S. Mahunka szerk.: Folia Entomologica Hungarica 54. (Budapest, 1993)

Examinations showed that in the cases of the most characteristic guilds and families of the foliage-dwellers there is no correlation between their frequencies and the age of the trees. It may be explained, in the first place, by the fact that the concrete habitat structure (structures of branches, pineneedles) may be considered relatively indentical idependently from the age of the trees. Similarly, in the case of the species and guild diversity values of foliage community (Tables 1 and 4, and Fig. 4) we find that not the age of the trees, but their location within the town is determinant. Using the lead accumulation of spruce trees for the bioindication of loads coming from road traffic, as well as from industry, is a widespread method (Wandtner and Lötschert 1978, Schinner 1980, Raclavsky et al. 1989). The values found in our study well correlate with those of the literature (Table 5) (Kovács etal. 1986). Table 5. Lead burden of spruce trees - and characteristics of spruce-living spiders (d - species richness, Hs - species diversity, Hg = guild diversity) Numbering of the biotopes 10. 16. 18. 8. 14. 15. Pb mg/kg 17.79 7.99 4.94 4.91 1.93 1.91 d 3.60 3.64 4.96 5.80 3.87 3.02 Hs 0.875 1.045 1.034 1.089 1.018 0.931 Hg 0.259 0.366 0.391 0.490 0.480 0.440 I have already stated that biotope 10, where the highest values were recorded (17.8 mg/kg) is the busiest thoroughfare of the town. The relative high values of biotopes 16 and 18 (7.9 4.9 mg/kg) may be the effect of the air polluted by an electronic plant nearby. H 0,5 0,4 03020,712 3c,5S7S9lO -< 1 1 1 1 > i ' ' - rmnl 11 12 U H /5 16 17 18 19 20 Pb Ilia! Fig. 5. Correlation between the changes of guild-diversity of spruce-living spiders and lead content in needles of spruce (Pb nig/1 kg dry vegetation matter)