This paper presents a phytosociological study of dry and mesophilous meadows and pastures in the Locarnese region (Insubria - Southern Switzerland). Seventy-one vegetation relevés were analysed using both hierarchical classification and nonmetric multidimensional scaling (NMDS) ordination. Seven main clusters were identified and described as follows: (i) xerophytic grasslands on sandy soil dominated by Koeleria macrantha; (ii) mesophilous meadows with Arrhenatherum elatius and Centaurea transalpina; (iii) semi-dry meadows with Chrysopogon gryllus; (iv) semi-dry grasslands with Carex fritschii and Thalictrum minus; (v) nutrient-poor Phyteuma betonicifolium-Festuca nigrescens montane zone grasslands; Nardus stricta grasslands dominated by (vi) Festuca paniculata or (vii) Carex pilulifera. From a phytosociological point of view, a new association named Phyteumo betonicifolii-Festucetum nigrescentis, classified into the Nardo strictae-Agrostion tenuis alliance was proposed. In addition, we confirmed the presence of the Holco-Chrysopogonetum grylli association, within the Bromion erecti, which up to now was provisional only.

dry meadows, Festuco-Brometea, Insubria, Molinio-Arrhenatheretea, Nardetea strictae, phytosociology, pastures

The Semi-natural temperate grasslands are plant communities that arose from the non-intensive use of pastures and meadows (Küster and Keenleyside 2009). European semi-dry grasslands are among the most important hotspots of vascular plant diversity (Wilson et al. 2012). Grasslands are a prominent feature in present‐day landscapes, but both the intensification of management practices and land abandonment during the past decades have resulted in a widespread loss of traditional grasslands, their homogenization and a concomitant loss of biodiversity (Poschlod et al. 2009; Prévosto et al. 2011).

The first study on Swiss grassland vegetation was published in 1887 by Stebler & Schröter. Since then, studies have been performed in various regions of Switzerland (Studer-Ehrensberger 1995). A synthetic overview of mesophilous species-rich meadows is provided by Studer-Ehrensberger (2000). Literature on Swiss meadows has been reviewed for the classes Caricetea curvuleae, Elyno-Seslerietea and Molinio-Arrhenatheretea as part of the classification system of Swiss plant associations PhytoSuisse (Prunier et al. 2014, 2019). The elaboration of the classification of mesophilous meadows and pastures is primarily based on the relevant national literature (Koch 1926; Marschall 1947, 1951; Berset 1965; Dietl 1972, 1983) as well as for dry meadows (Zoller 1954; Braun-Blanquet 1961, 1976; Meyer 1976; Delarze 1986; Eggenberg et al. 2001).

In Switzerland, so far, only few studies have dealt with the flora and vegetation of the Insubrian region South of the Alps (Schröter 1936; Oberdorfer 1964; Reisigl 1996). In particular, Chrysopogon gryllus meadows (Koch 1943; Meyer 1976, 1977) and grasslands with Festuca paniculata (Vittoz et al. 2005) were considered. An overview of the dry grasslands of the lowlands in the whole Insubrian range was also provided (Studer-Ehrensberger 1993).

For the Canton of Ticino, early comprehensive studies were performed by Jäggli (1908) and Bär (1914). Further studies were carried out by the “Prati magri ticinesi” confederation project at the beginning of the 1990s (Antognoli 1995; Häfelfinger 1996; Pestalozzi 1990). However, the phytosociological classification of the siliceous communities of the Locarnese region has been neglected so far (but see Bär 1914; Pestalozzi 1990). Current Swiss reference literature (Delarze et al. 2015; Prunier et al. 2019) is accurate for the grassland communities of the northern Alps, but is incomplete with regard to those in the Southern Alps, in particular the meadows and pastures on siliceous soils. Nutrient-poor montane zone grasslands with Festuca rubra and Agrostis capillaris have already been described (Thomet et al. 1989; Pestalozzi 1990; Häfelfinger 1996; Studer-Ehrensberger 2000; Dietl in Klötzli et al. 2010) but were not integrated in the current classification systems in Switzerland (Delarze et al. 2015; Prunier et al. 2019). The same holds true for the xerophytic grasslands on sandy soils (Studer-Ehrensberger 1993).

