Biodiversity of a boreal mire, including its hydrographic network (Shichengskoe mire, north-western Russia)

Abstract Background The paper is based on the dataset whose purpose was to deliver, in the form of GBIF-mediated data, diverse materials on the biodiversity of a large mire, Shichengskoe mire (Vologda Region, north-western Russia), including its various mire sites and intra-mire water bodies. The dataset was based on our materials collected for two decades (from 2000 to 2021) in different parts and biotopes of the Shichengskoe mire and complemented by scarce data obtained previously by other researchers. The data contain materials on the diversity of Animalia (2886 occurrences), Bacteria (22), Chromista (256), Fungi (111), Plantae (2463) and Protozoa (131). Within the study period, the most detailed and long-term biodiversity studies were carried out for higher plants and invertebrates. On the other hand, the data on the composition of lichens, protozoa, algae, basidiomycetes, some groups of invertebrates and, to a lesser extent, lichens and vertebrates are far less comprehensive and require further substantial research efforts. The list includes occurrences from both the peatland (mire sites and mire margins different in typology) and the objects of the mire hydrographic network. In a standardised form, this article summarises both already published (mainly in Russian) and unpublished materials. New information The paper summarises the results of long-term research on the biodiversity of a boreal mire, including its hydrographic network. A total of 5869 occurrences were included in the dataset published in the Global Biodiversity Information Facility (GBIF, gbif.org) for the first time. According to the GBIF taxonomic backbone, the dataset covers 1358 taxa, including 1250 lower-rank taxa (species, subspecies, varieties, forms) and 108 taxa identified to the genus level. Several species found in the Shichengskoe mire, mainly belonging to Bacteria, Chromista and Protozoa, have never been listed in GBIF for the territory of Russia before. The overwhelming majority of occurrences and identified species came from the territory of Shichengskiy Landscape Reserve. Due to our work, this Reserve is now the most studied regional reserve in the Vologda Region with respect to biodiversity. By the number of revealed species, it is close to two federal protected areas: Darwinskiy State Nature Biospheric Reserve and National Park "Russkiy Sever".


Introduction
The first data on the biodiversity of the Shichengskoe mire were obtained during short visits of scientists from the Vologda State Pedagogical University to study the lakes in the region back in 1972 and to investigate the territory in order to create a new protected area in the Vologda Region back in 1986; the materials of these works were published in a very condensed form (Vorobyev et al. 1981, Bobrovskiy et al. 1993. By the beginning of the 21 century, data on the biodiversity of Shichengskoe mire and surrounding area were very scarce (Vorobyev 2007).
In July-August 2000 and 2002, two field studies by Svetlana P. Bobrova with a group of secondary school students were carried out in Shichengskoe Lake, Polyanok Lake and Plakunovskoe Lake (Smirnov 2002, Evgrafova 2004).
Our studies of the Shichengskoe mire began in 2000 and continue to the present day. Between 2000 and 2003, field research was carried out by Dmitriy A. Philippov as part of his university graduate thesis supervised by Andrey N. Levashov. The graduate thesis entitled "Flora of the Shichengskiy Landscape Reserve and its analysis" contained data on 177 species of vascular plants. For several following years, the biodiversity studies of the Shichengskoe mire were fragmentary.
Since 2009, a purposeful collection of data on the composition and structure of various groups of living organisms in the Shichengskoe mire has begun. Mikhail V. Dulin took part in liverworts research in May 2009; vascular plants, fungi and lichens were investigated with the help of Victoria V. Yurchenko in early October 2009.
Thus, over the past two decades, a significant amount of multifaceted materials on the biodiversity of the Shichengskoe mire and its hydrographic network has been accumulated, which we summarised in a GBIF dataset ).

Project description
Title: Biodiversity and conservation of mires of Nothern Russia Personnel: Dmitriy A. Philippov

