DNA barcoding: how many earthworm species are there in the south of West Siberia?

Earthworms are a widespread and ecologically important group of animals, which has the highest total biomass in some ecosystems and often defines the composition of soil fauna. Earthworms are known to have high cryptic genetic diversity. In this study we attempted to estimate earthworm species diversity in the south of West Siberia by DNA barcoding. This method employs short fragments of the genome to identify species, and allows one to work with specimens that cannot be identified by conventional techniques, as well as to search for new species and predict their phylogenetic affinities. As the target sequence we took a fragment of the mitochondrial cytochrome oxidase 1 (cox1) gene. The studied territory (Novosibirsk and Tomsk oblasts, Altai krai, and the Altai Republic) is known to contain 16 species and subspecies of earthworms. We analyzed 259 individuals from twelve locations and detected 27 genetic clusters. Ten of them correspond to known species (A. caliginosa, E. fetida, O. tyrtaeum, D. r. tenuis, D. octaedra, E. balatonica, E. sibirica, as well as three genetic lineages of E. nordenskioldi nordenskioldi). Seventeen of the 27 clusters do not have close sequence similarity to any known earthworm species. Representatives of some of these novel clusters are morphologically similar to the Eisenia n. nordenskioldi/E. n. pallida species complex and may belong to new genetic lineages of this complex. The rest of the novel clusters probably represent new earthworm species. Therefore, we can conclude that a large portion of earthworm biodiversity in the south of West Siberia is still unexplored

Impact of No-Tillage on Soil Invertebrate Communities in the Southern Forest Steppe of West Siberia: Preliminary Research

The aim of our study is to assess changes in soil macroinvertebrate biodiversity when conventional tillage (CT) is replaced by no-tillage (NT) in agroecosystems of the southern part of the West Siberian forest steppe. The research was conducted in the Novosibirsk region at the end of May 2017, May 2018, and in June 2018. The agricultural plots with CT and NT were located close to each other on identical soils, at a distance of about 200 m from the nearest forest shelterbelts. NT technology has been applied on the experimental plot since 2007. Sampling of invertebrates was conducted in two ways, namely soil sampling and pitfall trapping. The majority of basic physicochemical properties of soil were the same or similar between the CT and NT plots. However, depending on the type of tillage, different soil invertebrate communities had already developed in the control (CT) and experimental (NT) plots during this time. The community of the CT plot includes a large number of flying predatory Carabidae species typical of early successional stages (such as Bembidion properans and B. quadrimaculatum, Poecilus spp.) and phytophages, i.e., larvae of Elateridae. The NT plot has significantly higher density and species richness of earthworms (Eisenia nordenskioldi and synanthropic E. fetida in the NT plot versus one individual of E. nordenskioldi in the CT plot). The NT plot has a significantly richer and more abundant assemblage of spiders (especially in spring) and a poor assemblage of insect predators (except for the superdominant ground beetle Poecilus cupreus and the subdominant P. versicolor in summer 2018). Large numbers of larvae of some carabids (e.g., Amara consularis) were found in the NT soil, suggesting that they complete a full life cycle in this habitat