The Rybachy and the Sredny Peninsulas are situated at the 69^th latitude and washed by the Barents Sea (Fig. 1). The study area is within the zone of Subarctic Tundra (Aleksandrova 1977).

Geological structure. The Peninsulas' bedrocks consist of upper Proterozoic solid rocks, such as sandstones, shales and conglomerates. It makes them different from the mainland coast of Murmansk Region, which generally consists of granites and granitoids. Pre-Quaternary deposits form the most part of Rybachy Peninsula's coast. The Peninsulas' inland is built up with glacial deposits of the Last Glacial Period, which are mainly sandy loam and loamy with rubble or boulders with lenses and interlayers of sand and clay. The Rybachy and the Sredny Peninsulas are mostly similar to the Varanger Peninsula (Finnmark, Norway) due to the geological structure of the bedrocks (Siedlecka and Siedlecki 1967).

Landscape. The inland high plains rise up to 200-300 m. The coast is abrasional and has the pediment plain up to 50 m in altitude (Miloserdov 1971) with a series of accumulative marine terraces well developed in bays.

Climate. The climate is oceanic, influenced by the southern extension of the Nord Cape stream making it milder than the climate of the Kola Peninsula. According to the data received from the Vaida-Guba (Fig. 1) weather station for the last 10 years, the mean annual temperature is +2.4°С (calculated on the data from www.rp5.ru). During the last 100 years, the mean annual temperature has increased by 1.2°C (Kapfer and Popova 2020). The annual precipitation is about 700 mm and has changed twice for the last ca. 100 years. The vegetation period (the time when the daily mean temperature is more than +5°С) lasts for more than 100 days (Miloserdov 1971). The depth of the snow cover does not exceed 40 cm. During the last 10 years, it was up to 18 cm (calculated on the data from www.rp5.ru).

Soil cover. The Peninsulas are mainly covered by podzols rich in aluminium (Al) and iron (Fe). The layers cannot be well-defined due to the bedrock structure. Permafrost is not spread in the area, but it can be found in some spots (Koroleva and Pereversev 2007).

Vegetation. The Peninsulas are mostly covered by dwarf shrub tundra with the dominance of Empetrum nigrum ssp. hermaphroditum, Vaccinium vitis-idaea, Vaccinium uliginosum and Vaccinium myrtillus. The heterogeneity of the terrain and the abundance of small rivers and lakes create a lot of microsites for different types of vegetation. The most common plant communities are dwarf shrub tundra, birch krummholz, willow-shrub communities, bogs, fens, meadows, grasslands on sand dunes, salt-marshes, chasmophytic vegetation of rocks, vegetation of scree habitats and ruderal communities of trampled habitats.

The Peninsulas are not the only location covered by tundra communities in Murmansk Region, but they differ from other parts of the Region in some features of geological structure, climate and land use. Most of all, this territory can be regarded as a model of the vegetation modification in the Arctic following the climate change.

The protected area "The Rybachy and the Sredny Peninsulas" was created on the largest part of the Peninsulas in 2014. This area has a status of regional Natural Park. Our vegetation and flora studies started as part of a nature conservation project and then continued to adjust the protection regime, to catalogue the vegetation cover and to identify the vegetation development patterns.

The data were collected using the vegetation plot method as described below; the observations are located irregularly reflecting the habitat distribution. In the summers of 2008, 2009, 2011, 2014 and 2015, the authors of this paper sampled 991 vegetation plots (relevés). For each relevé, we recorded the cover of the layers and the cover of each species, the relevé area size, slope aspect and slope ratio and height of each vegetation layer. The plot sizes varied due to the size of the plant communities. For tundra and bog communities, the size of the plots was 400 m² (20 × 20 m). The other communities were often less than 400 m² in area; thus, the relevés were made within the boundaries of the plant community. In this case, the plot size varied from 1 m² to 400 m². In the current dataset, we do not present this information. We also recorded the location of the plots (geographical coordinates in WGS84). The sampling process was conducted with direct observations and active search for plant species, i.e. vascular plants, mosses, liverworts and lichens.

The vegetation database was created using the Turboveg software (Hennekens and Schaminée 2001). The database was converted into the Darwin Core format (Wieczorek et al. 2012) for integration with GBIF. All supporting information (i.e. ecological information and covers) was deleted. The duplicates (the same species with the same coordinates) were detected and also deleted. The dataset was hosted by the Moscow State University.

All the taxa in the dataset have the rank "species". We did not include the specimens, which were not identified at the species rank. The plant names are provided according to Cherepanov (1995) (vascular plants), Ignatov et al. (2006)(mosses), Urbanavichus (2010) (lichens) and Potemkin and Kotkova (2019) (liverworts).

Species difficult for field identification were collected for further work and the specimens were identified by the authors. The moss herbarium specimens, collected in 2008, 2009 and 2011, were included in the dataset. Identifications of mosses were made and/or confirmed by E. A. Ignatova and V. E. Fedosov (Lomonosov Moscow State University). Herbarium specimens of problematic vascular plant taxa were checked by experts from several institutions: Komarov Botanical Institute - N. N. Tzvelev (Poaceae, Sparganium, Potomogeton), V. I. Dorofeev (Brassicaceae), V. V. Petrovskyi (Draba), T. V. Egorova (Carex), A. E. Grabovskaya-Borodina (Rumex), G. Yu. Konechnaya (various taxa), I.B. Kucherov (Alchemilla); Lomonosov Moscow State University - M.N. Kozhin (Betula, Atriplex); Polar-Alpine Botanical Garden-Institute - V. A. Kostina (specimens collected in 2008). The specimens after identification and revision were deposited to the Herbaria of the Moscow State University (MW), Institute of North Industrial Ecology Problems (INEP), Karelian Research Centre (PTZ) and Komarov Botanical Institute (LE).

