Ecomorphological Groups of Earthworms Found in a Beech Wood in the Bieszczady National Park (South-Eastern Poland)

Earthworms play an important role in the soil quality, including forest soils. Their presence in zooedaphone, as well as their abundance and species diversity, indicate the state of the soil profile. The species diversity of the representatives of this group of macrofauna in a beech forest in the Bieszczady Mountains is recounted in this article. Earthworms were investigated in the soil of four sites selected near Ustrzyki Górne in Carpathian Dentario glandulosae – Fagetum beech woods within the Bieszczady National Park (sites in D. g. Fagetum festucetosum, – typicum, – lunarietosum and – allietosum), every month during the annual cycle during two periods: a/ in 1986–1987 and b/ in 2009–2010. It was done according to the Zicsi’s recommendations, using the Zajonc combinated method, on each site, six 25×25×20 cm samples were extracted. The soil was divided into two layers (0–10 cm and 10–20 cm) and the earthworms were selected manually from them. From deeper layers, they were driven out with a weak (0.4%) formalin solution. In the 1980s, thirteen earthworm species were found (total of 1805 specimens) in the soil of four sites investigated. In a decreasing order of numbers there were: Dendrobaena alpina alpina (Rosa 1984), Allolobophora cernosvitoviana (Zicsi 1967), Aporectodea rosea rosea (Sav.,1826), Aporectodea caliginosa (Sav., 1826), Lumbricus terrestris L., 1758, Octolasium lacteum (Orley,1881), Allolobophora carpathica (Cog., 1927), Fitzingeria platyura montana (Cer., 1932), Octodrilus transpadanus (Rosa, 1884), Dendrobaena octaedra (Sav., 1826), Eisenia lucens (Waga, 1857), Lumbricus rubellus (Hoffm., 1843), Dendrodrilus rubidus tenuis (Eisen, 1874). Twenty years later, in the years 2009-2010, eleven earthworm species were found in the soil of the same four sites investigated (total of 660 specimens). There was no occurrence of L. rubellus, and O. transpadanus. For all the cited species, the vertical distribution dynamics in an annual cycle was investigated as well as the preferred soil layer in terms of soil profile. The features of the afore-mentioned earthworm species and the soil levels they prefer allowed their affiliation with the ecological groups defined by Bouche to be considered or determined. The knowledge on the association of earthworms to ecomorphological groups in natural or a slightly changed ecosystem is becoming very useful, for example at the time of the reclamation of degraded soils with Lumbricidae as bioindicators.