Baikalsky State Nature Biosphere Reserve and its buffer zone: floristic data

Abstract Background Baikalsky State Nature Biosphere Reserve is situated in the central part of the Khamar-Daban Range (Southern Baikal, Siberia), in three administrative districts of Republic of Buryatia (i.e. Kabansky District, Dzhidinsky District and Selenginsky District), Russia. In general, this territory has been relatively well studied by botanists, but until now there was no detailed information about the flora of the Reserve with precise geographic localities. Moreover, some records in the Baikalsky Reserve's flora were published without references to documenting herbarium specimens. New information The dataset contains 39,238 unique occurrences of 875 taxa (854 species, 14 subspecies, five varieties and two species aggregates) from the Baikalsky Reserve and its buffer zone. All the data were acquired during the field studies by the author in 2009–2021, when 152 taxa (17.3% of all the taxa included into the dataset) were first recorded by the author from the study area. Herbarium vouchers are preserved in the Moscow University Herbarium (MW). This dataset is the first attempt at creating a database of vascular plants of the Baikalsky Reserve and its buffer zone, based on modern research. These data will provide the background for the updated check-list of the Baikalsky Reserve's flora.


Introduction
Baikalsky Reserve was established in 1969 to protect local plant communities of the Khamar-Daban Range within all the altitudinal zones. The Baikalsky Reserve's flora includes several relict plant species (Epova 1956, Chepinoga et al. 2017b. To protect the unique natural complexes of this area, Baikalsky Reserve was assigned the status of Biosphere Reserve in 1986. Therefore, a special buffer zone surrounding its borders was created (buffer zone is obligatory for all the Biosphere Reserves in Russia). The Baikalsky Reserve is one of the key natural protected areas in the system of nature conservation in southern Siberia. The Reserve is also a part of the Lake Baikal World Heritage Site since 1996 (Unesco World Heritage Center (2021)).
First detailed botanical studies here began in the middle of the 20 century. Scientists from Irkutsk described the vegetation of the Khamar-Daban Range and collected herbarium specimens (herbarium vouchers are preserved now in the Herbaria IRK and IRKU). N.A. Epova studied the vegetation and relict species and made the first map of floristic division of this territory (Epova 1956, Epova 1957, Epova 1960, Epova 1961. M.M. Ivanova continued this work and also explored the alpine flora of the Khamar-Daban Range (Ivanova 1967). The first check-list of vascular plants of the Baikalsky Reserve was published in 1978 (Vasilchenko et al. 1978) and contained 777 taxa. Floristic investigations continued and several additions to the flora were published later (Volotovsky and Ermolenko 1985, Ivanova 1991, Krasnopevtseva et al. 2008a). The second check-list was published in 2008 (Krasnopevtseva et al. 2008b) and contained 886 taxa; new additions followed soon (Abramova et al. 2009). The third check-list, including 991 taxa, was published in 2011 (Abramova and Volkova 2011). Several additions to the flora of the Baikalsky Reserve and its buffer zone were published since 2011 (Gamova and Dudov 2012, Krasnopevtseva and Krasnopevtseva 2012, Gamova and Krasnopevtseva 2013, Verkhozina et al. 2013, Ivanova et al. 2016, Sutkin et al. 2016, Tupitsyna and Chepinoga 2016, Chepinoga et al. 2019, Gamova et al. 2019, Sutkin and Krasnopevtseva 2020. In 2009 new taxa were first recorded by the author and added to the flora of the Baikalsky Reserve and its buffer zone. For other 18 new taxa, firstly found in recent years by other botanists, the author has recorded new localities. Open-access data with precise geographic references are essential for modern research as it allows a computational approach to analysing spatial patterns of species distributions. This is the first comprehensive dataset focusing on the flora of the Baikalsky Reserve th covering its whole territory and all the taxonomic groups of vascular plants. Several datasets, including some data from the territory of the Baikalsky Reserve amongst other areas, were published in recent years (Chepinoga et al. 2017a, Brianskaia et al. 2021, Seregin 2021. However, these datasets focused on various aspects, namely on the distribution of alpine endemic plants of northern Asia, on digitising grid maps from the "Flora of Central Siberia" (1979) or on digitising herbarium collections of Moscow State University, neither of them aimed at thoroughly studying the Baikalsky Reserve's flora. Thus, the aim of the present work is to narrow this gap in the knowledge of the vascular plant species distributions in the Baikalsky Reserve.

General description
Purpose: The main purpose of the dataset (Gamova 2021) is to give access to the modern floristic data from the Baikalsky Reserve, which is situated in a hard-to-reach area in the central part of the Khamar-Daban Range and to study the plant diversity of this territory. Systematic data collection enabled us to reveal the local species richness.

