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Aim: Natural disturbances influence forest structure, successional dynamics and consequently, the distribution of species through time and space. We quantified the longterm impacts of natural disturbances on lichen species richness and composition in primary mountain forests, with a particular focus on the occurrence of endangered species.Location: Ten primary mountain spruce forest stands across five mountain chains of the Western Carpathians, a European hotspot of biodiversity.Methods: Living trees, snags and downed logs were surveyed for epiphytic and epixylic lichens in 57 plots. Using reconstructed disturbance history, we tested how lichen species richness and composition was affected by the current forest structure and disturbance regimes in the past 250 years. We also examined differences in community composition among discrete microhabitats.Results: Dead standing trees as biological legacies of natural disturbances promoted lichen species richness and the occurrence of threatened species at the plot scale, suggesting improved growing conditions for rare and common lichens during the early stages of recovery post disturbance. However, high-severity disturbances compromised plot-scale species richness. Both species richness and the number of oldgrowth specialists increased with time since disturbance (i.e., long-term uninterrupted succession). No lichen species was strictly dependent on live trees as a habitat, but numerous species showed specificity to logs, standing objects or an admixture of tree species.Conclusions: Lichen species richness was lower in regenerating, young and uniform plots compared with overmature and recently disturbed areas. Natural forest dynamics and its legacies are critical to the diversity and species composition of lichens. Spatiotemporal consequences of natural dynamics require a sufficient area of protected forests for provisioning continual habitat variability at the landscape scale. Ongoing climatic changes may further accentuate this necessity. Hence, we highlighted the

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Mountain spruce- and beech-dominated forests (SDPF and BDPF) are of major importance in temperate Europe. However, information on the differences between their historical disturbance regimes, structures, and biodiversity is still incomplete. To address this knowledge gap, we established 118 circular research plots across 18 primary forest stands. We analysed the disturbance history of the last 250 years by dendrochronological methods and calculated disturbance frequency, severity, and timing. We also measured forest structure (DBH, tree density, volume of deadwood, and other parameters). Breeding bird populations were examined by point count method during the spring seasons 2017–2018 (SDPF) and 2019–2020 (BDPF). Using direct ordination analysis, we compared the disturbance history, structure and bird assemblage in both forest types. While no differences were found regarding disturbance regimes between forest types, forest structure and bird assemblages were significantly different. SDPF had a significantly higher density of cavities and higher canopy openness, while higher tree species richness and more intense regeneration was found in BDPF. Bird assemblage showed higher species richness in BDPF, but lower total abundance. Most bird species which occurred in both forest types were more numerous in spruce-dominated forests, but more species occurred exclusively in BDPF. Further, some SDPF- preferring species were found in naturally disturbed patches in BDPF. We conclude that although natural disturbances are important drivers of primary forest structures, differences in the bird assemblages in the explored primary forest types were largely independent of disturbance regimes.