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Questions: We assessed interactions between climate change, bedrock types and snow cover duration on the trajectories of taxonomic and functional composition of subalpine plant communities. We predict (i) an increase in species richness on siliceous bedrock due to a reduced competition and a decrease in richness on calcareous bedrock due to increasing drought stress; (ii) decreasing snow cover duration should induce a higher shrub encroachment in hollows as compared to ridges; and (iii) increasing growing season temperature should induce taller sizes and more conservative growth traits, in particular in hollows. Location: Subalpine belt of the Grandes Rousses mountain range, southwestern Alps (France). Methods: 189 vegetation plots were sampled in 1997 and 2017–2018. The duration of snow cover was assessed during two years in 1995–1997 and five functional traits were measured on 108 species in 2021. We performed multivariate analyses, quantified community‐weighted means (CWM) of traits and used ANOVAs to detect responses to local‐scale factors and changes in snow cover, temperature and precipitation since 1997 according to a nearby meteorological station. Results: Overall, taxonomic composition weakly changed and changes were more dependent on the position of communities along the snow cover duration gradient than on their bedrock type. The abundance of drought‐tolerant species increased at the border of hollows and there was, over all communities, a slight increase in the abundance of dwarf shrubs and tall herbaceous species, a strong decrease in short herbaceous species and, thus, an overall decrease in species richness. There were important overall changes in CWM of size traits, in particular leaf area which increased the most in hollows irrespective of bedrock types. Conclusion: In this subalpine site the effects of decreasing snow cover duration overwhelmed the effects of bedrocks, which may explain the overall increase in competitive species and decrease in species richness. [ABSTRACT FROM AUTHOR]

Warming in mountain regions is projected to be three times faster than the global average. Pronounced climate change will likely lead to species reshuffling in mountain plant communities and consequently change ecosystem resilience and functioning. Yet, little is known about the role of inter‐ versus intraspecific changes of plant traits and their consequences for functional richness and evenness of mountain plant communities under climate change. We performed a downslope translocation experiment of intact plant‐soil mesocosms from an alpine pasture and a subalpine grassland in the Swiss and Austrian Alps to simulate an abrupt shift in climate and removal of dispersal barriers. Translocated plant communities experienced warmer and dryer climatic conditions. We found a considerable shift from resource conservative to resource acquisitive leaf‐economy in the two climate change scenarios. However, shifts in leaf‐economy were mainly attributable to species turnover, namely colonization by novel lowland species with trait expressions for a wider range of resource use. We also found an increase in vegetative height of the warmed and drought‐affected alpine plant community, while trait plasticity to warming and drought was limited to few graminoid species of the subalpine plant community. Our results highlight the contrast between the strong competitive potential of novel lowland species in quickly occupying available niche space and native species' lack of both the intraspecific trait variability and the plant functional trait expressions needed to increase functional richness under warming and drought. This is particularly important for the trailing range of many mountain species (i.e. subalpine zone) where upward moving lowland species are becoming more abundant and abiotic climate stressors are likely to become more frequent in the near future. Our study emphasizes mountain plant communities' vulnerability to novel climates and biotic interactions under climate change and highlights graminoid species as potential winners of a warmer and dryer future. Keywords: alpine grassland, functional diversity, invasion, species turnover, traitspace, translocation [ABSTRACT FROM AUTHOR]

Aim: Understanding how combinations of ecological traits at the community‐level vary with environmental conditions is crucial to anticipate and respond to the biodiversity crisis. While this topic is popular, most attempts to analyse and predict multiple traits in space and time ignore the inherent correlations between these traits. In doing so, the predicted traits in unobserved environments are likely to be flawed (i.e. unrealistic trait combinations). Here, we propose a framework that addresses this methodological question in functional biogeography. Innovation: Our framework relies on joint trait distribution models to quantify how combinations of mean trait values at the community level co‐vary as a function of environmental conditions. Making use of joint probabilities and the constraints imposed by trait correlations, our framework not only predicts the most suitable combination of traits in a given environment but also the envelope of possible alternatives. This innovation allows visualizing how the correlation structure between traits imposes a strong constraint (or not) on the expected combination of traits in a given environment. The stronger trait correlations, the smaller the envelope of likely alternative states. We provide an R package implementing our framework. Main Conclusions: Applied to plant communities in the French Alps, our framework quantifies the variation of trait combinations at the community‐level along environmental gradients that, otherwise, could not be identified. Strong correlations in community mean leaf traits led to a low diversity of alternative combinations of community means, which can only vary along the acquisition‐conservation spectrum. Instead, height varied partly independently of leaf traits, leading to a higher diversity in the combinations of mean community traits. Our framework allows for a more integrated understanding and prediction of the distribution of traits, thus moving a descriptive functional biogeography to a more predictive science. [ABSTRACT FROM AUTHOR]

