Document: IGG-3-91-10

Spatial analysis of selected soil attributes across an alpine topographic/snow gradient.

LITAOR, M.I.* ¹, T.R.SEASTEDT ² and D.A.WALKER ³

Tel-Hai College, Upper Galilee 12210 Israel ¹
University of Colorado, Boulder CO 80309 USA ²
University of Alaska,Fairbanks, AK 99775-7000 USA ³

Abstract:
The role of the topographic/snow gradient on alpine soil processes of the Colorado Front Range was assessed using geostatistical modeling and fractal approach. The mean snow depth, measured between 1984 and 1997 exhibited a smooth spatial continuity across the study grid area (550 by 400 meter). Soil color variables (CIE L*, a*, b*) showed a nested structure that was attributed to a confounded effect of catenary processes, dominant plant species and eolian deposition. The spatial structure of texture classes exhibited limited spatial structure and was partially explained by data sparsity and crytorbation processes that mask the expected long-distance variations (i.e., 550-m) of the catenary processes. Organic C, pH, bulk density and soil moisture content showed various degrees of spatial continuity but all indicated that the topographic/snow gradient is not the only dominating soil forming factor in this alpine ecosystem. The estimated fractal dimension D for the Saddle grid landform and the mean snow depth varied between 1.2 to 1.4 indicating that they vary smoothly with long-range variation. The estimated D of the soil variables ranged between 1.6 to 1.8 showing noisy appearance with short-range variations. These results firmly imply that most of the spatial variations exhibited by the alpine soil attributes resulted from the combined effect of relief, cryoturbation, biological activity and eolian deposition.

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This abstract is being presented at: 11:45 AM in session:
Oral Session #58: Landscape Ecology.