Late Weichselian and Flandrian Pollen Diagrams From South‐west Scotland

Abstract

SUMMARYThe history of Late Weichselian and Flandrian vegetation in south-west Scotland has been studied by examining sites ranging from near sea-level up to about 1500 ft O.D. (c. 500 m). Pollen was scarce or absent in Lower Dryas sediments, but the relatively high counts in Allerod sediments implied that an open herbaceous vegetation was established before this time. Throughout the Late Weichselian the vegetation was an herbaceous one which became more stable and denser during the Allerod, but was much reduced during Upper Dryas time. Early Flandrian vegetation remained open and the spread of birch woodland was delayed for some time. Once established the birch forests remained dominant or co-dominant for a long period and were never completely replaced by mixed-oak forest. Because of the differences in vegetation development it was difficult to correlate significant changes in the pollen curves with the standard British system of pollen zones. For this reason an attempt has been made to devise a system of zones appropriate for Scotland which bears comparison with the presently accepted scheme. Apparent breaks in sedimentation at Bigholm Burn and Culhorn Mains, only revealed by pollen analysis, are treated as local phenomena, the causes of which had no effect upon the character of the regional vegetation. Radiocarbon assay of samples from Bigholm Burn show that the ages of Allerod sediments are consistent with those from other parts of Britain, but early and mid-Flandrian dates are considerably younger than their biostratigraphical equivalents elsewhere. Until more dates are available from the region this apparent anomaly is regarded as being an effect of local factors influencing forest development and sedimentation. Although the distribution of sites about the Southern Uplands implies that glaciers were restricted to higher altitudes the present study does not add significantly to our knowledge of the extent of glaciation in this region during the Late Weichselian.

The Loch Lomond Readvance moraines of Mull and Menteith

“…The pollen and spore assemblages are comparable however, to those found in other Zone II pollen sites in Scotland by Donner (1957Donner ( , 1958, Moar (1969) and Newey (1970). The arboreal pollen content from these sites varies between 10 and 30% of the pollen totals and consists of Betula, Pinus, Salix and Juniperus.…”

A POST‐GLACIAL POLLEN SEQUENCE FROM LOCH A'MHUILINN, NORTH ARRAN: A RECORD OF VEGETATION HISTORY WITH SPECIAL REFERENCE TO THE HISTORY OF ENDEMIC SORBUS SPECIES

“…On the mainland to the west and north of Arran, at Loch Cill an Aonghais and at Na Lona Min, Juniperus and Empetrum show early Flandrian presence, preceding a major rise in Betula [Peglar (in Birks, 1980);Tipping, 1986]. At these and other southwest Scottish sites (Nichols, 1967;Moar, 1969;Birks, 1972;Dickson, 1981;Boyd, 1982Boyd, , 1986Stewart et al, 1984) Salix has a consistent if modest presence, frequently being more abundant during this period than at any subsequent period.…”

Three Flandrian Pollen Profiles From the Teith Valley, Perthshire, Scotland

“…Although Pinus is poorly represented in most Flandrian pollen diagrams from lowland southeast Scotland (Newey, 1968), high percentages in some sites suggest scattered pinewoods in the mid-Flandrian forests of southwest Scotland (Moar, 1969). Pinus is also better represented at some upland sites in the Midland Valley where elevation and edaphic conditions may have favoured its local dominance, as for instance in the Campsie Fells (Eydt, 1960) and parts of eastern Lanarkshire (Fraser and Godwin, 1955).…”

“…Salix is the only shrub to continue to be well represented in the pollen diagrams, but this is probably related to extremely local growth of willow at each site (see below). Available radiocarbon dates from Scotland for rational Quercus, Ulmus and Pinus limits (Moar, 1969;Smith and Pilcher, 1973;Birks, 1975;Birks and Mathewes, 1978) suggest that a mixed forest phase began in much of Scotland about 7500 radiocarbon years ago. Ulmus and Quercus are represented by higher pollen percentages in the diagrams from southern Perthshire than in most Scottish pollen diagrams (discussed in the next section).…”