Additional information:
The dataset contains 39,238 occurrences from 3,156 sampling events. A total of 90.39% of the dataset (35,467 occurrences) is formed by species lists from 1,873 relevés (59.35% of all sampling events). The number of species per one relevé varies from 8 to 87, with 19 species on average. The flora of the Baikalsky Reserve has been actively studied since the Reserve was established, but only recently has it become possible to create a database containing exact geographic localities. Furthermore, both current species distributions and full check-list of the flora of the Baikalsky Reserve may require further verification.
The dataset aims at biodiversity monitoring and inventory in the framework of scientific research in the Baikalsky Reserve. This dataset does not cover a full list of vascular plants of the Baikalsky Reserve. It contains the data collected only by the author during her own field research. All the herbarium vouchers preserved at the Moscow University Herbarium (MW) have been made available online via GBIF (Seregin 2021). All findings of the taxa reported by the author for the first time for the Baikalsky Reserve and its buffer zone are documented with herbarium vouchers. This herbarium collection contains both common and rare species from the territory ( Fig. 1).
At present, the dataset contains 875 taxa at species and infraspecific levels. This is approximately 280 species less than in our preliminary unpublished check-list of the Baikalsky Reserve's flora which includes all records from all the published sources. Revisiting the herbarium collections in Irkutsk, Ulan-Ude and Tomsk revealed that ca. 150 species out of these 280 have never been documented by herbarium vouchers and their publications cannot be confirmed. All the herbarium specimens from our territory kept at the Novosibirsk Herbarium were mentioned in the check-list of the flora of Baikal's shores (Popov and Busik 1966), lacking the aforementioned 150 species, as well. Therefore, published reports without herbarium vouchers should be interpreted with caution. To date, only some records were rejected after our re-examination of herbarium specimens when original identifications were erroneous; for example, Achnatherum splendens, Carex selengensis, Hypericum ascyron etc. were re-identified and those species were excluded (Gamova et al. 2019) from our preliminary check-list. The presence of other species mentioned in earlier publications, but not confirmed by herbarium specimens, will be further verified via fieldwork.
As the majority of herbarium specimens collected by other researchers and not included in this dataset date back to the middle of the 20 century, they lack the geographic coordinates and the textual description of the locality does not allow georeferencing with the precision of 1-2 km. Sometimes, the description is even more vague and the uncertainty reaches 5-10 km. Approximately 30 species, recently recorded by other researchers and confirmed by herbarium specimens with geographic coordinates and, therefore, suitable for this type of dataset, were not included. Thus, the dataset with the original data collected by the author contains the majority of vascular plant species authentically known from Baikalsky Reserve and its buffer zone.
At the moment, a new check-list of the vascular plant flora of the Baikalsky Reserve, based on modern data and herbarium specimens, is being compiled. The data from the other herbaria will be further included into the updated check-list and georeferenced with the maximum available precision.

