Grasslands (meadows, pastures and ruderal communities) in CFR exist under the protection regime in the Reserve’s core area (Fig. 1) and under agricultural use in adjacent territories. The grasslands of the core area have not been used due to the protection regime since the early 1960s and several sites since the 1980s; thus, most of the grasslands were abandoned 30–60 years ago. In the core area of CFR, there are only small patches of grasslands in the places of former settlements (villages, farmsteads, forest huts). Having been abandoned for a long time, some communities still resemble grass-forb grasslands, while others have completely changed and turned into shrub or forest vegetation. Large areas are covered with subruderal tall-herb stands dominated by forbs (Anthriscus sylvestris (L.) Hoffm., Chamaenerion angustifolium (L.) Scop., Urtica dioica L. etc.). These communities can be found in the places of abandoned housing in former villages, as well as at the sites of wild boar digging (Cherednichenko and Borodulina 2018).

The grasslands in the core area of the Reserve are not managed anymore and, therefore, are being overgrown with forest. To date, the area of grasslands has significantly decreased: in 2017, the area of the grasslands per se was estimated as 0.02% of the total Reserve area, while forest glades and wastelands covered with herbaceous vegetation occupied 0.5% of the total Reserve area (Cadastral information on the Central Forest Reserve). For example, the area of the Krasnoe site covered with grassland vegetation has decreased almost 5 times over the past 35 years (from 26.6 ha to 5.54 ha) (Cherednichenko et al. 2021).

Grasslands occupy large areas around villages in the transition area and in the one kilometre buffer zone. At present, the vast majority of these grasslands are abandoned, while only limited areas of meadows and pastures are managed (irregular mowing and low intensity grazing). The managed grasslands were studied in the vicinity of the CFR headquarters and around inhabited villages, situated in both the buffer zone and the transition area of the Reserve (Cherednichenko and Borodulina 2018).

This dataset includes 209 sample plots of continental grasslands made in 2013 and 2014. In 2013, we sampled 88 plots at six sites in the south of the Reserve (Bol'shoe Fyodorovskoe, Mezha, Krasnoye, Ovsyaniki, Starosel’e, Zapovedniy). In 2014, we sampled 121 plots: 111 ones at nine sites in the north (Bol’shoe Makarovo, Gorbunovka, Gusevka, Kruglaya Luka, Moshary, Osinovka, Pogorelka, Shlyuz, Trozhkov Lug) and 10 sites in the south of the Reserve (Zapovedniy) (Fig. 1). The position of the centre of each vegetation plot was georeferenced using a Garmin GPS navigator in WGS84 datum. The dataset comprises most of the continental grasslands in the core area of CFR. However, we studied only a limited number of grassland sites in the transition zone of the Reserve due to its large area.

The size of each sample plot was 100 m², which is considered appropriate for grassland vegetation (Mirkin and Naumova 2012). Plots of this size were used to sample grassland vegetation in a number of works (Chytrý and Otýpková 2003). According to Chytrý and Otýpková (2003), 16 m² plots should be used as standard to sample most types of herbaceous vegetation. As we used larger sample plots (100 m²), we consider our vegetation samples for each plot complete in terms of their species composition. Within the sample plots, we collected the data on species composition.

Our data represent almost all grassland types in the Reserve (Table 1) according to their physiognomy and land use type. The sample plots were compiled in visually homogenous areas of vegetation along the visible gradients of the relief, as a rule from the edge to the centre of the grassland to cover the entire diversity of plant communities of each site.

We would like to highlight that the presence of two particular groups of species, namely the Red-listed species and the alien (including invasive) ones, in the dataset is closely connected with the type of the studied grasslands and their management. The alien and invasive species are provided according to Vinogradova et al. (2011), the Red-listed species follow the Red Data book of the Russian Federation (plants and fungi) (Bardunov and Novikov 2008) and the Red Data Book of Tver Oblast (Orlov and Sokolov 2016).

