GrassPlot marathon: the long way towards the first benchmarks of plant species richness of Palaearctic grasslands

The post provided by Idoia Biurrun, Iwona Dembicz, Jürgen Dengler and Remigiusz Pielech

Nested-plot sampling in an alpine grassland (Elyno-Seslerietea) in Grisons (Switzerland) (Photo credit: Jürgen Dengler)

This post refers to the article Benchmarking plant diversity of Palaearctic grasslands and other open habitats by Biurrun et al. published in the Journal of Vegetation Science (

In a few days, the great champion Eliud Kipchoge will run 42,195 m and try to win once again the Marathon at the Olympic Games in Tokyo, after his victory in Rio de Janeiro. Many people around the world wonder whether he will make it again and join Abebe Bikila and Waldemar Cierpinski in the Olympus of double Marathon winners. Kipchoge is the current world record holder, and he also delighted the world when, in 2019, he became the first human to run the Marathon in less than two hours.

We humans like to register and beat records. We have detailed records of the fastest men and women running and swimming along standard distances, but we also admire the fastest and strongest animals, as well as the biggest trees and the richest plant communities. Each athlete is specialized in running a distance, and the tough long-distance champions like Kipchoge cannot compete with the explosive sprinters able to run 100 m in less than 10 seconds. Similarly, in order to be able to establish which plant communities hold the highest plant richness, we need to measure this diversity on standard plot sizes. Although tropical forests hold the plant richness records in large plot sizes, it has already been demonstrated that grasslands are the richest communities at small plot sizes (< 100 m²) (Wilson et al. 2012; Chytrý et al. 2015). Likewise, it is to be expected that grain size will have an effect on the richness ranking of different types of grasslands and other open habitats.

Nested-plot sampling of a extremely rich meso-xeric grassland (Festuco-Brometea) in Armenia (Photo credit: Jürgen Dengler)

With this basic thought in mind, a group of enthusiastic researchers joined forces in 2016 to gather plant richness data from plots sampled in eight standard grain sizes: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1000 m2 (Dengler et al. 2016a). Special emphasis was put on the data quality, i.e., only precisely delimited plots were considered, which were sampled exhaustively, and priority was given to plots where not only vascular plants but also bryophytes and lichens were recorded (if present). In the centre of the efforts were nested-plot series, where the smaller plots are included in the larger plots, as in a matryoshka. All these ideas were formalized in a workshop at the University of Bayreuth in 2017, giving rise to the GrassPlot database (Dengler et al. 2018;, but also to the ambitious project aiming to provide richness benchmarks of Palaearctic grasslands and other open habitats.

Meso-xeric grassland in Navarre (Spain) with high-species richness at 0.1 m2: 34 vascular plants, 8 bryophytes (Photo credit: Jürgen Dengler).

Collecting and harmonizing the data was a slow task, but bit by bit GrassPlot grew. In the beginning, it gathered data from the EDGG Field Workshops and other similar sampling schemes, containing EDGG nested plots and 10 m2 single plots from several regions of Europe (Dengler et al. 2016a, 2016b). Later, our call for data spread along the community of vegetation ecologists, and yielded thousands of valuable plots from all over the Palaearctic, contributed by numerous scientists willing to participate in the collaborative efforts to establish these benchmarks.

Nested-plot sampling in a dwarf shrubland of the alliance Sideritido-Salvion (Ononido-Rosmarinetea) in Juniperus thurifera woodland (Soria, Spain) (Photo credit: Juan Antonio Campos)

While one main objective of this project was to provide the abovementioned richness benchmarks, the specialization of GrassPlot in nested-plot series allowed the analyses of large amounts of such nested series across a large geographic extent, which resulted in three papers dealing with species-area relationships (SARs) and the use of the exponent z of the power-law SAR as a measure of fine-grain beta diversity (Dengler et al. 2020; Dembicz et al. 2021; Zhang et al. 2021; Other projects using the high-quality data of GrassPlot for analyses of various other aspects of biodiversity, such as alpha diversity, broad-scale beta diversity, functional diversity, species-abundance distributions etc., are now also under way.

Distribution of plots in the biomes of the Palaearctic realm; pie-charts show the fraction of vegetation types represented by the plots (black dots) included in each biome (From Biurrun et al. 2021).

In parallel, GrassPlot continued growing (Dengler et al. 2018; Biurrun et al. 2019;, and our primary objective was running ahead, taking advantage of the fact that we were using much of our energy for entering new data and developing parallel projects. We started to fear that Kipchoge was overtaking us more and more, and we decided to stop the chronometer in 2020, when the Coronavirus pandemic disrupted our world. From that moment on, we got back to the race, and we hope that when Kipchoge crosses victoriously the finish line in Tokyo, our long-awaited article providing plant richness benchmarks of Palaearctic grasslands will be already available online in the Journal of Vegetation Science, where it has been published within the Special Issue on Macroecology of Vegetation.

Richness hotspots and coldspots of vascular plants across spatial grains in grasslands and other open habitats across the Palaearctic realm (From Biurrun et al. 2021)

We scientists are curious, like any other human being, about records and record-holders, and want to know which are the richest plant communities and which are these record values. However, maximum richness is only a small part of the story. Therefore, for this paper, we used 126,524 plots of the abovementioned grain sizes and calculated the mean richness and standard deviations, as well as maximum, median, and first and third quartiles for each combination of grain size, taxonomic group (bryophyte, lichen, vascular plants and the complete vegetation), biome, vegetation type and phytosociological class. These benchmarks are available as the open-access file “GrassPlot Diversity Benchmarks” and the online interactive tool “GrassPlot Diversity Explorer” (, providing users flexibility in exploring and visualizing richness data in GrassPlot. Both will be updated regularly.

