Reversing spontaneous succession to protect high‐value vegetation: Assessment of two Scottish mires using rapid survey techniques

Abstract

Abstract. Despite existing management agreements, significant change has occurred on Carnwath Moss and Coladoir Bog, two mire complexes in central and western Scotland. Spontaneous succession has accelerated, resulting in extensive degradation of the mire vegetation on both sites and, in particular, widespread expansion of Calluna vulgaris‐ and Molinia caerulea‐dominated vegetation types. Vegetation surveys across strong gradients of change were conducted with the aim of quantifying the extent of early (desirable) and late (undesirable) successional vegetation on both sites. For each site multivariate analyses of the vegetation data were carried out using TWINSPAN, which clearly differentiated higher quality and degraded surfaces. In management terms percentage Sphagnum cover can act as a useful proxy measure of water level and shrub layer height can also serve as a useful indicator of the degree of degradation. A broad‐based, five class condition continuum was developed for the Carnwath Moss site. While such an assessment scheme is a somewhat arbitrary means of allocating mesotope areas to specific condition classes, it is rapid to apply and simple enough to be applied by a range of users. A drawback is that the methodology is data‐light in temporal terms and is not a long‐term substitute for properly‐funded monitoring programmes for important sites. For both mires, recommendations are made for management with the main emphasis being on maintaining water tables at appropriate levels to maximise the floristic diversity of active mires.