Climate warming causes upward shifts in plant species distributions, resulting in an influx of species from lower elevations into alpine plant communities. Plant functional trait changes along elevation gradients and over time may reflect these changing conditions. Intraspecific trait variation measured from herbarium records offers a way to observe such changes in trait values over time.We selected four species: Poa alpina and Polygonum viviparum found in alpine grasslands, and Cardamine resedifolia and Ranunculus glacialis found in high‐alpine to subnival scree habitats. We measured several functional traits from (i) herbarium records collected between 1880 and 1950 and from (ii) individuals resampled in 2014 along an elevation gradient covering >1500 m within the same study region in the Swiss Alps. By comparing (i) against (ii) for each species separately, we analysed temporal changes in the distribution of traits along the studied elevation gradient.After a century of climate warming, the change in the relationship linking plant functional traits with elevation was species dependent. Size‐related and reproductive functional trait values for P. viviparum increased over time, increasing at lower, but not higher elevations. Poa alpina's size‐related traits increased consistently with time along the elevation gradient. Most of C. resedifolia's size‐related and flowering traits decreased over time at lower elevations and converged at higher elevations. Finally, R. glacialis traits did not respond to time alone—reproductive traits decreased over time at lower, and increased at higher elevations, reversing their historical trait distributions. The negative trend for vegetative trait values with elevation did not change over time, however. In 2014, at lower elevations, all species mainly occurred on their typical microhabitat types, but occurrence on other microhabitats increased with elevation for all species.Synthesis: Contrasting temporal changes in the distribution of growth and reproductive trait values between alpine grassland and alpine‐subnival scree species, especially at lower elevations, suggest that climate warming effects vary among species. Additionally, species' physiological constraints and availability of suitable microhabitats may further impact species' distribution changes. Further warming may confine the distribution of high‐alpine plant species to even higher elevations, or microclimates currently difficult to colonise by lower‐alpine species. [ABSTRACT FROM AUTHOR]

Question: Differences in understorey vegetation between ancient and recent forests have been thoroughly explored; however, few studies have investigated the legacies of different former land uses in recent forests. Indeed, due to more intense agricultural practices (tillage and fertilisation), legacy effects are expected to be stronger in former cropland or meadows than in former pastures. Our objectives were to compare soil conditions, taxonomic composition and functional composition of understorey plant communities in recent forests located on former pastures, meadows or cropland, with ancient forests as a reference. Location: Tarentaise Valley, Savoy, France. Methods: Based on land‐use maps surveyed between 1862 and 1864, we selected 82 forest sites with different former land uses in mountain forests in the French Alps and carried out soil sampling and botanical surveys. To account for potential confounding factors (altitude, canopy cover, tree species composition), we applied multiple linear regressions to analyse soil properties, canonical correspondence analysis to analyse plant taxonomic composition and multispecies generalised linear mixed‐effects models to analyse relationships between plant functional composition and former land uses. Results: The soils of former cropland were richer in nutrients and more alkaline compared to other past land uses, while soils on former pastures and meadows differed only slightly from ancient forests. Ancient forests were characterised by acidophilic, shade‐tolerant, low‐stature, forest‐dependent species, whereas former cropland was characterised by calcicolous non‐forest species. Former pasture and meadow communities displayed a distinct taxonomic composition compared to other past land uses, but a functional composition closer to ancient forest than to former cropland. Conclusion: Former cropland has a stronger legacy effect than former pastures or meadows. This could explain small differences between ancient and recent forests observed in previous studies conducted in mountain landscapes where former cropland was rare. [ABSTRACT FROM AUTHOR]

