Landscape patterns of CH4 fluxes in an alpine tundra ecosystem

We measured CH4 fluxes from three major plant communities characteristic of alpine tundra in the Colorado Front Range. Plant communities in this ecosy stem are determined by soil moisture regimes induced by winter snowpack dis tribution. Spatial patterns of CH4 flux during the snow-free season corresp onded roughly with these plant communities. In Carex-dominated meadows, whi ch receive the most moisture from snowmelt, net CH4 production occurred. Ho wever, CH4 production in one Carex site (seasonal mean = +8.45 mg CH4 m(-2) d(-1)) was significantly larger than in the other Carex sites (seasonal me ans = -0.06 and +0.05 mg CH4 m(-2) d(-1)). This high CH4 flux may have resu lted from shallower snowpack during the winter. In Acomastylis meadows, whi ch have an intermediate moisture regime, CH4 oxidation dominated (seasonal mean = -0.43 mg CH4 m(-2) d(-1)). In the windswept Kobresia meadow plant co mmunity, 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 eac h plant community. In the Carex plant community, CH4 emission was limited b y soil temperature. In the Acomastylis meadows, CH4 oxidation rates correla ted positively with soil temperature and negatively with soil moisture. In the Kobresia community, CH4 oxidation was stimulated by precipitation. Thus , both snow-free season CH4 fluxes and the controls on those CH4 fluxes wer e related to the plant communities determined by winter snowpack.We measure d CH4 fluxes from three major plant communities characteristic of alpine tu ndra in the Colorado Front Range. Plant communities in this ecosystem are d etermined by soil moisture regimes induced by winter snowpack distribution. Spatial patterns of CH4 flux during the snow-free season corresponded roug hly with these plant communities. In Carex-dominated meadows, which receive the most moisture from snowmelt, net CH4 production occurred. However, CH4 production in one Carex site (seasonal mean = +8.45 mg CH4 m(-2) d(-1)) wa s significantly larger than in the other Carex sites (seasonal means = -0.0 6 and +0.05 mg CH4 m(-2) d(-1)). This high CH4 flux may have resulted from shallower snowpack during the winter. In Acomastylis meadows, which have an intermediate moisture regime, CH4 oxidation dominated (seasonal mean = -0. 43 mg CH4 m(-2) d(-1)). In the windswept Kobresia meadow plant community, w hich 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 co rrelated with a different set of environmental factors within each plant co mmunity. In the Carex plant community, CH4 emission was limited by soil tem perature. In the Acomastylis meadows, CH4 oxidation rates correlated positi vely with soil temperature and negatively with soil moisture. In the Kobres ia community, CH4 oxidation was stimulated by precipitation. Thus, both sno w-free season CH4 fluxes and the controls on those CH4 fluxes were related to the plant communities determined by winter snowpack.