Sampling methods
Study extent: The list of occurrences of different taxonomic and ecological groups of organisms inhabiting a large wetland in north-western Russia, the Shichengskoe mire, is presented. At the time we started our studies, only fragmentary data on the biodiversity of the Shichengskoe mire had been obtained (dated 1972, 1986, 2000 and 2002). Our work began in 2000 and continues to this day. The most detailed and long-term biodiversity studies were carried out for higher plants and terrestrial and aquatic invertebrates. The data on the composition of lichens, protozoa, algae, basidiomycetes, some groups of invertebrates (e.g. Collembola), lichens and vertebrates are far more scarce and require further substantial research efforts. The dataset includes species observations made both within the peat bog (mire sites and mire margins differed in typology) and in the mire hydrographic network, which we consider a structural element integral to the mire ecosystem (Philippov 2017). This dataset includes both published and unpublished materials.
Sampling description: Biodiversity studies in the Shichengskoe mire were conducted from April to October, employing the route, reconnaissance and semi-stationary field approaches. Most microhabitats [a habitat which is of small or limited extent and which differs in character from some surrounding, more extensive habitat] were studied regularly during one or several vegetation seasons, but some were visited only once. The set of methods and techniques used in the field depended on both financial, time and logistical capabilities and the available specialists for specific taxonomic groups. We used a general approach to hydrobiological and ecological research of mires developed by the authors to study wetlands in Russia, described in the publication . Step description: I. Research problem formulation.
II. Logistic issues resolution, including planning the location of routes, selection of water object, time and duration of work.
III. Field stage: obtaining samples and other original materials on the biodiversity of various components of the mire ecosystem.
(a) Macrophytes. In the field, pictures of plants and floristic lists were made, some species were collected in a herbarium (Philippov 2015a, Bobroff et al. 2017; several hydrochemical parameters (water temperature, total dissolved solids, pH and electrical conductivity) were measured using portable devices. On the model sampling plots, relevés were made for mire sites different in microrelief (strings/ridges, hummocks, lawns, hollows, hollow-pools).
(b) Fungi. Basidiomycetes and lichens were studied on the way; as a rule, they were photographed and some samples were collected in the herbarium (Czhobadze and Philippov 2015).
(c) Algae. Samples were collected from the surface layer of water in several spots within the studied microhabitat using a plankton nylon net with a 20 μm pore diameter and a plastic sampler. Samples were fixed with 4% formalin (Kapustin et al. 2016b).
(d) Protozoa. Samples of heterotrophic flagellates and centrohelid heliozoans were collected in various microhabitats (water, upper peat or sediment layers, plants -by squeezing or washing off). Samples were collected in plastic tubes and transported to the laboratory at 4°C (Prokina et al. 2017, Prokina and. To study testate amoebae diversity, Sphagnum mosses were collected in plastic tubes; the number of individual plants varied depending on different species growth densities (Philippov and Leonov 2017).
(e) Aquatic invertebrates. Zooplankton samples were collected at the model mire sites (lake, hollow-pool, fen strip, hollow and mire stream) by filtering water (5 to 50 litre) through a plankton net with 74 µm mesh. Samples were preserved with 4% formalin , Zaytseva et al. 2017. Benthos invertebrates were collected at the model mire sites (lakes, fen strip and mire stream) with a bottom scraper (20 × 20 cm area). Each sample was washed through a 250 μm mesh nylon sieve, put in a plastic container and preserved in 40% formaldehyde. In mire streams and lakes, macrophyte-associated invertebrates were sampled; for that, water mosses clumps and aquatic plants with floating leaves were placed in plastic containers and preserved in 40% formaldehyde Philippov 2013, Ivicheva andPhilippov 2017). The composition of aquatic, semi-aquatic and amphibiotic beetle communities was studied using trampling and sweeping procedures , Sazhnev et al. 2019b, Sazhnev et al. 2020) and ethanol preservation of imagines and larvae.
