Due to ongoing global changes, it is essential to establish a baseline record from which to determine future shifts in species distributions and community assembly patterns. In this context, we used digitised historical bryophyte distribution data along a 1021 m elevational gradient in Terceira Island (Azores) to determine how bryophyte species distribution varies with elevation and which spatial and climatic drivers contribute to this variation. We used ordinary least squares analysis to test for climatic and spatial data as explanatory variables for bryophyte richness and Mid-Domain Null simulations to assess the influence of spatial constraints on species distributions. Bryophyte richness follows a hump-shaped pattern, with mosses predominating in the first half of the gradient and liverworts in the second half. While moss richness did not correlate to any climatic variables and responded weakly to the presence of forest cover, liverwort presence was related to temperature, rainfall, humidity and the occurrence of native forest areas, suggesting that these plants are more sensitive to changes in their environment and can thus be used as better indicator species for climate change. Despite their inherent biases, our study shows that historically compiled data can be a valuable tool for preliminary assessment of macroecological patterns.

Background: Functional trait-based approaches link species diversity patterns to ecosystem functioning. In the context of global change, understanding these links is vital for developing holistic biodiversity management strategies. Bryophytes, important ecosystem components owing to their biogeochemical functions, have not been the focus of many functional studies. Aims: This is the first assessment of bryophyte functional diversity in the Azores archipelago, aiming to uncover multivariate trait richness and composition patterns along the elevational gradient on Terceira Island. Methods: Based on five water acquisition and retention traits of leafy liverworts and mosses, we calculated functional diversity metrics within and among six bryophyte communities sampled along a 1021-m elevational transect. Results: Trait composition differed significantly between coastal and mountain communities. Mosses presented inrolled leaves and ornamented leaf cells at low elevation but not at high elevation. These patterns were associated with an uphill shift from drier and warmer conditions to a moister and cooler environment. Conclusions: Future climatic changes might affect bryophyte functional diversity patterns in Terceira Island, particularly for mosses. These results can be directly compared with those obtained for other archipelagos where the same protocol has been applied, allowing a joint assessment of insular vegetation functional diversity patterns.

Trait databases are invaluable sources of information in ecological studies exploring the links between species traits and their surrounding environment. While digital vascular plant trait databases are already numerous, sets of bryophyte trait data are not equally available online. To help fill in this gap, we present the BRYOTRAIT-AZO database, a trait dataset for the Azorean bryoflora which aims to gather and facilitate access to all the published morphological information for the archipelago's bryophytes. As an example of its applications we examined the variation of moss leaf size, orientation and nerve extension along Terceira Island's elevational gradient, testing hypothesis related with trait presence and function. We identified a shift from mosses with twisted and shorter but longly costate leaves at lower elevation to mosses with longer untwisted leaves, with short or absent nerves at higher ground. These changes reflect the transition from sunnier, warmer and drier conditions at low elevation to shadier, cooler and damper settings at the island summit, in accordance with the hypothesis that smaller, twisted and longly costate leaves are better adapted to more xeric environments. As exemplified, this database can be a valuable tool for future studies at a regional or even a global scale, coupling functional data with bryophyte distribution information to identify trait roles on ecosystem functioning, but also general diversity and species co-occurrence patterns and community assembly rules.

Altitudinal gradients offer powerful natural frameworks to investigate how environmental factors shape biodiversity, especially on young oceanic volcanic islands where short spatial distances encompass sharp climatic transitions. This study documents bryophyte diversity and examines how elevation, substrate, and environmental variables influence the structure of bryophyte communities on Flores Island (Azores). Across five sites and 385 microplots, 89 species from 37 families were recorded, with liverworts predominating (liverwort-to-moss ratio of 1.41). Species richness and abundance followed a unimodal pattern, peaking at mid-elevations (400–600 m a.s.l.), where humid and thermally stable conditions favor the coexistence of lowland and montane taxa. Even modest altitudinal shifts corresponded to pronounced turnover in community composition, revealing strong ecological filtering along the gradient. Substrate type further influenced diversity patterns, with liverworts dominating epiphytic and lignicolous habitats, while mosses were more diverse on terricolous and rupicolous substrates. The presence of several Azorean and Macaronesian endemics, including threatened taxa, highlights the conservation importance of mid-elevation habitats. Overall, these results show that fine-scale altitudinal variation generates substantial ecological differentiation, underscoring the role of montane forests as refugia for hygrophilous and endemic bryophytes and as sensitive indicators of environmental change in island ecosystems.