This paper proposes a phytosociological overview of the siliceous meadows and pastures in the foothills and montane zone of the Locarnese region (200–1,500 m a.s.l.). The aims of the study were to describe and classify grassland communities occurring in the area. The study is expected to shed new light on the phytosociological classification of these grasslands and to test the occurrence of new plant associations specific to the Insubrian region.

Poo bulbosae-Festucetum trachyphyllae Lonati and Lonati 2007 (Tab. 1)

Characteristic and differential species : Koeleria macrantha, Rumex acetosella.

High frequency Taxa : Artemisia campestris, Carex caryophyllea, Euphorbia cyparissias, Koeleria macrantha, Lotus corniculatus, Peucedanum oreoselinum, Plantago lanceolata, Ranunculus bulbosus, Rumex acetosella, Thymus pulegioides.

Species composition : This community was dominated by Koeleria macrantha (Φ 0.88; p-value<0.001) and Peucedanum oreoselinum (Φ 0.45; p-value=0.07), accompanied by less demanding xerothermophytes, e.g. Hieracium pilosella, Galium verum, Thymus pulegioides, Carex caryophyllea, Potentilla neumanniana and Helianthemum nummularium. Among the other species, Rumex acetosella (Φ 0.40; p-value=0.02) and Euphorbia cyparissias (Φ 0.90; p-value<0.001) showed significant values for the ISA. Pioneer grassland on sand species, like Jasione montana, Trifolium arvense or Aira caryophyllea, and mesic meadows species, like Achillea millefolium aggr, Plantago lanceolata were present. The clustering split the community into two groups. One relevé (number 71) had a higher cover of Festuca trachyphylla, Aira caryophyllea, Hypochaeris radicata and typical dry grassland on sandy soil species. The others (42, 8, 7, 66) were in different secondary transitional stages dominated by semi-dry grassland species, like Bromus erectus, Lotus corniculatus, Trifolium montanum and the presence of the protected species Orchis ustulata and Orchis morio. The number of species per relevé ranged between 21 and 25, with an average of 21.8.

Geographic distribution : These grasslands were found along the Maggia and the Melezza river. This community can be found in the entire Insubria region from Torino to Brescia (Studer-Ehrensberger 1993).

Synecology : The pH ranged between 4.5 and 5.0. The mean weighted Landolt indicator values were as follows: temperature (T) 3.58, continentality (K) 3.13, light (L) 3.85, moisture (F) 1.68, soil reaction (R) 2.90 and nutrients (N) 2.13, Humus (H) 2.89 (Fig. 5). The community is present on silicious stabilized sandy soil. That is no longer flooded along river terraces, representing a secondary successional stage maintained by agricultural practices The altitude in the hillzone ranged from 220 m a.s.l. to 310 m a.s.l. The surfaces were either mowed or extensively grazed by sheep. Each plot was on a site listed in the national inventory of dry meadows and pastures.

Figure 5. 

Boxplots showing the variability of altitude and other environmental indicators (i.e. Landolt's moisture, light, temperature, continentality, soil reaction, nutrients, humus) for each plant community. The abbreviations used are referred to the following plant association: Phy-Fes for Phyteumo-Festucetum, Car-Nar for Carici-Nardetum, Cen-Arr for Centaureo-Arrhenatheretum, Hol-Chr for Holco-Chrysopogonetum, Poo-Fes for Poo-Festucetum and Phy-Mes for Phyteumo-Mesobrometum.

Syntaxonomical discussion : This plant community is included to the Stipo-Poion xerophilae alliance by the occurrence of Achillea collina, Festuca trachyphylla and Carex liparocarpos. This plant community was initially described in Insubria by Studer-Ehrensberger (1993) as the "Jasione montana-Koeleria macrantha community" within the Koelerio-Phleion alliance. She hypothesized that its presence was linked to the Insubrian climate. Lonati & Lonati (2007) identified Poo bulbosae-Festucetum trachyphyllae, which belongs to the Stipo-Poion carniolicae alliance, also confined to the Insubrian region with a pronounced subatlantic climate. Although Lonati & Lonati (2007) did not reference Studer-Ehrensberger's work, a comparison of the species lists and relevé locations suggests that the Jasione montana-Koeleria macrantha community is synonymous with Poo-bulbosae-Festucetum trachyphyllae. Both combined a high number of species characteristic of Festuco-Brometea with species principally occurring in the Koelerio-Corynephoretea class. Similar meso-xeric grasslands had previously been classified as the Jasiono montanae-Festucetum ovinae association in the Hyperico perforati-Scleranthion perennis alliance (Becker et al. 2012) within the Koelerio-Corynephoretea canescentis class. According to Chytrý (2010), all three alliances share diagnostic and constant species, such as Festuca ovina aggr. (cfr. F. trachyphylla), Hieracium pilosella, Jasione montana, Rumex acetosella, Thymus pulegioides, and Hypericum perforatum, all of which are found in our relevés. The high percentage of semi-dry meadow grasses (Koeleria macrantha, Bromus erectus, Carex caryophyllea) in these relevés brings them closer to the Festuco-Brometea class.

