Alpine Habitats Research Articles

Food habits of the Japanese serow (Capricornis crispus) in an alpine habitat on Mount Asama, central Japan

Abstract We investigated the food habits of the Japanese serow (Capricornis crispus) in alpine habitats using direct observations at Mount Asama, central Japan. We observed the feeding behavior of 13 identified adult serows throughout the year, from April 2016 to October 2017. The animals’ food habits were evaluated by the feeding probability among 2129 observation bouts. The most important food throughout the year was grasses (feeding probability, 57.6%), followed by forbs (43.5%) and dwarf bamboos (11.4%). However, the feeding probability for each food category drastically changed in relation to the season; in particular, grasses and forbs were especially important foods from spring to autumn, whereas dwarf bamboos and conifers were important in winter. These results suggest that the food habits of the serow are flexible and will vary according to seasonal changes in vegetation. The findings also suggest that the feeding ecology of the serow in an alpine area tends to match that of an intermediate feeder rather than a browser, as was reported by several previous studies conducted in forested habitats. However, the food habits of the serows in the alpine habitats were similar to those of other alpine caprids, such as the mountain goat (Oreamnos americanus), alpine chamois (Rupicapra rupicapra) and Pyrenean chamois (Rupicapra pyrenaica). This is the first study to demonstrate that the food habits of the serow are variable according to the season and/or population. Similar to other alpine caprids, the flexible food habits of the serow in alpine habitats are likely an adaptation to an environment with a characteristically unstable food supply.

Alpine accentors as monitors of atmospheric long-range lead and mercury pollution in alpine environments.

Mercury and lead are deposited in the West Carpathians as long-range transported air pollution. The Alpine accentor (Prunella collaris) was recognized as a cost-effective biomonitor, and used to investigate the bioavailability of contaminants in large alpine areas. The outer tail feathers and blood of the alpine accentors were used for assessment of atmospheric mercury and lead contamination, respectively. Mean mercury levels in feathers of accentors averaged at 1.15μg/g (SE = 0.105, n = 40). There were no temporal variations in mercury concentrations. Mean blood lead levels were at 5.2μg/dL (SE = 0.5, n= 27), showing a slight decreasing trend from July to October. Juveniles were not more susceptible to lead accumulation than adults. Bone lead concentrations that increase with age reflect a bioaccumulation effect. A statistically significant negative correlation was found between the length of erythrocytes and the concentration of lead, which may show the first symptoms of microcytosis. In comparison to aquatic ecosystems, the biogeochemical factors that influence methylmercury availability in alpine habitats are not yet completely known and require further investigation. Our findings show that birds in alpine terrestrial ecosystems may contain surprisingly high levels of methylmercury. The mercury levels in the feathers of accentors probably indicate that alpine autotrophs make sufficient amounts of mercury available to the terrestrial food web. The blood lead levels of accentors likely approach the threshold level for further hematological effects. We found a clear tendency in erythrocytes to change their shape from ellipsoid to smaller and rounder with increasing amounts of lead in their blood. The shape of bird erythrocytes appears to be a very sensitive indicator of critical levels of lead in the alpine environment.

The compounding consequences of wildfire and climate change for a high‐elevation wildflower (Saxifraga austromontana)

AbstractAimHigh‐elevation plants are disproportionally affected by climate change. As temperatures rise, the amount of available alpine habitat in the Rocky Mountains will decrease resulting in potential local extinctions of plant species. In addition to the direct effects of climate‐driven habitat loss, alpine plants must also respond to indirect effects, such as changes in disturbance regimes. One notable shift is the increase of wildfire frequency in regions where fire was previously rare or absent, including the alpine. We hypothesized that direct climatic changes compounded with increased wildfire frequency will reduce the future suitable habitat of high‐elevation plants more than if climate was considered alone.LocationRocky Mountain Floristic Region, western North America.TaxonSaxifraga austromontana (Saxifragaceae), a wildflower endemic to high elevations of the Rocky Mountain Floristic Region.MethodsOur approach integrated historical herbarium records, field surveys, remote sensing, species distribution models, historic wildfire data, and predictive models.ResultsOur results indicate wildfire has significantly reduced the abundance and increased the likelihood of extirpation for S. austromontana. Increased fire frequency compounded with direct climatic changes will likely reduce the range of the species by approximately 43% by 2050 compared to 38% due to climate alone, under a moderate CO2 emissions scenario. The influence of wildfire varies regionally. For instance, the Middle Rockies will likely lose 74% of its suitable habitat of which 16% may be lost due to fire, while other regions, such as the northern range, will be less negatively affected by direct and indirect effects.Main ConclusionsOur evidence that increased wildfire frequency will compound the impacts of climate change on alpine taxa in North America led to the development of a new, general hypothesis on the fundamental interaction between direct and indirect effects of climate change on species range reductions.

