CONSERVATION & MANAGEMENT
Investigation into the use of field edges by small mammals on the Writtle College Estate
GRAHAM WATKINS AND ROBIN FIELD
Centre for the Environment and Rural Affairs (CERA), Writtle College, Lordship Road, Writtle,
Chelmsford, CM] 3RR
Abstract
A study to investigate the use of field edges by small mammals was conducted in the autumn and
spring over two years. A total of 1203 individuals from seven species was captured, with Wood
Mouse, Bank Vole and Common Shrew being the most abundant. The Countryside Stewardship
Scheme two-metre-wide uncultivated margins and fields edges with no uncultivated margins did not
differ substantially in total numbers of mammals and there were no substantial seasonal differences.
However, individual species differed and this difference seemed to reflect the species habitat
preference. Wood Mouse was most abundant where there were no uncultivated margins, and Bank
Vole and Common Shrew were more abundant in the grassy uncultivated margins. It was concluded
that the value of the uncultivated margins might be affected by their siting, with a location that
abutted woodland or an established hedgerow possibly being of greater benefit.
Introduction
The Writtle College estate (TL 670070) extends over 210 hectares of mainly agricultural land and is
situated in the south-east of England, two kilometres west of Chelmsford in Essex. In 1996 Writtle
College entered into a Countryside Stewardship Scheme (CSS) agreement that included the creation,
in 1997, of two-metre-wide uncultivated grassy strips along the margins of several arable fields on the
college estate. The CSS makes payments to farmers and landmanagers for, amongst other things,
improving and extending wildlife habitats. On arable land this can include creating uncultivated
grassy field margins to provide feeding areas for wildlife, including small mammals (MAFF 2001).
Smith et al. (1993) suggests that small mammal conservation on farmland is benefitted by tall
grassy field margin vegetation which is left uncut in summer. Careful management of field boundary
habitats can encourage a diversity of small mammal species and this can have additional benefits,
for example, by providing prey for larger mammals and birds.
This investigation was conducted to compare the numbers of small mammals utilising the grassy
field margins with small mammals utilising the field edges without uncultivated grassy strips. This
paper aims to present the results of this study.
Methods
Four 150 metre sections of arable field margin were selected for this study, two sections with two-
metre-wide uncultivated strips created as part of the CSS agreement and two sections where the
fields were cropped up to the edge without leaving uncultivated strips. A total of 60 traps were set
as near as possible at 10 metre intervals, using 15 traps per section. All of the traps were covered
with dead grass or leaf litter to minimise excesses of heat or cold. In the sections without uncultivated
margins the traps were laid along the boundary of the field. Within the two-metre-wide margins the
Essex Naturalist (New Series) 21 (2004)
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