Farm-level phytodiversity of dairy farms is related to within-farm diversity of grassland management types

摘要

We analysed 163 vegetation releves from grassland plots of 24 conventional dairy farms in Lower Saxony, NW Germany. The sample covered farms with a different magnitude of the contribution of pasture to the roughage ration of the dairy cows: zero-grazing,grazing for <6 h d~(-1), or >14 h d~(-1). At each farm, the sward botanical composition of two plots per existing grassland management type was determined in one quadrat of 25 m~2 per plot. Average plot-level species numbers was distinct among types ofplot management (P<0.001) and ranged from 10.6 in intensively managed meadows to 15.0 in plots managed according to agri-environmental schemes. The species number of dairy cattle pastures did not differ significantly among farms implementing different daily grazing periods. The total species number at the whole farm-level ranged from 10 to 39 and increased significantly (,P=0.001) with the number of grassland management types implemented on the farms. Our results emphasize the importance of farm-level organizational structures for regional phytodiversity.