Mv. Kozlov et al., ABUNDANCE OF DAY-FLYING LEPIDOPTERA ALONG AN AIR-POLLUTION GRADIENT IN THE NORTHERN BOREAL FOREST ZONE, Entomologica Fennica, 7(3), 1996, pp. 137-144
Day-active lepidopterans were counted in the summers of 1991-1993 on t
ransects of 5 x 100 m in 12 localities representing five zones of poll
ution-induced forest deterioration in the Kola Peninsula, northwestern
Russia. A total of 671 specimens representing 19 species was observed
during 696 counts. Two butterflies (Clossiana euphrosyne, Vacciniina
optilete) and three day-active moths (Rheumaptera subhastata, Ematurga
atomaria, Sympistis heliophila) were used in the analysis; the remain
ing 14 butterfly species were too scarce for the statistical treatment
. At early stages of pollution-induced forest damage (mean annual SO2
concentrations 20-40 mu g/m(3)), the densities of the monitored specie
s increased by a factor of 1.5 to 5, but then declined with increase i
n pollution. Since the host plants of the monitored species, except th
at of C. euphrosyne, were found in all localities surveyed, the declin
e could be attributed to the SO2 toxicity rather than to the lack of l
arval food. Although transect counts did produce valuable information
about the impact of pollution on subarctic forest ecosystems, the meth
od is poorly suited for routine bioindication of pollution in northern
regions.