Effects of nature management practices on the bryophyte flora of grassland and heathland in Drenthe, The Netherlands

A study was carried out on the effects of hay-making, hay-making after sod removal, and grazing with different intensities on the bryophyte flora in a moist grassland dominated by Holcus lanatus and in a very wet grassland dominated by Juncus effusus. The effects of grazing and the abandoning of a heathland area were also compared. The bryophytes were recorded in 1972, 1976 and 1983. In the grazed and the cut plots in the moist grassland area the average number of bryophytes and the degree of cover did not differ, but in the cut plots the degree of cover of bryophytes characteristic for litter became smaller. In the grazed plots, in which the vascular plant composition diverged with the grazing intensity, the bryophyte flora did change, but not diverge. After sod cutting mainly colonist species were present initially, but after 10 years, the number of perennials had increased considerably. In the cut plots in which sods had been removed the degree of cover of bryophytes, especially colonists, became greater than in the cut plots in which sods had not been removed. In the grazed and the cut plots in the very wet grassland area the average number of bryophytes did not diverge, but in the cut plots the degree of cover became highest and the proportion of litter species became smallest. The number of bryophytes remained high in the grazed heathland, but declined in the abandoned area, whereas the degree of cover decreased in both areas. Several species characteristic for heathland disappeared in the grazed area, whereas all ‘heathland-species’ disappeared in the abandoned area, which turned into woodland.