Picea purpurea has a physiological advantage over its progenitors in alpine ecosystems due to transgressive segregation

ABSTRACTPicea purpurea originated from the homoploid hybrid speciation, which occupy novel alpine habitats in the north-east region of the Qinghai-Tibet Plateau (QTP) where its progenitors, P. wilsonii and P. likiangensis are excluded. Alpine habitats are usually characterized by low atmospheric CO2 concentrations and strong solar radiation with a large fraction of shortwave radiation (i.e. blue light). To test whether P. purpurea has the transgressive segregation in photosynthetic capacity and stomatal characteristics contributed to occupying such extreme habitats, we investigated the leaf gas exchange properties at two level of CO2 concentration (Ca: 200 and 400 μmol mol−1), light responsive curves of photosynthesis under three light qualities (red, blue and a mixture of both red and blue light at the ratio of 94:6), stomatal and other relative physiological traits for all three species. Our results show evidence of transgressive segregation in hybrid species; for instance, under blue and red light P. purpurea was demonstrated has the higher quantum yield of CO2 assimilation (φ) and maximum CO2 assimilation rate (Amax) than its progenitors. Particularly φ and Amax in P. purpurea were 2-fold higher than these in P. likiangensis. P. purpurea also exhibited higher stomatal conductance at low CO2 concentrations and instantaneous water use efficiency under all light qualities, have greater leaf pigments content, longer guard cell length and lower linear stomatal density relative to its progenitors. These traits may have enhanced the physiological fitness of P. purpurea and facilitated its colonization to alpine habitats.

Range extension and high elevation record for the endangered woolly flying squirrel Eupetaurus cinereus in Western Himalaya, India

Abstract The woolly flying squirrel (Eupetaurus cinereus Thomas, 1888) is one of the least-known endangered mammals of the Himalayas and recorded only from few localities at 2400–3600 m in Hindu Kush and North-Western Himalayas. We report first confirmed record of this species from Upper Bhagirathi Basin, Uttarakhand, Western Himalaya. The squirrel was photo-captured twice in camera traps placed in temperate and alpine habitats. The photo-capture at 4800 m is higher than the described upper elevation range limit of any other flying squirrels. Continuous monitoring would reveal the extent of threats to this rare species in its newly described range.

Increased microbial uptake and plant nitrogen availability in response to simulated nitrogen deposition in alpine meadows

As global industry and intensive agriculture increase in response to an expanding human population, oligotrophic ecosystems such as alpine and subalpine habitats are increasingly vulnerable to transported atmospheric nitrogen (N) pollution. Even at low levels, N deposition can alter soil chemistry via changes in decomposition rates and mineralization of N from soil organic matter. We used fertilization to mimic N deposition in three National Park alpine meadow ecosystems in the Pacific Northwest (PNW) of the United States (an area of low ambient N deposition) over a 3-year period. Our sites were two moist heath meadow ecosystems in the western Cascade Mountains and one dry meadow ecosystem in the eastern Olympic Mountains. We assessed alpine soil chemistry and N cycling responses to simulated N deposition, using soil inorganic N availability to plants as a critical loads indicator. Soil solution inorganic N supply as measured by resin probes increased in response to N treatment at all sites by Year 3 in plots fertilized at the 10 kg N ha−1 yr−1 treatment level. At the heath meadow sites, we observed increased soil NO3-N during the summer and decreased extractable organic carbon (C) during the fall in response to applied N. We also observed seasonal increases in the proportion of soil N contained in microbial biomass in response to treatment. These data indicate season-specific increases in microbial N uptake and mineralization in response to fertilizer treatment. The carbon-rich, fine-ash volcanic soils of the North Cascades were the most sensitive to N treatment with low microbial N uptake. From those soils, we derived an empirical critical load of 6 kg N per ha−1 yr−1 for increased soil N availability. However, alpine meadow soils in the Western Cascades undergo N limitation in the fall and may have less potential for N leaching with fall rains. In contrast, soils at the dry meadow site had much greater potential for N mineralization, and are temperature- and moisture-limited rather than N limited. Changes in soil chemistry in response to N deposition were site-specific and resulted from differences in plant uptake and soil N mineralization capacity, indicating two very different regimes for response to N deposition for N-limited alpine meadows vs moisture-limited alpine meadows.

