Spiders (Arachnida: Araneae) of the Visimskiy Nature Biosphere Reserve (Middle Urals)

Arachnological research is a part of Visimskiy Reserve research projects on complex study of soil- and litter-living invertebrates carried out within "Nature Chronicles" – conservation monitoring on the condition of ecosystems and its components on protected areas. The project is devoted to inventory and long-term monitoring of the epigean invertebrate animals, including mollusks (Mollusca), carabid beetles (Carabidae), carrion beetles (Silphidae) and other taxa. The aim of the article as a part of the project is to summarize all literature and material data about spiders in order to obtain an up-to-date list of spider species and occurrences. Also, some other results can be seen in the published literature (Esyunin and Efimik 1995, Esyunin and Ukhova 1996, Ukhova and Esyunin 1996, Esyunin et al. 1996, Esyunin et al. 2000, Ukhova 2001, Esyunin and Ukhova 2011).

The vegetation of Visimskiy Reserve is primarily forested. Forests cover 87% of territory according to the 2000-2001 forest stock-taking, and are represented by both boreal and nemoral types. The reserve is situated within mountain taiga belt, which is divided into two sub-belts. Lower one (up to 400±50 m above-sea level) is colder and composed of temperate boreal dark-coniferous forests. Higher sub-belt is composed of nemoral and subnemoral forests (Kirsanov et al. 1979). The most detailed forest inventory has shown 11 types of primary associations (Kolesnikov et al. 1974). However, native fir-spruce (Abies-Picea) 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 catastrophic windthrow in 1995. Later, in 1998, the heavy forest fire has destroyed most of the woodstand, undergrowth and herb layer at all windthrown areas. The fire repeated in a few windthrown and untouched areas. After that, there were only three types of primary forests remain: ferns and grasses Abies-Picea forests, large-ferns Abies-Picea forests, Abies, Picea and Pinus sibirica forests with fern and horsetail. Recently, primary virgin forests cover only 3% of the reserve's territory (Sibgatullin 1987, Sibgatullin 2021) presented on peaks and slopes of mountains Bolshoy Sutuk, Maliy Sutuk, Dolgiy, Kuligi. The secondary woodstand assocoations are mixed uneven-aged forests, presented by Picea-Betula, Betula, Populus tremula. Some of post fire association with Chamaenerion angustifolium and Calamagrostis located on the Maliy Sutuk mountain have not been recovering with woodstand since the fires in 1998 and 2010 for a long time. Meadows occupy no more than 1% of the territory of reserve. They are formed on the former forest areas harvested for crop fields and haymaking grasslands. Some of meadows are about 300 years old. There are almost no bogs within the reserve. The long-term monitoring of soil and litter invertebrate complexes covers 8 permanent plots having unique abbreviations officially. They are established in primary ferns and grasses fir-spruce (Abies-Picea) forest (PZP-02 until 1995, PZP-19), in their derivatives - post-fire associations on the various succession stages (PZP-07, PZP-20), in secondary birch (Betula) forests formed after wood cutting (Lines 1, 2, 3 & 4). We describe all of them in details below.

The data are based mainly on the complex soil- and litter-living invertebrates research, which was performed at 8 permanent sampling plots. This source has produced about 3/4 of the occurrences. Each sample has a brief landscape-geographical and geobotanical description. There was obvious succession on the permanent sampling plots, so the provided description are appropriate at the time of collecting and reflect the relevant succession stage. The last 1/4 occurrences were obtained as an addition from temporary sampling plots and sporadic collecting. The vast majority of records are georeferenced and have crucial metadata such as date, altitude, habitats (including succession stage if available), collecting method, 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.