Bryophytes are a diverse group of organisms with unique properties, yet they are severely underrepresented in plant trait databases. Building on the recently published European Red List of bryophytes and previous trait compilations, we present the Bryophytes of Europe Traits (BET) data set, including biological traits such as those related to life history, growth habit, sexual and vegetative reproduction; ecological traits such as indicator values, substrate and habitat; and bioclimatic variables based on the species' European range. The data set includes values for 65 traits and 25 bioclimatic variables, containing more than 135,000 trait values with a completeness of 82.7% on average. The data set will enable future studies in bryophyte biology, ecology and conservation, and may help to answer fundamental questions in bryology.

Across environmental gradients, community‐level functional traits of plants can change due to species turnover, intraspecific variation and their covariation. Studies on vascular plants suggest that species turnover is the main driver of trait variation across gradients, although intraspecific variation can also be important. However, there is limited knowledge about whether this holds for non‐vascular primary producers such as lichens and bryophytes. We hypothesized that intraspecific variation is more important for non‐vascular than for vascular primary producers because they lack specialized structures to maintain homeostasis and should therefore be more responsive to extrinsic factors. To assess the relative importance of species turnover versus intraspecific variation for vascular plants, lichens and bryophytes, we estimated species abundance and measured chemical (tissue nitrogen (N) and phosphorous (P) content, N:P ratio and pH) and non‐chemical (specific leaf or thallus area, dry matter content and water holding capacity) functional traits along an elevational gradient in alpine southern Norway. We calculated community‐weighted mean traits and quantified the relative contribution of species turnover, intraspecific variation and their covariation to total trait variation across the gradient. We found mixed support for our hypothesis: the contribution of intraspecific variation to total trait variation for N and N:P was higher in lichens than in vascular plants and bryophytes, but in general the contribution of intraspecific variation differed among functional traits and producer groups. Nutrient variables (N, P and N:P) were significantly impacted by intraspecific variation for vascular plants and lichens but not for bryophytes. Non‐chemical traits and pH were mainly driven by species turnover effects in all primary producer groups. Our results highlight that while nearly all studies on primary producer trait variation across environments have focused on vascular plants, trait variation of other largely neglected but ecologically important producer groups, such as lichens and bryophytes, may show very different responses to the same environmental factors. In order to fully understand how future environmental changes impact on community‐ and ecosystem‐level processes, traits of primary producers other than vascular plants—and their within‐species variation—need to be considered in systems where these groups are abundant. A free Plain Language Summary can be found within the Supporting Information of this article.

We measured community-level traits of vascular plants, lichens, and bryophytes in an alpine Dryas octopetala L. heath in Finse, Norway, after nearly two decades of experimental warming by open-top chambers. We hypothesized that under warming (1) vascular plant traits would shift from resource conservative towards more resource acquisitive, and (2) lichen and bryophyte traits would shift to those associated with drier conditions, due to increased evapotranspiration. Both hypotheses were not supported, as vascular plant nitrogen concentration decreased, whereas carbon to nitrogen ratio increased with warming, indicative of a less resource acquisitive strategy, and lichen specific thallus area and water holding capacity were unresponsive. Bryophyte specific shoot length increased, and carbon concentration and water holding capacity tended to decrease under warming, concurrent with increased vegetation height and litter cover indicating stronger competition from vascular plants. Intraspecific variation was most important for vascular plant and lichen traits, whereas species turnover was the main driver of bryophyte trait variation. This indicates that bryophytes may be affected more strongly by future warming than vascular plants and lichens in our study system. We highlight the importance of studying traits of different primary producer groups simultaneously, as they may respond differently to the same environmental changes.

Vascular plants and lichens often produce a diversity of carbon‐based secondary compounds (CBSCs) to protect them against biotic and abiotic stresses. These compounds play important but often compound‐specific roles in community and ecosystem processes by affecting herbivore and decomposer activity. However, our understanding of what drives community‐level CBSCs among ecosystems or across environmental gradients is limited. We measured concentrations and compositions of CBSCs for all dominant vascular plant and lichen species present across a 500‐m alpine elevational gradient. These measurements were combined with data on species composition and abundance to obtain whole‐community measures of plant and lichen CBSCs across the gradient. At the whole community level, plant CBSCs had the lowest concentrations while lichen CBSCs had the highest concentrations at the highest elevations. Further, plant CBCSs shifted from those associated with herbivore defence towards those protecting against light and oxidative stress as elevation increased, while lichen CBSCs showed the opposite pattern. Synthesis. Our findings that individual compounds show contrasting responses to the same environmental gradient highlight the importance of studying qualitative as well as quantitative changes in CBSCs. Further, the divergent responses between vascular plants and lichens reveal that in systems where both groups are abundant, they need to be considered simultaneously to better understand how future environmental changes may impact on ecosystem‐level processes. A free Plain Language Summary can be found within the Supporting Information of this article.