Late‐glacial and Holocene vegetation history of the Flow Country, northern Scotland

Abstract

SUMMARYThe vegetation history of an important conservation area, the Flow Country in northern Scotland, is descrihed using the results of pollen analysis from two closely spaced cores from the Cross Lochs, eastern Sutherland. Buried lake sediments and shallower surface peats yieid a continuous record covering the Devensian Late-glacial and the Holocene. The earliest Late-glacial pollen spectra recovered suggest a transition from open habitat to more stable communities, dominated by *Empetrum heath. This Windermere Interstadial vegetation shows some variability, with a phase of increased growth of juniper and birch, followed by deteriorating climate and less stable soil conditions in the transition to the Stadial, with Huperzia selago and Salix. There are poorly defined Loch Lomond Stadial and Stadial-Holocene transition periods, characterized by Rumex/Oxyria, after which much warmer, Holocene conditions occur, with a succession of birch-jumper and birch-hazel woodland. Birch persists in small amounts locally, but the presence of other arboreal pollen is thought to be mostly due to long distance pollen transport. From c. 5500 BP, the landscape is largely treeless, apart from a brief phase of local pine forest c. 4500-4000 BP. These changes are compared with other pollen records for northern Scotland. The trends in the Late-glacial vegetation are hroadly similar to those displayed by other sites, although many of the changes appear to be less extreme than for areas to the south and west. The lack oi Artemisia during tbe Loch Lomond Stadial in the east Sutherland and Caithness area is particuiarly noteworthy. This may imply more extensive snow cover. The early Holocene is similar to the rest of northern Scotland, but invasion of Betula was more rapid and the later growth of this genus and hazel was not so dense. The lack of pine in the early Holocene allies the site with eastern Caithness and the Northern Isles, rather than north-west Scotland and the Grampians, It is suggested that the effects of early human populations on such margina] forest areas may have been underestimated in the past. The paradoxical existence of pine macrofossiis with no pollen evidence in several areas of Scotland is explained, at least in part, by the lack of temporal precision of pollen diagrams rather than by low pollen productivity, extremely localized occurrences of the species or strong prevailing winds.

Reconstruction of a Lateglacial (Younger Dryas) mountain ice field in Sutherland, northwestern Scotland, and its palaeoclimatic implications

“…13-11 ka) (Pennington et al, 1972;Pennington, 1977;Birks, 1984Birks, , 2003Charman, 1994). Based on the evidence presented above, a Younger Dryas age for the glacial landforms mapped in this study is ascribed with some confidence.…”

A reconstruction of Holocene climatic changes from peat bogs in north‐west Scotland

“…Gear & Huntley (1991) attributed this inferred range expansion to a brief phase of drier and warmer conditions. Palynological data from south-eastern Skye (Birks & Williams 1983) and from central Sutherland (Charman 1994), both near the range limits of Scots pine during the mid-Holocene, also show evidence for a brief phase of increased pine abundance prior to its decline around 4000 years ago. With the pine pollen decline at ES, G C and some sites in western Sutherland exhibiting a two-phase pattern, as described above, it can be speculated that the dry phase after 4500 cal BP may have slowed the reduction in pine abundance in these regions until c. 4000 cal BP, when a second phase of climatic deterioration tipped the balance against remaining pinewoods.…”

Patterned fen development in northern Scotland: Hypothesis testing and comparison with ombrotrophic blanket peats

“…However, a skeletal pollen diagram was constructed for the ombrotrophic mire at Cross Lochs using 20 counts of 200 TLP. This provides good chronological control when compared with the Devensian Late-glacial and Holocene dated profile from the Cross Lochs area (Charman, 1994b). There are several clear regional markers in this published diagram, listed with their dates and equivalent depths in the ombrotrophic site in Table 2.…”