The effect of disturbance on the bryophyte flora of Salisbury Plain, western Europe's largest chalk grassland

The military training area on Salisbury Plain contains the largest area of chalk grassland in western Europe. The grassland swards, though relatively tall, are often rich in flowering plant species. The bryophyte flora of areas disturbed in five different ways (prehistoric earthworks, twentieth century rifle ranges, ant-hills, vehicle tracks and shell-holes) was compared to that of adjacent, relatively undisturbed grassland. There was no significant difference in bryophyte cover between quadrats on disturbed ground and the controls, but the disturbed sites supported more bryophyte species per quadrat. Of the 55 taxa recorded, 38 species were at least three times more frequent in the disturbed than the undisturbed sites, compared to four which were at least three times more frequent in the control sites. The species favouring disturbed conditions included several bryophytes characteristically associated with chalk soils in southern England, including some that fruit freely (e. g. Microbryum curvicollum, Tortula lanceola) and others that fruit very rarely (e. g. Abietinella abietina, Entodon concinnus). These results are discussed in relation to the conservation of bryophytes and other disturbance-tolerant and disturbance-dependent species on Salisbury Plain and in the wider context of the protection of the bryophytes of chalkland habitats.