Bryophytes are some of the most sensitive biological indicators of environmental change.Springs have a significant presence of bryophytes and hence they are ideal habitats for studying their relationship with the environment. We tested whether bryophyte assemblages can be explained with macro-, meso-and micro-ecological variables (i.e., seasonal climate, altitude, water pH and conductivity) sampling bryophytes from 198 semi-natural springs distributed along montane regions in the north-eastern Iberian Peninsula. We tested the influence of environmental variables on bryophyte assemblages in springs using sparse Partial Least Squares (sPLS). Our results show that variability in bryophyte assemblages is explained by seasonal climate (temperature and precipitation from winter, spring, summer and autumn and temperature and precipitation seasonality), altitude and water conductivity. The results obtained by the present study will be useful for predicting bryophyte diversity in springs using simple and easy to obtain variables such as climate, water pH and conductivity.

1. Climate change is predicted to progressively shift habitat characteristics that will alter the distribution and eco-physiological responses of organisms. Highelevation stream insects without extensive dispersal are expected to be highly vulnerable if they are unable to track predicted shifts. Understanding dispersal is therefore crucial to implement practical solutions in conservation.2. The evolutionary history of the Palaearctic genus Annitella (Trichoptera), the population dynamics and habitat distribution (present and future) of two endemic species (A. esparraguera and A. iglesiasi) confined to Baetic Mountains (SE-Iberian Peninsula) were assessed to gain fundamental insights into species responses to climate warming and to identify populations at risk.3. Diversification of Annitella was dated to the Pleistocene and was likely associated with southern and extra-Mediterranean refugia located across Europe. The two endemic species belong to distant lineages that preferred similar cold headwater pristine habitats. The range of A. esparraguera was larger than that of A. iglesiasi. Both species showed low genetic diversity in cox1, but only A. esparraguera exhibit locally unique haplotypes, indicating limited gene flow. For A. esparraguera, modelled future habitat suitability showed 88.4% range contraction by 2050 (RCP scenario 8.5) and a displacement of 41.5% of the current potential distribution to higher elevations. 4. Populations of A. esparraguera are predicted to be lost because of the reduction of optimal habitat and limited propensity for tracking future suitable conditions. Beyond the preservation of their current habitat, their conservation might require proactive measures (translocations). Similar predictions may apply to other Mediterranean endemic headwater specialist restricted to isolated high-elevation streams.

Summary Across environmental gradients, some functional strategies are favoured over others resulting in differences in local species composition and distribution of any given functional trait. This generates among‐Species Trait Variability (STV) across the gradient (reflecting species turnover), as well as spatial Intraspecific Trait Variability (ITV), which together contribute to Community Trait Variability (CTV). Understanding functional trait responses of freshwater biota is critical for elucidating the mechanisms that operate during community assembly and addressing community level responses to climate warming. In freshwater insects, temperature and ecological conditions regulate growth rates. Here, we examined size‐related trait variability components of short‐dispersing stoneflies (Insecta: Plecoptera) within and among multispecies stonefly assemblages (henceforth referred to as communities), located along an elevational gradient in Sierra Nevada (Spain) to assess the components of trait‐elevation matching (STV, ITV, CTV). Relative to downstream reaches, headwaters hypothetically show greater internal physical habitat heterogeneity (large exposed rocks, tree roots, woody debris) and greater local species richness of cool‐water adapted stoneflies. As a result, we expected CTV to increase with elevation, with a higher contribution of STV than ITV in upper reaches due to higher species richness and trait divergence among them. In contrast, the pattern of ITV should vary depending on whether the main driver across elevation is species richness (decrease due to niche partitioning) or ecological conditions (increase associated to physical habitat heterogeneity). Eleven streams were sampled every 2 weeks over 1 year and five size‐related traits were measured on 6,893 individuals belonging to 16 species. Overall, STV made a much larger contribution to CTV than ITV, which only became an important contributor in species‐poor assemblages, especially in winter and autumn. Within each season, the trait‐elevation matching was weak. Functional species‐specific responses to the elevational gradient most often did not mirror the response of the entire communities, since highly variable (and even opposed or discontinuous) contributions to ITV were found across species. Overall, ITV contributed little to trait‐elevation matching, which suggests high vulnerability of short‐dispersing stoneflies to habitat shifting associated to future climate warming due to limited phenotypic plasticity. Moreover, varying functional trait patterns across species emphasise species‐specific responses to climate change as opposed to a unique whole community response. However, further trait‐based macroecological studies across freshwater macroinvertebrates lineages are needed to compare patterns and establish generalisations.

A fundamental question in macroecology is how contemporary and historical environments, species interactions and evolutionary processes contribute to determining community structure and shape current large‐scale taxa distributions. We used a novel perspective simultaneously considering taxonomic, functional, and phylogenetic diversity to elucidate how these factors have shaped regional diversity patterns in composition of Trichoptera (Insecta) at the genus level among 62 mountain stream reaches located across six regions from Morocco to Sweden. The biogeographical range paradigm postulates declining diversity with latitude, but our results showed that taxonomic diversity was unrelated to latitude and local richness was similar in both previously glaciated and unglaciated southern regions. Also, taxonomic β‐diversity across regions was mostly driven by turnover rather than the expected nestedness component. High taxonomic diversity and several indicator genera (i.e. genera characteristic of any specific region) were found in Mediterranean regions, but also in the Carpathians and across central‐eastern Europe. Functional traits revealed phylogenetic trait conservatism. Phylogenetic diversity and functional richness did not decrease with latitude. Phylogenetic structure of central and eastern communities was clustered (i.e. communities composed by closely related genera), whereas south‐western communities were phylogenetically overdispersed (i.e. less closely related than expected by chance). Overall, latitudinal patterns of taxonomic turnover and variable phylogenetic community structure indicate an important role of contemporary ecological conditions in structuring community composition, probably by environmental filtering. However, the signature of biogeographical history is also relevant to understanding the large‐scale distribution of taxa. The permanence of caddisfly communities in temperate regions during Pleistocene glaciations demonstrates the presence of refugia there and, therefore, broadens the spatial extent of refugia beyond Mediterranean areas. This contrasts with theories which placed refugia exclusively in Mediterranean areas.

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