ALBERT

Description: The altitudinal gradient involves changes of the partial pressures of atmospheric gases such as CO 2 . This omnipresent phenomenon likely represents an evolutionary selective agent. We asked whether high altitude plant species had evolved specific response strategies to cope with high altitude pressure conditions. Plants of the high altitude species Arabis alpina and the low altitude species Arabidopsis thaliana were cultivated in growth chambers with high altitude pressure conditions (corresponding to 3000 m a.s.l.) and low altitude conditions (560 m). In both species, high altitude conditions resulted in the narrowing of stomatal aperture as well as a decrease in leaf area and weight. A. alpina produced significantly more stomata under high altitude conditions compared to low altitude conditions, while A. thaliana did not. Under low altitude conditions, however, stomatal density of A. alpina was smaller compared to A. thaliana . The increase in stomatal density of A. alpina was strongly related to the decrease in the partial pressure of CO 2 under high altitude conditions. Thus, the adaptation of the high altitude plant A. alpina to high altitude pressure conditions does not consist in a genetically fixed elevated stomatal density but in a different response strategy of stomatal development to environmental factors compared to the lowland plant A. thaliana . A. alpina developed stomata largely uncoupled from other environmental factors than CO 2 . The increased stomatal density of A. alpina may ensure an optimal CO 2 supply during the periods of favourable weather conditions for photosynthesis that are relatively rare and short in the alpine life zone.

Description: Recent years have seen a surge of interest in understanding patterns and processes of plant invasions into mountains. Here, we synthesise current knowledge about the spread of non-native plants along elevation gradients, emphasising the current status and impacts that these species have in alpine ecosystems. Globally, invasions along elevation gradients are influenced by propagule availability, environmental constraints on population growth, evolutionary change and biotic interactions. The highest elevations are so far relatively free from non-native plants. Nonetheless, in total nearly 200 non-native plant species have been recorded from alpine environments around the world. However, we identified only three species as specifically cold-adapted, with the overwhelming majority having their centres of distribution under warmer environments, and few have substantial impacts on native communities. A combination of low propagule availability and low invasibility likely explain why alpine environments host few non-native plants relative to lowland ecosystems. However, experiences in some areas demonstrate that alpine ecosystems are not inherently resistant to invasions. Furthermore, they will face increasing pressure from the introduction of pre-adapted species, climate change, and the range expansion of native species, which are already causing concern in some areas. Nonetheless, because they are still relatively free from non-native plants, preventative action could be an effective way to limit future impacts of invasions in alpine environments.

Description: Fossil evidence, phylogeographic analyses, species distribution modelling and ancient DNA analyses have all shown that plant distributions have been highly dynamic through time. We use the geographical distribution of intra- and interspecific hybrids in Sempervivum , a western Eurasian high mountain oreophyte, as evidence for the past range dynamics of their parents. Sequences of the nuclear ribosomal internal transcribed spacer (ITS), parts of the nuclear ribosomal intergenic spacer region (IGS), and the three chloroplast markers atp I– atp H, rps 16-intron and trn Q– rps 16 were generated for 101 individuals of Sempervivum from across its entire distribution range. Hybrid individuals were identified by the presence of double base calls in direct sequencing of polymerase chain reaction products of ITS and IGS. Parentage was inferred from comparison with sequences without double base calls and with cpDNA sequences. We identified 27 hybrid individuals, which were found outside the current distribution range of one parent in 10 cases and with both (or all three) parents in eight cases. Geographical distance of hybrids and allopatric parents ranged from 25 to 2100 km. The distribution of hybrid individuals in relation to their parents provides evidence for past range dynamics and migration over sometimes large geographical distances. As all taxa involved had been postulated to be of Quaternary origin in an earlier study, we hypothesise that hybridisation took place in glacial refugia where the parental species came into contact.

Description: Stem rust, caused by Puccinia graminis f. sp. tritici , can be a serious disease problem of barley in some production areas of the world. Deployment of resistant cultivars is the best means for controlling the disease. In North America, stem rust of barley has been kept in check for more than 70 years through the widespread use of the resistance gene Rpg1 , which was derived from a landrace collected in Switzerland. Rpg1 is effective against many, but not all races of P. graminis f. sp. tritici . With the threat of Rpg1 -virulent races like TTKSK and QCCJB from Africa and North America, respectively, it is important that additional sources of stem rust resistance be identified in barley. Given that resistance was previously identified in germplasm from Switzerland, the primary objective of this study was to characterize a collection of Swiss barley landraces from the mountainous regions of canton Graubünden for their reaction to stem rust races TTKSK and QCCJB as well as HKHJC, which is diagnostic for detecting Rpg1 . From the stem rust phenotyping of 73 barley landraces, we found a remarkably high frequency (〉43 %) of resistance to the virulent P . graminis f. sp. tritici races of TTKSK and QCCJB. In nearly every case, this resistance was due to the rpg4 / Rpg5 gene complex as determined by a molecular assay. Two landraces were also found to carry Rpg1 based on their diagnostic resistant reaction to race HKHJC and presence of an amplicon specific for the gene. These results demonstrate that landraces from the mountainous areas of eastern Switzerland are valuable sources of important resistance genes for protecting barley from the devastating disease of stem rust.

