Soil invertebrates of coniferous forests along a gradient of air pollution in Komi Republic - "Russia 2021"

Alla Kolesnikova, Tatyana Konakova, Anastasia Taskaeva, Alexey Kudrin

The study was carried out in the European part of Russia, Komi Republic, vicinity of Syktyvkar City (Fig. 1). Soil macro- and mesofauna at the production area of Mondi Syktyvkar JSC was reviewed. Mondi Syktyvkar JSC is the largest pulp and paper industry in the European part of Russia and also a source of industrial emissions of various pollutants into the air basin. It has been operating since 1964. The emissions include sulphur and nitrogen oxides, hydrogen sulphide, sulphur anhydride, mineral dust containing calcium and sodium carbonates and sulphides (Torlopova and Robakidze 2012). Since 2002, the enterprise has been carrying out large-scale work aimed at reducing the impact of airborne man-made emissions on the environment. According to the company's public environmental reports, the total amount of emissions in 1999 was 31, in 2006 - 20 and in 2015 - 10 thousand tonnes (Robakidze and Torlopova 2018). In the area of the enterprise emissions, three zones with different levels of technogenic load were conditionally identified (Table 1, Fig. 2) according to the calculations of the pollution index (Zc) i.e. the sum of the excess concentrations of substances in the melt water of snow samples from the contaminated area relative to the concentrations of substances in background samples. There are no clear boundaries in space between different emissions' zones and there are some transitional strips of a greater or lesser extent where the values of index Zc can be higher or lower for the denoted emission area. The impact zone (zone of the strong impact of emissions) includes the territory of the working zone of the pulp and paper enterprise within a radius of 3.5 km, where the levels of technogenic load exceed the background onesby 100-150 times and values of pollution index (Zc) are 129 – 391. The territory, with (Zc) values over 128, is classified as an extremely dangerous pollution area. The buffer zone consists of two sub-zones - areas with significant and moderate impacts of emissions. The first subzone is located concentrically at a distance of up to 6 km from the emission centre along the line of the prevailing wind direction. Here, the levels of technogenic load exceed the background onesby 20-100 times and values of pollution index (Zc) are 65 – 128. In the second subzone (at a distance of up to 14 km), the levels of technogenic load exceed the background ones by 4-20 times and values of pollution index (Zc) are 33 – 64. Unification of territories with significant and moderate impact of emissions into one buffer zone is possible, since the reduction of emissions from the enterprise contributes to the shift in the boundaries of these conventionally- allocated zones. The territory, with (Zc) values over 32, is classified as a dangerous pollution area. The values of (Zc) are 0 – 32 at a distance from the boundaries of the buffer zone to the boundaries of the background zone. So, the absence of any emissions impact is allowed. The analysis of emissions dispersion from Mondi Syktyvkar JSC showed that the distribution of the main emissions components occurs at a distance of up to 18 km. Therefore, coniferous forests located at a distance of 22–50 km from the enterprise were chosen as sites of the background zone (Baturina et al. 2020).

Figure 1.  

Study area (European part of Russia, Komi Republic, Syktyvkar).

Figure 2.  

The map-scheme of study area (lichen pine forest is marked orange, bilberry pine forest - blue, bilbery spruce forest - yellow colour).

This project was supported by The Ministry of Science and Education of Russian Federation АААА-А17-117112850235-2 "Distribution, systematics and spatial organisation of fauna and animals population in taiga and tundra landscapes and ecosystems at the Northeast European Russia"; agreement with JSC "Mondi SLPK" № 45-2018/180405 "Assessment of long-term impact of Mondi Syktyvkar JSC on the biological diversity in the production area".

We built our database by compiling sampling events of soil invertebrates, based on an exhaustive search in published and unpublished authors' sources, as well as from the Zoological Museum of the Institute of Biology Komi SC UB RAS. The data paper is based on three datasets. The datasets about macrofauna and collembolans provides temporal data on the number of their individuals in soil cores collected in pine and spruce forests of the production area of the pulp and paper industry enterprise. The dataset about macrofauna also contains the material collected by the pitfall traps and information on the age stages (larvae and imago) of invertebrates. Nematodes were collected in pine and spruce forests of the production area of Mondi Syktyvkar JSC only in 2018-2019, so these data are not temporal. The dataset about Nematoda provides information on the number of their individuals in soil cores. Three datasets have differences in data presentation. We have combined them into one data paper, since a comprehensive study of the effect on soil invertebrates from the pulp and paper industry has not previously been carried out.

