The effect of Asulox spraying on the recovery of natural upland grassland after bracken invasion

Abstract

Bracken (Pteridium aquilinum) spreads rapidly as a response to the removal of forest and woodland, invading land cleared for agriculture. In Upper Teesdale bracken has encroached into a juniper woodland and may be preventing regeneration of this species. Recovery of vegetation after the removal of bracken has been examined by considering the nature, abundance and distribution of all species. Shading by the bracken canopy, the accummulation of bracken litter and the grazing by rabbits and sheep all influence the recovery of vegetation along a gradient of successive herbicide spraying of the bracken. The persisitence of the bracken litter layer is important in the recovery of the shade-intolerant species which flourish where bracken has been cleared, since there is generally a time-lag between removal of the bracken canopy and establishment of the grassland community. Areas of high and low bracken density behave differently when cleared, but in terms of abundance, rather than range, of species.