The species in Plot 71 of the inventory of dry grasslands are very similar to Poo-bulbosae-Festucetum trachyphyllae. However, the data does not specify which species of Festuca ovina aggr. is present. Festuca trachyphylla could only be confirmed in our own relevé 42. Relevés 8, 7, and 66 have a much higher proportion of mesophilic species, which could potentially represent a degradational stage due to pasture and are considered as a mesophilic variant without Festuca trachyphylla.

Holco-Chrysopogonetum grylli Lagnaz, Trotta, Prunier, Krüsi et Boscutti 2023 ex Meyer 1976 (Tab. 2)

Lectotypus : Tab. 1, relevé 75 in Meyer (1976)

According to the International Code of Phytosociology (Theurillat et al. 2021), the name published by Meyer (1976) is not valid as it is a provisional name (Art. 3b). Therefore, we propose to validate the original name (Art. 6).

Characteristic and differential species : Brachypodium rupestre, Chrysopogon gryllus, Danthonia decumbens

High frequency Taxa : Achillea millefolium aggr., Anthericum liliago, Anthoxantum odoratum, Brachypodium rupestre, Carex caryophyllea, Carex pilulifera, Festuca filiformis, Lotus corniculatus, Silene nutans, Thymus pulegoides.

Species composition : This community was characterised by the dominance of Chrysopogon gryllus (Φ 0.3; p-value<0.05) and Anthoxantum odoratum. One relevé showed dominance of Chrysopogon gryllus combined with Bromus erectus. Other species with a significant fidelity according to ISA analysis were Danthonia decumbens (Φ 0.74; p-value<0.001) and Brachypodium rupestre (Φ 0.37; p-value<0.05). The protected species, Serapias vomeracea, was found in one relevé. Mesophilous meadow species, like Plantago lanceolata, Centaurea transalpina and Rumex acetosa were combined with typical semi-dry meadow species, such Bromus erectus, Carex caryophyllea, and Silene nutans. The latter had a higher frequency. The number of species per relevé ranged between 28 and 35, with an average of 30.2. One relevé (54) was an outlier with a dominance of Molinia arundinacea and other fringe vegetation species.

Geographic distribution : These grasslands are present in the Terre di Pedemonte and the outer part of Centovalli.

Synecology : They are present on exposed southern slopes (max. 30 degrees) in the hill belt of the Terre di Pedemonte and the outer area of Centovalli. In the Terre die Pedemonte, the altitude for this plant community ranged between 373 m a.s.l. and 507 m a.s.l. One relevé was located in Centovalli at 820 m a.s.l. and the pH was near 4.5. The Landolt indicator values were as follows: temperature (T) 3.41, continentality (K) 2.82, light (L) 3.55, moisture (F) 2.37, soil reaction (R) 2.66 and nutrients (N) 2.34 (Fig. 5). The surfaces were a combination of mowed and extensive pastures.