Description: 〈h3〉Abstract〈/h3〉 〈p〉Polyploidisation—and, additionally, agmatoploidy (concerted fission of chromosomes) in some plant groups—have significantly contributed to the diversification of alpine plant species. Both processes have driven the diversification of 〈em〉Luzula〈/em〉 sect. 〈em〉Luzula〈/em〉, leading to a number of different karyotypes, rendering it one of the most intricate plant groups in the Alps. For the Eastern Alps eight species with six karyotypes were reported, but their distribution is insufficiently known. A herbarium revision of 1044 specimens revealed that 〈em〉L. alpina〈/em〉, 〈em〉L. campestris〈/em〉, 〈em〉L. exspectata〈/em〉, 〈em〉L. multiflora〈/em〉 and 〈em〉L. sudetica〈/em〉 are widespread across the Eastern Alps; 〈em〉L. exspectata〈/em〉 is thus new for the Northern Alps and new for Germany, France and possibly Croatia. 〈em〉Luzula divulgata〈/em〉 is distributed in the easternmost Alps and adjacent areas, with only a few indications for the western Eastern Alps. 〈em〉Luzula divulgatiformis〈/em〉 is new for the Alps where it was recorded in the Southern Alps and southerly adjacent areas. 〈em〉Luzula campestris〈/em〉, 〈em〉L. divulgata〈/em〉 and 〈em〉L. divulgatiformis〈/em〉 are distributed from lowlands to the montane belt, 〈em〉L. alpina, L. exspectata〈/em〉 and 〈em〉L. sudetica〈/em〉 are high-elevation species and 〈em〉L. multiflora〈/em〉 occurs from lowlands to the alpine belt. Additionally, we estimated genome size (GS) and karyotypes for 20 populations and revealed four karyotypes corresponding to three ploidy levels. The GS of diploid 〈em〉L. exspectata〈/em〉 and 〈em〉L. sudetica〈/em〉 was 0.83 pg DNA, tetraploid 〈em〉L. alpina〈/em〉 had a double (1.63 pg) and hexaploid 〈em〉L. multiflora〈/em〉 a triple (2.48 pg) GS. Our study underlines the importance of large-scale herbarium revisions of intricate taxa, combined with cytological methods, even in well-studied mountain areas such as the Alps and poses new hypotheses regarding the evolution of this polyploid–agmatoploid group.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Climate refugia are locations where plants are able to survive periods of regionally adverse climate. Such refugia may affect evolutionary processes and the maintenance of biodiversity. Numerous refugia have been identified in the context of Quaternary climate oscillations. With climate warming, there is an increasing need to apply insights from the past to characterize potential future refugia. Mountainous regions, due to the provision of spatially heterogeneous habitats, may contain high biodiversity, particularly important during climate oscillations. Here, we highlight the importance of mountaintops as climate refugia, using the example of high-mountain oaks which are distributed on the ranges of the Himalaya–Hengduan Mountains, and at high elevations in tropical rainforests. The occurrences of cold-adapted high-mountain oaks on mountaintops amidst tropical rainforest indicate that such locations are and will be climate refugia as global warming continues. We examine factors that predict the occurrence of future climate refugia on mountaintops using recognized historical refugia. Future research is needed to elucidate the fine-scale processes and particular geographic locations that buffer species against the rapidly changing climate to guide biodiversity conservation efforts under global warming scenarios.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The impacts of climate change on alpine summit floras have been widely investigated. However, only few studies included alpine grasslands and generally concluded that snowbeds, with a long snow cover duration and a short growing season, and windy ridges, with a short snow cover duration and strong winter frosts, are the most sensitive alpine grasslands. However, these habitats were mostly investigated in different regions, where local factors (e.g. nitrogen deposition, grazing) can co-vary with climate changes, potentially obscuring differences between habitats. Here, we focused on the Zermatt region (Swiss Alps) to investigate the impacts of climate change on snowbeds and windy ridges. Forty-three exhaustive historical plant inventories on windy ridges (acidophilic or basophilic) and 31 inventories in snowbeds (typical or wet) were repeated in quasi-permanent plots after approximately 23 years. Historical and recent records were compared with the Simpson index, Bray–Curtis dissimilarity, a PCA, ecological indicator values and the frequency and cover changes of species. There was a general increase in α-diversity and a decrease in β-diversity (homogenisation). Most of the new species in the plots were generalists from surrounding grasslands. The plant composition tended to be more thermophilous on acidophilic windy ridges and in typical snowbeds. The flora of acidophilic windy ridges became more similar to that of basophilic windy ridges and more eutrophic. We interpreted this as possibly arising from fertilisation by the aeolian dust deposition coming from the expanding glacial moraine in the valley. In snowbeds, the species indicated increasingly drier conditions, especially in wet snowbeds. Warming climate induces lower snowfall and earlier snowmelt, leading to a shorter snow cover duration. Hence, wet snowbeds are certainly among the most threatened plant communities by climate change in the Alps.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Leaf shape variations and developmental instability were examined for the first time in natural populations of 〈em〉Prunus avium〈/em〉 (L.) L. in the central Balkan region (Bosnia and Herzegovina) at different elevational points, from 230 to 1177 m. above sea level. Geometric morphometric tools were applied to assess the variability of leaf shapes and sizes, while a fluctuating asymmetry leaf index was used as a measure of leaf developmental instability. According to the results of canonical variate analysis for the symmetric component of shape variation and hierarchical analysis of variance for centroid size, the studied populations could be partially differentiated into three groups. The co-variation between leaf form (shape and size) and climate variables was significant, estimated by two-block partial least square analysis. Climate variables (the sum of precipitation in May and the De Martonne aridity index) mostly influenced leaf shape and size. A population situated at the highest elevation had the highest value for fluctuating asymmetry leaf index, which was an indication of developmental instability. High natural variability and interpopulation differences were observed for all studied leaf traits (leaf shape, centroid size, fluctuating asymmetry leaf index, leaf area, leaf length and width, petiole length). For well-known traditional morphometric measures (leaf area, leaf length, leaf width, and petiole length) in accordance with previous studies, intrapopulation variability was greater than interpopulation variability. For centroid size and the fluctuating asymmetry leaf index (measures used in geometric morphometrics) variability was higher among populations than within them. This indicates that geometric morphometrics could give new insights into infra-specific variability.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Diversity patterns of tropical alpine vegetation is poorly studied. We estimated vascular plant floristic richness for two typical afro-alpine communities in Mount Kenya using a series of nested plots sized from 25 to 100 m〈sup〉2〈/sup〉. The 〈em〉α〈/em〉-diversity was low for all plot sizes (4.8–7.8 and 12.8 species per one and 100 m〈sup〉2〈/sup〉, respectively). Comparative analysis of 〈em〉α〈/em〉-, 〈em〉β〈/em〉- and 〈em〉γ〈/em〉-diversity across 22 plant communities from five Mountain regions (Mount Kenya, European Alps, Caucasus, Tibet, New Zealand Alps) revealed that area of mountain system was the only significant variable shaping the local richness; this effect became stronger with increasing spatial scale. Beta-diversity, by contrast, showed neither latitudinal trends nor significant correlation with other geographical or climatic variables. We conclude that the total area of mountain system is one of the main factors determining the regional species pool and, ultimately, the local diversity of alpine plant communities (the “echo-effect”). Small area and isolation of Mt. Kenya are considered as the main reasons for low local richness of its afro-alpine vegetation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Plants growing along steep elevational gradients experience variations in abiotic conditions. The elevational gradient also affects the diversity and abundance of pollinators associated with these plants. As a result, plants may have locally adapted floral traits. However, detailed assessments of multiple floral traits along elevational gradients are often neglected despite the traits being important for plant sexual reproduction. We tested the association of floral traits with pollinators in response to elevation by identifying pollinators and measuring morphological and biochemical floral traits as well as studying the breeding systems of ten aggregated 〈em〉Rhododendron〈/em〉 species in the Sikkim Himalaya. Corolla length, nectar volume and distance between stamen and stigma significantly decreased with elevation. In contrast, nectar concentrations were positively associated with elevation. Birds, bumblebees and flies were the three dominant pollinator groups. Bird visits showed a strong negative association with elevation while visits by bumblebees and flies increased with elevation. Species with longer corollas and higher nectar volumes showed higher rates of bird visits, while bumblebees were associated with species that had higher nectar concentrations. Fruit set following cross-pollination was high compared to self-pollination, and higher pollen limitation and auto-fertility were observed among species in higher elevations. These observed patterns in the association between floral traits and pollinator groups in response to elevation may help generate testable hypotheses on alpine plant–pollinator responses to climate warming.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Mosses are a dominant ground cover in a wide array of ecosystems, especially in those developing under cold-stressed environments such as arctic and alpine ice-melting glacial forelands. Consequently, mosses may influence the performance and distribution of other plants. Here, we assessed the nature of interactions between vascular plants and cushion-forming mosses in three alpine communities in the northern Patagonian Andes. We recorded species richness, plant abundance and cover of vascular plants within and outside moss cushions, measuring also patch area and moss layer depth. To determine the effect of mosses on vascular plant assemblages, we calculated the relative interaction index (RII) in terms of richness, abundance and cover of all vascular plants, and of individual species. Moss-cushion patches showed higher species richness, plant abundance and cover in comparison with bare ground areas. Overall, the diversity of vascular plants increased with both moss-cushion area and layer depth. Species-specific RII values revealed that the effects of moss cushions on neighboring vascular plants were predominantly positive for all three plant communities surveyed. These results highlight the role of mosses as nurse plants in alpine ice-melting glacial forelands and, thus, as ecosystem engineers that can be key in maintaining vascular plant diversity.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The occurrence of triploid hybrids in nature is scarce due to the so-called triploid block representing formation of nonviable progeny after mating diploid with tetraploid. Here we describe frequent presence of triploids originating from hybridization of diploid 〈em〉Festuca pratensis〈/em〉 with tetraploid 〈em〉F. apennina〈/em〉 in the Swiss Alps. 〈em〉F. pratensis〈/em〉 is a forage grass grown in lowlands and up to 1800 m a.s.l., while 〈em〉F. apennina〈/em〉 is a mountain grass found in elevations from 1100 to 2000 m a.s.l. In the overlapping zone these species often grow sympatrically and triploid hybrids have been observed. We show that elevation is the main factor in the distribution of plants with various ploidy levels. Diploids occupy lower elevations, while triploids predominate in the mid-elevation zones and tetraploids are the most frequent in higher elevations. Other factors, such as topography and soil composition probably have only marginal effects on the distribution of the plants with different ploidy levels. Triploids seem to be frequently formed in the Swiss Alps and crosses in both directions are involved in the formation of triploid hybrids. As shown by chloroplast DNA analysis, 〈em〉F. apennina〈/em〉 more frequently serves as female. Our analysis suggests that in the mid-elevation zones, triploids have a higher level of competitiveness than both parents. Triploids can overgrow microhabitats to a much higher extent than tetraploids. Such frequent occurrence and local dominance of triploids can at least be partially explained by asexual reproduction. Using DNA markers, we show that triploids can disperse ramets of a single clone over a distance of at least 14.4 m.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The highly invasive knotweeds (Reynoutria spp.) are still infrequent in mountain regions. Despite their current low abundance, they may represent a significant threat for high elevation ecosystems if their population dynamics remain as aggressive as in lowlands during their range expansion to higher elevation. The aim of this study is to assess the knotweed’s invasion potential in mountainous regions by studying patch dynamics along an elevational gradient (between 787 and 1666 m a.s.l.) and by reviewing existing literature on their presence and performance in mountains. The outlines of 48 knotweed patches located in the French Alps were measured in 2008 and in 2015 along with biotic, abiotic and management variables. Based on these variables, knotweed’s cover changes and patch density were predicted using mixed models. Results showed that elevation has no effect on knotweeds dynamics along the studied elevational gradient. It appeared that the local expansion of knotweed patches is essentially controlled by the patches’ initial size and the distance to roads and rivers, i.e. to obstacles and sources of disturbance. Shade and patches’ size also impact knotweed patch density, probably through an effect on the species’ clonal reproduction and foraging strategies. Interestingly, patches seemed insensitive to the gradient of mowing frequency sampled in this study (between zero and five times per year). All evidences indicate that the knotweed complex is able to colonize and thrive in mountains areas. However, due to the particularities of its spatial dynamics, adequate and timely actions could easily be undertaken to prevent further invasion and associated impacts and reduce management costs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Dioecious plants often exhibit deviations from expected 1:1 sex ratios. Genus 〈em〉Salix〈/em〉 is a notable example of the female-biased sex ratio. Quite surprisingly, there are very few studies retesting observed bias patterns from the different parts of the species range. We have determined whether isolated subalpine populations of 〈em〉Salix lapponum〈/em〉 exhibit a biased secondary sex ratio, measured the size of the plants, and tested the spatial and ecological correlations of the bias at fine and broad scales. Males were generally taller than females, suggesting that a different allocation of resources may occur in both sexes. Despite this, we found consistent female bias with females on average twice as common as males in most populations studied. No correlations of sex ratio with elevation as a proxy of environmental harshness and proportion of non-flowering individuals were found. Additionally, no differences in spatial sex segregation and microhabitat preferences were found between males and females at a fine scale within the studied populations. Our results suggest that the biased sex ratio in 〈em〉S. lapponum〈/em〉 is not environment-dependent and probably originates during early stages of ontogenetic development (seeds).〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Polyploidy may affect a species’ eco-physiology, which might, in turn, trigger a shift in the distribution of its cytotypes. The arcto-alpine 〈em〉Hieracium alpinum〈/em〉 (Asteraceae) encompasses two geographically allopatric cytotypes: diploids occurring in the South-Eastern Carpathians and triploids occupying the remaining, much larger part of the species range. We ask whether the natural populations of these two cytotypes, growing under partially different biotic and abiotic conditions, also differ in selected eco-physiological traits. To answer this question, we analyzed specific leaf area, foliar carbon (C) and nitrogen (N) contents, and their stable isotope compositions in plants sampled in 27 populations across the species range. Our results did not show any differences in these traits, except foliar N content being significantly higher in diploids. This pattern was mostly driven by the Scandinavian triploid populations exposed to significantly lower amounts of solar radiation and precipitation during the growing season when compared to the continental populations. As a consequence, in addition to lower foliar N content, the Scandinavian populations exhibited also lower foliar C content, but higher C/N ratios than continental populations regardless of their cytotype. Across the species range, foliar N and C contents were positively associated with the amount of precipitation, whilst δ〈sup〉15〈/sup〉N was positively associated with temperature and negatively with the surrounding species richness and vegetation cover. Significantly lower values of δ〈sup〉13〈/sup〉C in Scandinavian populations are likely the effect of increased atmospheric pressure due to the lower elevational position of Scandinavian sites. Reproductive output was positively linked to amounts of foliar nitrogen and δ〈sup〉15〈/sup〉N. Our data thus show that (1) the latitudinal-driven abiotic and biotic factors affected eco-physiological traits in significantly larger extent than ploidy level and that (2) continental and Scandinavian populations, though all confined to the alpine belt, considerably differ in their eco-physiology likely reflecting different adaptation strategies.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Functional plant traits are used in ecology to explain population dynamics in time and space. However, because the germination niche is an essential stage in alpine plant life cycles and is under strong environmental pressure, we hypothesised that inter-specific variability in germination traits might contribute to alpine plant distributions. Germination traits of seven closely related species from calcareous and siliceous habitats were characterised in the laboratory, including base, optimum and ceiling temperatures (〈em〉T〈/em〉〈sub〉b〈/sub〉, 〈em〉T〈/em〉〈sub〉o〈/sub〉, 〈em〉T〈/em〉〈sub〉c〈/sub〉, respectively), base water-potential (〈em〉Ψ〈/em〉〈sub〉b〈/sub〉) and the pH range of the germination phenotype. Species’ vegetative traits (specific leaf area, leaf area and leaf dry matter content) were obtained from the TRY-database. Traits and habitat similarities and dissimilarities were assessed. Species were plotted in a multivariate space using two separate principal component analyses: one each for germination and vegetative traits. Species from calcareous habitats showed significantly higher 〈em〉T〈/em〉〈sub〉b〈/sub〉, lower 〈em〉Ψ〈/em〉〈sub〉b〈/sub〉 and lower capacity to germinate under acidic pH than species from siliceous habitats. Moreover, high 〈em〉T〈/em〉〈sub〉o〈/sub〉 and 〈em〉T〈/em〉〈sub〉c〈/sub〉, a narrow temperature range for germination at dispersal, and vegetative traits values were similar across both habitats. Whilst plant traits seem to have adapted to the shared environmental conditions of the two alpine habitats, some germination traits were affected by the habitat differences. In conclusion, species occurrence in two habitats (calcareous, siliceous) appears to be limited by some germination constraints and provide greater differentiation of species habitat preference than that defined by vegetative traits.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Alpine plants growing along wide elevational gradients experience very different abiotic and biotic conditions across elevations. As a result of genetic differentiation and/or plastic response, conspecific plants growing in high elevations, as compared to low elevations, generally have shorter stems and lower number of flowers, but larger flower size. However, most often, detailed models of elevational variations were not examined. To reveal the pattern of elevational changes in a set of fitness-related morphological traits, tests of linear and unimodal models were performed based on measurements of 1047 S〈em〉olidago minuta〈/em〉 plants collected from 47 sites distributed along a 1000 m elevational gradient in the Tatra Mountains. Nearly all of the investigated floral traits, i.e. inflorescence and flower heads size, and number and size of individual flowers, expressed unimodal relationships with elevation having their maxima in the centre of the elevation range. This pattern suggests the existence of a local optimum with respect to sexual reproduction at the centre of the elevational range. Possible explanations of observed elevational variations are discussed in the context of pollinator selection and the ‘resource-cost compromise’ hypothesis. Best floral performance in the centre of the elevational range of 〈em〉S. minuta〈/em〉 may also support the idea that the favourability of habitat conditions declines from the centre to the margin of the distribution, and species are expected to be more abundant, increase reproduction and perform better in the centre of the range.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Despite the strong environmental control of seed dormancy and longevity, their changes along latitudes are poorly understood. The aim of this study was to assess seed dormancy and longevity in different populations across the distribution of the arctic–alpine plant 〈em〉Silene suecica〈/em〉. Seeds of seven populations collected from alpine (Spain, Italy, Scotland) and subarctic (Sweden, Norway) populations were incubated at four temperature regimes and five cold stratification intervals for germination and dormancy testing. Seed longevity was studied by exposing seeds to controlled ageing (45 °C, 60% RH) and regularly sampled for germination. Fresh seeds of 〈em〉S. suecica〈/em〉 germinated at warm temperature (20/15 °C) and more in subarctic (80–100%) compared to alpine (20–50%) populations showed a negative correlation with autumn temperature (i.e., post-dispersal period). Seed germination increased after cold stratification in all populations, with different percentages (30–100%). Similarly, there was a large variation of seed longevity (p〈sub〉50〈/sub〉 = 12–32 days), with seeds from the wettest locations showing faster deterioration rate. Subarctic populations of 〈em〉S. suecica〈/em〉 were less dormant, showing a warmer suitable temperature range for germination, and a higher germinability than alpine populations. Germination and dormancy were driven by an interplay of geographical and climatic factors, with alpine and warm versus subarctic and cool autumn conditions, eliciting a decrease and an increase of emergence, respectively. Germination and dormancy patterns typically found in alpine habitats may not be found in the arctic.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Soil fauna are critical for litter decomposition via physical fragmentation, chemical digestion, and changing activity of microorganisms, yet a few studies have been performed regarding the effects of soil fauna on alpine tundra litter decomposition. To better understand the effects of soil fauna on alpine tundra litter decomposition, we set up a litterbag experiment to determine the characteristics of the 〈em〉Dryas octopetala〈/em〉 decomposition, and the diversity of the soil fauna in the litterbags, as well as the influence of the soil fauna on the decomposition in the tundra of the Changbai Mountains over a 36-month period. We found that the decomposition rate of the coarse mesh (2 mm) litterbags was faster than that of the fine mesh (0.01 mm) litterbags. The percentage of the mass lass of litter in the coarse mesh litterbags (2 mm) was 47.60%, while that in the fine mesh (0.01 mm) litterbags was 34.11% at the end of the experimental period (36th month of decomposition), and the contribution of soil fauna to the litter decomposition was confirmed to be 30.50%. The characteristics of litter decomposition exhibited some seasonal and annual differences. In addition, the diversity of the soil fauna in the litterbags was different during each of the years of the experiment. However, there were no significant differences observed during the same year. The effect of soil fauna on the litter decomposition was not obvious at the beginning of the experiment, and soil fauna contribution had a significant negative relationship with mass loss of litter. Our results provide experimental evidence that soil fauna can promote the decomposition of 〈em〉Dryas octopetala〈/em〉 litter, but soil fauna contribution decreased with litter decomposition in the alpine tundra ecosystem.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Phenotypic changes conferred by polyploidisation likely alter the ecological niche of polyploids, coming along with differences in performance compared to their diploid ancestors. However, it is largely unknown whether these performance differences remain constant during the life history of plants. Diploid 〈em〉Senecio noricus〈/em〉, tetraploid 〈em〉S. disjunctus〈/em〉, and hexaploid 〈em〉Senecio carniolicus〈/em〉 s. str. of the autopolyploid species complex of 〈em〉S. carniolicus〈/em〉 (Asteraceae) from the easternmost Alps were reciprocally transplanted to address the following questions: Are there differences in species performances indicating niche differentiation? If so, does the resident or the higher ploid species—which is taller growing and possibly more tolerant against challenging abiotic and biotic conditions—show higher performance? Are performance differences consistent between the early and late life-history stages? Our data suggest that the hierarchy of species performance depends on the life-history stage. For early life-history stages (seeds and seedlings), we mainly observed superior performance of 〈em〉S. carniolicus〈/em〉 s. str. even on resident sites of the two other species. In contrast, vital rates of adults were predominantly highest for the resident species. The resident site of 〈em〉S. carniolicus〈/em〉 s. str., which was expected to be environmentally least stressful (i.e., longest growing period, least affected by frost), turned out to be the most selective one, with high mortality and (nearly) no reproduction of the foreign species most likely due to top soil desiccation. Our study illustrates that there may be no clear-cut answer to the question if the resident or the higher ploid species shows superior performance in polyploid complexes, but rather suggests that relative performance may depend on life-history stage.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Phenotypic variation may be genetically determined or reflect phenotypic plasticity. More common plants are expected to be less differentiated between and within regions and more adapted than less common ones. However, such differences might not develop in hybridizing species which cannot evolve completely independently. We collected 311 genets of 〈em〉Carex flava〈/em〉, 215 of 〈em〉C. viridula〈/em〉 and 46 of their hybrid 〈em〉C〈/em〉. × 〈em〉subviridula〈/em〉 from 42 natural populations in cold temperate Estonia, mild temperate Lowland Switzerland and alpine Highland Switzerland. Three plantlets from each genet were planted to three experimental gardens, one in each region. We measured survival, growth, reproduction and morphological traits. The experimental transplants showed strong plasticity and grew smallest in the alpine garden. The less common 〈em〉C. viridula〈/em〉 was slightly more differentiated between regions of origin than the more common 〈em〉C. flava〈/em〉 and the hybrid. However, this depended on the experimental garden. Significant origin-by-garden-by-taxon and taxon-by-garden interactions suggest differential adaptation among populations and taxa. Regional differed from non-regional plants in several traits indicating both adaptations and, especially for 〈em〉C. viridula〈/em〉, maladaptations to the home regions. For 〈em〉C. flava〈/em〉, plant seed production was higher when mean annual temperature and precipitation were more similar between population of origin and garden, suggesting local adaptation to climate. Hybrids were intermediate between parental taxa or more similar to one of them, which was retained across gardens. We conclude that plasticity, genetic variation and genotype–environment interactions all contributed to regional differentiation of the closely related species. Hybridization did not completely align evolutionary patterns, and the less common species showed slightly more genetic differentiation between populations and more maladapted traits than the more common one.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Environmental gradients in alpine systems may lead to differences in both abiotic conditions and species interactions in very short distances. This may lead to reproductive and phenotypic changes in plants to enhance fitness in each environment. In this study, we explored how the Central Andean 〈em〉Viola maculata〈/em〉 responds to the elevation gradient, where it is distributed, with an expected increase in water availability and a decrease in pollinator availability with elevation. We hypothesized that: (1) plants would be more water-stressed at low elevations; (2) investment in and success of cleistogamous flowers (closed, self-pollinated) would increase with elevation; and (3) correlation patterns between floral and vegetative traits would vary along the gradient according to changes in biotic/abiotic selection pressures across sites. We partially confirmed the inverse gradient of water stress with elevation, with 〈em〉V. maculata〈/em〉 populations in the lowest site experiencing lower soil moisture and showing thicker leaves and lower stomatal conductance. Cleistogamy was more prevalent and successful at the highest site, thus confirming the hypothesis of maintenance of a mixed-mating system as reproductive assurance. Correlation patterns between flower and leaf size differed across sites, with stronger vegetative–floral correlation at the lower sites and a weak correlation at the highest site. This finding disagrees with the notion of pollinators as drivers of correlation between floral and vegetative traits. Our study shows how a narrow gradient in an alpine system may affect not only reproductive and physiological responses in plants, but also floral and vegetative covariances.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The functional diversity and composition of plant traits within communities are tightly linked to important ecosystem functions and processes. Whereas vegetative traits reflecting adaptations to environmental conditions are commonly assessed in community ecology, floral traits are often neglected despite their importance for the plants’ life cycle. The consideration of floral traits covers important aspects such as sexual plant reproduction and pollinator diversity, which remain unobserved in studies focussing on vegetative traits only. To test whether vegetative and floral traits differ in their responses to elevation, we measured morphological and chemical traits of plant species occurring in pastures at seven elevations in the Austrian Alps. Variation in functional composition was examined using the concept of 〈em〉n〈/em〉-dimensional hypervolumes and vector analysis. Our data show that vegetative and floral traits vary differently with the elevational gradient. Whereas vegetative traits changed in a predictable manner with elevation, floral traits did not specifically respond to elevation. Overall variation in vegetative traits mainly resulted from phenotypical differences between plants in different elevations, whereas total variation in floral traits was a result from a high variation within communities. The assessment of functional changes in vegetative and floral traits along mountain slopes thus reveals different patterns in plant responses to elevation and may help to generate testable hypotheses on functional responses to current climate warming.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Mountain ecosystems are becoming increasingly threatened by non-native plant invasions. In this paper, the occurrence of non-native plant species was examined in a protected area (Laojun Mountain Area) in the eastern Himalayas, China. Sampling plots were systematically set up along elevation from 1950 to 3500 m a.s.l. Sixty-one non-natives were recorded that account for 24% of the roadside flora. The number of non-native species decreased continuously with increasing elevation and significant nestedness was found between the low- and high-elevation plots. Moreover, all non-native species distributed at high elevation were also found at low elevation and mountain specialists were not found among non-natives. These results indicate that the eastern Himalayan ecosystem is not immune to invasion and most of the non-natives spread from lowland areas upward to the highlands. Future efforts to manage plant invasions in this region should concentrate on low-elevation areas where agriculture and disturbances by tourism are increasing rapidly.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉While introduced plants often have restricted distributions at high elevations, their impacts may be more extensive if they compete for native pollinators, potentially reducing pollinator services to native biotically pollinated plants. Conversely, introduced biotically pollinated plants might facilitate improved pollinator services to native plants by supporting higher pollinator densities and extending the flowering season. We examined weekly pollinator visitation to native and introduced plants, at five elevations over two flowering seasons on The Remarkables range, south-central South Island, New Zealand. In this area, introduced plants dominate the vegetation at lower elevations but are restricted to disturbed areas above treeline. We tested whether pollinator visitation rates and quantities of introduced pollen on insects or transferred to native flowers differed with elevation and community context, or with the local abundance of introduced flowers regardless of elevation. Introduced biotically pollinated plants produced more flowers and flowered later than most native species and were extensively utilised by native solitary bees. Weekly visitation rates to native flowers were higher in the first half of the flowering season than the second half, and were positively correlated with visitation rates to co-occurring introduced flowers. Introduced flower abundance did not affect visitation to native flowers but did significantly predict the occurrence of introduced pollen on native insects and stigmas of native flowers. Pollen contamination was also higher in the latter part of the flowering season. While an increase in introduced flowers at high elevations may benefit native pollinators by increasing the quantity and duration of floral resources available, the heavy use of introduced flowers by native bees will lead to at least localised stigma contamination, particularly for late flowering species. However, more information is required on foraging ranges of native pollinators and pollen limitation in native species to understand the consequences of introduced species expansion into alpine areas.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Mountaineering, since the beginning of its history, has played an inconspicuous but key role in the collection of species samples at the highest elevations. During two historical expeditions undertaken to reach the summit of Mount Everest in 1935 and 1952, mountaineers collected five species of vascular plants from both the north and south sides of the mountain, at ca. 6400 m a.s.l. Only one of these specimens was determined immediately following the expedition (〈em〉Saussurea gnaphalodes〈/em〉), and the remaining four were not identified until quite recently. In 2000, the second specimen from the 1935 expedition was described as a new species for science (〈em〉Lepidostemon everestianus〈/em〉), endemic to Tibet. In this paper, the remaining three specimens from the 1952 Everest expedition are reviewed and analysed, bringing the number of species sharing the title of “highest known vascular plant” from two to five. I identify one of the 1952 specimens as 〈em〉Arenaria bryophylla〈/em〉, and describe two novel taxa based on analysis of the herbarium records: 〈em〉Saxifraga lychnitis〈/em〉 var. 〈em〉everestianus〈/em〉 and 〈em〉Androsace khumbuensis〈/em〉. Although elevation records on their own do not inform us about the ecological conditions and physiological capacity of plants at the upper limit of their distribution, this taxonomic investigation contributes to our knowledge of the biogeography of Himalayan flora and opens the way for future field-based investigations of mechanisms limiting plant growth on the roof of the world.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Quaternary climatic oscillations have been a major factor in shaping plant diversity and distribution in the European Alpine System (EAS). Plants responded to these oscillations with repeated changes in their abundance and geographical distribution. However, oscillating shifts in geographical distribution have only rarely been reported in molecular analyses of genetic variation across the EAS. 〈em〉Homogyne〈/em〉, a genus endemic to the EAS, contains three species. While 〈em〉H. discolor〈/em〉 and 〈em〉H. sylvestris〈/em〉 are confined to the periphery of the Eastern Alps, 〈em〉H. alpina〈/em〉 is widespread across the EAS. In phylogenetic reconstructions of a broad sample of 〈em〉Homogyne〈/em〉 using DNA sequence data sets of the nuclear ribosomal internal transcribed spacer (ITS), plastid DNA (〈em〉ndhF-rpl32, rpl〈/em〉32-〈em〉trnL, psbA〈/em〉-〈em〉trnH〈/em〉) and genotyping-by-sequencing (GBS), accessions of 〈em〉H. alpina〈/em〉 from the Pyrenees and the Cantabrian Mts. form a clade which groups in conflicting positions. While the exact relationship of this Pyrenean/Cantabrian clade of 〈em〉H. alpina〈/em〉 remains unclear, our data clearly imply that this clade is a lineage distinct from the remaining accessions of 〈em〉H. alpina〈/em〉 (〈em〉H. alpina〈/em〉 s.str.). An ancestral area analysis unambiguously revealed the Eastern Alps as the ancestral area of the genus. Considering that relationships within 〈em〉H. alpina〈/em〉 s.str. clearly illustrate East to West expansion, the identification of a Pyrenean/Cantabrian clade implies that westward expansion from an ancestral area in the Eastern Alps took place twice in the genus. Although the extant distributions of the Pyrenean/Cantabrian clade and 〈em〉H. alpina〈/em〉 s.str. are mutually exclusive, plastid DNA evidence may imply past contact and hybridization between the two clades.〈/p〉