Environmental gradients generate and maintain biodiversity on Earth. Mountain slopes are among the most pronounced terrestrial environmental gradients, and the elevational structure of species and their interactions can provide unique insight into the processes that govern community assembly and function in mountain ecosystems. We recorded bumble bee–flower interactions over 3 years along a 1400‐m elevational gradient in the German Alps. Using nonlinear modeling techniques, we analyzed elevational patterns at the levels of abundance, species richness, species β‐diversity, and interaction β‐diversity. Though floral richness exhibited a midelevation peak, bumble bee richness increased with elevation before leveling off at the highest sites, demonstrating the exceptional adaptation of these bees to cold temperatures and short growing seasons. In terms of abundance, though, bumble bees exhibited divergent species‐level responses to elevation, with a clear separation between species preferring low versus high elevations. Overall interaction β‐diversity was mainly caused by strong turnover in the floral community, which exhibited a well‐defined threshold of β‐diversity rate at the tree line ecotone. Interaction β‐diversity increased sharply at the upper extreme of the elevation gradient (1800–2000 m), an interval over which we also saw steep decline in floral richness and abundance. Turnover of bumble bees along the elevation gradient was modest, with the highest rate of β‐diversity occurring over the interval from low‐ to mid‐elevation sites. The contrast between the relative robustness bumble bee communities and sensitivity of plant communities to the elevational gradient in our study suggests that the strongest effects of climate change on mountain bumble bees may be indirect effects mediated by the responses of their floral hosts, though bumble bee species that specialize in high‐elevation habitats may also experience significant direct effects of warming. [ABSTRACT FROM AUTHOR]

Outside controlled experimental plots, the impact of community attributes on primary productivity has rarely been compared to that of individual species. Here, we identified plant species of high importance for productivity (key species) in >29,000 diverse grassland communities in the European Alps, and compared their effects with those of community‐level measures of functional composition (weighted means, variances, skewness and kurtosis). After accounting for the environment, the five most important key species jointly explained more deviance of productivity than any measure of functional composition alone. Key species were generally tall with high specific leaf areas. By dividing the observations according to distinct habitats, the explanatory power of key species and functional composition increased and key‐species plant types and functional composition‐productivity relationships varied systematically, presumably because of changing interactions and trade‐offs between traits. Our results advocate for a careful consideration of species' individual effects on ecosystem functioning in complement to community‐level measures. [ABSTRACT FROM AUTHOR]

We announce the formation of the "GLORIA ITALIA NETWORK" and present an overview of the Italian alpine plant communities changes that have occurred in the last 20 years. This network will provide coordination between Italian GLORIA sites and enhance public awareness of changes in alpine plant diversity under climate change. [ABSTRACT FROM AUTHOR]

Medium‐to‐high elevation grasslands provide critical services in agriculture and ecosystem stabilization, through high biodiversity and providing food for wildlife. However, these ecosystems face elevated risks of disruption due to predicted soil and climate changes. Separating the effects of soil and climate, however, is difficult in situ, with previous experiments focusing largely on monocultures instead of natural grassland communities. We experimentally exposed model grassland communities, comprised of three species grown on either local or reference soil, to varied climatic environments along an elevational gradient in the European Alps, measuring the effects on species and community traits. Although species‐specific biomass varied across soil and climate, species' proportional contributions to community‐level biomass production remained consistent. Where species experienced low survivorship, species‐level biomass production was maintained through increased productivity of surviving individuals; however, maximum species‐level biomass was obtained under high survivorship. Species responded directionally to climatic variation, spatially separating differentially by plant traits (including height, reproduction, biomass, survival, leaf dry weight, and leaf area) consistently across all climates. Local soil variation drove stochastic trait responses across all species, with high levels of interactions occurring between site and species. This soil variability obscured climate‐driven responses: we recorded no directional trait responses for soil‐corrected traits like observed for climate‐corrected traits. Our species‐based approach contributes to our understanding of grassland community stabilization and suggests that these communities show some stability under climatic variation. [ABSTRACT FROM AUTHOR]

