Long-term changes in agricultural practices and wildfowling in an internationally important wetland, and their effects on the guild of wintering ducks.
Changes in the Marais Poitevin wetland, France, are described. The area of grasslands decreased by 50% between 1970 and 1995, principally as a result of conversion to arable farmland. The rate of change was greatest in the 1980s when water levels, and the size of the flooded area, were reduced. The number of ducks decreased during 1979-96, and although the number of wildfowlers decreased, the number of birds killed did not decrease and may have increased. Loss of grasslands was considered the main reason for the reduction of the wild bird population but the strong decrease in mallard (Anas platyrhynchos), pintail (A. acuta) and shoveler (A. clypeata) indicated that reduced flooding or shooting had also played a part. Changes in the management of water levels and shooting are suggested.