Description: 〈p〉The Editor-in-Chief has retracted this article [1] because the three studies included in the meta-analysis [2,3 and 4] (cited as references 16, 17 and 18) have been retracted due to concerns regarding the data, which has rendered the results of this meta-analysis invalid.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Light environments can influence variation in plant morphology, development and susceptibility to herbivores. Our research interest was to investigate the patterns of herbivore damage and developmental stability in dioecious understory forb 〈em〉Mercurialis perennis〈/em〉 in contrasting light habitats, located at 1700 m a.s.l. on Mt. Kopaonik. Male and female plants from two light habitats, open (a sun-exposed field) and shaded (a spruce forest) were examined with respect to: herbivore damage (percentage of leaf area loss), fluctuating asymetry (FA) as a measurement of developmental stability, plant morphological and, specifically, leaf size traits, as well as biochemical traits relating to nutritional quality and defence, taking into account the possible presence of intersexual differences. Our results show that herbivore damage was significantly higher in open habitat, as well as one out of four univariate FA indices and the multivariate index. Morphological and biochemical traits, apart from defensive compounds, had higher values in the shade, pointing to sun-exposed habitat being more stressful for this species. Intersexual differences were observed for foliar damage, defensive compounds (phenolics and tannins), all leaf size traits, total leaf area, and protein content. Contrasting light habitats affected most of the analysed traits. Both foliar damage and FA were higher in a more stressful habitat; within habitats, no positive correlations were found. Herbivore damage was significantly male biased in open habitat. The analysis of intersexual differences in developmental stability measured by leaf asymmetry levels provided no evidence that female plants were more sensitive to environmental stress.〈/p〉

