Sampling multi-scale and multi-taxon plant diversity data in the subalpine and alpine habitats of Switzerland: Report on the 14th EDGG Field Workshop

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By Jürgen Dengler, Beata Cykowska-Marzencka, Timon Bruderer, Christian Dolnik, Patrick Neumann, Susanne Riedel, Hallie Seiler, Jinghui Zhang & Iwona Dembicz

Sampling an acidic subalpine grassland at Alp Glivers, canton of Grisons, Switzerland, with the nested-plot methodology of EDGG. Photo credit: Jürgen Dengler.

Every year, the IAVS Working Group EDGG (Eurasian Dry Grassland Group) organizes an international Field Workshop to study grassland diversity with a standardized method, involving seven different grain sizes and at least three taxonomic groups (vascular plants, bryophytes, lichens, sometimes also animal taxa). The data of EDGG Field Workshops are, after completion, fed into the GrassPlot database and EDGG’s new online tool, the GrassPlot Diversity Explorer. Since EDGG originated as a network of researchers with a special interest in dry grasslands, the first 13 such Field Workshops dealt with dry grasslands in the wider sense, while the scope of EDGG since long has been expanded to cover now all open habitats of the Palaearctic biogeographic realm. Originally the 14th EDGG Field Workshop had been planned to be conducted in Ukrainian steppes in May 2020, but then Covid-19 thwarted our plans. This prompted a much smaller group to plan an alternative event in autumn 2020 in Switzerland, after the 13th Field Workshop in 2019, which had been conducted in the dry grasslands of the inner-alpine valleys of the country. However, for the first time, we selected now habitats of the subalpine and alpine belts and did not restrict ourselves to grasslands, but also considered a wide range of other vegetation types.

Although it does not look particularly spectacular, it is one of the most diverse plots ever recorded in the Palaearctic biogeographic realm when considering also bryophytes and lichens, with up to 109 species on 10 m² and approx. 150 species on 100 m². A stand of a base-rich alpine grassland at Fisetengrat in the canton of Uri, Switzerland. Photo credit: Jürgen Dengler.

While the determination of critical bryophyte, lichen and sterile vascular plant species is still on-going, this Scientific Report summarizes some important findings on species diversity patterns that already can be concluded without final identification of all specimens. We found that mean total species richness (i.e. vascular plants, terricolous bryophytes and lichens) increased from 2.7 species in 0.0001 m² (1 cm²) to 38.1 in 10 m². This is significantly more than the values found one year before in semi-dry and dry grasslands of the lower elevations in the same region (and much more if we take only the subalpine-alpine grasslands). Moreover, the contribution of bryophytes and lichens to total richness was generally quite high, with up to 33 bryophyte and 22 lichen species in 10 m². In one stand of a natural alpine grassland over limestone, we found even 109 species in 10 m² and approx. 150 species in 100 m² (according to raw data even 163, but for the largest plots, we expect 5–10% decrease of the final number when the determinations are finalized). For 100 m², this would be one of the highest numbers ever recorded in Palaearctic grasslands (see GrassPlot Diversity Explorer). Regarding total species richness, generally, grasslands had the highest values and screes/moraines the lowest, with fens, heathlands and snowbeds being intermediate. Interestingly, we could confirm for vascular plants and bryophytes that in each pair of habitats the types over base-rich bedrock were richer than those over acidic bedrock. However, for lichens, it was the opposite, with the maximum richness found in acidic heathlands.

Two final hints for those who got interested in EDGG Field Workshops: You find some impressions from the 14th Field Workshop in the Photo diary in the Appendix of the Scientific Report. And of course, you can apply for participation when the next such Field Workshop is announced in the EDGG media.

This is a plain language summary for the paper of Dengler et al. published in Palaearctic Grasslands (https://edgg.org/sites/default/files/page/PG_47_14_42.pdf). This post was prepared by Jürgen Dengler.