Grazing exclusion and phosphorus addition as potential local management options for the restoration of alpine moss-sedge heath

High grazing pressures and elevated atmospheric nitrogen deposition are considered to be causing widespread degradation of upland plant communities including Racomitrium heath, the UK's most extensive near-natural alpine habitat. Management strategies are urgently required to halt further habitat decline and to aid in restoration of this important moss-dominated summit community. Grazing exclosure and phosphorus (P) addition experiments were conducted at 10 sites across the UK to assess the potential of Racomitrium heath to respond to (1) the removal of grazing pressure, and (2) the addition of P. a measure intended to alleviate the impacts of high N deposition. After two years, growth and depth of Racomitrium lanuginosum, the dominant moss species, were significantly enhanced by both treatments. However, while the addition of P resulted in increased cover of R. lanuginosum and decreased grass cover, grazing exclusion resulted in the opposite effects. While both practices clearly have the potential to promote improvement in the condition of Racomitrium heath, their suitability for individual sites appears to differ. Results indicate that for the most degraded heaths, where grass abundance is high, complete removal of grazing pressure may, at least initially, stimulate grass performance, potentially leading to further habitat decline. The addition of P, on the other hand, appears to produce desirable effects in terms of both R. lanuginosum performance and community composition, and thus could be used as a local management option to kick-start recovery in the most damaged heaths. (C) 2012 Elsevier Ltd. All rights reserved.