The standard methods of soil zoology were applied. Sampling and pitfall trapping were carried out in pine and spruce forests of the impact, buffer and background zones of the enterprise production area.

Two sampling methods were used for collection of macrofauna at each site.

1. Soil sampling method. About 8-10 soil cores were randomly taken to a depth of 5-10 cm at each site. A quadrangular frame of 25 × 25 cm or 10 × 10 cm was used for sampling. Actively moving animals were placed into containers with 70% alcohol as a fixative. Further, in laboratory conditions, the extraction of invertebrates from soil cores into 70% alcohol was carried out in the funnels.

2. Pitfall trapping. Pitfall traps of the same type (plastic glasses, depth 10 cm, diameter 12.0 cm, salt water (30% vol.) and formalin (5% vol.) as a fixative) were used at each site. The traps were emptied once per 7-10 days; all collected invertebrates were preserved in 95% alcohol for subsequent identification with a binocular microscope.

One sampling method was used for Collembola collection. In each site, 10 soil samples were taken. Samples were taken to the full depth with division into two layers - litter and mineral horizons; in further analysis, the data on the layers were combined. Extraction was carried out according to the generally- accepted method using Berlese – Tulgren funnels in 96% alcohol for 7–10 days - the time sufficient to achieve an air-dry soil state. Collembolans from the samples were sorted under a binocular microscope. All individuals were mounted in slides in Phoera liquid according to a standard procedure (Potapov and Kuznetsova 2011).

The soil sampling method also used for Nematoda collection. Soil samples were collected from the organic and mineral soil horizons. In pine forests, eight soil cores (5 × 5 cm, 10 cm depth) were taken at each site. In spruce forests, five soil cores (5 × 5 cm, 10 cm depth) were taken at each site. Nematodes were extracted from 50 g of fresh soil using the modified Baermann Method (Ruess 1995). Extraction lasted for 48 h. Extracted nematodes were euthanised at 60°C and then preserved in 4% formaldehyde.

The material includes data collected during the period of modernisation and reduction of emissions of the enterprise. Thus, the real changes in soil invertebrate communities can be estimated.

The data were collected by specialists from the Institute of Biology of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences. Lumbricidae, Lithobiidae, Julidae, Polyzoniidae, Coleoptera (Carabidae, Staphylinidae, Elateridae, Curculionidae, Ostomatidae) and some Hemiptera were identified to species by specialists from the Institute of Biology. All specimens of Collembola and Nematoda were also identified to species and genera, respectively, by specialists from the Institute of Biology. Different taxonomic keys were used for identification of large soil invertebrates (Lohse 1964, Gurjeva and Kryzhanovskij 1965, Lohse 1974, Vsevolodova-Perel 1997, Andersson et al. 2005), Collembola (Fjellberg 1998, Potapov 2001, Fjellberg 2007) and Nematoda (Jairajpuri and Ahmad 1992, Bongers 1994, Brzeski 1998). The material (invertebrates fixed in alcohol and formalin, on preparations and in entomological collections) is kept in the Zoological Museum of the Institute of Biology. On each slide and/or label, the following fields were filled out: “Collection date”, “Locality” (with geographic coordinates), “Habitat”, “Collector name” and “Determined by” (identification).

The study area is located in the middle taiga zone of Komi Republic. The Mondi Syktyvkar JSC production area is located on the Vychegda River bank in the vicinity of Syktyvkar City. There are arrays of spruce and pine forests in the research area.

Coordinates: 61°40′35″ Latitude 1 to 62°27′58″ Latitude 2; 50°48′35″ Longitude 1 to 50°66′76″ Longitude 2.

The datasets contain all of the information obtained during the sampling for macrofauna, Collembola and Nematoda. A decrease of nematodes abundance (Fig. 3) and the decline in the species richness of macrofauna (Figs 4, 5) was noted in spruce and pine forests along the pollution gradient. There are changes in the abundance and number of Collembola species along the pollution gradient before and after emission reduction (Table 2).

Figure 3.  

Nematodes abundance (ind./100 g, along the ordinate axis) along the pollution gradient.

Figure 4.  

The number of macrofauna species in spruce forests along the pollution gradient.

Figure 5.  

The number of macrofauna species in pine forests along the pollution gradient.

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