Problems of Hydrology and Plant Distribution in Mires

Abstract

Early concepts of the causes of differences in mire vegetation are inadequate in situations where the ground water is mobile. Many mires are traversed by water tracks, whose characteristic vegetation appears to differ from that of water through the peat of the tracks. The physical basis of such movement may be correlated with differences in the amplitude of oscillations in water table height. Both components may influence plant distribution primarily by affecting the rate of supply of inorganic nutrients to the peat and by facilitating their subsequent uptake by the roots of seedlings. Aeration effects are probably secondary. Ion exchange in the peat may influence the nutrition of seedlings, as may the flux of ions through the living and decaying tissues of adult plants. Seedling competition is also important, but the implication of mycorrhizal associations cannot yet be assessed. Aspects of these mechanisms are illustrated with data from the Inverpolly National Nature Reserve.