The plant species were predominantly identified in the field; when it was not possible to unambiguously identify the specimen, it was herborised for further identification at the laboratory. Most of the species were identified using the keys (Tsvelev 2000, Maevsky 2014) by Oxana Cherednichenko. In difficult cases of species, the identification was confirmed by Alexey Seregin, sedges were confirmed or identified by Yuriy Alekseev and Mikhail Kozhin and specimens of the genus Pilosella were identified by Alexander Sennikov. The collected specimens are deposited at Moscow University Herbarium (MW) and are publicly available in Moscow Digital Herbarium. In 2013, 33 herbarium specimens were collected, in 2014 - 230 herbarium specimens.

The plant scientific names in the dataset were checked against the database of TROPICOS using the iPlant Taxonomic Name Resolution Service (TNRS).

As a habitat characteristic, we used the classification of grassland types described in Cherednichenko and Borodulina (2018). The grassland types were determined using cluster analysis, indicator species analysis and phytoindication assessment. Thus, we distinguish four types of grasslands: managed mesic (Fig. 2), abandoned mesic (Fig. 3), wet (Fig. 4) and subruderal mesic grasslands (Fig. 5), that are presented in Table 1; they are also available in the GBIF dataset (Cherednichenko 2021).

Figure 2.  

Managed mesic grassland, Bol’shoe Fyodorovskoe site, plot MW-C054 (Latitude 56.45102964 Longitude 32.97338868). Dominant species: Carex leporina L. and Festuca pratensis Huds.

Figure 3.  

Abandoned mesic grassland, Starosel’e site, plot MW-C05 (Latitude 56.47998819 Longitude 33.02556393). Dominant species: Angelica sylvestris L., Centaurea phrygia L., Festuca pratensis Huds., Leucanthemum vulgare Lam. and Pimpinella saxifraga L.

Figure 4.  

Wet grassland, site: Bol’shoe Fyodorovskoe, plot MW-C042 (Latitude 56.45129258 Longitude 32.97338742). Dominant species: Filipendula ulmaria (L.) Maxim. and Lysimachia vulgaris L.

Figure 5.  

Subruderal mesic grassland, Krasnoe site, plot MW-C015 (Latitude 56.48472472 Longitude 32.98469234). Dominant species: Anthriscus sylvestris (L.) Hoffm., Chamaenerion angustifolium (L.) Scop., Dactylis glomerata L. and Heracleum sibiricum L.

Although the community is dominated by Chamaenerion angustifolium (L.) Scop., this is not a clearing, this grassland had formerly been mown and was abandoned 30 years ago. The dominance of Chamaenerion angustifolium (L.) Scop. may be connected with wild boar digging, as wild boars completely destroy the vegetation cover of this site once in a few years. This is a typical appearance of abandoned vegetation in the Reserve, not only at Krasnoe site, but also at a number of other sites.

These four grassland types differ in management, floristic composition and ecological conditions, as well as in the proportion of coenotic and functional groups (including forbs, graminoids and woody species). Managed mesic grasslands (Fig. 2) are communities with the dominance of grasses and forbs under moderate grazing and irregular mowing. Their indicator species are Cynosurus cristatus L., Leontodon autumnalis L., Plantago major L., Potentilla anserina L. and Taraxacum officinale Wigg. Abandoned mesic grasslands (Fig. 3) were mown or grazed in the past and they still resemble typical meadows with the dominance of forbs and grasses. Their indicator species are Hieracium umbellatum L., Potentilla erecta (L.) Raeusch., Rumex acetosa L., Trollius europaeus L. and Viola canina L. Wet grasslands are tall-herb meadowsweet communities (Fig. 4), forming in small relief depressions and along temporary streams, probably in the places of abandoned hayfields. Their indicator species are Cirsium palustre (L.) Scop., Crepis paludosa (L.) Moench, Filipendula ulmaria (L.) Maxim., Galium palustre L. and Viola palustris L. Subruderal mesic grasslands (Fig. 5) are not currently managed and are totally covered with ruderal and nitrophilous species. Their indicator and dominant species are Anthriscus sylvestris (L.) Hoffm., Chamaenerion angustifolium (L.) Scop., Cirsium arvense (L.) Scop., Dactylis glomerata L. and Urtica dioica L.

