THE USE OF SOIL DISTURBANCE IN THE MANAGEMENT OF BRECKLAND GRASS HEATHS FOR NATURE CONSERVATION

The effect over 3 years of different combinations of ploughing, forage harvesting and rotovation on vegetation composition and soil nutrients were assessed by a replicated block experiment in an area of lichen-rich calcareous Breckland grass heath. Rotovation resulted in shorter vegetation, increased rabbit activity, increased species density of plants, decreased percentage cover of species dominant in the control and a higher percentage cover of bare ground, winter annuals, summer annuls, saxicolous lichens and cushion-forming mosses. Rotovation favoured a number of annual and ruderal species unrecorded from the control. Ploughing had fewer beneficial effects than rotovation. A number of vegetation components experience greater reductions in percentage cover than in rotovated treatments, and a greater number of species are lost from treated areas. Regeneration of the vegetation will take longer with a greater reliance on external sources of inoculi. Cutting and removal of vegetation has small benefits for vegetation composition. Ploughing treatments significantly reduced total nitrogen in the upper 0-10 cm of soil, rotovation did not reduce total nitrogen within the first 3 years after treatment. No significant short-term effects on total or extractable phosphorous were found. Soil disturbance may be used as a management tool within grass heaths to create a diverse and heterogeneous mosaic of plant sub-communities and habitat microstructure. Such management has an historical justification. © 1994 Academic Press. All rights reserved.