The ongoing debate on the causes and modalities of the Messinian Salinity Crisis (MSC) from 5.971 Ma needs to be implemented by an in-depth knowledge of the events and changes, on a global to regional scale, that have preceded its onset. Here we use palynological (pollen and dinocysts) and micropaleontological (foraminifers and calcareous nannoplankton) quantitative analyses from the Govone sedimentary succession (Northern Italy, western Mediterranean) to reconstruct the cyclical changes in atmosphere, surface, and deep-water hydrographic conditions during the Late Miocene, prior to the onset of the MSC (from ca 6.6 Ma) and across it (up to 5.96 Ma). On land, plant communities were dominated by arboreal life forms typical of warm and humid conditions. However, mid- to high altitude coniferous taxa attest to a sequence of cold to cool conditions, some coinciding with glacial obliquity-controlled phases, notably those across the MSC onset (i.e. TG34 and TG32). Dominant trees were Taxodioideae, especially in freshwater swamps, during warm and humid phases. The latter alternate with relatively less warm, and less humid phases characterised by the reduction of Taxodioideae, according to the precession-controlled sedimentary cyclicity (sapropel-marl couplets). The absence of any significant expansion in the herbaceous cover is evidence of no substantial increases in aridity at insolation minima. In the marine realm, the precession-controlled cycles correspond to prevalent alternations between warm water, oligotrophic (sapropel, insolation maxima) and cool water, eutrophic (marls, insolation minima) conditions. The progressive decrease of oceanic/outer neritic dinocyst taxa, along with a more continuous occurrence of the inner neritic ones, confirm the progressive restriction of Mediterranean and Atlantic connections, despite oceanic influxes, the latest at 6.14 Ma and 6.05 Ma. On the other hand, the occurrence of freshwater episodes, according to dinocysts, does not exclude possible connections with Paratethys, at 6.18 Ma and 6.07 Ma. All calcareous nannoplankton and foraminifera apparently disappear from the sedimentary record before the onset of the MSC, at ca 6.02 Ma; however, dinocysts allow the documentation of the history of pre-evaporitic conditions up to the beginning of the MSC onset, when lagoons, marked by frequent salinity changes, expanded in the inner neritic zone of the Govone intermediate depth basin, during ca 60 kyrs. Plant assemblages attest a long-lasting increase of seasonality (from 6.2 Ma) as well as a peculiar inversion in the dominant vegetal patterns of the sapropel-marl couplets, between ca 6.02 Ma and 5.96 Ma, corresponding to the uppermost four cycles. The significant restriction of the marine environment, after 6.02 Ma, possibly promoted atmospheric changes marked by reduced vs enhanced activity of the Mediterranean storm-track in phase with precession. This, in turn, regulated the amounts of runoff in the Northern Italian sectors from the Alps. • Humid conditions persist across the MSC in the northern Mediterranean. • Broad-leaved evergreen-warm mixed forests extended north of 42°N in the Mediterranean. • Calcareous microfossils vanished from sediments 50 ka before the MSC onset. • Dinocysts trace the aquatic environmental changes across the MSC onset. • Nannobarbophora , a warm acritarch, marks the MSC onset. [ABSTRACT FROM AUTHOR]

Theory predicts that a large fraction of phytochemical diversity—the richness of individual chemical compounds produced by plants—governs the complexity of interactions between plants and their herbivores. While the effect of specific classes of chemical compounds on plant resistance against herbivores has been largely documented, the effect of community‐level variation in phytochemical diversity on plant–herbivore interactions has so far received minimal consideration.We hypothesized that plant communities bearing on average higher levels of phytochemical diversity should sustain lower herbivory rates, overall. Yet, the magnitude of this effect could vary across different environmental conditions, potentially because of climate‐mediated effects on phytochemical production and changes in herbivore community richness and composition.To address these hypotheses, we used previous knowledge of species‐level phytochemical make‐up for more than 400 plant species of the Swiss Alps. Using common garden experiments, we estimated season‐wide herbivore damage on low (average 3,500 unique molecules) and high (average 4,500 unique molecules) phytochemical diversity plant communities that were planted in the colline, mountain and alpine vegetation sites along two elevation transects in the Alps.We found that high phytochemical diversity plant communities showed reduced levels of herbivore damage in the colline (low elevation) sites, but this pattern reversed in the alpine (high elevation) sites. Our results suggest that the outcome of phytochemical diversity on plant–herbivore interactions depends on the characteristics of the local herbivore communities, together with trade‐offs between chemical defences and other plant traits (i.e. physical defences and plant palatability).Synthesis. Phytochemical diversity is a key component of functional diversity, influencing community composition and dynamics. We show that the effect of phytochemical diversity on herbivory is environmental‐dependent, generating ecological switches when moving from low to high elevation. Through upward movement of plants under climate change, phytochemical community structure will be likely modified, ultimately disrupting local community assembly processes. [ABSTRACT FROM AUTHOR]

