COMMUNITY AND SPECIES-PERFORMANCE PATTERNS ALONG AN ALPINE POOR-RICH MIRE GRADIENT

Vegetation, water table depth and water chemistry of 16 peatlands in t he southern Alps, Italy, were analysed in 115 sample plots. A poor-ric h gradient could be detected along the first axis of a partial Detrend ed Canonical Correspondence Analysis. Both vegetation and hydrochemist ry vary gradually along the gradient. Vascular plants have much broade r niches along the gradient than bryophytes. Mosses (except Sphangnum) and hepatics have narrower niches than Sphagnum. The various species of Sphagnum segregate more clearly from each ether along the moisture gradient than along the poor-rich one. The positions of species optima along the latter gradient largely reflect the ecological preferences of mire plants in peatlands with respect to nutrient status.