Terrestrial invertebrates of the Visimskiy Nature Biosphere Reserve (Middle Urals)

Ukhova N.L., Esyunin S.L., Farzalieva G.Sh., Mazura N.S., Shumilovskikh L.S., Sozontov A.N.

General description

The Ural Mountains spread from north to south at more than 2000 km and are the border between Europe and Asia. The studied region, the Visimskiy Reserve, is located in the Middle Urals, the lowest part of the Urals. The major part of the Reserve lies on the western macroslope and only a minor part lies on the watershed crest (Prokaev and Kuznetsova 1974). The climate here is typical for the temperate continental boreal zone. The yearly average air temperature is +1.1°С and the average annual precipitation is 598.5 mm, according to data provided by the "Visim" meteorological station from 1976 to 2022.

The soddy-podzolic and brown forest soils are the most widespread soils on the Reserve territory (Gafurov and Korkina 2021). According to the forest vegetation subdivision, the Reserve belongs to the south taiga county of the Middle Ural low-mountain province of the Ural forest-mountain area (in terms of Kolesnikov (1960)). The primary vegetation is fir-spruce (Abies sp. and Picea sp.) forests, with birch (Betula sp.) forests being the most common derivative vegetation. Currently, the protected part of the Visimskiy Reserve encompasses 335 km². A buffer zone of 461 km² surrounds it. Forest cuts of different ages, mostly in the middle stages of secondary succession, predominate at this buffer. There is a service road, rarely used, along the northern reserve border, which is closed to public access. There are no permanent living buildings within the Reserve, but there are forest lodges for temporary stays. There is a small village "Bolshye Galashki" in the buffer zone, 1 km from the western Reserve border. Only three families live year-round here, with a few more residing during the summer period.

Flora and vegetation

The vegetation of Visimskiy Reserve is primarily forested. Forests cover 87% of the territory according to the 2000–2001 forest inventory and are represented by both boreal and nemoral types. The Reserve is situated within the mountain taiga belt, which is divided into two sub-belts. The lower one (up to 400 ± 50 m above sea level) is colder and composed of temperate boreal dark-coniferous forests. The higher sub-belt is warmer and composed of nemoral and sub-nemoral forests (Kirsanov et al. 1979). Yu.P. Gorichev (2014) explains this case of altitudinal zonation inversion in the Visimskiy Reserve by temperature inversion which is caused by sinking of cold air masses from peaks to topographic lows and accumulating there.

The most detailed forest inventory has shown 11 types of primary associations (Kolesnikov et al. 1974). However, native fir-spruce (Abies sp. and Picea sp.) forests have been altered by the industrial development of the Ural Region over the past 300 years. The remaining woodstand has been damaged in a mosaic pattern by a catastrophic wind-throw in 1995. Later, in 1998, a heavy forest fire destroyed most of the woodstand, undergrowth and herb layer in all wind-thrown areas. The fire repeated in a few wind-thrown and untouched areas. After that, there remain only three types of primary forests: 1) ferns and grasses Abies-Picea forests; 2) large-ferns Abies-Picea forests; 3) Abies, Picea and Pinus sibirica Du Tour, 1803 forests with fern and horsetail.

Currently, primary virgin forests cover only 3% of the Reserve's territory (Sibgatullin 1987, Sibgatullin 2021) and are found on the peaks and slopes of the mountains Bolshoy Sutuk, Maliy Sutuk, Dolgiy and Kuligi. The secondary woodstand associations are mixed uneven-aged forests, dominated by Betula sp., Picea sp. and Betula sp. mixture or Populus tremula L., 1753. Some of the post-fire associations with Chamaenerion angustifolium (L.) Scop., 1771 and Calamagrostis sp., located on the Maliy Sutuk Mountain, have not recovered woodstand since the fires in 1998 and 2010.

Meadows occupy no more than 1% of the territory of the Reserve. They are formed on the former forest areas harvested for crop fields and hay-making grasslands. Some of the meadows are about 300 years old. There are almost no bogs within the Reserve.