Syntaxonomical discussion : The association belongs to the alliance Bromion erecti by the occurrence of the characteristics species Thymus pulegoides, Silene nutans, Luzula campestris, Ranunculus bulbosus. In Switzerland, plant communities with Chrysopogon gryllus are limited to the Canton of Ticino. Chrysopogon gryllus has a wide amplitude and can be found also in different xerophytic communities in the central Alps extending to the Balkans, where its sociologic optimum occurs in the associations of the East continental order Festucetalia valesiacae (Ilijanić & Topić, 1989; Redzic, 1999). Chrysopogon gryllus grasslands in Ticino were first described by Koch (1943), as Andropogonetum grylli insubricum. It included siliceous and basophilous variants. The author defined Festuca filiformis, Carex pilulifera, Agrostis capillaris as differential species for the two variants. Meyer (1976) referred the two variants to Carici humilis-Chrysopogonetum grylli (basophilous) and Holco-Chrysopogonetum grylli prov. (acidophilous). Studer-Ehrensberger (1993) includes Holco-Chrysopogonetum grilli prov. in a new association, Phyteumo-Mesobrometum, within Bromion alliance. This attribution can be discussed. The Phyteumo-Mesobrometum association is characterized by a higher number of species in mown meadows, such as Arrhenatherum elatius, Trisetum flavescens, Cerastium fontanum. Furthermore, the dominance of Chrysopogon gryllus along with Danthonia decumbens and their absence in the Phyteumo-Mesobrometum grasslands validate the association described by Meyer (1976) Korneck (1978) placed semi-dry meadows on siliceous soils in the Mesobromion alliance. Recent phytosociological references agree that the Mesobormion alliance is limited to calcareous soil while dry meadows on siliceous soil should be placed in the Koelerio-Phleion alliance (Chytrý 2010; Biondi et al. 2014; Mucina et al. 2016). In the Locarnese region, typical species of Koelerion-Phleion are missing. Therefore, we propose to classify this association within the Bromion alliance. The occurrence of many mesophilous species like Brachypodium rupestre, Holcus lanatus, Lotus corniculatus and Anthoxantum odoratum are probably due to a legacy of traditional agricultural practices. The reference natural guide of habitats in Switzerland (Delarze et al., 2015) is limited to Brachypodium pinnatum and did not consider Brachypodium rupestre. Generally, the frequency and dominance of Brachypodium pinnatum in grasslands is linked to the intensification of pasture (Ellenberg and Leuschner 2010) or the abandonment of regular management, meaning Brachypodium pinnatum grasslands have been considered to be transitory vegetation stages (Häfelfinger, 1996; Bonanomi & Allegrezza, 2004). However, Brachypodium rupestre communities are well known where diverse associations have been described (Ubaldi 1988, Blasi et al. 2000, Di Pietro et al. 2015, Prunier et al. 2018). Based on works from Biondi et al. (2005), the Polygalo mediterraneae-Bromion erecti includes mesophilous non-calciphilous grasslands of the Apennines (Di Pietro et al. 2015). The option of creating a new sub-alliance or alliance should be considered in any further study.

Phyteumo-Mesobrometum Studer-Ehrensberger 1993 (Tab. 3)

Characteristic and differential species : Carex fritschii (Φ 0.50; p-value<0.001), Thymus pulegoides (Φ 0.22; p-value<0.1), Thalictrum minus (Φ 0.30; p-value<0.05)

High frequency Taxa : Luzula campestris, Achillea millefolium aggr., Brachypodium rupestre, Silene nutans, Anthoxantum odoratum, Festuca nigrescens, Ranunculus bulbosus.

Species composition : All the diagnostic species showed a significant fidelity to this association (Carex fritschii, Φ 0.50, p-value<0.001; Thymus pulegoides, Φ 0.22, p-value<0.1; Thalictrum minus, Φ 0.30, p-value<0.05). Two variants could be distinguished: one variant (plots 22, 49, 50, 52) was drier than the second one (plots 11, 16, 17, 19, 33, 37, 53, 57, 59). The first one comprised three meadows of national importance. They contained Festuca ovina aggr. and a more abundant cover of species typical of dry grasslands, like Helianthemum nummularium, Dianthus carthusianorum and Carex caryophyllea and a presence of very dry indicators, like Sedum annuum and Sedum telephium. These plots were also characterized by the presence or dominance of species indicating short-term abandonment, like Carex pairae, Vincetoxicum hirundinaria or dominance of Brachypodium rupestre. The second variant was characterized by the presence of Carex fritschii with a cover abundance between 2 and 3 in all surveys. Anthoxantum odoratum was dominant and species typical of semi-dry meadows were also present, like Centaurea scabiosa, Arabis hirsuta, Galium verum and Pimpinella saxifraga. Species typically from Arrhenatheretelia like Centaurea transalpina, Galium album, Poa pratensis were present in the second variant and absent in the first one. Bromus erectus was present but never dominant. The protected species, Lilium bulbiferum and Orchis ustulata, were also found. The number of species per relevé ranged between 17 and 41, with an average of 31.6.

Geographic distribution : These grasslands had a wide amplitude and were spread throughout the study area.

