A multi‐site assessment of the effectiveness ofPteridium aquilinumcontrol in Great Britain

Abstract

AbstractQuestions:The objectives of this study were to assess the effect ofPteridium aquilinum(bracken) control treatments, at the national scale, and the impact of restoration practices, at the local scale, onP. aquilinumperformance.Hypotheses:1. Geographical location (locally between and within sites) affects the control ofP. aquilinumthrough time. 2. Are theP. aquilinumcontrol treatments successful at all sites, and if so which ones? 3. The treatments applied at the individual site level to restore vegetation influences the performance ofP. aquilinumthrough time.Location:Four geographically distinct acid grassland and heathland sites infested withP. aquilinumacross Great Britain.Methods:Six main‐plot, bracken control treatments were applied to all sites with site‐specific vegetation restoration treatments. Response variables (P. aquilinumcover, frond length and density) were monitored twice yearly, in June and August between 1993 and 2003.Results:Between‐ and within‐site spatial variation was found, although impact is perhaps less than suggested from shorter‐term data. Despite local variation all sites responded similarly to bracken control treatments; asulam treatment resulted in a rapid reduction in frond performance followed by a continued recovery taking approximately ten years to return to untreated values. Cutting treatments tended to have a slower impact at the start but an increasing one over time, especially cutting twice per year. Restoration treatments had a limited impact; the only significant effect in August was grass seeding on frond length at Sourhope. In June only, the plots where sheep were fenced out showed a significant reduction inP. aquilinumcover at Peak.Conclusions:Long‐term control ofPteridium aquilinumat all sites and on all measures was best achieved using a continuous cutting treatment, preferably twice per year.