The Development of Streamlined Bog Islands in the Continental Interior of North America^*

* Limnological Research Center Contribution Number 343.

Abstract

Boreal peatlands within the interior of North America have developed vegetation landforms that simulate the shape of geologic landforms, such as islands and river channels. The genesis and development of these vegetation landforms can be inferred from spatial transitions from one landform pattern to another and from the quantitative analysis of their shapes in plan view. The spatial transitions indicate that the bog islands develop (1) downslope from flow obstructions in catchments that have irregular relief and (2) by the fragmentation of a large bog (>20 km²) by the development of water tracks in catchments that are nearly level. The dimensions of these bog islands correspond to a lemniscate loop or the streamlined airfoil that minimizes resistance to a flowing fluid. The bog islands therefore seem to be equilibrium forms that represent a stable adjustment to the alkalinity and volume of runoff in the water tracks.