Synecology : These grasslands were found on exposed southern and eastern slopes (from 10 to 45 degrees in gradient). The altitudes ranged from 334 m a.s.l. to 1274 m a.s.l. The pH ranged between 4.0 and 4.5. The Landolt indicator values were as followed: temperature (T) 3.35, continentality (K) 2.98, light (L) 3.56, moisture (F) 2.31, soil reaction (R) 2.85 and nutrients (N) 2.42, Humus (H) 3.18 (Fig. 5). Not all the areas seemed to have been mowed every year. A combination of mowing and grazing could also be noticed on the field. In some cases, this plant community can be found on old river terraces.

Syntaxonomical discussion : The association belongs to the alliance Bromion erecti by the occurrence of the characteristics species Ranunculus bulbosus, Luzula campestris, Silene nutans. Semi-dry grasslands on silicious soils in Ticino were described by Studer-Ehrensberger (1993) as Phyteumo-Mesobrometum. She distinguished two subassociations: chrysopogonetosum grylli and achilletosum millefoli. The subassociation achilletosum millefoli has many similarities with the relevés of the Locarnese, as they share many species (e.g. Phyteuma betoncifolium, Bromus erectus, Thalictrum minus). The main differences concern the cover of Bromus erectus and the presence of Carex fritschii. Bromus erectus is often dominant according to Studer-Ehrensberger and Carex fristchii is absent. Our relevés showed a presence of Bromus erectus, but this was never dominant, unlike Carex fristschii. We consider the relevés with a high cover of Carex fritschii as a locally variant associated with specific ecological and management attributes linked to elevation and mowing frequency.

Centaureo transalpinae-Arrhenatheretum Oberd. 1964 nom. mut. prop. Prunier et al. 2019 (Tab. 4)

Original name : Centaurea dubiae-Arrhenatheretum elatioris Oberdorfer 1964, art. 43

Synonyms : Centaureo carniolicae-Arrhenatheretum elatioris Oberdorfer 1964 corr. Poldini et Oriolo 1994, Arrhenatheretum elatioris Pedrotti 1964 non Scherrer 1925, Arrhenatheretum elatioris Buffa et al. 1989 non Scherrer 1925

Lectotypus : Tab. 9, relevé 4 in Oberdorfer (1964) by Poldini and Oriolo (1994)

Characteristic and differential species : Centaurea transalpina.

High frequency Taxa : Achillea millefolium aggr., Arrhenatherum elatius, Silene vulgaris, Festuca nigrescens, Dactylis glomerata, Plantago lanceolata, Anthoxantum odoratum, Trifolium pratense, Leontodon hispidus.

Species composition : These grass-rich meadows were generally dominated by Arrhenatherum elatius (Φ 0.45; p-value=0.06) and Anthoxanthum odoratum. Centaurea transalpina was the only other species whit a significant ISA value (Φ 0.58; p-value<0.01). Trisetum flavescens was present in all plots above 650 m a.s.l. but was never dominant. One meadow (relevé 29) showed signs of extensive management, with a dominance of Chaerophyllum villarsii and Thalictrum minus. All plots were characterized by nutrient rich grassland species, like Dactylis glomerata, Trifolium repens, Ranunculus friesianus. Agrostis capillaris and Viola tricolor indicated soil acidity. The presence of species from the Southern part of the Alps was typical for this association, particularly Centaurea transalpina and Achillea roseo-alba (which was aggregated into Achillea millefolium in the present work). Two variants could be distinguished: the first one contained meadows (relevés 15, 21, 24, 25, 34, 35, 36) that were more intensively managed on flat areas or gentle slopes (10-20 degrees) and was found below 700 m. The number of species was lower (average 24.7) than the second variant (relevés 2, 3, 9, 10, 12, 20, 23, 47, 48, 51, 58). The second variant had an average of 31.9 species. These were present on slopes up to 45 degrees. Some of them were found on formerly cultivated terraces. In one meadow, we found the locally protected species, Lilium bulbiferum subsp. croceum. These grasslands were generally found above 700 m. They had a high frequency and cover of montane species like Chaerophyllum villarsii and Phyteuma orbiculare. They could be considered as a transitional stage to Centaureo transalpinae-Trisetetum flavescentis. The number of species per relevé ranged between 11 for the most intensively managed meadow to 35, with an average of 23.8.

