The checklist of the syntaxa within the Russian Arctic: current state with vegetation classification

Introduction. A revision of syntaxa was carried out within the framework of the classification of the Brown-Blanquet school identified in the Russian Arctic. A geodatabase (GDB) and GIS, which include several interconnected main modules (see: Matveyeva et al., 2019a, b), with information on species composition, structure, ecology, and geography of syntaxa of all levels, integrated in these databases, became the basis of the presented checklist. This is the first result of compiling information on the vegetation classification, performed with the prospect to produce Prodromus of syntaxa, identified in this territory, with detailed information (character/differential/diagnostic species, ecology, zonal position, geography, bibliography), available in the GDB. It will be in time included in the Prodromus and later will become the basis for a volume in multivolume series on the vegetation of the Russian Federation (see: Plugatar et al., 2020). Territory. The checklist contains information on syntaxa established in the Russian Arctic within the boundaries of the Circumpolar Arctic Vegetation Map (hereafter CAVM) (CAVM Team, et al., 2003; Walker et al., 2005; Raynolds et al., 2019), as well as on the Barents Sea coast of the Kola Peninsula, which is referred to the tundra zone in accordance with the zonation of the Russian Arctic flat territory (see: Matveyeva, 1998). The list includes syntaxa found north of the treeline — in the tundra zone (subzones of the southern, typical, and arctic tundra) and polar deserts.1 Hence, it follows that there are no syntaxa from the forest-tundra as well as those above the treeline in the mountains adjacent to the tundra zone (Putorana and Anabarskoe plateaus). The syntaxa from the territory of the «Russian Arctic» (Barentsburg, Pyramida) on the West Spitsbergen Island (Spitsbergen archipelago) are also not taken into account (their positioning is logical in Spitzbergern syntaxonomy). History. The study of the Russian Arctic plant cover began in the second third of the XIXth century in the north-east of the European Russia (Schrenk, 1855) and in Siberia on the Taymyr Peninsula (Middendorf, 1860–1867). After a significant break, it continued in the USSR in the pre-war time and intensified after the end of the Great Patriotic War. The most intense (both in the size of the studied areas and the numbers and duration of the field works) was the period from the mid-1960s to the early 1990s. Researchers working both in other zones and in the Arctic processed the obtained data in accordance with the approaches of the dominant classification, and the relevés were either not published or presented in a small (4–5) number for association. Despite the obvious limitations of this approach, there were published (both in the form of text with listing of few dominants and with relevé tables) both general (Gorodkov, 1935) and regional (Andreev, 1932; Bogdanovskaya-Giyenef, 1938; Smirnova, 1938; Dedov, 2006 [1940]; Aleksandrova, 1956, 1983; Gorodkov, 1956, 1958 a, b; Katenin, 1972) classifications, and checklists — a draft classification of vegetation of the whole Arctic (Aleksandrova, 1979) and classification of Taymyr vegetation (Matveyeva, 1985). In the late 1980s, Russian phytosociologists turned to the Brown-Blanquet floristic (= floristic-sociological (Theurillat et al., 2021), or ecological-floristic (Mirkin, Naumova, 2014)), classification system as the most conceptually substantiated, with generally accepted rules for describing communities in the field and the technique of relevé tabular processing, and also with clear rules for the formation of syntaxon names. In this system, the obligatory publication of the original data and the requirements for its validity when describing the basic syntaxon are strictly postulated, which provides an objective comparison and classification of any plant community types, in whatever system these data are not submitted. Just as it is impossible to imagine the development of taxonomy without the existence of herbarium collections, so it should be an axiom for phytosociologists that since the relevé is the only documentary reflection of a natural phenomenon named «plant community» (Matveyeva, 2008), it should be available for analysis to all syntaxonomists. Since the second decade of the XXth century, the followers of the Braun-Blanquet system have published thousands of relevés from different regions of the globe, which made it possible to produce a unified classification of vegetation from the Arctic to the tropics and its constant replenishment. Currently, the process of creating electronic databases (archives) of relevés, including the Arctic Vegetation Archive, which accumulates information on circumpolar vegetation is accumulated, is actively underway (Walker et al., 2018). The starting point when Russian tundra experts began to work consistently, following the principles of this classification, is