Long-term monitoring plots

The long-term monitoring of soil and litter invertebrate complexes covers eight permanent plots. They are established in primary ferns and grasses fir-spruce (Abies sp. and Picea sp.) forest (PZP-02 until 1995, PZP-19); in their derivative vegetation communities – post-fire associations on the various succession stages (PZP-07, PZP-20); in secondary birch (Betula sp.) forests formed after wood cutting (Lines 1, 2, 3 and 4). We describe all of them in detail below. Briefly, the chronology of changes in the vegetation of the plots is shown in Fig. 2.

Figure 2.  

Chronology of the vegetation changes across the sampling plots.

PZP-02 (compartment 112, sub-compartment 3) was established in 1985 in the ferns and grasses Abies-Picea forest. The plot is located 560 m above sea level (57.3960°N, 59.7419°E), on the upper part of the slightly sloping mountain "Maliy Sutuk". There are brown mountain forest soils here, middle or heavy loamy. The catastrophic wind-throw destroyed the primary forest here in 1995. Losses were about 80% of the tree stand. The sparse remaining trees dried, which led to the fire in 2010 and the permanent sampling plot was burned in a mosaic pattern, with the remaining sporadic Betula sp. and Abies sp. undergrowth only. There has been a post-fire association here since 2010, mainly formed by Rubus idaeus L., 1753, Chamaenerion angustifolium and Calamagrostis sp. We have registered the beginning of undergrowth recovery with sparse Betula sp. and Salix sp. trees since 2013.

PZP-07 (compartment 123, sub-compartment 2) was established in 1991 in Calamagrostis and grass Betula forest, which itself is a derivative vegetation of primary ferns and grasses Abies-Picea forest. The plot is located 560 m above sea level (57.3884°N, 59.7430°E), on the upper part of the "Maliy Sutuk" mountain slope in the south-western direction. The microrelief is flattened here. There are brown mountain forest soils here, middle or heavy loamy. The forest damage caused by the wind-throw in 1995 was not dramatic, only 2% of trees died. The current tree stand consists of Betula sp., Populus tremula, Picea sp. and Abies sp. in the ratio 5:2:2:1. The sparse undergrowth is mainly formed by Sorbus aucuparia L., 1753 and Daphne mezereum L., 1753.

PZP-19 (compartment 112, sub-compartment 3) was established in 1996 at 570 m above sea level (57.3982°N, 59.7367°E), on the upper part of the "Maliy Sutuk" mountain slope in the north-western direction. There are brown mountain forest soils here, middle or heavy loamy. Vegetation is a primary ferns and grasses Abies-Picea forest. It includes Picea sp. and Abies sp. at a ratio of 2:1, with the addition of Betula sp. and Pinus sibirica. The tree stand is sparse. The main undergrowth is Rubus idaeus with a mix of Rubus matsumuranus H. Lév. & Vaniot. (1905), Sambucus racemosa L. (1753), Ribes spicatum E.Robson, 1796 and Prunus padus L., 1753. Burned areas, wind-throws and secondary uneven-aged Betula forests surround this spot of native forest, but the primary forest on the monitoring plot was not damaged. Being almost identical to PZP-02 by soil, vegetation and hydrological conditions, PZP-19 can serve as a model plot for succession processes in such types of forests and their derivative vegetation along with PZP-02, PZP-20 and PZP-07.

PZP-20 (compartment 112, sub-compartment 1) was established in 1998 as a model plot for wind-throw-driven and post-fire succession monitoring. The plot is located 530 m above sea level (57.4000°N, 59.7301°E) on the middle part of the "Maliy Sutuk" mountain's slight slope in the north-western direction. There are brown mountain forest soils here, middle or heavy loamy. The catastrophic wind-throw damaged a primary forest here in 1995, losses were about 80% of the tree stand. There was an intense ground fire here in 1998, which left no alive trees and only a few dry dead trunks remain. The remaining dead trees have been drying and falling gradually after that. The first stage of ecosystem restoration was the post-fire association, which included herbs and shrub vegetation. The association was formed by Rubus idaeus, Chamaenerion angustifolium and Calamagrostis sp. mainly with a mix of Sambucus racemosa, Lonicera caerulea L. (1753), L. altaica Pall. (1784) and Rosa acicularis Lindl., 1820. A weak ground fire happened later in 2010, which destroyed already dead trees only. Therefore, the post-fire association remained, but Calamagrostis obtusata Trin. (1824) and Calamagrostis langsdorffii Nyman (1882) increased their part within vegetation. We observed the first recovery in 2013 which was presented by single Salix caprea L., 1753, Populus tremula and Abies sibirica Ledeb., 1833 plantlets, but it was only on a part of the sampling plot. Over the subsequent years, elks have consistently grazed on the young undergrowth in this area, preventing the natural establishment of the tree stand. By 2018, young trees surpassed the herb layer in height and begun to form a dense canopy in certain areas. However, in 2018–2022, spider collection activities were not performed in the plot.

