Bryophytes provide key ecosystem services at the global scale such as carbon storage and primary production in resource limited habitats, but compared to vascular plants knowledge on how these organisms face recent climate warming is fragmentary. This is particularly critical because bryophytes differ fundamentally from vascular plants in their ecophysiological and biological characteristics, so that community alterations most likely have different dynamics. In a comparative approach, we analysed thermophilisation of bryophyte and vascular plant communities in 1146 permanent plots distributed along an elevational gradient of nearly 3.000 m in Switzerland (Central Europe) that were visited in 5-years intervals between 2001 and 2021. We estimated thermophilisation from changes in unweighted mean temperature indicator values of species, compared it to expected thermophilisation rates given the shift of isotherms and addressed differences between the two lineages, major land use types (managed grasslands, forests, unmanaged open areas), life strategy types (long- and short-lived species) and in elevation. Thermophilisation of bryophyte communities was on average 2.1 times higher than of vascular plant communities and at high elevations it approximated the expected rate given the shift of isotherms. Thermophilisation of both, bryophyte and vascular plant communities was not driven by a loss of cryophilic species but by an increase in thermophilic and mesophilic species, indicating an in-filling process. Furthermore, our data show that thermophilisation is higher in managed grasslands than in forests. We suggest that the higher responsiveness of bryophytes compared to vascular plants depends on their poikilohydry and dispersal capacity and that lower thermophilisation of forests communities is related to the buffering effect of microclimatic conditions in the interior of forests. Our study emphasises the heterogeneity of climate warming effects on plants because response dynamics differ between taxonomic groups as well as between land use types and along elevational gradients.

Sylvo-pastoral systems are species-rich man-made landscapes that are currently often severely threatened by abandonment or management intensification. At low tree densities, single trees in these systems represent habitat islands for epiphytic cryptogams. Here, we focused on sycamore maple (Acer pseudoplatanus) wooded pastures in the northern European Alps. We assessed per tree species richness of bryophytes and lichens on 90 sycamore maple trees distributed across six study sites. We analysed the effects of a range of explanatory variables (tree characteristics, environmental variables and isolation measures) on the richness of epiphytic bryophytes and lichens and various functional subgroups (based on diaspore size, habitat preference and red list status). Furthermore, we estimated the effect of these variables on the occurrence of two specific bryophyte species (Tayloria rudolphiana, Orthotrichum rogeri) and one lichen species (Lobaria pulmonaria) of major conservation concern. Bryophytes and lichens, as well as their subgroups, were differently and sometimes contrastingly affected by the variables considered: tree diameter at breast height had no significant effect on bryophytes but negatively affected many lichen groups; tree phenological age positively affected red-listed lichens but not red-listed bryophytes; increasing isolation from neighbouring trees negatively affected lichens but not bryophytes. However, the high-priority bryophyte species T. rudolphiana was also negatively affected by increased isolation at small spatial scales. Orthotrichum rogeri was more frequent on young trees and L. pulmonaria was more frequent on trees with thin stems and large crowns. The results indicate that local dispersal is important for lichens, whereas long distance dispersal seems to be more important for colonisation by bryophytes. Furthermore, our study highlights that different conservation measures need to be taken depending on the taxonomic and functional species group or the individual species that is addressed. In practice, for the conservation of a high overall richness in sylvo-pastoral systems, it is crucial to sustain not only old and large trees but rather a wide range of tree sizes and ages.

A new species of Orthotrichum, O. dentatum T.Kiebacher & Lüth, is described from the European Alps. The new species belongs to the subgenus Pulchella (Schimp.) Vitt, section Diaphana Vent. Orthotrichum dentatum is similar to O. schimperi Hammar but differs from the latter in that it features a hairy calyptra, denticulate to dentate leaf apices and strongly keeled leaves. Orthotrichum dentatum grows as an epiphyte on a variety of deciduous trees. So far, the new species has only been found in Italy and Switzerland.

Schistidium foraminis-martini is described as a new species from the Austrian and Swiss Alps. The taxon is characterized by a warm brown coloration, ovate, concave and muticous leaves with rounded apices, ellipsoid capsules, constricted at mouth, the presence of stomata and a reduced, truncate peristome. Based on sequences of the ITS region the new species is phylogenetically rather isolated, exhibiting the closest relationship to S. agassizii which shares the muticous leaves but differs in having narrowly lingulate-lanceolate, almost flat leaves, cyathiform capsules and a perfect peristome. Schistidium foraminis-martini grows on moist calcareous rocks in the alpine and nival belt.

We provide an example of ecological vicariance among two epilithic, high mountain taxa of mosses. Phylogenetic analyses using plastid (rps4-trnS, atpB-rbcL, trnL-trnF) and nuclear (EST-115, EST-317, ITS region) markers and morphological data revealed the distinctiveness of the neglected Orthotrichum killiasii, here resurrected from the synonymy of Lewinskya speciosa and newly combined in Lewinskya. Furthermore, our data indicate a speciation process within O. killiasii related to the rock type inhabited (silicate vs. carbonate). We translate this into the recognition of two subspecies, corresponding to O. killiasii s.s. and the recently described O. simonyi. The incongruence between nuclear and plastid markers in some accessions and the partial but rare incongruence between ITS ribotypes and the morphological manifestation in phenotypes indicate incomplete lineage sorting with respect to rather recent segregation and possible gene flow between the two entities.