Variability in an edaphic indicator in alpine tundra

Spatial patterns of soil in alpine tundra just above timberline may determine patterns of advance by woody species. Patterns of advance since the Little Ice Age show spatial aggregation. If soil resources have similar patterns of aggregation, they might determine the pattern of vegetation change. Effective soil depth (ESD), which takes into account stoniness, was measured in tundra just above present timberline on regular grids at two scales and across solifluction treads and risers. No non-random spatial pattern was found, nor was there any difference related to relict solifluction patterns. Current patterns of woody vegetation could not have developed in direct response to the pattern of effective soil depth found in tundra. These patterns may develop in response to other soil factors, but may also include positive feedback.