Summary

1.3. Earthworm impact on gricultural land quality bioindication
Earthworms are one of the most suitable soil organisms in the non-specific
bioindication. It is easy to identify them by few external morphological
characteristics. They are comparatively immobile, with stable sezonal taxocenosis
that eases population change determination. Also, it is much easier to get repetitions
of necessary samples, in order to obtain statistic representative data (Bauchhenβ,
2006).
Earthworms have impact on one of the most important processes of the soil-
organic matter breakdown and nutrition circulation. Earthworm fauna and its changes
actually reflect structural, microclimatic and nutrition circumstances of the soil, as
well as the toxicity of the soil (Kuhle, 1983). Change earthworm population,
biomass, ecological groups, structure and domination of the species. All of these
indicators reflect the antropogenic factors, e.g., after-effects of soil cultivation
(Christensen et al., 1987; Daugbjerg et al., 1988; Bauchhenβ, 2006). Stable
environment ensures constant species complexes during greater period of time, but in
non-stable environment, e.g., arable lands, species complexes are inconsistent and
lean (Lee, 1985). The structure of earthworm species communities is a good indicator
to assess the agroitechnical activity impact on soil. If more sensitive species are
found in agricultural lands, it indicates either on ecological factors suitable for
earthworms, or careful agrotechnical activities (Ivask et al., 2006; Ivask et al., 2007).
13