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.

The vertical distribution of planktonic animals, such as Daphnia, in overlapping gradients of food concentration and risk of visual predation should depend on Daphnia population density and should be the result of the group effect of optimizing decisions taken by each individual (juvenile or adult), trading-off a high growth rate to low mortality risk. We tested this hypothesis by comparing the theoretical distributions from simulations based on an experimentally parameterized, optimizing individual-based model (consistent with the assumptions of the concept of the interference ideal free distribution with costs) with distributions observed in laboratory experiments. The simulations were generated for two scenarios, where the shape of the functional response of fish is consistent with either type II or III. The results confirmed the hypothesis. The greatest similarity of the distributions obtained in the experiments and simulations was found for the simulations based on the scenario assuming the type III rather than type II for both age classes of Daphnia. This was consistent with the results of the experiments for the model parameterization, which revealed the type III functional response of fish. Therefore, the results suggest that aggregating may be maladaptive as an anti-vertebrate-predation defense in the case of zooplankton.

absTRacT. During the survey of Łempis Nature Reserve (Augustów Forest, NE Poland) 353 species of vascular plants were recorded, including 32 considered threatened with extinction in Poland (7 species from the Polish "red data book" and 32 species from the Polish "red list"). Among them there were 41 species protected under the Polish law, including 19 strictly protected species and four species listed in the Annex II of the EU Habitats Directive. Ten orchid species were recorded, including the most valuable plants of the nature reserve -Cypripedium calceolus, Hammarbya paludosa, Liparis loeselii and Listera cordata. Among 32 noted Cyperaceae species (including 26 members of the Carex genus), there was a number of threatened plants, e.g. Baeothryon alpinum, Carex chordorrhiza, C. loliacea and Eriophorum gracile. Other rare species included Agrimonia pilosa, Cladium mariscus, Laserpitium latifolium, Linnaea borealis, Potamogeton gramineus and Pulsatilla patens. The presence of anthropophytes was significant (4.5% of the flora), probably due to the past forest management practices as well as proximity of settlements. The extremely rich flora, along with pristine wetland ecosystems (mesotrophic lakes, various mire forests and fens), places the Łempis Nature Reserve among the most valuable nature reserves in Poland.key woRDs: red list species, neophytes, ancient forest species, wetland, Cyperaceae, Orchidaceae