Ecological relationships between vegetation and soil-related variables along the mire margin-mire expanse gradient in the eastern Julian Alps, Slovenia

摘要

In the NW part of Slovenia, at the southern border of the Sphagnum-mire area in Europe, the plant species diversity and vegetation structure of mires (sedge fen, spruce mire and dwarf-pine bog) and spruce forests were investigated using ordination techniques (detrended correspondence analysis, DCA). The mires studied occur at around 1200 metres above sea level. The correlation between plant distribution patterns and ecology, with particular reference to soil variables, was examined. Based on DCA ordination, the sedge fens were clearly distinguished from the dwarf-pine bogs and the spruce mires, as well as from the spruce forests on the mineral soils. A significant correlation between the first DCA axis and the plant species diversity was found. The Shannon diversity index and the species richness were highest in the sedge fen and on the mire-forest border zone. The first DCA axis was interpreted as a reflection of the gradients of the soil pH, the amount of calcium and the base saturation level. The first axis clearly differentiated the Sphagnum species (e.g. S. girgensohnii, S. magellanicum, S. russowii, S. flexuosum., S. capillifolium) from the moss species belonging mostly to Amblystegiaceae (e.g. Drepanocladus cossonii, Campylium stellatum, Calliergon cordifolium, Cratoneuron decipiens). The second DCA axis was interpreted in terms of the soil water content, total carbon content, ON ratio and peat depth. It evidently differentiated the spruce forest on the mineral soil from the various mire ecosystems.