the first International Meeting on the Classification and Mapping of Arctic Vegetation, which took place in 1992 in Boulder, CO (USA). For the publication of its data, a special issue of the Journal of Vegetation Science (1994, Vol. 5, N 6) named «Circumpolar arctic vegetation» (where 4 papers by Russian syntaxonomists were published) was provided. After 1992, when the intensity of field works decreased sharply, the number of publications with complete characteristics of the communities of the Russian Arctic increased rapidly.The proposed checklist of syntaxa is the result of this almost 30-year acti­vity. The checklist structure. The arrangement of syntaxa of class rank is mainly the same as in the EuroVegChecklist — hereafter EVC (Mucina et al., 2016): zonal and intrazonal communities of the polar desert zone (one class); zonal (one class) and landscape-forming intrazonal (five classes) communities of the tundra zone; intrazonal communities (13 classes), united into groups according to the gradients of moisture, snow depth and soil mechanical composition. A syntaxon is represented as follows: — higher units of the rank Class/Order/Allian­ce (Suballiance): number (for Class), abbreviated rank in English (Cl., Ord., All. (Suball.)), in square brackets — code (if any) from EVC (Mucina et al., 2016); full name, author(s) and year; below is a brief description in two languages: English — in general as in the cited paper with some corrections due to the specificity in syntaxon geography and ecology in the Asian part; Russian — partly in accordance with the English version and/or to Prodromus of higher vegetation units of Russia (Ermakov, 2012), sometimes with minor corrections or clarifications. For new orders and alliances within the zonal tundra class differential taxon combinations are listed; — syntaxa of the rank Association, Community Type, Community, established on the territory of the Russian Arctic: abbreviated rank in English (Ass., Com. Type, Com.), name, author(s) and year (besides association, the cited papers are included in the Refe­rences). If syntaxon was previously described by European/American authors outside the Russian Fede­ration, the link to the publication, where it was found in the Russian Arctic, is placed in brackets. The ­arrangement of associations is alphabetical; — syntaxa of units of a lower (within association) rank (subassociation and vicariant, variant, subvariant, facies): abbreviated rank in English (subass. and vicar., var., subvar., fac.), name, in brackets author, year (besides subassociation, the cited papers are included in the References). The arrangement of the syntaxa is as follows: typicum(-cal, -ca), inops, then alphabetically. For subass. typicum authors are not listed (Theurillat et al., 2021), but if it was described by another author and/or in another paper, then the link to it is given in brackets and the paper is included in the References. All names of syntaxa are given in the author’s edition (as it was published), including the endings of a typical syntaxon within an association (subassociation, vicariant, variant, facia) — typicum, typical, typica. In different papers, there are two English spellings of Russian surnames: Aleksandrova/Alexandrova, Andreev/Andreyev, Bogdanovskaya-Giyenef/Bogdanovskaya-Gienef, Pristyazhnyuk/Prystyazhnyuk, Savich/Savič. A uniform (the first one) spelling of the surname is used here. If there was something that caused a disagreement with the author’s decision (including the assignment of an association to a syntaxon of a higher rank), there is a superscript number before the syntaxon name, or before the author’s surname (when it is in brackets), referring to critical comments. Critical comments. 1 – The name is invalid or needs change because: 1a – no reference to the nomenclature type; 1b – published ineffectively (names published as ‘manuscript’ or ‘unpublished’); 1c – not accompanied by a sufficient diagnosis, no tables with original relevés; 1d – suggested by the author as preliminary; 1e – not obvious from what species syntaxon epithet is formed and it cannot be extracted from the diagnosis and/or tables); 1f – syntaxon with the same name was described earlier (including the case of inversion); 1g – the form of the syntaxon name does not correspond to Art. 10 of «International Code of Phytosociological Nomenclature» — hereafter ICPN (Theurillat et al., 2021); 1h – the given nomenclature type belongs to a different syntaxon, validation does not correspond to ICPN; 1i – the relevé chosen as an association or subassociation nomenclature type does not contain the name-giving taxon of this syntaxon; 1j – there is a subspecies in the original diagnosis and in the tables, while in the syntaxon name the species name is used; 1k – the nomenclature type is given for 2 variants of the vicariant, among which there is no tyicum one; 1l – published or validated in 2002 or later with no indication of novelty (like, Ass. nov.). 2 – the author(s) did not place the syntaxon amo