The effect of environmental pollution by heavy metals and sulphur on defoliator activity was studied in the oak-hornbeam stands, in 10 sample areas located at increasing distance from the main source of pollution (metal works). Loss of the biomass of leaves caused by caterpillars were estimated, as well loss of photosynthetic production and wood production.
Annual defoliation, expressed in biomass, was from 240 kg/ha to 1470 kg/ha. Defoliation significantly with increasing distance from the emitters (source of pollution). According to the equation:
y = exp(5.475 0.0372x), r = 0.883, p = 0.01. Loss of leaf biomass due to grazing also resulted in loss of potential photosynthetic production, i.e., from 600 kg/ha near the emitters to 4700 kg/ha in the most distant sample area. This loss grew with increasing distance from the source of pollution according to the equation: y = exp(6.299 0.0415x), r = 0.821, p = 0.02.
A comparison of the degree of environmental pollution to the level of defoliation showed that gradations in defoliation accompanied rather moderate pollution. In the sample area near to the emitters, where the heavy metal and sulphur concentrations in the soils were 5 times greater than in the control area, and where the heavy metal content in leaves was 4.6 times greater than in the control, grazing affected about 1215% of the surface of leaves. When the concentrations of heavy metals in the soil and leaves exceeded that in the control area by 30% and 70%, respectively, and sulphur in soil exceeded the control by 90%, the level of grazing was much greater (4687%).
Key words: defoliation consumption, loss of production, pollution.
Correspondence: Ewa Bandola-Ciolczyk, Institute of Nature Conservation, Polish Academy of Sciences, 46 Lubicz St., 31-512 Krakow, Poland
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