Description: Many studies have highlighted the importance of mountain ecosystems as hotspots of biodiversity and endemism. In this study, we used biogeographic partitioning to explore the diversity patterns of high-mountain flora in south-western Europe by analysing the richness of the main floristic elements in relation to geographical and ecological factors (climate, isolation, elevation, etc.). Taxa that inhabit above 1600 m a.s.l. in the Iberian Peninsula were selected using bibliographic sources. Hierarchical agglomerative clustering and non-metric multidimensional scaling (NMDS) were used to explore the patterns of taxonomic diversity across the main biogeographic elements. Six environmental variables were calculated to account for inter-range variation in species richness and biogeographic elements. The results showed that at a broad scale, the main floristic elements correlated with specific eco-geographical factors. The Arctic–Boreal element was strongly, negatively correlated with summer drought and showed a higher taxonomic distinctness than expected. The Iberian endemic element was related to isolation and maximum elevation and although it was the richest element, it demonstrated a relatively low taxonomic diversity, in particular in the Baetic Range. Biogeographic origin is an important driver of the diversity patterns of high-mountain flora. In the Iberian Peninsula, these patterns show a North–South gradient, which reflects historical processes of migration and speciation that were constrained by climatic fluctuations during the Ice Ages. Although species richness is the usual biodiversity measure considered in conservation strategies, the use of taxonomically related indices helps to understand better the general diversity patterns and to better document strategies of biodiversity conservation.

Description: Under climate change, regeneration from seeds is becoming increasingly important for species persistence, migration and conservation, especially in high-elevation environments. In this regard, the ability of seeds to remain viable for a long time is a crucial prerequisite for seed persistence in the soil and in germplasm banks. However, little is known about the effects of climate warming on seed longevity of alpine plants. Here, we analysed the effects of a moderately warmer parental growth environment generated by open top chambers on subsequent seed longevity of four alpine snowbed species. Seeds from plants exposed to natural and warmed climate during the growing season were subjected to laboratory-controlled accelerated ageing and then regularly sampled for germination tests. Initial viability ( Ki ), deterioration rate ( σ − 1 ) and time taken for viability to fall to 50 % ( p 50 ) were estimated using probit analysis. Across species and treatments, p 50 varied from 4.9 to 23.1 days. Seeds produced by plants exposed to warmer temperatures were significantly longer lived than those from plants at natural conditions. Under warming, the seed progeny showed either a higher Ki or a slower σ − 1 . Under moderate climate warming (about + 2 K), alpine snowbed species produced seeds with an extended resistance to heat stress indicating an effective rapid response to the new environment. Such plastic response may play a key role for survival and persistence of alpine snowbed species facing climate change and may also have important implications for ex situ conservation.

