and {The Heather Trust, The Cross, Kippen, Stirlingshire FK8 3DS, UK Summary 1. A characteristic of some heath and moorland areas in maritime north-west Europe is the widespread dominance of Molinia caerulea (purple moor grass). The overwhelming local supremacy of this species concerns farmers, owing to its relatively low palatability for grazing stock, and conservationists, owing to the monotonous, species-poor landscapes that often result under Molinietum. 2. In some environmentally sensitive areas (ESAs) in England and Wales, Molinietum is believed to have ousted Callunetum in recent decades; experiments sponsored to control the species have predicated its in®ltration and replacement of heather-dominated stands. 3. Experimental control of Molinia in ESAs on Exmoor, England, was paralleled by palaeoecological studies to verify its recent rise, assess its status in moorland, and test the utility of the techniques for such research. 4. Peat pro®les from two localities on Exmoor were sampled and subjected to recently developed techniques of plant macrofossil counting and to conventional pollen analysis. One locality was`white moor', clearly dominated by Molinia; the other was`grey moor' (an admixture of ericaceous shrubs) that had become invaded (allegedly recently) by Molinia. 5. Dating of pro®les employed a range of methods, including conventional radiocarbon dating, Accelerator Mass Spectrometry (AMS) dating and the counting of spheroidal carbonaceous particles, to attempt to delimit horizons of recent peat growth. 6. The pollen and macrofossil data con®rmed the recent ousting of Calluna and rise to dominance of Molinia in the grey moor, but also provided evidence of an earlier unsuspected (pre-Callunetum) presence of Molinia. The overwhelming dominance of Molinia in the white moor was also a recent phenomenon, but was only partly at the expense of Calluna. The palaeoecological data indicated a greater antiquity and former abundance of Molinia than is often appreciated and suggested that, over the past millennium, vegetation dominance has alternated between Callunetum and grass moor containing at least some Molinia, while the former Calluna-dominated grey moor itself developed originally from grass moor. 7. These ®ndings have implications for conservation management and for restoration targets in`degraded' moorland. Similar palaeoecological studies have since been adopted in Wales, directly to inform conservation and management policy.

Summary 1.Molinia encroachment has been viewed as a major threat to moorland conservation in the UK and elsewhere in Europe. In England and Wales agri-environment schemes are in place that aim to reduce Molinia caerulea and encourage the development of dwarf shrub vegetation. We tested a range of management treatments to achieve these objectives in two regions (the North Peaks and Yorkshire Dales) in England. 2. Within each region, the same experiment was carried out on two types of moorland vegetation, Molinia -dominated 'white' moorland and a mixture of Molinia and Calluna vulgaris 'grey' moorland. Burning, grazing and herbicide (glyphosate) treatments were applied in factorial combination at each of the four sites (two regions × two moor types). The responses of both vegetation and individual species were assessed. In addition, on the white moors two techniques for Calluna re-establishment were investigated, (i) removal of Molinia litter by raking and (ii) application of Calluna seed. 3. The data were analysed using a combination of univariate and multivariate analysis of variance to identify trends in this complex data set. 4. The only treatment that had consistent effects in the univariate analysis of variance was glyphosate application, which had similar effects on Molinia at all study sites. There was little difference between the use of low and high application rates (0·27 and 0·54 kg ai ha). There was little impact of herbicide use on other moorland species. Some species were affected on some sites in some years, but there were no consistent effects. Tentative identification of species that responded positively, negatively and erratically to glyphosate application was made. 5. Greater Calluna seedling densities were found in the plots where herbicide was applied, the Molinia litter was removed and seed was added. However, after initial colonization, there was a reduction in Calluna seedling densities as the Molinia recovered. This indicated that disturbance, seed addition and follow-up management are required for successful Calluna establishment. 6. There were significant differences in community response between both the regions and moorland types. The Dales had a relatively greater contribution of grassland species than the Peaks, where the grey site had a relatively greater dwarf shrub component. 7. Burning had little effect on community composition but both grazing and herbicide application had important effects. Grazing of the grey sites, even at the very low levels used in this study, tended to push the communities towards bog-moorland vegetation, but little effect was found at the white sites. Glyphosate treatment tended to push communities towards acidic grassland at the Dales grey site but not at the Peaks. Successional change was also noted, with marked change between the third and fourth year and again between the fifth and six year. Grey sites showed the greatest temporal change. 8. Synthesis and applications . In terms of Molinia control and subsequent restoration of dwarf shrubs, there was...