Postglacial Environmental History of Rannoch Moor, Scotland III. Early-and Mid-Flandrian Pollen Stratigraphic Data from Sites on Western Rannoch Moor and Near Fort William

Abstract

This final paper in the present series on the Postglacial environ- mental history of Rannoch Moor describes pollen-stratigraphic investigations at two sites in the lee of the mountains that delimit the western margins of Rannoch Moor, and two sites at a lower altitude to the west of those mountains near Fort William. Radiocarbon dates were obtained from the basal horizons in two of the sites, but the significance of these age determinations is difficult to assess as one set is somewhat younger than dates from similar biostratigraphic horizons at other sites on Rannoch Moor, while the second series appears to have been considerably affected by hard-water error. The pollen-stratigraphic data suggest a measure of synchroneity in the timing of deglaciation from the Loch Lomond Advance maximum between Rannoch Moor and the valleys to the west, and that immediately following ice wastage, Empetrum heath and juniper scrub became established in both areas prior to the expansion of birch woodland. Follow- ing the spread of Corylus into the western Grampian Highlands, marked differ- ences developed in forest composition, with pine and birch woodland covering large areas of the Rannoch plateau, while birch, hazel and oak forests character- ized the lower ground to the west. The arrival of alder in large numbers coincided with the onset of blanket peat growth, the latter being largely responsible for the decline in the woodlands. The principal findings of the Rannoch Moor project are discussed in a concluding section to the paper.