Aims: This paper presents the results of phytosociological research on scree vegetation in the northern Apennines with the aim of comparing vegetation types classified in different syntaxa. The specific objectives were: 1) to identify, classify and describe the vegetation units of scree communities; 2) to pinpoint the main ecological gradients underlying different vegetation units; and 3) to identify a possible hierarchy of predictor variables explaining floristic differences between vegetation types. Study area: The study area lies on the northern border of the Italian Peninsula, between 44° and 44°45' N and 9°20' and 10°45' E, characterized by a large variety of scree habitats and representing both a centre of endemism and a phytogeographic transition zone between the Alps and Apennines. Methods: The study was based on a dataset including 364 relevés taken according to the Braun-Blanquet method, which were then classified following an unsupervised numerical procedure. Species fidelity was used to define the diagnostic species of the associations. PCA and RDA ordinations were employed to perform ecological analyses using both Ellenberg Indicator Values as indirect variables and directly measured or calculated variables. Results: A total of 15 plant associations were identified, belonging to 6 alliances and 4 different orders (Thlaspietalia rotundifolii, Arabido alpinae-Petasitetalia paradoxi, Achnatheretalia calamagrostis and Androsacetalia alpinae) within the class Thlaspietea rotundifolii. All associations were described according to their floristic composition, structure, syntaxonomy, habitat and distribution. Conclusions: Nine scree associations and two alliances - endemic to the study area - are described here for the first time. The syntaxonomic scheme followed is in accordance with that proposed in the EuroVegChecklist, with a few important exceptions. The largest variation in vegetation types was found along complex environmental gradients and the most important factors driving the difference between the four orders were gravel size, elevation and the geological substrate. [ABSTRACT FROM AUTHOR]

Aim: Plant–soil interactions can be major driving forces of community responses to environmental changes in terrestrial ecosystems. These interactions can leave signals in aboveground plant functional traits and belowground microbial activities and these signals can manifest in observed covariations. However, we know little about how these plant–soil linkages vary in response to environmental conditions at biogeographic scales for which experiments are impossible. Here, we investigate patterns of direct and indirect linkages between plant functional traits, soil microbial activities and environmental conditions in mountain grasslands along elevational gradients. Location: The French Alps. Taxon: Vascular plants and soil microbiota. Methods: We analysed observational grassland data sampled along 14 elevational gradients across the entire French Alps (between 1500 and 2800 m of elevation). Using Graphical Lasso, we inferred a partial correlation network to tease apart direct and indirect plant–soil linkages without defining the direction of interactions a priori. Results: We found tight spatial associations of plant traits with microbial activities, climate driving the former and soil properties the latter. In these plant–soil linkages, the dominance of specific plant traits was more important than their diversity. We then showed that in sites with conservative plant traits and reduced organic matter quality, soil microbes invested strongly in nutrient acquisition. Main conclusions: By investigating plant–soil linkages along elevational gradients in the French Alps, we showed that plant functional traits and belowground microbial activity are tightly linked and how they depend on environmental conditions. Overall, we demonstrated how soil functioning can be integrated in studies of ecosystem shifts under environmental change at large spatial scales. [ABSTRACT FROM AUTHOR]

