Aims: Understanding fine‐grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine‐grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups).Location: Palaearctic biogeographic realm.Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m² and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class.Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi‐natural) grasslands and natural grasslands are the richest vegetation type. The open‐access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats.Conclusions: The GrassPlot Diversity Benchmarks provide high‐quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation‐plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology.

Central Pamir-Alai, which is located almost entirely within the area of Tajikistan, is one of the world hotspots of biodiversity, harbouring ca. 4,300 species and 1,400 endemic plants. The first application of the IUCN Red List criteria reveals that among all native species occurring in Tajikistan 1,627 taxa (38.11%) are threatened, including 23 extinct (0.54%), 271 (6.34%) critically endangered (CR), 717 (16.79%) endangered (EN) and 639 (14.96%) vulnerable (VU). Globally, 20 taxa are extinct, 711 (16.65%) threatened, including 144 (3.37%) critically endangered, 322 (7.54%) endangered and 245 (5.73%) vulnerable. As we found positive correlation between human density and the number of threatened species, we suspect this indirect factor responsible for the species diversity decline. Extinct or threatened taxa have short blooming periods in spring or early summer, have limited geographical range and inhabit mainly valley bottoms at lower altitudes. Threatened taxa occupy extremely dry or wet habitats, such as deserts, semi-deserts, water reservoirs and fens. The group of threatened plants consists mostly of Central Asian, Indo-Indochinese and Arctic species. Ornamental plants have a higher extinction risk than other plants, but species collected for medicinal reasons and used for forage or food reveal lower retreatment rate. Our assessment fills a gap for important plant area and provides the data for raising the effectiveness of plant diversity conservation.

Aims: We introduce ReSurveyEurope — a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.Results: ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover–abundance classes such as variants of the Braun‐Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.Conclusions: ReSurveyEurope is a new resource to address a wide range of research questions on fine‐scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well‐established European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.

Aims: To complete the syntaxonomic scheme for tall-forb vegetation of the montane and alpine belts in the Pamir-Alai and western Tian Shan Mountains in Tajikistan and Kyrgyzstan with some remarks on its environmental predictors. Study area: Middle Asia: Tajikistan and Kyrgyzstan. Methods: A total of 244 relevés were sampled in 2013–2019 using the seven-degree cover-abundance scale of the Braun-Blanquet approach. These were classified with a modified TWINSPAN algorithm with pseudospecies cut-levels 0%, 5% and 25%, and total inertia as a measure of cluster heterogeneity. Diagnostic species were identified using the phi coefficient as a fidelity measure. NMDS was used to explore the relationships between the distinguished groups. Results: Our classification revealed 19 clusters of tall-forb vegetation in Middle Asia. Among others we found forb communities typical for Tian Shan, western Pamir-Alai, forb-scree vegetation of Pamir-Alai, dry tall-forbs and typical forbs of the alpine belt. A total of eight new tall-forb associations and five communities were distinguished. The forb vegetation of Middle Asia has been assigned to the class Prangetea ulopterae Klein. The main factors differentiating the species composition of the researched vegetation are elevation, mean annual temperature, sum of annual precipitation and inclination of the slope. Conclusions: The paper presents the first insight into the comprehensive classification of the alpine forb vegetation in Middle Asia and fosters progress in explaining the relationship of boreo-temperate and Mediterranean-like (Irano-Turanian) vegetation in western Asian and central Asian subregions of the Irano-Turanian phytogeographical region. Taxonomic references: The nomenclature of the vascular plants follows generally Cherepanov (1995) and for Bromus spp. The Plant List (2020) Version 1.1. http://www.theplantlist.org/. Syntaxonomic references: The names of syntaxa are used in accordance with Ermakov (2012), Gadghiev et al. (2002) and Nowak et al. (2018). Abbreviation: NMDS = Non-metric Multidimensional Scaling.

This paper presents new data on the occurrence of 16 vascular plant species from five Eurasian countries obtained during field explorations, as well as during taxonomic revisions of herbarium materials. Five taxa (Draba fladnizensis, Gentiana orbicularis, Helianthus giganteus, Symphyotrichum cordifolium, Thalictrum alpinum) are recorded for the first time from Poland, five (Achnatherum jacquemontii, Arrhenatherum elatius, Dittrichia graveolens, Geranium pyrenaicum, Stipa × balkanabatica) from Tajikistan, three (Achnatherum sibiricum, Asyneuma thomsonii, Stipa × balkanabatica) from Kyrgyzstan, one (Orobanche bartlingii) from Turkey, one (Calamagrostis obtusata) from China and one (Calamagrostis emodensis) from the Gansu Province in China. In addition, Hieracium piliferum, considered extinct in Poland, was rediscovered. For each species, synonyms, taxonomy with remarks on recognition and differentiation of the species from the most similar taxa occurring in a given area, general distribution, habitat preferences, as well as a list of recorded localities (often far from the previously known areas) are presented. As a result of the morphological comparison of specimens representing Stipa × balkanabatica collected in Tajikistan and Kyrgyzstan with the type specimen collected from Turkmenistan, we decided to describe a new variety named S. × balkanabatica var. alaiensis M. Nobis & Klichowska, var. nov. Additionally, based on the analysis of phytosociological relevés prepared during field studies in the western Pamir Alai Mts (in Kyrgyzstan and Tajikistan), a new association of chasmophytic plants named Asperulo oppositifoliae–Achnatheretum jacquemontii M. Nobis, Klichowska & A. Nowak, is also described.

Anthropogenic biodiversity decline threatens the functioning of ecosystems and the many benefits they provide to humanity¹. As well as causing species losses in directly affected locations, human influence might also reduce biodiversity in relatively unmodified vegetation if far-reaching anthropogenic effects trigger local extinctions and hinder recolonization. Here we show that local plant diversity is globally negatively related to the level of anthropogenic activity in the surrounding region. Impoverishment of natural vegetation was evident only when we considered community completeness: the proportion of all suitable species in the region that are present at a site. To estimate community completeness, we compared the number of recorded species with the dark diversity-ecologically suitable species that are absent from a site but present in the surrounding region². In the sampled regions with a minimal human footprint index, an average of 35% of suitable plant species were present locally, compared with less than 20% in highly affected regions. Besides having the potential to uncover overlooked threats to biodiversity, dark diversity also provides guidance for nature conservation. Species in the dark diversity remain regionally present, and their local populations might be restored through measures that improve connectivity between natural vegetation fragments and reduce threats to population persistence.