Action: Manage heather, gorse or grass by burning
- A long-term replicated controlled trial in Switzerland found that annual spring burning of calcareous grassland did not increase plant species richness relative to abandoned plots, after 15 years.
- A replicated controlled trial in Northern Ireland found that heather moorland subject to a single burn had more plant species eight years after the management, than control unburned plots.
This intervention may involve controlled burns to stimulate heather re-growth, modify the heathland/grassland plant communities or create a patchwork of heather of different ages.
See also ‘Maintain upland heath/moorland’ for studies that used burning as a management tool to maintain upland heath/moorland, and ‘Manage heather by swiping to simulate burning’ for studies that use swiping as an alternative to burning.
Supporting evidence from individual studies
A long-term replicated controlled trial from 1978 to 1993 in the Jura Mountains, Switzerland (Ryser et al. 1995), found calcareous grassland plots that were burned annually in February or March had fewer plant species after 13-15 years than plots cut annually or every second year (in October or July). Burned plots had 50 plant species/40 m2, and 31 species/m2 on average, compared to 53 species/40 m2 and 37 species/m2 on average in plots cut every year or two years. Burned plots did not have significantly more plant species than abandoned control plots with no management. Burning also changed the species composition, reducing the cover of one of the three most abundant species, meadow brome Bromus erectus, from around 40% in July-mown plots to around 10%. There were three replicate 50 m2 plots for each treatment, and the experimental management regimes were carried out from 1978 to 1993. The percentage cover of plant species was estimated in 40 m2 and 1 m2 sample areas in each plot, in the last week of June 1991 and 1993.
A replicated, controlled trial in Northern Ireland (McEvoy et al. 2006) found that heather moorland plots subject to burning in 1996 had more plant species in 2004, eight years after management, than control unmanaged plots. Burned plots had 28 species/site on average (average of 15 moss and liverwort species), and control plots had 24 species/site (10 moss and liverwort species). One year after the management, in 1997, both burned and control plots had had 22 plant species (8-10 moss and liverwort species) on average. The cover by mosses and liverworts increased significantly between 1997 and 2004 on burned sites (numbers not given). Burned sites had higher cover of heather in 2004 than six flailed sites in the same study (about 35% compared to 30% heather Calluna vulgaris cover). Eight sites burned in 1996 to stimulate heather regeneration were surveyed in 1997 and again in 2004. Plants were surveyed in four 4 m2 quadrats per site. Adjacent unburned control areas were surveyed at each site.
- Ryser P., Lagenhauer R. & Gigon A. (1995) Species richness and vegetation structure in a limestone grassland after 15 years management with six biomass removal regimes. Folia Geobotanica and Phytotaxonomica, 30, 157-167
- McEvoy P.M., Flexen M. & McAdam J.H. (2006) The Environmentally Sensitive Area (ESA) scheme in Northern Ireland: ten years of agri-environment monitoring. Biology and Environment: Proceedings of the Royal Irish Academy, Section B, 106, 413-423