Dry grasslands of the central valleys of the Alps from a European perspective: the example of Ausserberg (Valais, Switzerland)

Abstract

The upper Rhone valley in the Swiss canton of Valais is one of the driest and most continental of the inner-alpine valleys and harbours a rich xerothermic flora. We studied syntaxonomy and ecology of dry grasslands and their species richness patterns. In 2018 we recorded 28 vegetation plots (10 m2) and three nested-plot series of 0.0001 to 100 m2 on the south-facing slopes above the village of Ausserberg. Mean richness of all species ranged from 1.7 on 1 cm2 to 47.3 on 100 m2, with little contribution of bryophytes and lichens. The species-area relationship for total richness closely followed a power function. Modified TWINSPAN yielded a three-cluster solution, which could easily be matched with three orders of the class Festuco-Brometea: Stipo pulcherrimae-Festucetalia pallentis (xeric, rocky), Festucetalia valesiacae (xeric, non-rocky) and Brachypodietalia pinnati (meso-xeric). The subdivision of the xeric types into two orders is new for Swiss dry grasslands, where these types up to now had been joined in a single alliance Stipo-Poion within the Festucetalia valesiacae.

Xeric grasslands of the inner-alpine dry valleys of Austria – new insights into syntaxonomy, diversity and ecology

“…By contrast, our values for the first two orders (20.0 species for rocky grasslands, 26.9 species for xeric grasslands in 10 m²) were rather similar to richness data found for such types in the inner-alpine valleys of Italy (Wiesner et al 2015: 25 species in 10 m²) and Switzerland (Dengler et al 2019: 26.3 species for rocky and 24.3 species for xeric grasslands in 10 m²). Actually, if we exclude the high-elevation associations (transitional to Elyno-Seslerietea) of the meso-xeric grasslands also there the richness values were below average and similar to those found in Aosta Valley and Valais (Wiesner et al 2015;Dengler et al 2019). While for the Austrian stands one might be tempted to explain the low plot-scale richness with the small size of the majority of remaining patches, this is not the case for the two other regions where there are still large and well-managed dry grasslands persisting.…”

“…Phytosociological studies are well suited for evidence-based decisions in nature conservation. However, most studies of the inner-alpine dry valleys (Buschardt 1979;Wagner 1979;Kratochwil 2004, 2012;Wiesner et al 2015;Dengler et al 2019) focused on the more (south)western parts of the Alps with a severe summer drought, and merely touched the Eastern Alps, which have only a moderately continental climate that is influenced by cyclones from the Adriatic Sea.…”

Long term changes of the inner-alpine steppe vegetation: the dry grassland communities of the Vinschgau (South Tyrol, Italy) 40–50 years after the first vegetation mapping

“…In general, this aggregate is very rich in form and includes hybrid populations (Wilhalm et al 2006). According to Dengler et al (2019), H. velutinum differs also from Hieracium pilosella s. str. ecologically, as it occurs on much drier sites.…”

“…= species. Mucina et al (2016) and Dengler et al (2019Dengler et al ( , 2020. These authors outlined the Eastern European Festucion valesiacae as "non rocky grassland of the Swiss inner-alpine valley" and we highly agree to use this definition also for the investigated Vinschgau' dry grasslands.…”

“…However, apart from the general syntaxonomic overview of the entire inner-alpine dry vegetation by Braun-Blanquet (1961), which still represents the most comprehensive classification of the inner-alpine xerophytic vegetation so far, and the more recent and more ecologically focused overview by Kratochwil (2004, 2012), there are only few phytosociological studies on a regional scale. Recently, inner-alpine dry grasslands in Switzerland were studied (Dengler et al 2019(Dengler et al , 2020 and new syntaxonomical classifications on the European level for the class Festuco-Brometea were published (Willner et al 2017(Willner et al , 2019. However, none included data from the Vinschgau.…”