Individual study: The effects on wintering wildfowl of fish removal from gravel pit lakes at Great Linford, Buckinghamshire, England
Phillips V.E. (1992) Variation in winter wildfowl numbers on gravel pit lakes at Great Linford, Buckinghamshire, 1974-79 and 1984-91, with particular reference to the effects of fish removal. Bird Study, 39, 177-185
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Reduce inter-specific competition for food by removing or controlling competitor species
A controlled before-and-after study in southern England between the winters of 1984/5 and 1990/1 (Phillips 1992) found that following the removal of 6.5 tonnes of coarse fish from a gravel pit lake (17 ha) in November 1987, there was a significant increase in the average populations of mute swan Cygnus olor (3.6 individuals in 1984-1987 vs. 69.3 in 1987-91), gadwall Anas strepera (1.1 vs. 19.6), shoveler A. clypeata (4.3 vs. 36.3), pochard Aythya ferina (40.0 vs. 82.2) and coot Fulica atra (2.1 vs. 203.1). There was a non-significant increase in tufted duck Aythya fuligula population, concurrent with a general increase in the area, and no change in populations of mallard Anas platyrhynchos, teal A. crecca or wigeon A. penelope. There were no corresponding changes at a control (13 ha) lake that did not have coarse fish removed. Increases were thought to be due to increases in benthic invertebrate and macrophyte abundance.