Geoheritage is a component of geodiversity constituted by all the elements of geodiversity recognized by society for their particular values. The definition of these values, including the importance of geoheritage for biodiversity, plays a key role in the process of heritage recognition and geoconservation policymaking. In mountain environments, dynamic geomorphosites have a strong influence on plant diversity because the active geomorphological processes responsible for their formation act as renovators for habitats of pioneer species. In this paper, we propose criteria to assess the ecological value of dynamic mountain geomorphosites. We show that the interest of plant communities (species richness and presence of rare or protected species) and the influence of geomorphological processes on plant communities (disturbances, surface movement and soil) are fundamental criteria for assessing the ecological value in an exhaustive and objective way and that the question of the scale (local and national scales) is also a crucial parameter. We then illustrate this methodological proposal by evaluating the ecological value of three dynamic geomorphosites and a talus slope in the western Swiss Alps. [ABSTRACT FROM AUTHOR]

Community assembly is a result of dispersal, abiotic and biotic characteristics of the habitat as well as stochasticity. A direct comparison between the assembly of microbial and 'macrobial' organisms is hampered by the sampling of these communities in different studies, at different sites or on different scales. In a glacier forefield in the Austrian Alps, we recorded the soil and plant microbiome (bacteria and fungi) and plants that occurred in the same landscape and in close proximity in the same plots. We tested five predictions deduced from assembly processes and revealed deviating patterns of assembly in these community types. In short, microbes appeared to be less dispersal limited than plants and soil microbes, and plants strongly responded to abiotic factors whereas the leaf microbiome was plant species specific and well buffered from environmental conditions. The observed differences in community assembly processes may be attributed to the organisms' dispersal abilities, the exposure of the habitats to airborne propagules and habitat characteristics. The finding that assembly is conditional to the characteristics of the organisms, the habitat and the spatial scale under consideration is thus central for our understanding about the establishment and the maintenance of biodiversity. [ABSTRACT FROM AUTHOR]

In the current biodiversity crisis, one of the crucial questions is how quickly plant communities can acclimate to climate warming and longer growing seasons to buffer the impairment of community functioning. Answering this question is pivotal especially for mountain grasslands that experience harsh conditions but provide essential ecosystem services to people.We conducted a reciprocal transplant experiment along an elevation gradient (1,920 m vs. 2,450 m) in the French Alps to test the ability of plant species and communities to acclimate to warming and cooling. For 3 years, we measured weekly the timing of phenological events (e.g. start of flowering or greening) and the length of phenological stages linked to demographic performance (e.g. lengths of flowering or greening periods).We found that warming (and cooling) changed the timing of phenological events strongly enough to result in complete acclimation for graminoids, for communities in early and mid‐season, but not at all for forbs. For example, warming resulted in later greening of communities and delayed all phenophases of graminoids. Lengths of phenological stages did not respond strongly enough to climate change to acclimate completely, except for graminoids. For example, warming led to an acclimation lag in the community's yearly productivity and had a strong negative impact on flowering of forbs. Overall, when there was an acclimation failure, responses to cooling were mostly symmetric and confirmed slow acclimation in mountain grasslands.Synthesis. Our study highlights that phenological plasticity cannot prevent disruption of community functioning under climate warming in the short term. The failures to acclimate after 3 years of warming signals that species and communities underperform and are probably at high risk of being replaced by locally better‐adapted plants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Spatial distribution analysis to check mandatory features for EU habitat definition. • Calculating favourable reference values using percentiles thresholds. • Nardus grasslands at ecological extremes have less diversity and typical species. • Broad EU habitat interpretation negatively affect conservation status assessment. In this study, taking as an example the species-rich Nardus stricta grasslands (habitat 6230*) within the Natura 2000 network of the Lombardy region (northern Italy, central southern Alps), we evaluated i) whether the spatial distribution of the habitat 6230* corresponded to essential features for its identification, and ii) whether a broad habitat interpretation could affect its regional conservation status assessment. We analysed the spatial distribution of habitat 6230* regarding the elevation, geological substrate, forest treeline, land use types and other habitat types. Using the regional database of habitat relevés, we calculated the threshold values of conservation status for a range of indicators of structure, functions and future prospects. To this end, we used a subset of relevés of the subalpine sub-type of habitat 6230*, as it corresponds to plant communities where habitat interpretation can easily be extended beyond its definition. The mapped distribution of habitat 6230* did not entirely match the essential features required for its identification. Some polygons were located at the ecological extremes of habitat 6230*, on carbonate substrates and in the alpine belt. In those conditions, the habitat showed an Unfavourable-bad (U2) conservation status, decreasing species richness and typical species dominance and frequency. Our findings highlighted that plant communities representing ecological extremes of the habitat type 6230* should no longer be referred to the same habitat type. The proposed indicators can help identify habitat sub-types more conducive to successful restoration measures, thereby ensuring favourable conservation status. In turn, this guarantees sustainable agricultural land use, which simultaneously promotes biodiversity and high-quality food products. Furthermore, the procedure could be extended to other habitat types for early identification of priority monitoring areas, especially when their interpretation has gone beyond their definition, with little consideration given to the consequences on the regional conservation status assessments. [ABSTRACT FROM AUTHOR]

