Monitoring the abundance of a canopy-dwelling butterfly species
Data obtained from the fixed time observation point and transect methods were converted to number
of observations per hour to enable comparison.
Results
The total number of S. w-album observations made at each of the sites over the monitoring period
ranged from only eight at site A to seventy-two at site B (Figure 1). The environmental conditions of
each of the sites in the study varied considerably (Table 1).
Fig. 1. Total number of Satyrium w-album observations
made at each site during the monitoring period
A B C D E F G
Site
Table 1: Summary of the conditions found at each of the sites in the study
Site
A B C D E F G
Site area (m2) 270 477 620 576 549 320 539
No. of Ulmus trees 9 35 35 20 30 10 40
Litmus spp.* a b b b a a a
Dutch Elm Disease (%) 22 0 0 0 36 60 14
Height tallest Ulmus tree (m) 11.1 18.3 20.4 21.5 10.7 12.2 13.8
Cover f,7m«« spp. (%) 50 60 60 35 50 35 80
Cover other trees/shrubs (%) 45 35 35 40 10 40 15
Cover Rubus fruticosus (%) 30 35 25 30 15 40 15
Cover other possible nectar 6 8 10 5 8 10 12
plants (%)
Sunshine**_____________________2 13 3 2 12
* a = Ulmus procera, b = Ulmus carpinifolia
** 1 = Sunshine >75% of the day
2 = Sunshine approximately 50% of the day
3 = Shade most of the dav
Essex Naturalist (New Series) 18 (2001)