(f) Terrestrial and soil invertebrates. The study of terrestrial insects and arachnids was carried out mainly on three model sites (fen strip, a ridge-hollow site and a mire stream valley at the mire margin) using a sweeping technique (30 sweeps in triplicate; diameter of the hoop 30 cm) ("Pollard walks") . Manual collection of insects was performed outside the model sampling plots. Captured arthropods were euthanised with diethyl ether (Golub et al. 2021). Ticks were studied mainly in Sphagnumdominated communities. Within the selected mire sites, samples were collected in microhabitats -on certain Sphagnum species from mire sites different in microrelief (ridge, carpet, hollow). Sphagnum moss samples for mite extraction were collected using a 10 × 10 cm frame to the depth of living moss plants (including capitula and the length of stems). Collected samples of moss substrates were placed in plastic zip bags and transported to the laboratory (Minor et al. 2016, Minor et al. 2019).
(g) Vertebrates. Along with studying other groups of organisms, visual observations of vertebrates and their traces were carried out (Philippov and Shabunov 2013). Whenever possible, animals and their traces were photographed, feathers or other fragments of animals or faeces were collected. Fishing was carried out with a float rod within legallyapproved periods.
IV. Data collection: analysis of samples not identified in the field or verification of the identification data by the experts. (c) Algae. Sedimented phytoplankton for qualitative and quantitative analysis was examined in a Nageotte counting chamber (0.01 cm ) using a ZeissAxiolab, NikonEclipse 3 to the closest possible low-range taxon.
(d) Protozoa. In the laboratory, heterotrophic flagellates and centrohelid heliozoans samples were enriched with a suspension of Pseudomonas fluorescens Migula bacteria at the ratio of 0.15 ml of suspension per 5 ml of sample and placed in Petri dishes. Samples were kept at 22°C in the dark and observed for 10 days to reveal the cryptic species diversity according to the accepted methodology (Vørs 1992). For observations, an AxioScope A1 light microscope (Carl Zeiss, Germany) with DIC and phase contrast and water immersion objectives (total magnification 1120x) was used. Video recording was made by an AVT HORN MC1009/S analogue video camera. Electron microscope preparations were carried out according to the approved method (Moestrup and Thomsen 1980) and observed in a JEM-1011 transmission electron microscope (Jeol, Japan). Testate amoebae samples were analysed immediately after transportation to the laboratory. NU-2E and Peraval-Interphako with water and oil immersion and an MBI-3 light microscope with a KF-5 phase-contrast installation in transmitted light were used. Analysis of heterotrophic flagellates, centrohelid heliozoans and testate amoebae abundance in the samples was not performed.
(e) Aquatic invertebrates. All specimens of zooplankton and zoobenthos were identified with an MBS-10 stereoscopic microscope and a Mikmed-6 microscope (LOMO, Russia). Aquatic insects were identified using Micromed MC-5-ZOOM LED and Leica M165C stereoscopic microscopes. These materials are deposited in the Papanin Institute for Biology of Inland Waters Russian Academy of Sciences (IBIW RAS): "Collection of autotrophic and heterotrophic organisms of mire ecosystems, IBIW RAS" and the entomologic collection.
(f) Terrestrial and soil invertebrates. On the day of sampling, sweep samples of terrestrial arthropods were primarily sorted by the main taxonomic groups (spiders, beetles, dipterans etc.). Separate samples were then fixed in ethanol. Detailed analysis, identification and counting were performed later by experts. Part of the collection was deposited in the Science Museum of the Institute of Biology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences. Mites from moss samples were extracted in modified Berlese funnels for five days. Adult Oribatida and Mesostigmata were identified to a species level and counted. Taxonomic identification of mites was carried out by the Acarology research group of Tyumen State University.
(g) Vertebrates. Found fragments of animals and their traces were collected and studied in the laboratory. Faunal lists were compiled.
Records list compilation. The dataset field names were chosen according to Darwin Core (Wieczorek et al. 2012). Georeferencing was made using a GPS navigator or Google maps. In all cases, the WGS-84 coordinate system is used.

