Habitats and abundance of butterflies on agricultural land at Writtle College
Table 1. Habitat type and management regimes for each section
Key
W Woodland
M Grassy meadow
V Roadside verge
II Hedgerow
G Grazed pasture
A Arable field
S Scrub
S/S Set-aside
0 Orchards
The surveys were conducted once a week from April through to September for five years beginning
in 1996 using the criteria outlined in Pollard & Yates (1993). A total of 26 weeks were to be
surveyed each year although in most years unfavourable weather meant some surveys had to be
abandoned. Because of the difficulty of distinguishing Essex Skipper Thymelicus lineola and Small
Skipper Tlrymelicus sylvestris in flight, both species were recorded combined as Thymelicus species.
Data for both species are also combined in the results. The scientific names follow those in Asher et
al (2001) and Stace (1997).
Results
A total of 24 species were recorded over the five years with the most abundant species being Meadow
Brown Maniola jurtina, Gatekeeper Pyronia tithonus, Small White Pieris rapae and Green-veined
White Pieris napi. Rarer species on the estate included Ringlet Aphantopus hyperantus, Wall Brown
Lasiommata megera. Small Copper Lycaena phlaeas and Brown Argus Aricia agestis. A total of 18
species were recorded each year, although the number of species seen declined from 24 in 1996 to 19 in
1999. This decline in species is in evidence on both transects (Table 2) with the rarer and more interesting
species such as L. megera and L. phlaeas being recorded in the first three years of monitoring but then
disappearing. Severe declines occurred in the number of individuals per visit on the two transects
(Table 2) with the reduction in numbers being particularly severe on the College Transect.
Table 2. Species richness and numbers of individuals per visit
for both transects from 1996 to 2000
Key: 1 Coenonympha pamphilus 2 Lasiommata megera 3 Aricia agestis
4 Lycaena phlaeas 5 Aphantopus hyperantus
Essex Naturalist (New Series) 18 (2001)
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