP effects on autotrophic biomass, organic matter, and ER; and organic matter effects on ER. 6. Overall, consideration of the data separated by land‐use categories showed reduced inter‐regional variability in rates of metabolism, indicating that the influence of agricultural and urban land use can obscure regional differences in stream metabolism. |
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| Keywords: | ecosystem respiration land use metabolism primary production stream |
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