[Display omitted] • The temporal development of nutrient pools can be studied along chronosequences in glacier forelands. • Carbon and nitrogen pools were constantly increasing in the first 10,000 years of landscape development. • Potassium, calcium, magnesium and phosphorous pools peaked after a few hundred years of landscape development. • Bedrock type was a major factor influencing the development of nutrient pools along the proglacial chronosequences. Climate change accelerates glacial retreat worldwide, leaving large areas of unconsolidated terrain. Glacial retreat opens the possibility to study the temporal development of ecosystems, their functions and services by use of a space-for-time-approach. Nutrient pools are important indicators of various ecosystem services as they are critical in supporting the establishment and growth of plant communities, which in turn support the food webs and ecological processes that sustain the ecosystem and downstream communities. In this study, we examined the temporal development of nutrient pools in soils and vegetation communities over a period of more than 10,000 years. We analyzed a comprehensive dataset that embraces repeated measurements of carbon (C), nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg) and phosphorous (P) pools in above- and belowground biomass, litter and soil across alpine chronosequences from two glacier forelands with contrasting bedrocks (silicate vs carbonate). We found that total nutrient pools of C and N, being closely linked to the biomass, increased rapidly along both chronosequences, whereas nutrient pools of K, Ca, Mg, and P were large at first and decreased steadily with time, though at different rates related to the two parent materials. We also observed a remarkable difference in the P pool development between the two glacier forelands. The calcareous soils started out with much more P than the siliceous locations. The plant availability of P was, however, higher in the siliceous soils due to the neutral pH, but decreased with acidification. In the calcareous soils, plant P availability was low at the beginning due to a high pH, but improved as decalcification progressed and pH lowered to slightly acidic conditions. The results of this work highlight that assessing the temporal development of ecosystems services using long-term proglacial chronosequences enhances our understanding of landscape evolution. [ABSTRACT FROM AUTHOR]

Climate change and associated environmental alterations affect plant communities, potentially decoupling links between plants and their associated soil microbial communities. This may in turn affect processes like litter decomposition, an important function that controls nutrient and carbon cycling as well as many other ecosystem processes. Microbial decomposers have been proposed to specialize, being able to easier decompose litter from its 'home' community than litter from other communities, in what is termed the home field advantage (HFA) hypothesis. We report a litter decomposition experiment including four alpine meadow communities spread along a geographical gradient that ranged from the Atlas in Morocco to the Iberian Peninsula to the Swiss Alps. We tested whether litter decomposition rate would differ depending on litter and soil origin, expecting interactions between litter and soil microbial communities to be at the core of responses. We expected to find HFA in all four alpine communities. HFA ranged from very negative to neutral to positive along our geographical gradient, in a variation that could be attributed to the interaction of microbial communities with soil and plant traits, and linked to the relative abundance of microbial groups performing specific functions. Litter decomposition depended on litter quality and on the fungal community, which seemed adapted to deal with poor-quality, recalcitrant litter, leading to HFA. Climate plays a role as well, indirectly through plant community composition. Phyllosphere communities competed with soil communities when in interaction, a fact that may have blurred results of some previous HFA experiments. In summary, there is a clear HFA in systems with low-quality litter that requires a specialised fungal community to maximize decomposition. By contrast, high-quality, easy to decompose litter would be dealt with by any decomposer community, not showing evidence of HFA. • Litter decomposition depends on links between plants and soil microbial communities. • Microbes might decompose easier litter from its own community than from elsewhere. • Patterns of this so-called 'home-field advantage' (HFA) are unclear. • Systems with low–quality litter require specialised fungal communities, showing HFA. • Systems with high-quality litter have no specialised communities and show no HFA. [ABSTRACT FROM AUTHOR]

