Boreal forests are important reservoirs of biodiversity, carbon and timber stocks. However, timber harvest can alter biodiversity in these forests without clear evidence on the duration needed for biotic groups to recover. Resilience of boreal forest biodiversity to clear-cut harvest was examined with a meta-analysis of 190 datasets from boreal and hemi-boreal forests of Europe/Russia and North America for arthropods, birds, small mammals, lichens, bryophytes and vascular plants. We modelled similarity of community composition between harvested and unharvested stands versus years post harvest. In approximately half of cases, predicted times for recovery to pre-harvest composition were ≤30 years. In other cases, recovery took much longer or had not occurred within the timeframe of our data; for example, in conifer forest: >100 years (bryophytes), >55 years (small mammals), ~95 years (lichens) and ~85 years (vascular plants). Saproxylic beetles showed no resilience within the 16 (conifer forest) or 29 (mixed forest) years post harvest for which we had data. Recovery generally took longer in conifer and mixed than in broadleaf forests, which always showed either resistance (bryophytes, vascular plants) or resilience with recovery within 12–25 years. Conserving biodiversity in boreal forests will require extended rotations, management for ‘old forest’ structural elements and areas protected from harvesting.

Plant ecologists have demonstrated the usefulness of functional traits in explaining vascular plant community structure and ecosystem functioning. Functional trait-based approaches have been increasingly applied to cryptogams over the last 30 years. However, the application of vascular plant-based traits to non-vascular photoautotrophs (NVP; here bryophytes and lichens) remains challenging due to their differing ecophysiological characteristics. Several elements of NVP functional ecology do not have parallels in vascular plant ecology, such as traits related to morphology (shoot, ramet or thallus architecture, and leaf structure), water relations (poikilohydry, desiccation tolerance), and reproduction (vegetative, spores), as well as the scales (e.g., colony) at which some of these traits are measured. Another issue concerns data availability, with relevant information scattered across the literature and NVP trait measurements conducted in a variety of ways that are not always comparable. Here, we propose a hierarchical trait ontology and a thesaurus for NVP to drive future research. Our literature review resulted in a final corpus of 598 articles published between 1967 and 2024. Two hundred thirty-two traits were identified, with the majority (70%) being used as response traits related to growth and reproduction in individual organisms. The number and diversity of traits used in NVP studies have increased markedly over time, resulting in substantial heterogeneity in terminology, definitions, and measurement protocols across the literature. We also found that ecological performance indices were frequently treated as traits, highlighting a widespread conceptual confusion that complicates data synthesis and cross-study comparisons. The use of the trait-based approach in vascular plant studies has been supported by the development of standardized centralized definitions, protocols, and databases, a foundation not yet developed for NVP research. Based on this review, we propose an ontology for structuring NVP trait data and definitions. Together with more standardized protocols, we hope this framework will enable the future development of consistent functional trait databases of NVP, ultimately advancing our understanding of how traits mediate functions and responses of these organisms in ever-changing environments.