The decline of Arrhenatherum meadows in the Swiss lowland and its consequences for biodiversity

A comparison of historic and current vegetation surveys of intensively managed meadows reveals a dramatic decline of species diversity in Swiss lowland grassland. In the 1950s, the most intensively managed meadows were Arrhenatherum meadows. Over 85 % of these achieved the QII standard defining meadows with «high biodiversity value», and more than a third significantly surpassed the QII threshold. A current inventory shows that since the 1950s, Arrhenatherum meadows have been almost completely replaced by species-poor, highly intensified grassland. The remaining Arrhenatherum meadows – nearly all managed and funded as «ecological compensation areas» – make up less than 2 % of the permanent grassland area in the Swiss lowlands. These remaining Arrhenatherum meadows have impoverished species richness. On average, it has declined by 30 % from 38 plant species per 100 m2 in 1950 to 27 today. The number of species characteristic of the Arrhenatherum grassland communities has declined by 64 % from 25 to 9. Today 71 % of the few remaining Arrhenatherum meadows fail to reach the QII standard. The loss of animal diversity in Swiss lowland grassland is even more severe than the plant diversity decline, a