Landscape patterns of CH4 fluxes in an alpine tundra ecosystem |
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| Authors: | A.E. West P.D. Brooks M.C. Fisk L.K. Smith E.A. Holland C.H. Jaeger III S. Babcock R.S. Lai S.K. Schmidt |
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| Affiliation: | (1) E.P.O. Biology, University of Colorado, 80309-0334 Boulder, CO, USA;(2) USGS-WRD, 3215 Marine St., 80303 Boulder, CO, USA;(3) Department of Natural Resources, Cornell University, 14853 Ithaca, NY, USA;(4) CIRES, University of Colorado, 80309-0216 Boulder, CO, USA;(5) National Center for Atmospheric Research, PO Box 3000, 80307-3000 Boulder, CO, USA;(6) Department of Ecosystem Sciences, Policy and Management, University of California, 108 Hilgard Hall, 94720 Berkeley, CA, USA |
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| Abstract: | We measured CH4 fluxes from three major plant communities characteristic of alpine tundra in the Colorado Front Range. Plant communities in this ecosystem are determined by soil moisture regimes induced by winter snowpack distribution. Spatial patterns of CH4 flux during the snow-free season corresponded roughly with these plant communities. InCarex-dominated meadows, which receive the most moisture from snowmelt, net CH4 production occurred. However, CH4 production in oneCarex site (seasonal mean=+8.45 mg CH4 m–2 d–1) was significantly larger than in the otherCarex sites (seasonal means=–0.06 and +0.05 mg CH4 m–2 d–1). This high CH4 flux may have resulted from shallower snowpack during the winter. InAcomastylis meadows, which have an intermediate moisture regime, CH4 oxidation dominated (seasonal mean=–0.43 mg CH4 m–2 d–1). In the windsweptKobresia meadow plant community, which receive the least amount of moisture from snowmelt, only CH4 oxidation was observed (seasonal mean=–0.77 mg CH4 m–2 d–1). Methane fluxes correlated with a different set of environmental factors within each plant community. In theCarex plant community, CH4 emission was limited by soil temperature. In theAcomastylis meadows, CH4 oxidation rates correlated positively with soil temperature and negatively with soil moisture. In theKobresia community, CH4 oxidation was stimulated by precipitation. Thus, both snow-free season CH4 fluxes and the controls on those CH4 fluxes were related to the plant communities determined by winter snowpack. |
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| Keywords: | alpine tundra methane trace gas |
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