Summary

of Aporrectodea caliginosa, emerge new earthworm species noncharacteristic to the
pine forest soils. Here are formed 3 to 4 earthworm species communities, who are
characteristic both- to conifer, and deciduous tree forests. They are considered as a
transition type species communities characterizing forest eutrophication processes. In
the non-eutrophicated pine forest soils such species communities have not been
found.
3.5. Earthworm communities change due to the industrial pollution in the pine
forests near Saulkalne
Saulkalne dolomite processing plant yearly emits into the atmosphere more
than 700 t of pollutants. In the 80’s of the last century, the production units
functioned in full load, but in the turn of the 80’s and 90’s, the production capacity
was rapidly decreased. The most common pollutants in the exausted emissions of the
factory are the dust containing calcium and magnesium compounds. Till 1995, when
installation of inovative purification filters was initiated the company operated
without strict requirements on the environmental protection (Vaivara, 2006).
3.5.1. Description of the sampling plots and sampling procedure
In order to determine the effect of the pollution created by Saulkalne dolomite
processing plant, in 1989 near the industrial area of Saulkalne were initiated lasting
observations on the forest dynamic. In the dominant wind direction for 6.3 km was
established transect with 5 sampling plots at different distances from the dolomite
processing factory (Table 3.4).
The sampling plots were created in areas, which conform to Vaccinio myrtilli –
Pinetum forest growth type. The forest stand age in 1989 was assessed to be from 41
to 63 years. Earthworms were sampled in the period from 1989 to 1991. The soil of
the sampling plots is formed of fine-grained sand. Organic matter and humus
accumulation horizon number in the first two sampling plots, closest to the emission
source, is higher (O, Ah, AhE). In these sampling plots, mineralization of the organic
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