Bog standards in Minnesota

摘要

The idea of a raised bog may seem some-thing of a contradiction in terms — most wetland habitats are low-lying and receive drainage water from a surrounding catchment. But the raised, or domed, bog is a very widespread, if declining, type of mire inthe temperate zone of the Northern Hemisphere, especially in the more oceanic regions (Fig. 1). The debate about how a wetland can maintain its surface several metres above the grdundwater table and yet avoid desiccation has simmered for a century. Do these domed Amasses of peat pull up water from below by capillarity? Or do they impede the downward movement of rain water as a consequence of the impermeable nature of compacted peat? Or are they dependent on hydrostatic pressure from below, as is suggested by research by Glaser, Siegel, Romanowicz and Shen reported in the current issue of Journal of Ecology?