Topographic patterns of above- and below ground production and nitrogen cycling in alpine tundra
- Univ. of Colorado, Boulder, CO (United States)
Topography controls snowpack accumulation and hence growing-season length, soil water availability, and the distribution of plant communities in the Colorado Front Range alpine. Nutrient cycles in such an environment are likely to be regulated by interactions between topographically determined climate and plant species composition. The authors investigated variation in plant and soil components of internal N cycling across topographic gradients of dry, moist, and wet alpine tundra meadows at Niwot Ridge, Colorado. They expected that plant production and N cycling would increase from dry to wet alpine tundra meadows, but they hypothesized that variation in N turnover would span a proportionately greater range than productivity, because of feedbacks between plants and soil microbial processes that determine N availability. Plant production of foliage and roots increased over topographic sequences from 280 g{center_dot}m{sup {minus}2}{center_dot}yr{sup {minus}1} in dry meadows to 600 g{center_dot}m{sup {minus}2}{center_dot}yr{sup {minus}1} in wet meadows and was significantly correlated to soil moisture. Contrary to their expectation, plant N uptake for production increased to a lesser degree, from 3.9 g N{center_dot}m{sup {minus}2}{center_dot}yr{sup {minus}1} in dry meadows to 6.8 g N{center_dot}m{sup {minus}2}{center_dot}yr{sup {minus}1} in wet meadows. In all communities, the belowground component accounted for the majority of biomass, production, and N use for production.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 290205
- Journal Information:
- Ecology, Vol. 79, Issue 7; Other Information: PBD: Oct 1998
- Country of Publication:
- United States
- Language:
- English
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