Present address: School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
Influence of agricultural management, sward structure and food resources on grassland field use by birds in lowland England
Article first published online: 28 JUL 2005
Journal of Applied Ecology
Volume 42, Issue 5, pages 932–942, October 2005
How to Cite
ATKINSON, P. W., FULLER, R. J., VICKERY, J. A., CONWAY, G. J., TALLOWIN, J. R. B., SMITH, R. E. N., HAYSOM, K. A., INGS, T. C., ASTERAKI, E. J. and BROWN, V. K. (2005), Influence of agricultural management, sward structure and food resources on grassland field use by birds in lowland England. Journal of Applied Ecology, 42: 932–942. doi: 10.1111/j.1365-2664.2005.01070.x
- Issue published online: 28 JUL 2005
- Article first published online: 28 JUL 2005
- Received 23 December 2004; final copy received 12 May 2005 Editor: Rob Freckleton
- 1Agricultural management of grassland in lowland Britain has changed fundamentally in the last 50 years, resulting in spatial and structural uniformity within the pastoral landscape. The full extent to which these changes may have reduced the suitability of grassland as foraging habitat for birds is unknown. This study investigated the mechanisms by which these changes have impacted on birds and their food supplies.
- 2We quantified field use by birds in summer and winter in two grassland areas of lowland England (Devon and Buckinghamshire) over 3 years, relating bird occurrence to the management, sward structure and seed and invertebrate food resources of individual fields. Management intensity was defined in terms of annual nitrogen input.
- 3There was no consistent effect of management intensity on total seed head production, although those of grasses generally increased with inputs while forbs were rare throughout.
- 4Relationships between management intensity and abundance of soil and epigeal invertebrates were complex. Soil beetle larvae were consistently lower in abundance, and surface-active beetle larvae counts consistently higher, in intensively managed fields. Foliar invertebrates showed more consistent negatively relationships with management intensity.
- 5Most bird species occurred at low densities. There were consistent relationships across regions and years between the occurrence of birds and measures of field management. In winter, there was a tendency towards higher occupancy of intensively managed fields by species feeding on soil invertebrates. In summer, there were few such relationships, although many species avoided fields with tall swards.
- 6Use of fields by birds was generally not related to measures of seed or invertebrate food abundance. While granivorous species were perhaps too rare to detect a relationship, in insectivores the strong negative relationships (in summer) with sward height suggested that access to food may be the critical factor.
- 7While it appears that intensification of grassland management has been deleterious to the summer food resources of insectivorous birds that use insects living within the grass sward, intensification may have been beneficial to several species in winter through the enhancement of soil invertebrates.
- 8Synthesis and applications. We suggest that attempts to restore habitat quality for birds in grassland landscapes need to create a range of management intensities and sward structures at the field and farm scales. A greater understanding of methods to enhance prey accessibility, as well as abundance, for insectivorous birds is required.