Line 1 (compartment 136, sub-compartment 3) was established in 2002, on the slight slope in the intermontane area (443 m above sea level, 57.3833°N, 59.7112°E). The line is located on the forest cutting of the middle 1970s and near the river-head of the Sakalya River. Forest vegetation here is formed by Betula pubescens Ehrh., 1789, Picea obovata Ledeb., 1833 and Abies sp. in a 7:2:1 ratio. The undergrowth consists of Picea sp., Abies sp. and a few Pinus sibirica. The shrub stratum is sparse and includes Rubus idaeus, Rosa acicularis and Prunus padus. The herb layer is dominated by Calamagrostis obtusata, with slightly less abundant Oxalis acetosella L. (1753), Maianthemum bifolium (L.) F.W.Schmidt (1794) and Linnaea borealis L. (1753).

Line 2 (compartment 150, sub-compartment 4) was established on the upper part of the Shishim Mountain, on the north-western direction of the slope (510 m above sea level, 57.3729°N, 59.6873°E). There was forest cutting here in 1975, now this is a birch forest with ferns and small grasses. The tree stand is formed by Betula sp., Picea sp. and Abies sp. in a 3:1:1 ratio. The undergrowth consists mostly of Picea sp. and only a little of Abies sp. The herb layer is dominated by Dryopteris expansa (C.Presl) Fraser-Jenkins et Jermy (1977), Calamagrostis obtusata and Oxalis acetosella, but also Maianthemum bifolium, Linnaea borealis, Fragaria vesca L., 1753 and Trientalis europaea L. (1753) are present.

Line 3 (compartment 162, sub-compartment 5) was established on the upper part of the Shishim Mountain, on the north-western direction of the slope (514 m above sea level, 57.3676°N, 59.6846°E). In the middle 1990s, there was a cutting of Abies-Picea forest. Now Abies-Picea forest with ferns and Allium ursinum L., 1753 is replaced by a mosaic birch forest. The tree stand is formed by Betula pubescens, Pinus sibirica and Abies sibirica in a 7:2:1 ratio, with the addition of Salix caprea, Populus tremula and Prunus padus. The sparse undergrowth is dominated by Betula sp., Salix sp. and Sorbus aucuparia. The shrub stratum includes Rubus idaeus, Rosa acicularis and Lonicera sp. The herb layer is sparse, dominated by Deschampsia cespitosa (L.) P. Beauv., 1812, Calamagrostis obtusata and Oxalis acetosella, with notable Allium victorialis L., 1753 in the spring season. Other herbs are less abundant in the community: Maianthemum bifolium, Linnaea borealis, Stellaria sp. and Gymnocarpium dryopteris (L.) Newman, 1851.

Line 4 (compartment 163, sub-compartment 1) was established in 2012, on the upper part of the Shishim Mountain, on the north-western direction of the slope (515 m above sea level, 57.3674°N, 59.6873°E), in a mature birch forest with Calamagrostis sp. and little grasses. The tree stand is formed by Betula sp. and Picea sp. (in a 3:2 ratio), with the same species in the second forest stratum. The sparse undergrowth consists of Sorbus aucuparia and Rosa acicularis. The herb and subshrub layer is dominated by Oxalis acetosella, Gymnocarpium dryopteris, Fragaria vesca, Calamagrostis obtusata and Stellaria sp. Other species are less abundant in the community: Vaccinium myrtillus L., 1753, Allium victorialis, Trientalis europaea, Linnaea borealis and various fern species.

