Vegetational history and land use: a radiocarbon-dated pollen diagram from Machrie Moor, Arran, Scotland


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    Present address: Department of Natural Sciences (8th Dept.), The Danish National Museum, Ny Vestergade II, 1471 Copenhagen K, Denmark


Pollen, plant macrofossil and charcoal analyses are presented from a radiocarbon-dated sequence of peat deposits from Machrie Moor, Arran. The deposits began forming at the close of the late glacial and the sequence continued unbroken into recent times. During this period there was a transition at the site from rich to poor fen and finally to blanket mire communities. The major deciduous forest tree species were late in migrating to the island, probably as a consequence of the sea acting as a harrier to fruit dispersal. The development of the local terrestrial vegetation during the Flandrian period was also heavily influenced by human activity. There is evidence for mesolithic disturbances as early as 8500 B.P. and these almost certainly played a role in depressing tree pollen values. The first cereal pollen grain (ef. Hordeum) was found at a level dated to an estimated 5375 B.P. Later, agriculture was apparently of such an intensity that there were periods during the late Neolithic and at the transition between the Bronze and Iron Ages when it could no longer he sustained with the resources available. I he latter period coincided with the onset of blanket peat formation. A similar episode of reduced agricultural activity is evident in the Dark Ages. It was followed by a clear resurgence in Viking and early medieval times which apparently coincided with the improvement of the climate during the so-called ‘little optimum’