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Questions: The alpine vegetation of the Alps is particularly vulnerable to climate change, as the temperature increase in this region is twice the global average and the available area for new colonisations decreases with increasing elevation. While numerous studies have investigated the response of vascular plants to a warming climate in the alpine belt, only a handful have investigated that of cryptogams in the European Alps. Based on a 21‐year monitoring project, we assessed the effects of climate change on cryptogams along elevation, from the treeline to the subnival belt. Location: Four GLORIA summits in Valais (Switzerland). Methods: Between 2001 and 2022, terricolous lichens and bryophytes (from 2008) were inventoried in 52 1‐m2 plots distributed across four summits: 2360 m a.s.l. (treeline), 2550 m (lower alpine), 2990 m (upper alpine) and 3210 m (subnival). Changes in species cover and richness were analysed using generalised linear mixed‐effects model (GLMMs). Results: For bryophytes, total cover remained stable overall. However, six species declined significantly between 2008 and 2022, and the species richness decreased after 2015. For terricolous lichens, total cover significantly increased on the lower alpine summit, while species richness increased on the upper alpine and subnival summits. Conclusions: Bryophytes have probably suffered from the increasingly dry conditions, with a succession of very warm and dry summers over the last decades. Terricolous lichens have taken advantage of the warmer conditions to increase their cover on the lower alpine summit, and new species have colonised the upper summits. However, as they compete with vascular plants for soil and light, they may suffer from shrub and tree encroachment in the future and will be limited upwards by the rarity of developed soils. The large topo‐climatic gradient (850 m) and the length of the time series suggest that similar trends are likely to be more widespread across the Alps. [ABSTRACT FROM AUTHOR]

Species turnover is ubiquitous. However, it remains unknown whether certain types of species are consistently gained or lost across different habitats. Here, we analysed the trajectories of 1827 plant species over time intervals of up to 78 years at 141 sites across mountain summits, forests, and lowland grasslands in Europe. We found, albeit with relatively small effect sizes, displacements of smaller‐ by larger‐ranged species across habitats. Communities shifted in parallel towards more nutrient‐demanding species, with species from nutrient‐rich habitats having larger ranges. Because these species are typically strong competitors, declines of smaller‐ranged species could reflect not only abiotic drivers of global change, but also biotic pressure from increased competition. The ubiquitous component of turnover based on species range size we found here may partially reconcile findings of no net loss in local diversity with global species loss, and link community‐scale turnover to macroecological processes such as biotic homogenisation. [ABSTRACT FROM AUTHOR]

Premise of the Study: With biodiversity and rates of climate change among the highest, the eastern Himalaya are critical for understanding the interaction of these two variables. However, there is a dearth of longitudinal data sets that address the effects of climate change on the exceptional alpine biodiversity of the Himalaya. Methods: We established permanent alpine vegetation monitoring plots in three mountain chains of the Hengduan Mountains, the easternmost Himalaya, which have warmed 0.03–0.05°C yr−1 since 1985. Recently, we resampled plots (176 1‐m2 quadrat plots and 88 sections of 11 summits in three Hengduan mountain chains) to measure changes in vegetation after 7 years. Key Results: Over 7 years, Tibetan alpine vegetation increased in number of species (+8 species/summit; +2.3 species/m2), in frequency (+47.8 plants/m2), and in diversity (+1.6 effective species/m2). Stepwise regressions indicated that warmer temperatures, southerly aspects, and higher elevations were associated with greater increases in these vegetation metrics. Unexpectedly, Himalayan endemic species increased (+1.4 species/m2; +8.5 plants/m2), especially on higher‐elevation summits. In contrast, the increase in relative abundance of non‐alpine species was greater at lower‐elevation summits. Plants used by local Tibetans also increased (+1.3 species/m2; +32 plants/m2). Conclusions: As in other alpine areas, biodiversity is increasing with climate change in the Himalaya. Unlike other areas, endemic species are proliferating at the highest summits and are indicators of change. [ABSTRACT FROM AUTHOR]

Aim In the alpine life zone, plant diversity is strongly determined by local topography and microclimate. We assessed the extent to which aspect and its relatedness to temperature affect plant species diversity, and the colonization and disappearance of species on alpine summits on a pan-European scale. Location Mountain summits in Europe's alpine life zone. Methods Vascular plant species and their percentage cover were recorded in permanent plots in each cardinal direction on 123 summits in 32 regions across Europe. For a subset from 17 regions, resurvey data and 6-year soil temperature series were available. Differences in temperature sum and Shannon index as well as species richness, colonization and disappearance of species among cardinal directions were analysed using linear mixed-effects and generalised mixed-effects models, respectively. Results Temperature sums were higher in east- and south-facing aspects than in the north-facing ones, while the west-facing ones were intermediate; differences were smallest in northern Europe. The patterns of temperature sums among aspects were consistent among years. In temperate regions, thermal differences were reflected by plant diversity, whereas this relationship was weaker or absent on Mediterranean and boreal mountains. Colonization of species was positively related to temperature on Mediterranean and temperate mountains, whereas disappearance of species was not related to temperature. Main conclusions Thermal differences caused by solar radiation determine plant species diversity on temperate mountains. Advantages for plants on eastern slopes may result from the combined effects of a longer diurnal period of radiation due to convection cloud effects in the afternoon and the sheltered position against the prevailing westerly winds. In northern Europe, long summer days and low sun angles can even out differences among aspects. On Mediterranean summits, summer drought may limit species numbers on the warmer slopes. Warmer aspects support a higher number of colonization events. Hence, aspect can be a principal determinant of the pace of climate-induced migration processes. [ABSTRACT FROM AUTHOR]

High mountain zones in the Mediterranean area are considered more vulnerable in comparison to lower altitudes zones. Lefka Ori massif, a global biodiversity hotspot on the island of Crete is part of the Global Observation Research Initiative in Alpine Environments (GLORIA) monitoring network. The paper examines species and vegetation changes with respect to climate and altitude over a seven-year period (2001–2008) at a range of spatial scales (10 m Summit Area Section-SAS, 5 m SAS, 1 m2) using the GLORIA protocol in a re-survey of four mountain summits (1664 m–2339 m). The absolute species loss between 2001–2008 was 4, among which were 2 endemics. At the scale of individual summits, the highest changes were recorded at the lower summits with absolute species loss 4 in both cases. Paired t-tests for the total species richness at 1 m2 between 2001–2008, showed no significant differences. No significant differences were found at the individual summit level neither at the 5 m SAS or the 10 m SAS. Time series analysis reveals that soil mean annual temperature is increasing at all summits. Linear regressions with the climatic variables show a positive effect on species richness at the 5 m and 10 m SAS as well as species changes at the 5 m SAS. In particular, June mean temperature has the highest predictive power for species changes at the 5 m SAS. Recorded changes in species richness point more towards fluctuations within a plant community's normal range, although there seem to be more significant diversity changes in higher summits related to aspects. Our work provides additional evidence to assess the effects of climate change on plant diversity in Mediterranean mountains and particularly those of islands which remain understudied. [ABSTRACT FROM AUTHOR]