Description: The timing of and relative investment in reproductive events are crucial fitness determinants for alpine plants, which have limited opportunities for reproduction in the cold and short growing seasons at high elevations. We use the alpine Anthyllis vulneraria to study whether flowering phenology and reproductive allocation have been under diversifying selection, and to assess genetic diversity and plastic responses to drought in these traits. Open-pollinated maternal families from three populations in each of two regions from the Swiss Alps with contrasting precipitation were grown in low and high soil moisture in a common garden. We measured onset, peak, and end of flowering, as well as vegetative and reproductive aboveground biomass. Population differentiation for each character ( Q ST ) was compared to differentiation at neutral microsatellite loci ( F ST ) to test for past selection. We found population differentiation in onset and peak of flowering which results from natural selection according to Q ST – F ST . End of flowering and biomass were not significantly differentiated among populations. Reduced soil moisture had no consistent effect on mean onset of flowering, and advanced peak and end of flowering by less than 1 week. Reproductive biomass was strongly decreased by lowered soil moisture. No genetic variation within or among populations was found for plasticity in any trait measured. The results suggest past heterogeneous selection on onset and peak of flowering in alpine Anthyllis vulneraria and potentially indicate local adaptation to differences in snowmelt date over distances 〈5 km. Limited variation in plastic responses to reduced soil moisture suggests that soil moisture might not vary between populations.

Description: The possible effects and implications of climate change on plant growth have not yet been studied in the central Chilean Andes, where a dry growing season differentiates this area from other mountainous areas around the world. At lower elevations, plants exposed to high temperatures and dry soil may experience severe water limitations, causing lower photosynthetic performance. At higher elevations, where water is not a limiting factor but air temperature is lower, an increase in temperature could have a positive effect on photosynthesis. We assessed whether experimental warming affects the photosynthetic performance and photoprotective mechanisms as photorespiration, Mehler reaction and cyclic electron flow in Phacelia secunda plants growing at 1600, 2800 and 3600 m elevation. Plants were exposed to a passive increase in the air temperature using open top chambers (OTC). Xylematic leaf water potential increased with elevation, and the OTC’s decreased xylematic water potential at the lower elevations but not at 3600 m. While warming was associated with a decrease in the maximal carbon gain assimilation at lower elevations, it was associate with an increase at 3600 m. Photorespiration differed among elevations and was increased by warming only at 1600 m. The Mehler reaction was higher at 1600, but not affected by warming. Warming increased the cyclic electron flow only in plants at 1600 m. Plants growing inside OTCs at all three elevations exhibited lower xanthophyll pools than control plants, but similar de-epoxidation states (DEPS). Our results show that alpine plant responses to warming will most likely depend on elevation, soil moisture availability and the combination of these two factors in relation to climate change.

Description: Stable carbon and nitrogen isotopes provide time-integrated signals of plant carbon and nitrogen relations. We assessed an entire alpine flora in the Swiss Alps at ca. 2400 m elevation, using year 2007 herbarium samples of 245 species, 141 genera and 42 families to explore functional trait diversity. Despite overall similar macro-environmental conditions (moisture, soils, elevation), signal variation covered the full spectrum known for C 3 plants. Variation among means for plant families for both δ 13 C and δ 15 N was smaller than variation among species within families. Species identity was of far greater importance than family affiliation. Similarly, tissue nitrogen and carbon concentrations varied in a rather species-specific manner, not permitting any a   priori plant functional group definition based on such traits. The study also yielded tissue-type specificity of isotope signals. The elevation signal in δ 13 C (known to be less negative at high elevation) was much less pronounced than observed previously in con-generic comparisons. Thus, elevational δ 13 C trends are hard to distinguish from species effects in mixed populations over narrow ranges of elevation. δ 15 N data offer more space for ecological interpretation and show family specificity of signals in few cases. Cyperaceae, the most prominent family in this region, show no discrimination against 15 N (like Fabaceae) and must have access to N sources different from most other families. This deserves experimental clarification, given the significance of Cyperaceae in cold environments. Overall, our study evidenced very high functional diversity among alpine plant species, as captured by these isotope signals.

Description: Little is known about the statistical consequences of plot size and their spatial arrangement when addressing biodiversity questions. Thus, we compared three vegetation plot sizes and two sampling designs with different spatial arrangements in alpine grasslands by analyzing their effects on common indices of alpha, beta and gamma plant species diversity. Data were collected in three 1-km 2 squares in summer pastures in the subalpine and alpine zones in Switzerland. In each square, 45 nested plots were distributed according to systematic random sampling (i.e., when the focus is on the abundances of the vegetation types and species) and maximum variation sampling (i.e., when the focus is on the set of vegetation types and species occurring). To compare the effects of the plot sizes and sampling designs on estimates of gamma diversity, we also estimated gamma diversity from an exhaustive sampling of the squares. Compared with systematic random sampling, maximum variation sampling hardly affected the indices of alpha diversity, but resulted in higher indices of beta and gamma diversity. More importantly, alpha and gamma diversity were found to be higher as plot size increased, whereas beta diversity was lower in the larger plots. Gamma diversity from the exhaustive sample was most similar to gamma diversity from maximum variation sampling on the largest plot sizes. Moreover, results from a variation partitioning analysis showed that landscape variability and plot size had a much larger effect on species diversity estimates than the sampling design. In conclusion, studies focusing on the occurring set of vegetation types and species within a landscape may apply maximum variation sampling if the most important (environmental) gradients for the stratification are known. Studies also focusing on the abundance of vegetation types or species may apply systematic random sampling.

Description: Plant taxonomic and phylogenetic composition of assemblages are known to shift along environmental gradients, but whether the rate of species turnover is regular or not (e.g., accelerations in particular sections of the gradient) remains poorly documented. Understanding how rates of assemblage turnover vary along gradients is crucial to forecast where climate change could promote the fastest changes within extant communities. Here we analysed turnover rates of plant assemblages along a 2500 m elevation gradient in the Swiss Western Alps. We found a peak of turnover rate between 1800 and 2200 m indicating an acceleration of grassland compositional changes at the transition between subalpine and alpine belts. In parallel, we found a peak in phylogenetic turnover rate in Poales between 1700 m and 1900 and Super-Rosids between 1900 and 2300 m. Our results suggest that changes in abiotic or biotic conditions near the human-modified treeline constitute a strong barrier for many grassland plant species, which share analogous elevation range limits. We propose that this vegetation zone of high ecological transitions over short geographical distances should show the fastest community responses to climate change from the breakdown of barrier across ecotones.

Description: Local cool spots (wind-holes) in lowland areas of midlatitudes may act as microrefugia for cold-adapted species outside of their typical alpine habitats. We examined the genetic structure of Vaccinium vitis - idaea , a common alpine species in Japan, in eight lowland wind-hole and five surrounding alpine populations. We collected leaf samples and genotyped seven microsatellite loci. Clonal patches (genets) were common in almost all populations. An analysis of annual shoot growth suggested that individuals in the wind-hole populations were long-lived (〉500 years old). Genetic diversity (allelic richness) and differentiation ( F ST ) of the wind-hole populations were lower and higher than those of the alpine populations, respectively. No significant isolation-by-distance trend in the genetic structure was detected for the wind-hole or alpine populations. All wind-hole populations had negative inbreeding coefficients ( F IS ), suggesting no tendency toward homozygosity due to inbreeding, regardless of the small populations geographically isolated from the large alpine populations. Therefore, wind-holes may harbor genetically isolated but stable populations due to clonal growth, limited gene flow, and abortion of selfed seeds by early acting inbreeding depression. Analysis of molecular variance demonstrated that genetic variations among and within populations contributed more to regional genetic diversity than those between wind-hole and alpine populations, suggesting that the wind-hole and alpine populations are important for maintaining the genetic diversity of midlatitude V. vitis - idaea populations. On the other hand, Bayesian clustering showed that some wind-hole populations geographically close to the alpine populations had mixed genetic compositions of the alpine and wind-hole populations.

Description: Alpine herbaceous plants employ two mechanisms to prevent freezing injury to leaves during the growing season, i.e., they avoid freezing by transient supercooling or tolerate the occurrence of extracellular ice. I examined seasonal changes in the two freezing resistance mechanisms in leaves of alpine plants from two temperate mountain regions, Niwot Ridge (3500 m) in the Front Range of the Rocky Mts. (USA) and Modré sedlo (1510 m) in the Giant Mts. (Czech Republic). Although plants from Niwot Ridge were on average ca. 2.6 K more resistant to freezing than plants from the Giant Mts., patterns of freezing resistance changes during the growing season were consistent between the two regions. Both freezing resistance mechanisms, i.e., avoidance by supercooling and tolerance of extracellular ice were encountered. Plants predominantly avoided freezing injury during early summer and tolerated extracellular freezing at the end of the growing season, and the seasonal change from avoidance to tolerance mechanisms was significant for both regions. The avoidance and tolerance mechanisms provided comparable freezing resistance to the plants during early summer but, unlike in avoidant plants, in tolerant plants resistance increased over the course of the season. The species formed three groups with regard to resistance mechanisms employed during the season: (1) species that avoided injury by supercooling during early summer and employed freezing tolerance towards autumn; (2) species that were freezing tolerant during the entire growing season; and (3) species with ephemeral shoots that solely avoided freezing by supercooling. Although freezing tolerance is a common feature in north-temperate alpine plants, avoidance by supercooling as a freezing resistance strategy might be selected for in species with particular life histories such as ephemeral hemiparasites.

Description: Although specific leaf area (SLA) has been proposed to reflect plant responses to climatic changes, the link between SLA and temperature has never been systematically evaluated. Using in situ measured SLA values for 223 species occurring in 29 calcareous grasslands along a temperature gradient in the Bavarian Alps, we explored the SLA–temperature relationship at population (intraspecific), species (interspecific) and community level and investigated the relative impact of other environmental factors on SLA variation along the temperature gradient at the community level. Only 14 % of the studied species showed significant changes in their SLA values along the temperature gradient, despite high intraspecific variability of the SLA values. At the species level, we revealed a very weak positive SLA–temperature relationship ( r 2  = 0.04, p  〈 0.001). A very strong positive correlation between SLA and temperature was detected at the community level ( r 2  = 0.70, p  〈 0.001). In addition to temperature, disturbance also had a significant influence on trait variation at the community level. We conclude that the variation in SLA along the temperature gradient comes primarily from changes in the relative abundances of species, whereas the trait variation at the population and the species levels was affected by other environmental factors. We therefore recommend the use of community-weighted mean values in studies employing SLA–temperature relationships because they reveal more regular patterns than the underlying distribution of within- and among-site SLA values.

