Bare Ground and open water are the classical starting points for describing ecological succession in vegetation, with its stages (often broken, delayed or diverted) towards climax that are adopted here as the main basis for formation-types in defining animal habitats. They were indeed the actual starting points for all those parts of the country’s surface covered by the last ice-sheet, or destroyed by frost and flood on the periphery (cf. Plate II). It is now quite established192 that a good many of the plants and at least some of the animals that had widely colonized the bare and open ground of Full-glacial and Late-glacial times — that is, over 10,000 years ago — have since survived on maritime cliffs and shingle and dune, or on mountains, where conditions are still sufficiently unstable or climatically extreme to maintain the right conditions. Godwin gives a list of eighty-one such species (for example the moss campion, Silene acaulis, and the dwarf willow, Salix herbacea) of open mountain or subarctic habitats that then occurred widely in the lowlands, and are now chiefly found on cliff-ledges, screes and subalpine meadows. He also has a list of forty-six ‘weeds’ of arable land, saying that ‘The very long list of species which we now regard as ruderals or weeds indicates the prevalence of open conditions, bare soil surfaces and freedom from competition in the Full-glacial and Late-glacial periods alike.’ Some of these species are really more meadow forms than weeds of arable land, e.g. the bladder campion, Silene cucubalus, and the greater knapweed, Centaurea scabiosa.
KeywordsBare Ground Animal Community Field Type Open Ground Field Layer
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