The Ecological Distribution of Adult Craneflies in Carnarvonshire

Abstract

THE county of Carnarvonshire, N. Wales, has a very great surface variety, unequalled by any other county in the British Isles. Its greatest length is 55 miles from east to west, but from north to south it is 25 miles in the extreme east, narrowing down to 20 miles in a line from Bangor to Portmadoc, and ending in the snout-like projection of Braich-y-pwll, and the island of Bardsey in the west. The total area, excluding water, is 362,203 acres, including water 365,986 acres. Looking at the sketch-map of Carnarvonshire (Fig. 1), one is at once struck by the fact that the county falls into two great divisions, an eastern and a western one; the east containing the mountains of Snowdonia, with the rugged passes and mountain torrents, while the west is a comparatively flat pastoral area. Furthermore the sea surrounds Carnarvonshire on the norbh, south, and west, while the two rivers, Conway and Glaslyn, form the greater part of its eastern boundary. The county may further be divided into four zones: the sea coast, the region of farms, the wooded slopes and the rugged mountain area or mountain complex. There are 117 miles of sea coast, sometimes bordered by cliffs, but more frequently by marsh land and sand flats. If the upper limit -of the second zone (the region of farms) be fixed at 500 feet (152 m.) above sea-level, it has been estimated that about 250 square miles is the content of the farm