Geographic distribution : This association is found South of the Alps in Ticino and Northern East Italy, from Comasco to Friuli (Poldini & Oriolo 1994; Studer-Ehrensberger 2000; Allegrezza & Biondi 2011) as in Slovenia (Velev 2018).

Synecology : The pH ranged between 4.5 and 5.0. This association had a wide amplitude. It was found across the whole study area in the hill and the lower montane zones at altitudes between 222 m a.s.l. and 1180 m a.s.l. The Landolt indicator values were as follows: temperature (T) 3.20, continentality (K) 3.02, light (L) 3.45, moisture (F) 2.66, soil reaction (R) 2.88 and nutrients (N) 2.92, Humus (H) 3.20 (Fig. 5). The areas were mowed. It was the only type of grassland in the study area used for hay production.

Syntaxonomical discussion : The association belongs to the alliance Arrhenatherion elatioris by the occurrence of the characteristic species Arrhenatherum elatius, Silene vulgaris, Rumex acetosa, Galium album, Viola tricolor, and Poa pratensis. Oberdorfer (1964) first described this association for the insubrian region. The phytosociological attribution of this community was due to the frequent occurrence of species only present in south side of the Alps, like Achillea roseo-alba and Centaurea transalpina. Poldini & Oriolo (1994) distinguished between the Centaureo transalpinae-Arrhenatheretum association in the Arrhenatherion alliance and a montane association called Centaureo transalpinae-Trisetetum flavescentis in the Polygono-Trisetion alliance, which corresponds to the Trisetetum flavescentis insubricum subassociation described by Marschall (1947) in the Leventina. As most of the diagnostic species, like Geranium sylvaticum, Heracleum sphondyllium and Carum carvi were absent and the Arrhenatherion species more frequent, this association could be excluded.

Phyteumo betonicifolii-Festucetum nigrescentis ass. nova (Tab. 5, Relevé 41 holotypus)

Characteristic and differential species : Festuca nigrescens, Phyteuma betonicifolium, Crocus albiflorus, Phleum rhaeticum, Poa chaixii, Ranunculus montanus, Chaerophyllum villarsii.

High frequency Taxa : Achillea millefolium aggr., Agrostis capillaris, Rumex acetosella, Thymus pulegoides.

Species composition : All diagnostic species showed a high fidelity to the association (Festuca nigrescens Φ 0.32, p-value<0.05; Phyteuma betonicifolium Φ 0.32, p-value<0.05; Crocus albiflorus, Φ 0.29, p-value<0.05; Phleum rhaeticum, Φ 0.40, p-value<0.05; Poa chaixii, Φ 0.4; p-value<0.05; Ranunculus montanus, Φ 0.49, p-value<0.05). These meadows were characterized by a mix of montane belt mesic meadow species (e.g. Chaerophyllum villarsii, Phleum rhaeticum), montane and subalpine belt mat-grass dry pasture species (Nardus stricta, Avenella flexuosa, Stellaria graminea), and meso-xerophytic grassland species (e.g. Thymus pulegoides, Silene nutans, Lotus corniculatus, Ranunculus bulbosus). In many relevés Festuca nigrescens was dominant. Two variants were distinguished. In the first one (5, 18, 27, 28, 39, 41) Festuca nigrescens was always present and was dominant in half of the relevés. Two protected species were found in the first variant: Lilium bulbiferum and Narcissus verbanensis. In the second variant (43, 44, 46, 60, 61, 64, 68) there was a higher frequency of species typical of Nardus stricta grasslands, like Nardus stricta, Carex pallescens, Alchemilla hybrida aggr., Galium rubrum, Poa chaixii. The number of species per relevé ranged between 19 and 44, with an average of 30.5.

Geographic distribution : The first variant included four relevés from the Centovalli, one from the lakeside and one from the Onsernone Valley. The second variant included four relevés from the Onsernone valley and three from the Vergeletto valley.

