Arachnids (Arachnida: Araneae, Opiliones) of Mountain Summits of the South Urals

Study Extent

The South Urals as a GLORIA target region comprises a suite of four summits which represent an elevation gradient from the natural treeline ecotone up to the uppermost vegetation zone. A target region (SUR) is the mountain area in which these four summits are located. All summits of a target region must be exposed to the same regional climate, where climatic differences are caused by elevation rather than by topographically determined weather divide effects. The ideal altitudinal positions of the four summits would be within the ecotones that form the transition between vegetation belts, because climate-induced changes are most likely to become first apparent in these transition zones (Pauli et al., 2015). The four summits for the South Urals as a GLORIA target region were chosen with the direct supervision of GLORIA coordinators in 2001. The sampling design for each summit provides the delimitation of four sections in the upper summit area (5-m summit area) and four sections in the lower summit area (10-m summit area). The size of the summit area section is not fixed but depends on the slope structure and steepness. For investigation of herpetobiont invertebrates (insects, arachnids, centipedes) the pitfall traps were established in each of four sampling areas (usually lower summit area sections) connected with cardinal directions (N, E, S, W) of every summit. The installation of pitfall traps was carried out according to the protocol included in the fifth edition of the official manual (section 7.2) of GLORIA project for extra approaches (Pauli et al., 2015). The sampling design for GLORIA summits was proposed by Mikhailov (2009) and later on included in the official manual (Mikhailov, 2015). In the South Urals he first results using this method were obtained in 2008, and the first resurvey was carried out in 2015. The results for insects and spiders after two surveys (2008 and 2015) were published (Mikhailov & Ermakov, 2016). However, in July 2015, before the survey period in Dalniy Taganay, the weather was cool and rainy, unfavourable for invertebrate activity, so the surveys there were repeated in 2016 during the better weather. A second resurvey in Dalniy Taganay was carried out in 2022 (22–25 June), but unusually cold weather in June resulted in poor sampling. To confirm the results, the survey was repeated on 6–9 July 2023. In 2023 another peak of the Big Taganay ridge was surveyed simultaneously (5–8 July) - Kruglitsa (1144 m above sea level). The first data on this peak were obtained in 2016. Like Dalniy Taganay it is one of the northernmost peaks in the Southern Urals where mountain tundra has been preserved. The summits Kruglaya or Malaya (Small) Poperechnaya (1389 m a.s.l.) and Bol’shoi (Big) Shelom (1407 m a.s.l.) of Zigalga mountain range are not the GLORIA summits. Although they were surveyed in 2023 and 2024 respectively with the same sampling design.

Sampling

In each sector 20 standard 75 mm diameter plastic cups were installed in a cross-shaped line, i.e. 10 traps were placed along the main line (north, south, west and east) at least 1 m apart, and another 10 traps were placed perpendicular to the first line. After three days, the lines were removed and the contents of the traps from each line were placed in specially marked containers. A preliminary sorting of adults and larvae of insects, arachnids and centipedes was carried out in the field. The analysis and identification of the collected material was later carried out in the laboratory. Additional miscellaneous materials were collected by various arachnological field methods: entomological net sweeping, litter sifting, trees shaking and manual collecting along with pitfall-traps.

Quality Control

The collection is stored in the Perm State University (PSU). A few specimens are stored in the Zoological Institute of the Russian Academy of Sciences, St.-Petersburg (ZIN). 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 informative value of somatic features (body size, shape and coloration, eyes configuration, chaetotaxy etc.). The taxonomical nomenclature accords the World Spider Catalog (WSC, 2024).

Method steps

1. 1. Insalling a standard plastic cups (75 mm in diameter) in a cross-shaped lines (20 cups per line);
2. 2. Exposing for 3 days and collecting the contents of the traps to a specially marked containers;
3. 3. Additionally collecting miscellaneous materials by entomological net sweeping, litter sifting, trees shaking and manual collecting along with pitfall-traps.

1. Araneae
   common name: spiders rank: order
2. Opiliones
   common name: harvestmen rank: order

Mountainous parts of Chelyabinsk region and the Republic of Bashkortostan