• Flower and pollen morphology of androsace brevis (Primulaceae), a narrow endemic plant of the southern central european Alps, are described for the first time. • Pollen morphology shows small size grains with a prolate shape. Pollen grains are radially symmetric, isopolar, and zonocolporate with three colpori that are not fused at the polar edge. • The morphology of the flower, with the location of both stamens and pistil inside the corolla tube and the coloured corolla mouths ranging from yellow to purple, suggests that A. brevis requires insect-mediated pollination. • The flower does not show a particular insect-selective pattern allowing many high-altitude flower-visiting insects to reach both nectar and pollen. Androsace brevis (Hegetschw.) Ces. (Primulaceae) is a narrow endemic plant of the Southern Central European Alps that lives only above 2000 m asl and flowers immediately after snowmelt for a very short period during which the plant must guarantee successful sexual reproduction. Despite the vulnerability of this species, mainly due to increasing temperature, competition with plant communities shifting to higher altitudes, and possible mismatches with pollinators, nothing is known about its pollen and floral morphology. In this study we aim to provide a detailed description of these traits and to investigate how they might be related to possible pollination strategies and vectors. Pollen and flower samples were collected from the Lepontine and Orobic Alps (Northern Italy) populations. The pollen grains are small (polar axis: 19.17 µm ± 0.09; equatorial axis: 10.84 µm ± 0.1) with a prolate shape. The morphology of the flower, with the location of both stamens and pistil inside the corolla tube, and the coloured corolla mouths, ranging from yellow to purple, suggest that A. brevis requires insect-mediated pollination. Moreover, floral morphology does not show a particular insect-selective pattern in that the presence of both stamens and pistil less than 1 mm below the corolla mouth (Ø: 0.76 mm ± 0.05) might allow many high-altitude flower-visiting insects to reach both nectar and pollen. A generalist pollination strategy could be fundamental in contests characterized by harsh environmental conditions as it could counteract potential plant-pollinator mismatches due to increase in temperatures. [ABSTRACT FROM AUTHOR]

Simple Summary: The Alps are among the most vulnerable ecosystems to climate change, as these modifications take place at a faster pace at higher elevations. Since butterflies are ideal model systems to investigate species responses to climate and habitat changes, we monitored a butterfly community of the Valasco valley in the Maritime Alps (NW Italy) by three sampling events covering a period longer than 40 years. We observed an overall increase in mobile, tolerant and thermophilous species, which eventually might cause an overall loss of community distinctiveness. The variations observed in the butterfly community can be explained by the notable increase in maximum temperatures and the reduction of grasslands, along with the increase of woodlands, supporting the hypothesis that local warming and land-use changes have ultimately affected the butterfly community composition. Our work aims to assess how butterfly communities in the Italian Maritime Alps changed over the past 40 years, in parallel with altitudinal shifts occurring in plant communities. In 2019, we sampled butterflies at 7 grassland sites, between 1300–1900 m, previously investigated in 2009 and 1978, by semi-quantitative linear transects. Fine-scale temperature and precipitation data elaborated by optimal interpolation techniques were used to quantify climate changes. The changes in the vegetation cover and main habitat alterations were assessed by inspection of aerial photographs (1978–2018/1978–2006–2015). The vegetation structure showed a marked decrease of grassland habitats and an increase of woods (1978–2009). Plant physiognomy has remained stable in recent years (2009–2019) with some local exceptions due to geomorphic disturbance. We observed butterfly 'species substitution' indicating a general loss in the more specialised and a general gain in more tolerant elements. We did not observe any decrease in species richness, but rather a change in guild compositions, with (i) an overall increased abundance in some widespread and common lowland species and (ii) the disappearance (or strong decrease) of some alpine (high elevation) species, so that 'resilience' could be just delusive. Changes in butterfly community composition were consistent with predicted impacts of local warming. [ABSTRACT FROM AUTHOR]