Synecology : Grasslands belonging to the first variant were North facing and at altitudes ranging from 747 m a.s.l. to 1050 m a.s.l. The ones in the second variant were found in the upper mountain belt and were mostly South facing. The altitude ranged from 1100 to 1,465 m a.s.l. The pH ranged between 4.0 and 4.5. The Landolt indicator values were as follows: temperature (T) 2.92, continentality (K) 2.95, light (L) 3.36, moisture (F) 2.63, soil reaction (R) 2.59 and nutrients (N) 2.55, Humus (H) 3.31 (Fig. 5). The new association is consistent with other Festuca rubra and Agrostis capillaris meadows as traditional communities of hay meadows in central Europe (Studer-Ehrensberger 2000, Poschlod et al. 2009). They are linked to extensive management without or with very little fertilisation, on nutrient poor soils. In our relevés, some were only mowed, but most of them exhibit a combination of extensive grazing and mowing. One of them (relevé 44) seemed abandoned or at least was no longer maintained on a regular basis and had a high cover of Vincetoxicum hirundinaria.

Syntaxonomical discussion : The association is included in the alliance Nardo strictae-Agrostion tenuis by the occurrence of the characteristic species Avenella flexuosa, Phyteuma betonicifolium, Carex pallescens, Poa variegata. In Ticino, Festuca rubra-Agrostis capillaris meadows have been described by different authors (Pestalozzi 1990, Häfelfinger 1996, Studer-Ehrensberger 2000, Dietl in Klötzli et al. 2010). Dietl in Klötzli et al. (2010) and Studer-Ehrensberger (2000) agree that the classification of these grasslands is difficult because of their intermediate position between well-defined alliances (Arrhenatherion, Polygono-Trisetion, Mesobromion, Nardus grasslands), which leads to a lack of diagnostic species. The attribution of this plant community is complicated by the fact that there are several approaches to classifying alliances within the Nardetalia order. Some consider two separate alliances Violion and Nardo-Agrostion to be in the same order (Mucina et al. 1993, Chytrý 2010, Mucina et al. 2016). Others consider the two alliances to be in separate orders (Biondi et al. 2014), or none of them (Delarze et al. 2015). The ordination diagram (Fig. 4) confirms the intermediate position of these grasslands between the Nardo-Agrostion and the Arrhenatherion. However, the cluster analysis (Fig. 3), clearly positions these surveys in relation to the Nardo-Agrostion grasslands.

We could consider placing these grasslands in the Violion alliance (acidophilous nutrient poor grasslands), as our relevés have a lot of species in common with the Polygalo-Nardetum described in Friuli (Poldini & Oriolo, 1997). The fact that Nardus stricta should be dominant in this association (Poldini & Oriolo 1997; Chytrý 2010) and was not in our surveys, and the fact that Violion occurs mostly in lowland to submontane belts, led us to follow Mucina et al. (2016) and classify it within the Nardo-Agrostion.

Carici piluliferae-Nardetum strictae Marschall and Dietl 1974 (Tab. 6)

Synonyms : Nardetum alpigenum ss-ass. à Carex pilulifera et Polygala serpyllifolia Berset 1969, Omalotheco sylvaticae-Nardetum strictae Gillet in Ferrez et al. 2011

Characteristic and differential species : Carex pilulifera, Nardus stricta.

High frequency Taxa : Carex pilulifera, Nardus stricta.

Species composition : Avenella flexuosa, Carex pilulifera (Φ 0.55; p-value<0.1), Festuca filiformis, Nardus stricta (Φ 0.61; p-value<0.01) were the dominant species. Three variants could be distinguished: the first one (relevés 4, 62, 63) presented several semi-dry meadow species like Festuca ovina aggr., Helianthemum nummularium, Thymus pulegoides and Silene nutans. The second variant (relevés 1, 26, 32, 38, 40, 67, 70, 71) was very poor in species (mean 16), mostly dominated by Carex pilulifera or Nardus stricta (cover-abundance 4 or 5), the third characherized by dominance of Festuca paniculata (cover-abundance 3, resp. 4) and Festuca filiformis. The number of species per relevé ranged between 7 and 34, with an average of 17.1.

Geographic distribution : Carici piluliferae-Nardetum strictae was present throughout the whole studied area, except from the Vergeletto Valley. One relevé was from Pizzo Leone, five from the Onsernone Valley and five from Centovalli and two on the lakeside of Lago Maggiore.

Synecology : These grasslands were mostly on exposed southern slopes at altitudes between 989 to 1,498 m a.s.l. The slopes varied from flat to 40 degrees. With a mean of 26 species, the first variant had significantly more species than the second variant and third variant. Two of them belong to the federal inventory of dry meadows and pastures of national importance. The Landolt indicator values were as follows: temperature (T) 2.95, continentality (K) 2.78, light (L) 3.37, moisture (F) 2.57, soil reaction (R) 2.26, nutrients (N) 2.38 and Humus (H) 3.33 (Fig. 5).