This dataset cannot be used as a vegetation database or a floristic checklist. We did not provide the information about species coverage and height and ecological conditions (terrain and soils).

The study area is located in the northern part of Pechengsky District of Murmansk Region, representing the northernmost part of continental European Russia (69°33′–69°56′ N, 31°44′–32°07′ E; Fig. 1). The study site is divided into two parts: the smaller southern part, the Sredny Peninsula and the larger northern part, the Rybachy Peninsula. The Sredny Peninsula is connected with the Rybachy by a 2-km-long isthmus in the north and separated from the mainland by a 4-km-wide fell – Mustatunturi Mountain.

The majority of occurrences are located in the Rybachy Peninsula (11,346, 70%). The Sredny Peninsula is covered by 4,536 occurrences (28%). The isthmus between the Peninsulas is represented by 133 occurrences (less than 1%). We also included several observations (274, 1%), located at the Mustatunturi Mt. nearby the Sredny Peninsula.

The locations of the occurrences are not regularly situated. By choosing the location of a vegetation plot, we tried to reveal the alpha, beta and gamma diversity to the fullest extent possible. Thus, the inland part of the Rybachy Peninsula, which is homogeneous in vegetation and not rich in species diversity, is covered by a fewer number of observations than the river valleys and the sea coasts.

The southeast part of the Rybachy Peninsula remains less studied than the rest of the territory, because it is hard to reach from both the land (due to the absence of roads) and the sea (due to the cliffs).

E31,8758° and E31,9367° Latitude; N69,7244° and N69,7182° Longitude.

Our dataset includes 16,289 records of georeferenced plant occurrences that belong to 568 species. There are 23 species of lichens (Ascomycota), 142 species of mosses (Bryophyta), three species of liverworts (Marchantiophyta) and 400 species of vascular plants (Tracheophyta) in the presented dataset.

Since our data (Popova and Razumovskaya 2021) are based on vegetation plots, they contain vascular plants, mosses, liverworts and lichens. The data on lichens, mosses and liverworts were included in the dataset because these groups are represented by few occurrences in GBIF. For example, the CRIS dataset (Cris and Melechin 2019) contains only 357 occurrences for the Peninsulas' territory, amongst them 339 occurrences of fungi (including lichens), 13 for liverworts and only one for mosses. We do not provide a complete list of mosses, liverworts and lichens. Our data include only the most frequent species. The lichens and liverworts species in our dataset represent about 2% and 1.5% of the total diversity in the Region, respectively (Melechin 2009, Konstantinova et al. 2009). Our data cover only about 30% of the total diversity of mosses or vascular plants in Murmansk Region (Belkina et al. 2009, Kostina and Fillimonova 2009).

Based on our estimates of the diversity of mosses and vascular plants on the Peninsulas (yet unpublished), the dataset covers approximately 80% of vascular plant species and about 50% of moss species on the Rybachy and the Sredny Peninsulas.

The majority of occurrences belong to vascular plants (Table 1). The most frequent species (with more than 300 observations) are Empetrum nigrum subsp. hermaphroditum, Betula nana, Solidago virgaurea and Avenella flexuosa. The most species-rich families are Poaceae (54), Cyperaceae (36), Caryophyllaceae (28), Rosaceae (24) and Asteraceae (22).

Although the data on vascular plants are relatively complete, they do not include several most difficult taxa. The majority of Alchemilla species still remain unidentified; the dataset includes only determined species of this genus. In apomictic genera (Taraxacum, Hieracium), we included only the species easy to identify: Taraxacum officinale (s.l.) and Hieracium umbellatum. Moreover, the dataset does not include the occurrences for several Ranunculus, Betula, Salix and Euphrasia species, which were observed at the plots, but remain unidentified.

The dataset includes the occurrences of legally protected species (Table 2). Some of them are really rare in Murmansk Region and known only by few (or even one) localities. These are Eritrichium villosum (1 locality in the Region: Kozhin et al. 2020b, Borovichev et al. 2019), Gastrolychnis apetala (2 localities in the Region), Gentianopsis detonsa (4 localities in the Region, Fig. 2), Lomatogonium rotatum (2 localities in the Region, Fig. 3) and Draba fladnizensis (3 localities in the Region). The number of localities is provided according to the Red Data Book of Murmansk Region (Konstantinova et al. 2014). Not least important are the occurences of the species, which are rare in Murmansk Region and in Russia, but are common in the Rybachy Peninsula or the Sredny Peninsula. One of such species is Alchemilla alpina (Fig. 4). It is a typical and usually dominant species of screes, roadsides, snowbeds and meadows on the Rybachy Peninsula. The second species is Cryptogramma crispa (Fig. 5), which has a large population on rocks in the Sredny Peninsula.

Figure 2.  

The rare species Gentianopsis detonsa (Rybachy Peninsula, photo by K. Popova, July 2011).

Figure 3.  

The rare species Lomatogonium rotatum (Rybachy Peninsula, photo by K. Popova, July 2011).

Figure 4.  

Plant community dominated by two Red List species, Alchemilla alpina and Polystichum lonchitis (Rybachy Peninsula, photo by K. Popova, August 2014).

Figure 5.  

The rare species Cryptogramma crispa (Sredny Peninsula, photo by K. Popova, August 2015).

The dataset contains the up-to-date information about the distribution of some rare species, which were observed in Murmansk Region only a few times and more than 50 years ago, for example, Gastrolychnis apetala, Eritrichium villosum, Gentianopsis detonsa (Fig. 2) and Lomatogonium rotatum (Fig. 3).