Description: Alpine areas are both regional water reservoirs and zones of high species endemism. Increasing temperatures and earlier snowmelt have already caused upward migration of species, changes in flowering phenology and increasing frost damage in plants. Thus, significant loss of diversity in alpine areas is imminent. Plant migration and distribution shifts occur mainly via seeds, which also provide the genetic diversity required for adaptation. The ability of plants to shift their distribution in response to climate change will depend on seed dispersal, germination and seedling success under new environmental conditions. Despite the critical importance of seeds and seedlings for species adaptation, migration and persistence, the majority of studies concerning climate change in alpine areas have mostly focused on the response of adult plants to warming. Temperature during seed development, as well as the temperature to which seeds are exposed post-dispersal, has been found to have strong effects on seed longevity, germination and seedling survival. Therefore, global change (particularly, warming) is expected to greatly impact regeneration of seeds in alpine areas. Despite evidence that climate change is advancing flowering phenology in several mountain ranges around the world, under natural and artificial warming, the cascade effects that early flowering can have on seeds and seedlings have been poorly studied. Indeed, while a literature search on Web of Science using the search terms “germination”, “alpine plants” and “climate change” revealed 50 studies, of which only 7 directly examined the effect of warming on germination and establishment of seeds of alpine plant species. Here, we discuss the findings of these studies. We identify critical questions regarding seeds and seedlings of alpine species that require urgent research and recommend experimental approaches. Answering these questions will assist in predicting the impacts of global warming and in conservation and management of plants in alpine areas.

Description: Molecular cytogenetics and the study of genome size have been used to understand evolutionary and systematic relationships in many species. However, this approach has seldom been applied to alpine plants. A group of dysploid–polyploid high mountain Artemisia species, distributed from the European Sierra Nevada to Central Asian mountains, through the Pyrenees, the Alps and the Caucasus, is a good model to consider changes at the genome and chromosome levels. These small perennial Artemisia , found frequently in isolated populations, present highly disjunct distributions. Some are considered rare or even endangered. Here, we show results for nine species and 31 populations, including genome size (2C-values), fluorochrome banding and fluorescent in situ hybridisation of ribosomal RNA genes (rDNA). Significant intraspecific genome size variation is found in certain populations of A. eriantha and A. umbelliformis , but without taxonomic significance due to the absence of morphological or ecological differentiation. The number and position of GC-rich DNA bands is mostly coincidental with rDNA although there is an expansion of GC-rich heterochromatin in centromeres in some taxa. Ancestral character states have been reconstructed and x  = 9 is inferred as the likely ancestral base number, while the dysploid x  = 8 has appeared repeatedly during the evolution of Artemisia . On the basis of cytological observations, Robertsonian translocations are proposed for the appearance of dysploidy in the genus. A remarkable presence of x  = 8-based species has been detected in the clade including high mountain species, which highlights the important role of dysploidy in the diversification of high mountain Artemisia . Conversely, polyploidy, though present in the alpine species, is more common in the rest of the genus, particularly in arctic species. Hypotheses on the mechanisms underpinning the relative abundance of dysploids and scarcity of polyploids in high mountain Artemisia are discussed.

Description: Mountain ranges cover around one-half of the territory of Iran. Although it is well-known that these mountains are characterized by high levels of endemism, no assessment of vascular plant endemism of Iranian mountains has been made. Here, we undertake a first analysis of the diversity and biogeography of high-altitude (=taxa, whose elevational distribution ranges are entirely or largely above 2500 m a.s.l.) endemic vascular plant species restricted to Iran. In total, our data set includes 569 endemic vascular plant taxa (incl. 43 subendemic taxa which slightly extend into adjacent countries), which correspond to 62 % of the entire alpine flora. The highest number of alpine endemics occurs in the Zagros, followed by Alborz, and the NW Iranian mountains. Screes, rocks and thorn-cushion grasslands are the most important habitats for the alpine endemics. The altitudinal distribution of Iranian endemic alpine plant taxa peaks at high altitudes at c. 3000 m a.s.l. Below and above this altitude, there is a steep decrease in endemic alpine species numbers. The analysis of description histories in time-to-event analysis framework suggests that the rate by which new Iranian endemic alpine plant species are described does not seem to level off. Therefore, the proportion of species that still remain to be described is difficult to estimate. However, time-to-event analysis shows that at least 7 % of the extant Iranian alpine endemic species are not yet known to science. In addition, on average, the time lag between the year of collection and species description was 18 years. We conclude that there is a need for a continued botanical exploration in particular of under-sampled mountain ranges and for taxonomic revisions of genera rich in endemics which have been insufficiently studied yet.

Description: 〈h3〉Abstract〈/h3〉 〈p〉All plant species reach a low temperature range limit when either low temperature extremes exceed their freezing tolerance or when their metabolism becomes too restricted. In this study, we explore the ultimate thermal limit of plant tissue formation exemplified by a plant species that seemingly grows through snow. By a combination of studies in alpine snowbeds and under controlled environmental conditions, we demonstrate and quantify that the clonal herb 〈em〉Soldanella pusilla〈/em〉 (Primulaceae) does indeed grow its entire flowering shoot at 0 °C. We show that plants resume growth under 2–3 m of snow in mid-winter, following an internal clock, with the remaining period under snow until snow melt (mostly in July) sufficient to produce a flowering shoot that is ready for pollination. When snow pack gets thin, the flowering shoot intercepts and re-radiates long-wave solar radiation, so that snow and ice gently melt around the fragile shoot and the flowers emerge without any mechanical interaction. We evidence bud preformation in the previous season and enormous non-structural carbohydrate reserves in tissues (mainly below ground) in the form of soluble sugars (largely stachyose) that would support basic metabolism for more than 2 entire years under snow. However, cell-wall formation at 0 °C appears to lack unknown strengthening factors, including lignification (assessed by confocal Raman spectroscopy imaging) that require between a few hours or a day of warmth after snow melt to complete tissue strengthening. Complemented with a suite of anatomical data, the work opens a window towards understanding low temperature limits of plant growth in general, with potential relevance for winter crops and trees at the natural climatic treeline.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The central Chilean Andes are located in a Mediterranean-type climate zone, characterized by dry summers and high irradiance. This creates a contrasting elevational gradient because higher elevations get more solid precipitation and lower temperatures, resulting in higher soil humidity along the growing season compared with severe drought at lower elevations. Therefore, species with wide elevational distributions, such as 〈em〉Phacelia secunda,〈/em〉 must have developed specific adaptations to cope with contrasting severity of drought stress-induced photoinhibition at different elevations. We hypothesize that 〈em〉P. secunda〈/em〉 from lower elevation, is more tolerant to drought stress-induced photo-damage than plants from high elevation. This higher tolerance will be associated to a higher diversity of photoprotective strategies in plants that naturally suffers severe drought every growing season. To test this hypothesis, plants from 2700 and 3600 m in the central Chilean Andes were grown under the common garden and then subjected to water restriction. We measured stress indicators, photochemistry of PSII and PSI and estimate alternative electron sinks. Drought affected 〈em〉P. secunda〈/em〉 photosynthetic performance differentially depending on the elevation of provenance. Plants from lower elevation exhibited higher drought tolerance than higher elevation ones. This was related to higher levels of heat dissipation and alternative electron sinks exhibited by plants from lower elevation under drought stress. We concluded that plants naturally subjected to recurrent drought are better adapted to respond to drought stress using additional photochemical photoprotective mechanisms and confirm the role of alternative electron sinks ameliorating photodamage.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Pleistocene climatic changes affected the current distribution and genetic structure of alpine plants. Some refugial areas for the high elevation species have been proposed in the Alps, but whether they could survive on nunataks, is still controversial. Here, the spatial genetic structure in 〈em〉Salix serpillifolia〈/em〉 revealed by chloroplast (cpSSR) and nuclear (nSSR) microsatellites was compared with the MaxEnt-modelled geographic distributions under current and past (Last Glacial Maximum) climate conditions. Our results suggest that the genetic pattern of differentiation detected in 〈em〉S. serpillifolia〈/em〉 may be explained by the existence of Pleistocene refugia, including nunataks. The geographical patterns of variation obtained from the chloroplast and nuclear markers were not fully congruent. The spatial genetic structure that was based on nSSRs was more homogenous, while the cpSSR-based pattern pointed at strong genetic structure along the Alps. Five populations from the Central Alps had a combination of local and unique cpSSR clusters and admixture of those occurring in the Western and Eastern Alps. These findings may indicate the local survival of small populations of 〈em〉S. serpillifolia〈/em〉 that were subsequently populated by new colonists in the postglacial period.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Climate change has resulted in shorter periods of snow cover in alpine meadows, increasing the duration of UV exposure. We established the relationship between increased exposure to UV light and anthocyanin pigment levels in host plant 〈em〉Sedum lanceolatum〈/em〉 and tested whether increased exposure changed the feeding behavior of its herbivore 〈em〉Parnassius smintheus〈/em〉. Anthocyanin concentrations were significantly greater in plants exposed to UV. Under field conditions, we found a preference of 〈em〉P. smintheus〈/em〉 caterpillars for plants with slightly above average levels of anthocyanin; however, no-choice feeding experiments in which larvae ranging from 1 to 3 days old were placed on UV-rich and UV-low plants showed no difference in feeding. These results indicate that the reduction of snow cover in alpine meadows will change the pigment profile of plants, but these changes may have little effect on herbivory.〈/p〉

Description: Alpine plants experience high levels of insolation, as well as cold nighttime temperatures throughout the summer growth period. These two stress factors in combination are now recognized as potentially important limitations to photosynthetic carbon gain. Although likely candidates, the possible occurrence of photoinhibition in alpine plants has been reported infrequently. We measured photoinhibitory stress under natural field conditions and after high-light treatments in an herbaceous species ( Caltha leptosepala DC) with structural traits that appeared especially susceptible to photoinhibition, i.e., large, broad, laminar leaves with a near-horizontal leaf orientation. Although photosynthesis declined gradually during the afternoon under natural field conditions, no evidence was found for photoinhibition of photosynthesis, despite incident sunlight levels of 〉2500 µmol m −2  s −1 . Also, values of \({{F_{\text{v}}^{{\prime }} } \mathord{\left/ {\vphantom {{F_{\text{v}}^{{\prime }} } {F_{\text{m}}^{{\prime }} }}} \right. \kern-0pt} {F_{\text{m}}^{{\prime }} }}\) (an indicator of dynamic photoinhibition) changed little (〈10 %) from early morning to late afternoon values. Moreover, an experimental test of photoinhibition was conducted in the field using artificially applied low (250 µmol m −2  s −1 ) followed by unnaturally high (3500 µmol m −2  s −1 ) light levels, led to only small reductions in \({{F_{\text{v}}^{{\prime }} } \mathord{\left/ {\vphantom {{F_{\text{v}}^{{\prime }} } {F_{\text{m}}^{{\prime }} }}} \right. \kern-0pt} {F_{\text{m}}^{{\prime }} }}\) (20 % maximum). Also, afternoon declines in photosynthesis and other gas exchange parameters were associated with significant decreases in xylem water potentials. Thus, accumulating daily water stress appeared to be a possible, greater physiological limitation than photoinhibition, even in this common, hypothetically susceptible alpine species.