Table 1 shows that abandoned and subruderal mesic grasslands were the most widespread in the study area, while wet grasslands, associated with specific, more humid conditions, were less frequent. Managed mesic grasslands were less widespread, since there are few inhabited villages in the transition area of the Reserve.

Tver Oblast, Russia

56.44882 and 56.64804 Latitude; 32.83221 and 33.02906 Longitude.

The dataset includes 261 unique scientific names of vascular plants (260 taxa were identified to species ranks and one taxon to aggregate rank only – Alchemilla vulgaris agg.). General taxonomic coverage is one phylum, four classes, 48 families, 154 genera and 261 species of vascular plants.

Thus, the dataset comprises 44.1% of the whole Reserve's flora, which consists of 592 species (Konechnaya 2012). Furthermore, the flora of the studied grasslands makes up 16.5% of the Tver Oblast checklist (1579 species) (Notov 2005).

There are 190 species typical of the grasslands per se in the list compiled by Konechnaya (2012) (the total number of species in this list is 529), while our dataset contains 261 species. A total of 141 species were included both in the list provided by Konechnaya (2012) and in our dataset, the rest of the species from our dataset are listed in Konechnaya (2012) as characteristic of forests and forest edges, as well as of ruderal and wet habitats. Five species that we recorded, namely Hieracium scandinavicum Dahlst., Potentilla intermedia L., Swida alba (L.) Opiz, Triticum aestivum L. and Vicia villosa Roth, are absent in the list compiled by Konechnaya (2012), all these species having low occurrence in the transition zone of the Reserve.

Revealing the complete grassland flora of the Reserve was beyond the scope of our study. The dataset we published is based on sampling the vegetation of particular grassland sites in the Reserve. Therefore, we detected less species than had previously been recorded (Konechnaya 2012) for the grasslands of the Reserve. Nevertheless, we provide the geographical coordinates for all the grassland species that we observed.

During our grassland studies, we found one vascular plant species included in the Red Data Book of the Russian Federation (Bardunov and Novikov 2008): Dactylorhiza baltica (Klinge) Nevski and three Red-listed species from the Red Data Book of Tver Oblast (Orlov and Sokolov 2016): Coeloglossum viride (L.) С. Hartm., Gymnadenia conopsea (L.) R. Br. and Salix phylicifolia L.

Ten alien species were recorded in the dataset, including eight invasive plants: Conyza canadensis (L.) Cronq., Epilobium ciliatum Rafin., Festuca arundinacea Schreb., Juncus tenuis Willd., Lepidotheca suaveolens (Pursh) Nutt., Lolium perenne L., Malus domestica Borkh. and Petasites hybridus (L.) Gaertn., B. Mey. & Scherb. (according to the list of Vinogradova et al. (2011)); and two cultivated species: Swida alba (L.) Opiz and Triticum aestivum L.

Vinogradova et al. (2011) list 100 invasive species for Tver Oblast and 39 species for Nelidovsky District, amongst them, species with low activity prevail. In general, the activity of the invasive flora in Nelidovsky District is low (Vinogradova et al. 2011). Invasive species were seldom observed at the study sites, occurring mostly in managed mesic grasslands and were completely absent in wet ones (Cherednichenko and Borodulina 2018). Juncus tenuis Willd. (35%) was the most widespread in managed mesic grasslands and Malus domestica Borkh. (32%) in abandoned mesic grasslands. The list of Vinogradova et al. (2011) does not include two alien species cultivated in the transition area of the Reserve which were observed at the study sites (Triticum aestivum L. and Swida alba (L.) Opiz).