Agroscope Reckenholz-Tänikon Research Station ART, Reckenholzstrasse 191, CH-8046 Zürich

Fertile grasslands in the Alps: floristic changes

In this study, we investigated how the floristic composition of fertile grasslands in the Alps has changed over the last 25 years. To do this, we repeated between 2002 and 2004 in four regions a total of 259 phytosociological relevés from the years 1975 to 1986 on the same sites. At the plot level, the relevés of the two surveys differed on average in 41 to 51% of the species detected, with accompanying species contributing to the change to a disproportionately large extent. The floristic changes were significant if less distinct at the landscape level, pointing to a slightly intensified management. In particular, there is now a higher incidence of plants which benefit from a high nutrient supply and/or have good mowing compatibility. In Tujetsch, intensification was restricted to favourable sites, whilst extensification took place on steep slopes and at high altitudes. Since both roughage quality and species richness were predominantly maintained or even increased, we conclude that grassland management over the last 25 years has been largely sustainable. However, on sites with the highest management intensity at Château-d’Oex, there was an increase in weed species indicating degenerated swards, with a corresponding decrease in the indicator value for roughage quality. To prevent this undesirable development from occurring on a large scale in the Swiss Alps, we recommend that management of fertile grasslands not be intensified beyond their productivity potential.

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