A comparison of techniques for restoring heathland on abandoned farmland.
Abstract
Recent changes in agricultural policies have reduced the extent of cultivated farmland. This has provided opportunities to restore heathland vegetation on lowland sites where it once occurred. Between December 1988 and April 1990 large-scale replicated experiments were established on abandoned farmland in southern Britain to compare the effectiveness of four treatments for heathland restoration: (i) the application of herbicide; (ii) the addition of harvested heather (Calluna vulgaris, Erica cinerea and E. tetralix) shoots; (iii) the addition of heathland topsoil; and (iv) the translocation of heathland turves. The number of seedlings of heathland plant species on each treatment was counted in December 1990 and 1991, and the shoot frequency of these species was recorded in January 1993. The grassland soil had a significantly higher pH and contained greater concentrations of extractable phosphorus and exchangeable calcium than that of the adjacent heathland. Despite this, the controls showed that there was some natural regeneration of heathers within the grassland. Herbicide treatment (5 litres glyphosate/ha) inhibited the regeneration of heathland plants. Cultivation followed by the application of harvested heather shoots increased the number of seedlings of heathland plant species, but some key species were missing. All the components of the heathland plant community occurred in greater numbers on the lots where heathland topsoil had been applied, and on the parts of transferred heathland turves which had died from drought. The large-scale translocation of heathland turf appeared to be feasible and instantly recreated the mature heathland plant community. However, some changes in the plant community occurred which probably resulted from differences in soil drainage characteristics between the donor and recipient sites. Of the different sources of heathland plant propagules, harvested heather shoots were a renewable resource, whereas the collection of heathland topsoil and turves involved the destruction of existing heathland.