Geographic coverage
Description: The study area is situated in the central part of the Vologda Region (59. 8988 -60.0590 N, 41.2327 -41.5540 E), north-western Russia, the southern part of the middle taiga zone (Fig. 1). Shichengskoe wetland is a large mire area including the peat bog (Shichengskoe mire), intra-mire lakes (Shichengskoe Lake, Plakunovskoe Lake, Polyanok Lake) and rivers (Glukhaya Sondushka River, Sondushka River, Shichenga River), nameless mire streams and brooks, fen strips and lags, Sphagnum hollows, secondary hollow-pools and disturbed areas (Philippov 2017). Chemical characteristics of the intramire water objects were reported earlier (Philippov and Yurchenko 2020), as well as the data on microclimate differences between the mire sites (Philippov and Yurchenko 2019).
The study area is characterised by a temperate continental climate with long, cold, snowy winters, short springs with fluctuating temperatures, relatively short, moderately warm summers and long and rainy autumn. The average annual air temperature is + 1.5 to + 2.0ºC, the average monthly temperature in July is + 16 to + 17.0ºC, in January, -12.5 to -13.0ºC. The average annual precipitation ranges from 650 to 750 mm; during the active growing season, from 350 to 375 mm. The prevailing wind direction is southwest and south (Skupinova 2007).
The study area is confined to the Permian-Triassic plateau. The bedrock sedimentary rocks occur at a depth of 20-40 m and are represented by limestones and clays with lenses of sandy loam of the Tatar stage of the Permian system. The main features of the relief of the region are determined by glacial accumulation in the terminal moraines formed during the Moscow glaciation. Shichengskoe wetland was formed mainly by the limnogenic process on the south-eastern spurs of the Kharovsk ridge in a vast lacustrine-glacial basin. The ancient lake basin is orientated from northwest to southeast and reaches 20-25 km across. The bottom of the basin is a typical lacustrine-glacial plain with absolute heights of 130-150 m above sea level (Savinov and Romanova 1970). At the beginning of the Holocene, the post-glacial lake was significantly drained by rivers and streams, overgrowth and peat accumulation followed and a peat bog began to form in its place. Currently, a large mire with a residual lake fill up the Shichengskiy ancient lake basin.
The main aquifers are lacustrine, lacustrine-glacial and fluvioglacial intermoraine Quaternary sediments confined to sands, less often to interlayers of sands in sandy loams and clays. The area is provided with low-mineralised groundwater (Savinov and Filenko 1970). The surface waters of the Shichengskoe wetland belong to the regional drainage basin of Kubenskoe Lake, the global drainage basin of the Arctic Ocean (White Sea).
The soil-forming rocks in the area are moraines, enriched with boulders, sometimes carbonate material, less often fluvioglacial and binomial deposits being the parent rocks in the study area (Komissarov 1987). Directly on the territory of the Shichengskoe mire, soils are predominantly hydromorphic and semi-hydromorphic and peat soils prevail over the occupied area.
According to geobotanical zoning (Abramova and Kozlova 1970), the Shichengskoe wetland is located in the southern part of the Verknevazhsko-Kuloiskiy geobotanical district of haircap-moss and berry-grass spruce forests, pine and birch forests, transitional mires and raised bogs. In the region, almost half of the forest formations grow on soils of varying degrees of waterlogging due to insufficient drainage of the prevailing moraine and lacustrine-glacial plains composed of loams. About 80% of the forested area is occupied by pine forests with low quality of locality and represented mainly by swamp forest coenoses. About 10% of the forested area is occupied by spruce forests, of which paludified types prevail. Small-leaved forests are mainly represented by birch forests, which formed mainly at clearings (Bobrovskiy et al. 1993).
According to the classification proposed by T.K. Yurkovskaya (Sirin et al. 2017), Shichengskoe mire belongs to Pechora-Onezhskii raised bog type of the North-Eastern European Sphagnum raised bogs group of Sphagnum mires. Currently, the main part of the mire is at the oligotrophic stage of development; however, there are areas of eutrophic and mesotrophic types of water-mineral nutrition. The mire is located on the territory of the Shichengsko-Kuloiskiy mire district (Abramova 1965), which is paludified by more than 19% (Filonenko and Philippov 2013) and characterised by the predominance of forested mesotrophic and oligotrophic mires of lacustrine origin.
Since 1987, about 90% of the Shichengskoe wetland has belonged to the regional Shichengskiy Landscape Reserve. This Reserve is the largest landscape reserve in the Vologda Region (136.1 km ).