Sampling methods
Study extent: The Baikalsky Reserve with its buffer zone is situated mostly in the mountains. The lowest point of this territory is situated on the Baikal shore (457 m a.s.l.) and the highest point is Mt. Sokhor (2,316.7 m a.s.l.) in the middle part of the Baikalsky Reserve. The Temnik River forms the southern border of the Baikalsky Reserve (1,100-830 m a.s.l. from west to east). Altogether the territory of the Baikalsky Reserve and its buffer zone covers ca. 2,000 km (167,871 ha and 34,788 ha, respectively).
The Khamar-Daban Range is one of the mountain chains framing Lake Baikal in its rift zone; its origin dates back to the Baikal Orogeny (650-550 million years). Despite the ancient age, alpine landforms are widespread here due to mountain glaciation. The territory of the Baikalsky Reserve belongs to the area with local distribution of permafrost; some permafrost spots are located in the highlands and on the southern side (Gerasimov 1965).
The climate of the northern side of the Khamar-Daban Range in its central part is relatively mild for southern Siberia. The mean annual temperatures vary from -0.3°C at Tankhoy meteostation (460 m a.s.l.) to -3.4°C at the Khamar-Daban meteostation (1,420 m a.s.l.). The mean July temperatures are +14.7°C and +12.7°C; the mean January temperatures are -17°C and -17.9°C, correspondingly. The mean annual amount of precipitation is 900-1,450 mm. Winter snow cover reaches at least 90-100 cm with an average depth of 150 cm and the maximum depth of 190-200 cm (Ladeishchikov et al. 1977). Both the annual amount of precipitation and the winter snow cover in the central part of the northern side of the Khamar-Daban Range are the maximal in the Baikal Region. The climate of the southern side is drier (400-600 mm annual precipitation) and more continental. The mean annual temperature here is about -5°C; the mean July temperature is +12°C and the mean January temperature is -22°C. The average duration of the vegetation period varies from 120-150 days on the Baikal shore to 100 days on the main watershed of the Khamar-Daban Range (Kartushin 1969).
According to "Zones and altitudinal zonality types of vegetation of Russia and adjacent territories", the study area within the central part of the Khamar-Daban Range belongs to the Khamar-Daban variant (Abies sibirica and Pinus sibirica forests, Pinus pumila elfin woods) of Tuva-Southern Transbaical group (nival-goltsy-tundra-taiga) of the Boreal (Taiga) type of altitudinal zonality (Ogureeva et al. 1999). The territory of the Baikalsky Reserve includes all the diversity of local altitudinal zonality (Epova 1957, Epova 1961, Tjulina 1976 The flora of the Khamar-Daban Range belongs to the Altay-Sayan Province of the Circumboreal Region of the Boreal (Holarctic) floristic kingdom, following Takhtajan (1986). The flora of the Baikalsky Reserve and its buffer zone by its origin consists of two main parts: native species and alien ones. Although the alien section of the flora reaches ca. 120-130 species (12% of total flora), it is concentrated in the narrow belt (0.5-4 km) of the buffer zone adjacent to the northern border of the Baikalsky Reserve near the Baikal shore. Several settlements (the major one is Tankhoy, a village with ca. 950 inhabitants, where the headquarters of the Baikalsky Reserve are situated), roads (highway Irkutsk -Ulan-Ude and the Trans-Siberian Railway) and communications (power transmission line) are situated also in the northern part of the buffer zone near Baikal. The western, southern and eastern parts of the buffer zone of the Baikalsky Reserve are situated in the mountains and are not anthropogenically disturbed. According to the "Atlas of Russia's intact forest landscapes" (Aksenov et al. 2003), the core zone of the Baikalsky Reserve is formally classified as intact. The world map of intact forest landscapes (Potapov et al. 2021) indicating forest losses in 2000-2013, 2013-2016 and 2016-2020, shows that no significant changes in the forest cover occurred in the recent years. Therefore, alien species are not widespread here. Only less than 10 taxa of alien species (Chaenorhinum minus, Conyza canadensis, Epilobium adenocaulon, E. pseudorubescens, Impatiens glandulifera, Puccinellia hauptiana, Senecio viscosus, S. vulgaris) are relatively common (or have become common in recent years) in the buffer zone of Baikalsky Reserve, while the majority of them have rare or single occurrences ). The flora of the Baikalsky Reserve includes several endemic or sub-endemic species. One of the most famous endemic species is Swertia baicalensis (Gentianaceae). It is known only from the western and central parts of the Khamar-Daban Range and the Baikalsky Reserve protects the main part of its distribution area. One of the new taxa -Eranthis tanhoensis (Ranunculaceae) -was described in 2020 (Erst et al. 2020). This species was named after Tankhoy Village. It is also an endemic of southern Baikal Region (Fig. 2).
Sampling description: All the data were obtained during fieldwork in summer seasons 2009-2021 (except 2020 due to the COVID-related lockdown), mostly between 10 June and 20-25 August, in some years also including the beginning of September. This time interval covers the major part of the vegetation development in this region. Ephemerous plant species are absent from the Baikalsky Reserve and ephemeroid plants begin to flower in May and continue in June. All of them remain noticeable until mid-July or August; thus, this group of species is adequately represented in the dataset. In general, the field works were conducted during 2-2.5 months per year, except 2011 when field data were collected only for three weeks.
The dataset contains information from different sources: 1.
Relevés made in various altitude belts and plant communities. The locations for the relevés were chosen carefully within the contours of homogeneous plant communities. The area of the relevés was 400 m for forest communities and 100 m for herbaceous ones. If the area of the plant community was less than those mentioned above, the community was described within its natural limits. The original data also contain additional information on the projective cover of species etc., but only the species list was included in the dataset.

2.
Plants collected as herbarium specimens. In all the cases, when species identification in the field was impossible and/or new taxa for the Baikalsky Reserve were recorded, specimens were preserved.

