THE INFLUENCE OF DIFFERENT TYPES OF GRASSLAND FIELD MARGIN ON CARABID BEETLE (COLEOPTERA, CARABIDAE) COMMUNITIES

A study of the impact of various field margin and field attributes on carabid beetle communities was implemented at IGER (North Wyke). Carabid beetles were caught in pitfall traps placed 0.5 m from either a hedge or a post and wire fence in 16 grassland field margins. The data were collected over the season April-mid November 1990. The relationship of the beetle assemblages to measurements of species numbers of field margin flora, sward husbandry, sward characteristics and physical attributes of the field margin itself was investigated. Contrary to expectations most species caught did not seem to be correlated to any measured variable. The majority of species trapped were present in both the hedge and fence field margins. However, a notable percentage (29.4) were present exclusively in the hedge margins, for example, Leistus fulvibarbis and Trechus obtusus. When the data were analysed by detrended correspondence analysis the margins were separated according to the soil moisture content and number of plant species in the margin; grazing regime and age of the pasture they surrounded.