class
The full scientific name of the class in which the taxon is classified. order The full scientific name of the order in which the taxon is classified. family The full scientific name of the family in which the taxon is classified. locality The specific description of the place. This term may contain information modified from the original to correct perceived errors or standardise the description. A variable (eight options: "Glukhaya Sondushka river", "Plakunovskoe lake", "Polyanok lake", Shichenga river", Shichengskoe lake", "Shichengskoe mire", Shichengskoe mire and lake", "Sondushka river"). organismQuantityType The type of quantification system used for the quantity of organisms. A variable (two options: "Braun-Blanquet scale", "percent cover").
sampleSizeValue A numeric value for a measurement of the area.

sampleSizeUnit
The unit of measurement of the area. A constant ("m "). year The four-digit number of year in which the Event occurred, according to the

Additional information
The studied biotopes of the Shichengskoe mire were placed in the following groups: (1) Mire expanse lake with its coastal area; this group combines Shichengskoe Lake, a 10.2 km flow-through shallow primary lake centrally situated in a mire expanse and the Lake's paludified coastal area formed mainly by raised bog sites.
(2) Non-central mire lakes with coastal areas; this group includes two small lakes, Polyanok Lake and Plakunovskoe Lake, about 0.04 km each, non-flow-through 6-7 m deep primary lakes located closer to the edge of the Shichengskoe mire and lakes' paludified coastal areas formed mainly by rich fen mire sites.
(3) Floating mats; this group includes peat-forming vegetation held together by roots and rhizomes and floating on water, developing in lakes and mire rivers.
(4) Mire rivers with banks; this group includes three small, 5 to 50 km long, rivers with river banks: Sondushka River and Glukhaya Sondushka River, draining into Shichengskoe Lake and Shichenga River, the outlet of Shichengskoe Lake.
(5) Mire streams with valleys; this group includes small watercourses with the weak flow, their paludified banks and weakly pronounced forested eutrophic valleys.
(6) Fen strip sites; this group includes structural elements of fen strips, specific water objects forming solely in mires, narrow mire areas receiving an inflow of water from the surrounding mire, almost without trees, with meso-or meso-oligotrophic with grass and grass-moss communities. In the Shichengskoe mire, these flow-through fen strips begin at the intra-mire islands.
(7) Rich fen sites; this group includes rich fens, peatlands receiving an inflow of water from the mineral soil, located closer to the mire's edge, having groundwater outlets and eutrophic peat.
(8) Raised bog feature and its elements; this group includes ridges, hummocks, lawns, Sphagnum hollows and secondary hollow-pools, the structural elements of oligotrophic mire sites (that occupy the most significant area in the Shichengskoe mirе), underlain by oligotrophic peat and having a set of plant communities characteristic of the taiga zone. Often these structural elements in various combinations form patterns, for example, a ridge-hollow pattern.
(9) Margins and edges; this group includes margins of a mire massif and paludified edges of intra-mire mineral islands.
(10) Disturbed areas; this group includes burnt places and bonfires, fishing grounds, trails and roads in a mire.
(11) Other biotopes; this group includes biotopes that did not fall into any of the previous groups and the occurrences of migratory birds and some mammals that pass through the mire or use several biotopes.
General view of a raised bog part including a ridge-hollow pattern, Shichengskoe mire (Vologda Region, Russia). Photo by Dmitriy A. .

Figure 11.
A ridge-hollow pattern in a raised bog part, Shichengskoe mire (Vologda Region, Russia). Photo by Dmitriy A. .
The studied biotobe groups were investigated unevenly (Table 1). A strong correlation was found between the number of occurrences and the number of lower-rank taxa found in the groups of biotopes (Spearman Rank Correlation Coefficient 0.98, p < 0.05). The greatest number of occurrences came from the raised bog features and their elements and fen strip sites which accounted for 359 and 371 lower-rank taxa, respectively. Mire streams with their valleys and margins and edges were studied much less, but these biotopes also showed significant biodiversity.   Half of the total occurrences came from the intra-mire water bodies that comprised 59.6% of lower-rank taxa ( Table 2). The most studied were fen strips and this biotope group showed the most significant biodiversity. It is worth noting that the second largest number of lower-rank taxa was found in Shichengskoe Lake, the mire expanse lake, the largest in the studied mire complex; it provided one-third of the lower-rank taxa, based on almost one-eighth of the number of occurrences.  Table 3 shows the distribution of species and lower-rank taxa recorded on the Shichengskoe mire by major taxonomic groups. This data allows us to conceive of the level of biodiversity exploration and prospects for further research.  Table 3.
Numbers of lower-rank taxa (species, subspecies, varieties, forms) and species in higher-rank taxa (kingdom, phylum) registered in the Shichengskoe mire (Vologda Region, Russia) During the studies, we found a significant amount of endangered species within the Shichengskoe wetland, five included in the Red Data Book of the Russian Federation (Danilov-Danilyan 2001, Bardunov andNovikov 2008): a stonewort Chara strigosa, a hawker dragonfly Anax imperator, a raptor Pandion haliaetus, a wader Numenius arquata and a songbird Lanius excurbitor. Notably, the first two species have not been included in the Red Data Book of the Vologda Region because no confirmed findings had been known in the region at the time. In the Red Data Book of the Vologda Region, 57 species found in the Shichengskoe wetland are listed (Bolotova et al. 2010, Suslova et al. 2013, Anonymous 2015 However, only 80% of the total number of rare and protected species was registered within the boundaries of the Shichengskiy Landscape Reserve. Philippov D et al