Heathland ecology and vegetation history of Tulloch Moor, Inverness-Shire

Abstract

Tulloch Moor is part of the RSPB reserve at Loch Garten. It contains a very good example of Calluna-Arctostaphylos heath. The vegetation of the moor was examined by means of 44 2x2m sample plots. 32 of these were in 8 permanently marked 4x4m quadrats, and provide a baseline to measure future change. 7 plots outside the permanent transect showed further variation in the heathland vegetation. The data indicate that time since burning, colonisation by trees, and variation in soil type are the important factors in determining the present variation. Ordination separated the Tulloch Moor heath releves from those given by McVean & Ratcliffe (1962) for the Arctostaphyleto-Callunetum which more often included Pyrola media and Dicranum scoparium, however the heath releves were more similar to the Arctostaphyleto- callunetum than to Callunetum vulgaris. The vegetation history of Tulloch Moor was investigated by pollen analysis of a sample of peat and a surface sample of moss. The peat sample was not dated. The pollen analysis indicates that there was a period when the Moor, or at least the sampling locality, was much more wooded than now, mainly with pine and some birch. Prior to this there was an open heath with some trees, much as now. Following the wooded period, the tree cover declined to a low level, and then increased in the recent past to its present level. Characteristics and measurements of Ericales reference pollen were compared with those of fossil pollen, and the results of the different methods of identification were compared. Most of the fossil pollen tetrads were Erica tetralix which presently grows on the peat bog surface. Very few tetrads of Arctostaphylos pollen were found, and these were at or near the surface. Examination of the peat for charcoal fragments indicates that fires have occurred in the area throughout the period represented by the peat sample. Some peaks in charcoal abundance are followed by a decline in tree pollen, indicating that fire was a cause of tree decline.