The data are based mainly on the complex soil- and litter-living invertebrates research, which was performed at eight permanent sampling plots (see the "Study area description" section and the "Long-term monitoring plots" subsection). This source has produced about 3/4 of the occurrences. Each sample has a brief landscape-geographical description and vegetation relevé. Due to the obvious succession on the permanent sampling plots, the provided descriptions reflect the relevant succession stage at the time of collecting spiders. The last 1/4 occurrences were obtained as an addition from temporary sampling plots and sporadic spider collecting. The vast majority of records are georeferenced and have metadata such as date, altitude, habitats (including a succession stage, if available), collecting method and sampling effort, so they can be used in quantitative ecological research. Weather data (absent in the dataset, but available upon request) comes from field journals and the "Visim" meteorological station.

Pitfall traps, litter sifting, entomological net-sweeping, tree and shrub crown shaking, manual collecting.

All data about epigeobiont, soil- and litter-dwelling spiders come from pitfall traps and litter sifting. Pitfall traps were usually installed in a line of 10 (from 4 to 11). Their duration was typically 1–2 weeks (from 3 days to 3 weeks). Glass cans (an opening diameter of 75 mm) or plastic glasses (an opening diameter of 65 mm) filled with formaldehyde or acetic acid solution were used as traps. We sampled soil litter from the surfaces of 50 × 50, 20 × 20 or 15 × 15 cm, sifted it and investigated it on white plastic film. Spiders of the herb layer were collected by entomological net-sweeping. Quantitative samples come from five replications by 20 sweeps, unless otherwise defined in the `samplingEffort` field. A small portion of faunistic material was picked by tree or shrub crown-shaking and by manual collecting.

The collection is stored at the Perm State University (abbreviated as "PSU" in the dataset). Esyunin S.L. has identified all the adult individuals to the species level. Juvenile individuals were identified to the species, genera or family level depending on the informative value of morphological features (body size, shape and colouration, eye configuration, chaetotaxy etc.). The taxonomical nomenclature accords with the World Spider Catalog (2023).

The project is long-term and continues.

The Visimskiy Biosphere Reserve is located in the Sverdlovsk Region and captures three city districts: Gornouralskiy, Kirovgradskiy and Verkhniy Tagil (Fig. 3). Originally, in 1971, the Reserve area was 9,531 ha (95 km²), being extended in 1973, 1980 and 2001, currently accounting 33,497 ha (335 km²). The territory is elongated east to west. Its main part is situated on the western macroslope of the Ural Mountain Range, upstream to the Sulyom River. A smaller part is located on the eastern macroslope and includes the watershed and upstream of the Vogulka River.

Figure 3.  

Map of the Visimskiy Reserve and sampling plots.

57.37 and 57.48 Latitude; 59.42 and 59.81 Longitude.

The dataset includes occurrences of 278 spider species (146 genera and 20 families in total) (Table 1). Of them, we list 18 species for the first time: Agnyphantes expunctus (O.Pickard-Cambridge, 1875), Agroeca lusatica (L.Koch, 1875), Argyroneta aquatica (Clerck, 1757), Cheiracanthium punctorium (Villers, 1789), Clubiona pallidula (Clerck, 1757), Dictyna major Menge, 1869, Entelecara congenera (O.Pickard-Cambridge, 1879), Euophrys frontalis (Walckenaer, 1802), Haplodrassus umbratilis (L.Koch, 1866), Improphantes complicatus (Emerton, 1882), Lophomma punctatum (Blackwall, 1841), Pardosa prativaga (L.Koch, 1870), Talavera thorelli (Kulczyński, 1891), Tetragnatha dearmata Thorell, 1873, Thyreostenius parasiticus (Westring, 1851), Walckenaeria kochi (O.Pickard-Cambridge, 1873), Xysticus kochi Thorell, 1872 and Zelotes electus (C.L.Koch, 1839). We also exclude two previously recorded species from this list (Pardosa palustris (Linnaeus, 1758) (Esyunin and Efimik 2000) and Megalepthyphantes nebulosus (Sundevall, 1830) (Esyunin and Efimik 1996a)), as wrongly provided because of mistypes and inexact georeferencing.

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