Description: In the European Alps, alpine species were able to survive periods of glaciation by retreating to lower-lying refugia surrounding the Alps. This temporary separation of populations in refugia has often led to genetic differentiation and the appearance of phylogeographic lineages, which are still detectable after postglacial recolonisation. Recently, evidence has been accumulating that glacial history also affected differentiation of phenotypic traits, but it is yet unknown to what extent postglacial connectivity among populations influenced the signature left behind by the history of glaciation. In this study, we demonstrate differentiation in phenotypic traits among three phylogeographic lineages of the widespread subalpine grassland herb, Geum montanum , using a common garden approach. We observed regional differentiation in 5 out of 16 traits, which was a small portion compared with a closely related species that has been previously studied, Geum reptans . This may possibly be due to species-specific differences in their respective distributions: G. montanum has well-connected populations whereas G. reptans occurs more often in isolated high-alpine environments. Results of a clipping treatment, designed to address responses in phenotypic traits to stress, showed regional differentiation in the response in number of flowers produced. This is potentially due to adaptations shaped by unknown histories of herbivory during glacial survival. We suggest that glacial history may leave its mark on the current phenotypic variability even of Alpine plants that are relatively common with well-connected populations.

Description: In arctic and alpine environments the highest biologically fixed nitrogen inputs are measured in the presence of leguminous plants, with a maximum annual nitrogen input recorded of about 10 kg ha −1  year −1 . Among the high-elevation legumes, Trifolium alpinum spreads over many southern European mountain grasslands as a dominant or co-dominant species, accounting for 30–40 % or more of total above-ground phytomass. We estimated the amount of symbiotic nitrogen fixation in T. alpinum -dominant communities using the 15 N isotope dilution technique and comparing the calculations derived from different non-fixing reference species. The estimated percentage of nitrogen derived from the atmosphere varied significantly depending on the reference species used and they were comparable to the ones reported in literature. No differences were detected among years. In the community studied, the use of one reference species instead of another can yield differences of more than 10 kg ha −1  year −1 , which may represent a considerable difference in the estimation of symbiotic nitrogen fixation in alpine ecosystems. Taking a very precautionary approach and using the grass Nardus stricta as the reference species, we estimated 21.9 kg ha −1  year −1 of nitrogen fixation in T. alpinum -dominant communities. This quantity of nitrogen is the highest ever estimated in a natural alpine grassland and it is related to the high annual above-ground phytomass of T. alpinum .

Description: Projections indicate that alpine tundra-specific vegetation may begin to disappear as global warming persists. We develop a context for possible changes to inform modeling, monitoring and mitigation strategies. We ask the degree to which similarity of floras is associated with climatic differences versus geographic distance and pattern among 56 mountain ranges in three major mountain systems across the western USA and southwestern Canada. We use, and contrast, Mantel tests and Canonical Correspondence Analysis incorporating Moran’s eigenvector mapping to analyze the dissimilarity among the floras. We use Sorenson’s dissimilarity for the floras, a distance matrix for all possible pairs, and broad-scale climate variables derived from the Daymet climate interpolation program. We also mapped the scores of ranges on the eigenvectors onto latitude and longitude and interpreted these visual patterns. The differences in vegetation among these sites are more strongly correlated to geography than to climate, but both winter and summer precipitations are still important. The importance of geography as geometry indicates that spatial processes affect the assemblage of floras. The explanatory power of geography means that changes in climate may not affect beta-diversity, and modeling, monitoring and mitigation strategies should include location factors.

Description: Vegetation succession on glacier forelands has been well-studied. However, most of the studies investigated only one or few glacier forelands. We studied regional variations in vegetation succession on 16 glacier forelands in the European Alps. To improve our understanding of how vegetation succession is regulated by environmental conditions, we took edaphic and climatic factors into account. We collected vegetation data in three stages (early; middle; late) along a successional gradient on glacier forelands in the Eastern and Western European Alps. The progressions of species richness, vegetation cover and composition during primary succession were compared between these two regions. In addition, the effects of climatic and edaphic factors and grazing were tested. Our results reveal that the vegetation from the early stage did not differ between the regions and different elevations. With progressing time, and especially in the late successional stage, several vegetation differences emerged. The forelands of the Western Alps already developed to open shrubland, while the forelands of the Eastern Alps so far only developed toward grassland. Surprisingly, these differences cannot be explained by different precipitation amounts, but possibly by different regional species pools and elevations of the treelines. We conclude that a complex of edaphic factors closely related to terrain age, regional differences in the species pool, and the different elevation of the treeline in the eastern and western Alps mostly influenced later stages of primary succession on glacier forelands.

Description: The elevation of treeline is rising in many areas throughout the world. Encroachment of forest into alpine regions fragments habitats and causes changes in microhabitat potentially altering the density and distribution of species. Our study investigates two species of alpine Crassulaceae, Sedum lanceolatum and Rhodiola integrifolia , as part of a larger project determining the effects of forest encroachment in the front ranges of the Rocky Mountains. Previous studies of S. lanceolatum showed a decrease in its density, but an increase in herbivory by larvae of the butterfly Parnassius smintheus with increasing distance from the treeline. To better understand the potential impact of forest encroachment on these species and the microhabitat associations of the plant species, we counted their abundance and determined soil depth, soil type, and dominant rock type in 8417 quadrats of 1 m 2 area spaced at 10 m intervals throughout 17 alpine meadows along Jumpingpound Ridge, AB, Canada. Using a geographic information system we extracted slope, aspect, elevation, and distance from treeline for each quadrat. S. lanceolatum was abundant in these meadows and its density was influenced by all factors examined, predominantly through effects on soil moisture. Its positive association with treeline was primarily at high elevation in meadows with west-facing aspects. R. integrifolia had a more restricted distribution and relatively low density; it was most abundant in gravelly soils with north-facing aspects and little slope. Comparing the distribution of each species to a model predicting future forest encroachment indicates that both will lose habitat to forest encroachment. R. integrifolia is predicted to lose 31 % of its current habitat area. S. lanceolatum , which occurs across a broader range of microhabitats, is predicted to lose 19 % of its current habitat area to forest encroachment. These losses will negatively affect P. smintheus , but the overall impacts of forest encroachment on the butterfly are predicted to be minimal.

Description: Phenolic compounds play important ecological roles in alpine plants such as offering efficient UV protection at high level of incident sunlight. Methods to study those compounds are limited, as they require sophisticated analytical tools and are time-consuming. An alternative and portable device—Dualex © —has been recently developed to estimate the plant epidermal flavonoids by fluorescence sensing. Here, we assessed if the Dualex device accurately estimates the phenolic contents of three alpine plant species along an elevational gradient and be an alternative to the commonly used chemical methods. We characterized their leaf epidermal absorbance measured by the Dualex device, total phenol content assessed by the Folin–Ciocalteu assay and total flavonoid content estimated by high-performance liquid chromatography. The results showed that leaf epidermal absorbance was slightly positively correlated to total phenols for Rhododendron ferrugineum and Dryas octopetala, but not for Vaccinium myrtillus and to total flavonoids for the first species, but not for the two others. The leaf epidermal absorbance estimated by the Dualex device is not an accurate and universal predictor of total phenols or total flavonoid contents for alpine plant species. The limitations of this optical method could be mainly explained by the high intraspecific variability of plant chemical composition in heterogeneous environmental conditions met in alpine areas. We thus recommend a cautious use of this device to avoid misinterpretations.

Description: The tropical alpine flora in the northern Andes has caught the attention of evolutionary biologists and conservationists because of the extent of its diversity and its vulnerability. Although population genetics studies are essential to understand how diversity arises and how it can be maintained, plant populations occurring above 4100 m a.s.l. in the so-called super-páramo have rarely been studied at the molecular level. Here, we use 11 microsatellite DNA markers to examine genetic structure in populations of Lupinus alopecuroides , a long-lived semelparous giant rosette known from only 10 geographically isolated populations. Each population is located on a different mountain top, of which three are in Colombia and seven in Ecuador. We analysed 220 individuals from all the ten known populations. We find low genetic variation in all but one of the populations. Four populations are completely monomorphic, and another five show only one polymorphic locus each. On the other hand, we find extremely high genetic differentiation between populations. We discuss the mechanisms that might cause this pattern, and we suggest that it is related to founder effects, lack of gene flow, and autogamy. The genetic relationships among the populations, and the lack of correlation between the genetic and geographic distances also point to the importance of founder effects and colonization history in driving differentiation among the populations.

Description: Hypochaeris leontodontoides is a rupicolous species endemic to the Atlas Mountains (Morocco), where it occurs in scattered populations. This study aims to understand the biogeographic structure of a high mountain species in a rather small area of NW Africa. We used Amplified Fragment Length Polymorphism (AFLP) to investigate the population structure and phylogeography of H. leontodontoides in 19 populations sampled from the entire species distribution range. Multivariate analyses including PCoA, UPGMA analysis, and Bayesian clustering were applied to infer the influence of past biogeographic events. The AFLP differentiation among the populations was high ( F ST  = 0.508). A significant geographical pattern by mountain region was found. The different phylogeographical analyses revealed four main groups corresponding to four well-defined geographic regions: Middle Atlas, Eastern High Atlas, Central High Atlas, and Western High Atlas, and highlighted the Western High Atlas as the most divergent group. Our data also indicate two regions as refuges during the Pleistocene ice ages: the Middle Atlas and the northernmost area of the Western High Atlas.

