Farming and Birds by Ian Newton

Author:Ian Newton
Language: eng
Format: epub
Publisher: HarperCollins Publishers
Published: 2017-06-28T04:00:00+00:00

FIG 140. The Yellow Wagtail Motacilla flava was once found in damp grassland across southern Britain, but along with its habitat, has now much declined (Richard Chandler).

DRAINAGE, SOIL MOISTURE AND WADERS

Most of the big wet grasslands of Britain were drained in several stages over two or more centuries (Chapter 15). From year-round flood-land which was largely useless for agricultural purposes, early farmers gained whenever land that was under water in winter dried out sufficiently in summer to give access to cattle in May or June or to be cut for hay in July or August. After further drainage, it often became possible to reduce the duration and extent of winter flooding, and to lengthen the summer grazing season. The next step was to drain the land so thoroughly that it seldom or never flooded, and allowed the growth of more productive grasses or arable crops, including autumn-sown cereal varieties. This last step often involved pump drainage, and once the water levels in ditches could be reduced, fields could then be under-drained and water tables reduced by a metre or more. These three stages were still apparent in different parts of some low-lying areas of Britain well into the 19th century, including the East Anglian Fens and the Somerset Levels. However, in the 20th century, and especially in the 1970s–90s with the encouragement of grant aid, lowland wet grassland in Britain was even more effectively drained. When fields were pipe-drained during this period, many of the old water-filled ditches were filled in, reducing the brood-rearing habitat for ducks, Coots and Moorhens, and destroying the tall ditch-fringing vegetation that held Water Rails, Sedge Warblers and Reed Buntings. Along any remaining ditches, pollarded willows and bushes were usually removed to allow easier ditch clearing by machinery. Old willows had provided sites for hole-nesting birds, such as Stock Doves and Little Owls, and in some areas also for Mallards and other ducks. At the same time, the land surface was levelled, removing the minor undulations that were so important to breeding waders (see here). Less than one-tenth of the lowland wet grassland present in Britain during the 1950s survived through to the end of the century, largely confined to poorly drained pockets of land along river valleys, and totalling less than 260,000 ha (Shrubb 2003).

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