Screenshot of the GrassPlot Diversity Explorer presenting richness of vascular plants across fine-level vegetation types at 100 m2 (

We are happy that we finished our first marathon, and that the benchmark data provided in this paper will allow scientists and practitioners not only to satisfy their curiosity about the richest grasslands, but also to use them in their studies on vegetation ecology, macroecology and biodiversity conservation, or just for data quality checking. However, more races are in front of us, and although exhausted after meeting our first objectives, we keep our eyes on the next ones. Many data have accumulated in the meanwhile and are waiting to be included, and even more are needed in order to achieve representativeness of all open habitat types and all the standard grain sizes across the Palaearctic regions. The better the data coverage, the more reliable the benchmarks provided by GrassPlot to the scientific community will be. Another important pending issue for us is the harmonization of the composition data in a unique file. Most datasets in GrassPlot also contributed composition data besides richness data and metadata, but the process of organizing all these data is still in progress.

GrassPlot marathon will have more editions, and we would like to invite new runners to participate and contribute many new data from grasslands and other open habitat types from all over the Palaearctic. New plant richness records will be registered, and diversity benchmarks will be updated. However, science is not an individual or tribal effort: as in a relay race, GrassPlot is collaborating with the generalist vegetation-plot databases EVA ( and sPlot (, so that suitable data from GrassPlot will also be contributed to EVA and sPlot after owners’ approval and therefore will be available to the scientific community for broad-scale vegetation survey and macroecological research. Data contributors will be rewarded with the possibility to participate in joint projects, and all grassland ecologists will be able to use these benchmarks in their studies. Last but not least, grasslands and other open habitats will have a better chance for their protection and conservation.

Nested-plot sampling of a dry grassland with Stipa iberica in the Basque Country (Spain) (Photo credit: Juan Antonio Campos)


  • Biurrun, I., Burrascano, S., Dembicz, I., Guarino, R., Kapfer, J., Pielech, R. et al. (2019) GrassPlot v. 2.00 – first update on the data‐base of multi‐scale plant diversity in Palaearctic grasslands. Palaearctic Grasslands, 44, 26–47.
  • Chytrý, M., Dražil, T., Hájek, M., Kalníková, V., Preislerová, Z., Šibík, J. et al. (2015) The most species-rich plant communities in the Czech Republic and Slovakia (with new world records). Preslia, 97, 217–278.
  • Dembicz, I., Dengler, J., Steinbauer, M. J., Matthews, T. J., Bartha, S., Burrascano, S. et al. (2021) Fine‐grain beta diversity of Palaearctic grassland vegetation. Journal of Vegetation Science, 32, e13045.
  • Dengler, J., Biurrun, I., Apostolova, I., Baumann, E., Becker, T., Berastegi, A., et al. (2016a) Scale-dependent plant diversity in Palaearctic grasslands: a comparative overview. Bulletin of the Eurasian Dry Grassland Group, 31, 12−26.
  • Dengler, J., Boch, S., Filibeck, G., Chiarucci, A., Dembicz, I., Guarino, R. et al. (2016b) Assessing plant diversity and composition in grasslands across spatial scales: The standardised EDGG sampling methodology. Bulletin of the Eurasian Grassland Group, 32, 13–30.  
  • Dengler, J., Wagner, V., Dembicz, I., García‐Mijangos, I., Naqinezhad, A., Boch, S. et al. (2018) GrassPlot – a database of multi‐scale plant diversity in Palaearctic grasslands. Phytocoenologia, 48, 331–347. 10.1127/phyto/2018/0267
  • Dengler, J., Matthews, T. J., Steinbauer, M. J., Wolfrum, S., Boch, S., Chiarucci, A. et al. (2020) Species–area relationships in continuous vegetation: Evidence from Palaearctic grasslands. Journal of Biogeography, 47, 72–86., J. B., Peet, R. K., Dengler, J. & Pärtel, M. (2012) Plant species richness: the world records. Journal of Vegetation Science, 23, 796–802.
  • Zhang, J., Gillet, F., Bartha, S., Alatalo, J.M., Biurrun, I., Dembicz, I. et al. (2021) Scale dependence of species‐area relationships is widespread but generally weak in Palaearctic grasslands. Journal of Vegetation Science, 32, e13044.

Brief personal summaries:

Idoia Biurrun is Associate Professor at the University of the Basque Country UPV/EHU in Spain. She is co-founder and manager of GrassPlot, and is interested in many aspects of vegetation diversity and ecology.

Jürgen Dengler is Professor of Vegetation Ecology at the Zurich University of Applied Sciences (ZHAW) in Switzerland. He is co-founder of EDGG and GrassPlot and deeply interested in all aspects of Palaearctic grassland vegetation, particularly its biodiversity and underlying drivers.

Iwona Dembicz is Assistant Professor at the Institute of Environmental Biology of the University of Warsaw in Poland. Her scientific interests include the ecology of grassland ecosystems, biodiversity patterns and nature conservation. She is involved in the management and development of GrassPlot.

Remigiusz Pielech is Assistant Professor at the University of Agriculture in Krakow in Poland. He is involved in the management of GrassPlot and developed the online tool GrassPlot Diversity Explorer.

GrassPlot is the collaborative, multi-scale vegetation-plot database of EDGG, the IAVS Working Group dealing with biodiversity, ecology and conservation of Palaearctic grasslands