Habitats and abundance of butterflies on agricultural land at Writtle College
ROBIN FIELD AND TIM GARDINER
Writtle College, Lordship Road, Writtle, Chelmsford, CM1 3RR
Abstract
Butterfly surveys were conducted on the Writtle College estate between 1996 and 2000, using the
transect method devised for the Butterfly Monitoring Scheme. Twenty-four species were recorded
including some of interest such as Brown Argus Aricia agestis. Declines in the number of species
and individuals recorded each year were evident, and species such as Large Skipper Ochlodes
venata experienced severe reductions in abundance. The major habitats for butterflies on farmland
are meadows, woodlands and green lanes.
Introduction
A method for surveying butterflies was established in 1976 with the creation of the Butterfly
Monitoring Scheme (Pollard & Yates 1993). The aim of the scheme is to monitor butterfly populations
in Great Britain (Sparks et al 2000) although most of the sites involved in the scheme are in nature
reserves or other protected areas. Very few sites arc on farmland and knowledge of butterfly
populations in these areas is limited (Sparks et al 2000). Farmland also constitutes 65% of land area
in Essex and is potentially a very valuable habitat.
The aim of this paper is to ascertain the main changes in butterfly abundance over several years on
the predominantly agricultural Writtle College estate and indicate the main habitats utilised.
Methods
Writtle College is located in the south-east of England, two kilometres west of Chelmsford in Essex
(TL 670070). The College estate extends over 210 hectares and consists of agricultural, horticultural
and conservation areas with amenity areas in the College grounds (Neate 1979). From the mid
1970s, many conservation areas have been established and these include mixed broadleaf plantations,
wildflower meadows in field corners and re-instatement of hedgerows along old field boundaries
(Sellers & Field 1997).
The method used for surveying butterflies was adapted from that used in the Institute of Terrestrial
Ecology's Butterfly Monitoring Scheme (Pollard & Yates 1993). This involves recording all butter-
flies seen within five metres of an observer whilst walking a set transect route, when the weather
conditions are suitable. Two transects were created on the estate, the College Transect and the
Lordships Transect (Figure 1). The two routes cover a large proportion of the farmed estate and the
conservation areas, following the field boundaries where butterflies would be concentrated. The
College Transect was divided into nine sections comprising different habitat types whilst the Lord-
ships Transect had eight sections. The habitat type and management regime for each section is
presented in Table 1.
Essex Naturalist (New Series) 18 (2001)
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