Description: In this investigation, we studied whether genetic variation and performance of the alpine plant species Dianthus callizonus differ between two different elevational zones of the southern Carpathians in Romania. We analysed 17 populations of the species from two study regions at 1700 and 2100 m above sea level in the Piatra Craiului Mountains applying AFLP analyses and morphological measurements. Following our results, population size differed between the two study regions and genetic variation within populations depended on population size. Population size and genetic variation within populations were higher in the study region located at 1700 m. By contrast, genetic variation between populations was nearly twice as large in the study region located at 2100 m. In a Mantel test, genetic and geographic distances between populations were clearly correlated. Moreover, individuals from the study region at 2100 m were significantly smaller, had fewer shoots, fewer flowers per shoot and produced seeds with a lower seed mass than individuals from the study region at 1700 m. The results of our study support the observation that changing environmental conditions along elevational gradients in mountain regions affect population size, genetic variation and performance of alpine plant species from different elevational zones, which should be considered in plant conservation.

Description: We analyzed the seasonal patterns of sap flow density ( Q s ) and stem radius variation (SRV) of Spartocytisus supranubius , a dominant, endemic tree-like shrub of the mountain vegetation at high elevation in Tenerife, Canary Islands. We tested the hypotheses that drought and its effect on water status and on radial growth (RG) is primarily related to cool–wet-season precipitation preceding the current year rather than to the dry summer per se . During 2013 and 2014 Q s and SRV were monitored with Granier-type sap flow sensors and automatic band dendrometers, respectively. Tree water deficit (Δ W ) was extracted from SRV, and standard meteorological factors were used to calculate daily reference evapotranspiration ( ET r ) and soil moisture deficit. In both years investigated Q s was highest during the dry summer coinciding with periods of high ET r , indicating that plants were able to tap water from deep soil layers originating from precipitation prior the current year’s growth. The high RG and low ΔW rates observed throughout both dry summers are consistent with a direct access of tap roots to deep soil water reserves. Seasonal variations in RG of S . supranubius were mainly determined by the course of Q s and thus dependent on temperature and tree water status.

Description: Botrychium s.s. is a cosmopolitan fern genus comprising about 35 currently recognized species. Despite unexpected high genetic diversity recently highlighted within Botrychium lunaria in the circumboreal region, few studies have included representative samples from Central Europe. Therefore, the aim of this work was to study the phylogeography of B . lunaria in the Central-European Mountain System and to compare it with that of flowering plants. Two noncoding chloroplast regions ( psb A- trn H and trn L-F) were sequenced (918 bp) from 87 individuals from 34 populations in the major European mountain chains (Sierra Nevada, Pyrenees, Massif Central, Jura, Vosges, Black Forest, Alps, Apennines, and Carpathians). Among the 24 haplotypes found in the B. lunaria aggregate in Europe, bayesian phylogeny and median-joining network support four main clades (LUN1, LUN2, LUN3, and TUN). NST and GST comparison as well as homogeneous groups indicated by SAMOVA indicate a clear phylogeographical pattern. However, unlinked to geographical distance, genetic diversity is greatest in the Prealps and highlights three main barriers to gene flow: S–N of Central Alps (Aosta-Lepontic Alps), and two separating E–W Alps (Lago di Como-Rhaetian Alps and Dolomites-Noric-Julian Alps). Our results indicate that alpine populations of the B. lunaria aggregate survived the Quaternary glaciations in situ in two main refugia, in the southern and eastern periphery of the Alps. Not only areas with higher values of genetic diversity, but also refugia and sites of geographical boundaries to gene flow, appear similar in both ferns and flowering plants.

Description: We used the broad elevational gradient of Kilimanjaro ranging from warm tropical lowland to cold Afro-alpine temperature regimes and the occurrence of natural, nearly untouched as well as of anthropogenic and heavily disturbed habitats to study how elevation and disturbance by humans affect the proportion of useful plant species in different habitat types. Of the 962 vascular plant species recorded in our 60 study plots, 563 species turned out to be listed as useful in the literature. We classified these species into six usage categories. With linear models we tested for relationships between the proportion of useful species per plot and elevation for natural habitats, and with analysis of variance we compared the proportion of useful species between plots in disturbed and natural habitats at similar elevation. The proportion of useful species for all usage categories increased from 860 to 2500 m asl and decreased with higher elevation. We also found an overall positive correlation between the number of useful plants and the species richness of our plots. Human-influenced habitats had higher proportions of useful species for all usage categories, except for construction and fuel wood usage which were higher in natural savanna and lower montane forest than in used habitats at these elevations. Given the high proportions of useful species, we conclude that preserving the biodiversity of Kilimanjaro ecosystems is indispensable for maintaining the diversity of useful plants species for the local people who rely on it for food, sustainable access to medicinal, fuel, construction and forage material.

Description: Mountains are hotspots of biodiversity. Yet, evaluating their importance in global biodiversity inventories requires the adoption of a pertinent definition of mountains. Here, we first compare the well-established WCMC and GMBA definitions, which both use geographical information systems. We show that the WCMC approach arrives at twice the global mountain area and much higher human population numbers than the GMBA one, which is explained by the inclusion of (mostly) low latitude hill country below 600 m elevation. We then present an inventory of the world’s mountains based on the GMBA definition. In this inventory, each of the 1003 entries corresponds to a polygon drawn around a mountain or a mountain range and includes the name of the delineated object, the area of mountainous terrain it covers stratified into different bioclimatic belts (all at 2.5′ resolution), and demographic information. Taken together, the 1003 polygons cover 13.8 Mio km 2 of mountain terrain, of which 3.3 Mio km 2 are in the alpine and nival belts. This corresponds to 83.7% of the global mountain area sensu GMBA, and 94% of the alpine/nival area. The 386 Mio people inhabiting mountainous terrain within polygons represent 75% of the people globally inhabiting mountains sensu GMBA. This inventory offers a robust framework for the integration of mountain biota in regional and larger scale biodiversity assessments, for biogeography, bioclimatology, macroecology, and conservation research, and for the exploration of a multitude of socio-ecological and climate change-related research questions in mountain biota, including the potential pressure on alpine ecosystems.

Description: Extinction of biodiversity due to human activities is a severe global problem. In Europe, however, only a few plant species died out so far. We investigated a dubious, disregarded taxon— Saxifraga oppositifolia subsp. amphibia —which became extinct in the 1960s. It exclusively occurred in a specific niche, namely in seasonally flooded waterside bank vegetation around Lake Constance in Germany and Switzerland. It has either been interpreted as a glacial relict or as a recent dealpine taxon. Using herbarium material, we conducted phylogenetic analyses based on ITS and cpDNA sequence variation. The taxon shared a chloroplast haplotype of S . oppositifolia , which is mainly distributed in the Alps, favouring the dealpine hypothesis. Nuclear data revealed several paralogous copies nested inside S . oppositifolia , most of which, however, differed from other S . oppositifolia accessions including those from the vicinity of Lake Constance. The oldest mean stem node ages of these ITS copies date between 0.91 and 0.28 my. Contradicting cpDNA, this may indicate that this saxifrage was a distinct taxon and possibly a relict originating in Middle Pleistocene glaciations. If so, the present study exemplifies that arctic-alpine plants survived in specific niches at low altitudes during interglacials and that corresponding taxa with a limited distribution are especially prone to extinction.

Description: The Alpine landscape is characterized by high spatiotemporal heterogeneity in environmental variables, such as climate and soil characteristics. This may lead to divergent selection pressures across plant populations and to local adaptation. Geum reptans , a widespread high-alpine clonal herb, has been the subject of several studies investigating phenotypic variation in populations across the Swiss Alps, yet so far, there is only little knowledge about local adaptation in this species from reciprocal transplantations across original field sites. Here, we reciprocally transplanted three populations of Geum reptans in the Central Swiss Alps, growing at close or far geographical distance from each other, and compared growth- and reproduction-related traits to investigate patterns of local adaptation. We further measured leaf morphological traits to assess potential selection at field sites, and quantified the relative importance of genetic vs. environmental variation (i.e., phenotypic plasticity) for all traits. Additionally, among and within population genetic differentiation was analyzed using microsatellite markers. Molecular diversity was high within populations, and molecular differentiation increased with geographic distance among populations, suggesting that gene flow is maintained at close range, but decreased with distance. Although extensive phenotypic variation was found across site × population transplant combinations, our study revealed little evidence for local adaptation in G. reptans populations. Plant traits also showed strong plasticity, as revealed by pronounced site effects, yet no direct linear selection was detected on leaf trait values within field sites. We suggest that the glacier forelands studied here, which are representative of the habitat of large G. reptans populations, are too similar in environmental conditions to lead to among population intraspecific differentiation in line with local adaptation. As G. reptans showed a great capacity to respond plastically to environmental conditions, we cautiously advocate that the evolution of phenotypic plasticity might have prevailed over genetic differentiation for the adaptation to the relatively narrow niche of this species.

Description: The tropical alpine ecosystem in eastern Africa is highly fragmented among biological ‘sky islands’, where populations of frost-tolerant organisms are isolated from each other by a ‘sea’ of tropical lowlands. One-third of the species in the afroalpine flora are exclusively alpine, but the other species can to varying degrees extend into grasslands and open forests of lower vegetation belts. A long-debated question is whether colonization of the alpine zone of these mountains and subsequent intermountain gene flow entirely depend on long-distance dispersal across unsuitable habitats, or whether suitable habitats shifted far enough downslope under past colder climates to form bridges enabling gradual migration. Here we address this question using a classification tree model. We mapped the extent of the current alpine habitat and projected it to the last glacial maximum (LGM) climate to assess whether gradual migration was possible for exclusively alpine taxa during this glacial period, and thus potentially also during earlier Pleistocene glaciations. Next, we modelled landcover under current and LGM climates to assess whether grassland and open forests could have served as migration corridors for alpine taxa that today extend into lower vegetation belts. We estimated that the LGM treeline was about 1000 m lower and the alpine habitat was about eight times larger than that today. At the LGM, we found that most of the currently fragmented alpine habitat of the Ethiopian highlands was interconnected except across the Great Rift Valley, whereas the solitary mountains of East/Central Africa remained isolated for exclusively alpine species. However, for drought-tolerant alpine species that today extend below the treeline, gradual migration through habitat corridors may have been possible among mountains during the dry glacial periods, and possibly also under the current climate before agriculture transformed the low-lying landscapes.