LUMBRICIDAE SPECIES COMPOSITION IN THE SOILS OF THE FOOTHILL BEYOND ILE ALATAU REGION

This article discusses the species composition of earthworms in the soils of the beyond Ile Alatau region. The role of earthworms in the soil is quite large. First of all, it is worth noting their loosening and structuring activities. During the movement process, these soil invertebrates mix a huge number of small fractions of soil. The loosening activity promotes moisture and sufficient oxygen. The most important is the destructive activity and enrichment of soils with active substances, as enzymes. The study of lumbricides began from the time of Charles Darwin, and is still of great importance the essence of such invertebrates in zoology. Scientific researchers had been carried out over two years (2018-2020) during the active vegetation of plants on the soils of the highest point of the beyond Ile Alatau region - in the peak of Talgar. As a result of the conducted research, the following earthworm species from the Lumbricidae family were found: Octolasium lacteum, Eisenia foetida, Eisenia nordenskioldi, Nicodrilus caliginosus, Nicodrilus longus, Lumbricus rubellus, Lumbricus terrestris, Dendrobaena octaedra. The most common species are Lumbricus rubellus and Nicodrilus caliginosus, and the rest are less common. In the seasonal dynamics of earthworm numbers, two peaks of activity were observed - in early June and at the end of August.

Earthworms (Oligochaeta, Lumbricidae) near the township Dombay of Teberda Reserve (Northwest Caucasus, Karachay-Cherkessia)

The population and characteristics of biotope distribution of earthworms near the township Dombay of the Teberda Reserve were studied. A mountain-forest belt, sparse growths of trees, elfin woodlands at the top edge of the forest, a sub-alpine meadow and lower mountain pastures were screened. Faunistic and quantitative surveys of earthworms were conducted in the soil and deadwood. The method of excavation and manual disassembly of soil samples was used in soil research. In the study of deadwood, trunks of Fagus orientalis and Picea orientalis of the 2nd and 3rd stages of decomposition were examined manually. Quantitative values were calculated per unit area (1 m2) and unit volume (1 m3). Twelve species of Lumbricidae were described in total. The Crimean-Caucasian endemic polymorphic species Dendrobaena shmidti, represented here by an unpigmented endogeic form, has the greatest abundance, biomass and widespread distribution. The highest species richness of Lumbricidae is in the mountainforest belt, which is inhabited by representatives of four morpho-ecological groups: epigeic, epi-endogeic, endogeic and anecic species. Forest communities are inhabited by 4–9 earthworm species. The lowest species diversity and abundance were observed in the sparse growths of trees, elfin woodlands at the top edge of the forest and the subalpine meadow. The highest abundance and biomass were observed on pasture. The endogeic earthworms were a dominant group in all communities. A high proportion of epigeic species in all forest communities was noted only for deadwood. The epi-endogeic group is represented primarily by Lumbricus rubellus, the abundance of which is particularly high in the pasture. The epi-endogeic species Eisenia fetida was found only in deadwood. The only anecic species, L. terrestris, was encountered in two forest communities and in a garden of Dombay. Small epigeic species Dendrobaena octaedra, Dendrodrilus rubidus tenuis and Dendrobaena attemsi play the main role in deadwood decomposition; deadwood serves as the main habitat for these species in spring and summer. Deadwood is an additional habitat for large-sized endogeic and epi-endogeic species; mature and juvenile worms live here in the litter and moss cover, the rotting wood is penetrated only by juveniles of large-sized species.

An experimental test of facilitation between non-native earthworms

Invasional meltdowns, in which facilitation between species causes an accelerating increase in the number of introduced species or impacts, can cause large impacts in invaded systems. Earthworm invasion of northern forests has been suggested as a meltdown, with litter-dwelling species altering soil structure and facilitating mineral-soil or deep-burrowing earthworms that may be less capable of invading intact forest floors. We examined facilitation and synergistic effects of a litter-dwelling species ( Dendrobaena octaedra Savigny, 1826) and a deep-burrowing species ( Lumbricus terrestris L., 1758). Boreal forest soil cores were inoculated with D. octaedra, L. terrestris, both species, a higher density of L. terrestris, or no worms. After 4.5 months, we found no differences in survival or biomass between treatments for either species. Cocoon production did not differ for L. terrestris, but D. octaedra produced significantly fewer cocoons with L. terrestris. The two species had an additive effect on organic horizon depths and bulk densities. Thus, they did not appear to facilitate each other or have synergistic effects as would be predicted in an invasional meltdown.

Earthworms (Lumbricidae) of an air-polluted area affected by ameliorative liming

The study was aimed at the area of the Krušné hory Mts. with stands of substitute species, soils disturbed by long-term acidification and affected repeatedly by aerial ameliorative liming. Ten species of earthworms were recorded. The highest abundance was shown by earthworms of Dendrobaena attemsi, Dendrobaena octaedra and Dendrobaena vejdovskyi, which are considered to be acidotolerant being, however, monitored in the high and balanced abundance at pH 2.8–6.2. Ubiquitous species developed in soils of markedly lower pH, viz. Lumbricus rubellus (2.8–5.6), Aporrectodea caliginosa (3.1–5.5), and Octolasion lacteum (3.2–5.2). Dendrobaena attemsi responded positively to low saturation of the base-exchange complex, low C/N ratio and high content of phosphorus, and negatively to the high level of calcium. D. octaedra responded positively to the higher level of calcium and D. vejdovskyi to the higher content of potassium.