Syntaxonomical discussion : The association is included in the alliance Nardo strictae-Agrostion by the high frequency and abundance of Phyteuma betonicifolium, Festuca nigrescens, and Carex pallescens. The Nardus-rich grasslands in Ticino are well known. Bär (1914) described them as “Nardus-desert”, in reference to the low number of species. In Europe, not much literature can be found about this association. Only the French prodrome and the swiss reference system retain it (de Foucault 2012; Prunier et al. 2019). Most of the descriptions are related to the Jura region (Gallandat et al. 1995; Vittoz 1998; Ferrez et al. 2011). The first variant (relevés 4, 62, 63) is clearly distinguished from the second (relevés 1, 26, 32, 38, 40, 67, 70, 71) by the presence of xero-termophilic species, such as Festuca ovina aggr. and Thymus pulegoides. An affiliation to the association Thymo-Festucetum was an option. However, the Indicator Species Analysis (ISA) did not showed statistically significant values. For this reason, these surveys were not separated from the other Nardus grasslands.

This study has contributed to providing new phytosociological knowledge for a region that has been poorly studied. We found six associations distributed in four alliances and three classes (Tab. 7). It has confirmed the existence of secondary grasslands in riverbeds, Poo bulbosae-Festucetum trachyphyllae. It has also confirmed the presence of two of semi-dry grasslands on siliceous soils, Holco-Chrysopogonetum grylli, which has been, until now, provisional association and Phyteumo-Mesobrometum. This study has also contributed to a better understanding of the phytosociological attribution of nutrient-poor montane grasslands, with the description of the novel association Phyteumo betonicifolii-Festucetum nigrescentis, in the Nardo-Agrostion alliance. The most widespread plant community was the Centaureo transalpinae-Arrhenatheretum association, within the Arrhenatherion alliance. Unlike the northern Alps, where this alliance is replaced by Polygono-Trisetion at around 700 m a.s.l., it has been found up to 1,180 m a.s.l. on South-facing slopes. Also represented throughout the study area, Carici piluliferae-Nardetum strictae have been found on very acidic soils at altitudes ranging from 989 m a.s.l. to 1,425 m a.s.l.

A further consideration about dry grassland composition and conservation concerns the frequency and abundance of Brachypodium rupestre. This species resulted dominant in some stands across different investigated plant communities suggesting for its plausible encroachment behaviour, especially where a regular mowing or grazing is missing.

Since the number of surveys is low for some plant communities, future studies should also shed light on the attribution of grasslands with Festuca paniculata and confirm the presence of the Thymo-Festucetum association within the Nardo-Agrostion alliance.

FESTUCO VALESIACAE-BROMETEA ERECTI Br.-Bl. & Tüxen ex Br.-Bl. 1949

BRACHYPODIETALIA PINNATI Korneck 1974

Bromion erecti Koch 1926

Holco-Chrysopogonetum grylli Lagnaz, Trotta, Prunier, Krüsi et Boscutti 2023 ex Meyer 1976

Phyteumo-Mesobrometum Studer-Ehrensberger, 1993

FESTUCETALIA VALESIACEAE Br.-Bl. et Tüxen ex Br.-Bl. 1949

Stipo-Poion xerophilae Br.-Bl. & Richard 1949

Poo bulbosae-Festucetum trachyphyllae Lonati & Lonati, 2007

MOLINIO-ARRHENATHERETEA Tüxen 1937

ARRHENATHERETALIA ELATIORIS Tüxen 1931

Arrhenatherion elatioris Koch 1926

Centaureo transalpinae-Arrhenatheretum Oberd. 1964 nom. mut. prop. Prunier et. al 2019

NARDETEA STRICTAE Rivas Goday in Rivas Goday & Rivas-Martínez 1963

NARDETALIA Preising 1950

Nardo strictae-Agrostion tenuis Sillinger 1933

Phyteumo betonicifolii-Festucetum nigrescentis ass. nova Carici piluliferae-Nardetum strictae Marschall and Dietl 1974

We thank Jean-Bernard Bächtiger for the field work support.

We greatly thank the Editor, the anonimous reviewer, and the reviewer Bruno Foggi for the insightful comments that greatly improved the quality of the manuscript.