3.
Field notes about plant occurrences. Additional localities for particular species, mostly rare and endangered ones, or remarkable localities for common species (for example, single trees above the timber line etc.).
The research was conducted systematically, the field routes being planned to access the maximal coverage of different parts of the Baikalsky Reserve and its buffer zone. The major part of the Baikalsky Reserve's territory is located in the mountains. The only highway (Irkutsk -Ulan-Ude) is situated north of Baikalsky Reserve. As the rest of the territory is inaccessible for motor transport, it was explored mostly on foot; pack horses were also used on the lower part of the southern side and half of the length of the Temnik River is accessible via airboat. Within the borders of the Baikalsky Reserve, four mountain passes (1,400-2,220 m a.s.l.) across the Khamar-Daban Range are predominantly used. The majority of paths follow the river valleys. To evenly study the territory, the routes were planned along the paths and radially around field camp sites. The total length of field routes comprised ca. 320 km in 2021; in the other years, it varied from 180 km to 420 km.
All the data reflect the spontaneous distribution of plants, both native and alien species. Cultivated plants from Tankhoy Village and other minor populated places situated in the buffer zone of the Baikalsky Reserve are not included into the dataset. To reveal the local vascular plant diversity to its full extent, the occurences, identified to the genus level, were also included into the dataset (i.e. 1432 occurrences or 3.65% of the dataset, for 53 genera). Alchemilla, Euphorbia, Hedysarum, Lepidium, Sinapis, Sparganium and Valeriana were identified to the genus level only. Other 46 genera have occurrences both at species and genus levels. These are mostly Allium, Betula, Calamagrostis, Carex, Salix and some others. In most cases, though, the choice for unidentified species could be considerably narrowed to a certain selection according to the check-lists of the flora of the Republic of Buryatia and Irkutsk Region (Anenkhonov et al. 2001, Chepinoga et al. 2008; such variants are mentioned below in alphabetical order of genera. Cases, where too many options are possible due to the species richness within the genus (as in genera Carex and Salix) or where new alien species can be found (Alchemilla ) or for some other reasons, are noted as "unknown".

Geographic coverage
Description: In general, all the territory of the Baikalsky Reserve and its buffer zone is covered by our field routes. The records are concentrated mainly along the paths and river valleys or some localities of particular botanical interest (Fig. 3).
The taxa included into the dataset belong to 410 genera of 89 plant families. Top-10 families with the largest numbers of taxa at the species or infraspecific level and the largest number of occurrences are mentioned in Tables 1, 2. The taxa from the top-10 plant families shown in Table 1 include 502 taxa (57.37% of the taxonomic diversity included into the dataset). The occurrences of plants from the top-10 plant families shown in Table 2 include 23,272 occurrences (59.31% of the dataset).   Although Pinaceae does not belong to the top-10 plant families with the largest number of taxa, it has the largest number of occurrences (3,534) in the dataset.

Taxa included:
Rank Scientific Name phylum Tracheophyta

Notes: Distribution of records by year is shown in
country The name of the country or major administrative unit in which the location occurs.
A constant ("Russian Federation"). countryCode The standard code for the country in which the location occurs. A constant ("RU"). stateProvince The name of the next smaller administrative region than country (state, province, canton, department, region etc.) in which the location occurs. A constant ("Republic of Buryatia").

minimumElevationInMetres
The lower limit of the range of elevation (altitude, above sea level), in m a.s.l. A variable. For example, "648". decimalLatitude The geographic latitude (in decimal degrees, using the spatial reference system given in geodeticDatum) of the geographic centre of a Location. A variable. For example, "51.5670". decimalLongitude The geographic longitude (in decimal degrees, using the spatial reference system given in geodeticDatum) of the geographic centre of a Location. A variable. For example, "105.3956".
geodeticDatum The ellipsoid, geodetic datum or spatial reference system (SRS) upon which the geographic coordinates given in decimalLatitude and decimalLongitude are based.
coordinateUncertaintyInMetres The horizontal distance (in metres) from the given decimalLatitude and decimalLongitude describing the smallest circle containing the whole of the location. A constant ("10"). georeferenceSources A list (concatenated and separated) of maps, gazetteers or other resources used to georeference the Location, described specifically enough to allow anyone in the future to use the same resources. A constant ("field GPS data").
identifiedBy A list (concatenated and separated) of names of people, groups or organisations who assigned the Taxon to the subject. A constant ("Natalia S. Gamova"). scientificName The full scientific name, with authorship and date information, if known. A variable.
For example, "Abies sibirica Ledeb.". kingdom The full scientific name of the kingdom in which the taxon is classified. A constant ("Plantae"). phylum The full scientific name of the phylum or division in which the taxon is classified. A constant ("Tracheophyta"). taxonRank The taxonomic rank of the most specific name in the scientificName. A variable (five options: "species", "subspecies", "genus", "variety", "species aggregate").
nomenclaturalCode The nomenclatural code (or codes in the case of an ambiregnal name) under which the scientificName is constructed. A constant ("International Code of Nomenclature for algae, fungi and plants"). taxonomicStatus The status of the use of the scientificName as a label for a taxon. A constant ("accepted"). Gamova N S (2021). Baikalsky State Nature Biosphere Reserve and its buffer zone: floristic data. Version 1.6. Lomonosov Moscow State University. Occurrence dataset https://doi.org/10.15468/g4sdvs accessed via GBIF.org on 2021-11-25.