Invertebrate abundance on cereal fields and set-aside land: implications for wild gamebird chicks.

Abstract

During June and July 1990 and 1991, insect samples were taken from several farms in Southern England. Fields in three land-management categories were sampled: fields that had entered the U.K's five-year set-aside scheme for the first time following a cereal crop in the previous year, fields in the second year of the scheme and fields in winter wheat. On each farm, samples were taken from winter wheat and one type of set-aside each year, within the headland area using a vacuum suction sampler.
Of the 12 invertebrate groups studied, most showed significant differences between the treatments. The Diptera, most Coleoptera, Symphyta and Aphididae were most abundant in wheat, whereas numbers of Collembola, and especially Heteroptera and Auchenorrhyncha were highest on set-aside. Many of these groups are eaten by gamebird chicks, which require an insect.-rich diet to survive. The abundance of chick food items was three times as high on set-aside than on cereals. When translated into chick survival rates, it spelt the difference between a declining partridge population (wheat) and an increasing one (set-aside).