Resolving the predator first paradox: Arthropod predator food webs in pioneer sites of glacier forelands.

Primary succession on bare ground surrounded by intact ecosystems is, during its first stages, characterized by predator‐dominated arthropod communities. However, little is known on what prey sustains these predators at the start of succession and which factors drive the structure of these food webs. As prey availability can be extremely patchy and episodic in pioneer stages, trophic networks might be highly variable. Moreover, the importance of allochthonous versus autochthonous food sources for these pioneer predators is mostly unknown. To answer these questions, the gut content of 1,832 arthropod predators, including four species of carabid beetles, two lycosid and several linyphiid spider species caught in early and late pioneer stages of three glacier forelands, was screened molecularly to track intraguild and extraguild trophic interactions among all major prey groups occurring in these systems. Two‐thirds of the 2,310 identified food detections were collembolans and intraguild prey, while one‐third were allochthonous flying insects. Predator identity and not successional stage or valley had by far the strongest impact on the trophic interaction patterns. Still, the variability of prey spectra increased significantly from early to late pioneer stage, as did the niche width of the predators. As such the structure of pioneer arthropod food webs in recently deglaciated Alpine habitats seems to be driven foremost by predator identity while site and early successional effects contribute to a lesser extent to food web variability. Our findings also suggest that in these pioneer sites, predatory arthropods depend less on allochthonous aeolian prey but are mainly sustained by prey of local production.

Enhanced cell dehydration tolerance and photosystem stability facilitate the occupation of cold alpine habitats by a homoploid hybrid species, Picea purpurea.

Homoploid hybrid speciation (HHS), characterized by hybrid speciation without a change in chromosome number and facilitated by ecological divergence, is well known in angiosperms but rare in gymnosperms. Picea purpurea as one of two demonstrably conifer diploid hybrid species in gymnosperms has been found to occupy colder alpine habitats than its parents. However, studies on whether leaf frost tolerance and hydraulic safety exhibit transgressive segregation and thus play a role in conifer HHS are still lacking. In this study, we compared the frost tolerance of photosystem stability (the maximum efficiency of PSII, Fv/Fm), pressure-volume parameters, and xylem resistance to dysfunction of leaves (current-year twigs) and stems (annual shoots) between P. purpurea and its progenitors. The results indicated that P. purpurea had significantly lower osmotic potential at full turgor, water potential at turgor loss point, water potential at 12 % loss of conductance of stem, the maximum hydraulic conductance of stem and the temperature causing a 50 % reduction in initial Fv/Fm than its parental species. In contrast, the leaf and stem xylem pressure inducing 50 % loss of hydraulic conductivity (leaf Ψ50 and stem Ψ50, respectively) and hydraulic safety margin in leaf Ψ50, stem Ψ50 in P. purpurea showed no significant difference with those of P. wilsonii, but significantly larger than those of P. likiangensis. This suggests that the frost tolerance of photosystem stability and the cell dehydration tolerance in P. purpurea are superior to its parental species, facilitating its successful colonization and establishment in colder habitats.

Den site selection by male brown bears at the population's expansion front.

Brown bears (Ursus arctos) spend about half of the year in winter dens. In order to preserve energy, bears may select denning locations that minimize temperature loss and human disturbance. In expanding animal populations, demographic structure and individual behavior at the expansion front can differ from core areas. We conducted a non-invasive study of male brown bear den sites at the male-biased, low-density western expansion front of the Scandinavian brown bear population, comparing den locations to the available habitat. Compared to the higher-density population core in which intraspecific avoidance may affect den site selection of subordinate bears, we expected resource competition in the periphery to be low, and all bears to be able to select optimal den sites. In addition, bears in the periphery had access to free-ranging domestic sheep during summer. We found that males in the periphery denned on high-elevation slopes, probably providing good drainage, longer periods of consistent, insulating snow cover and fewer melting-freezing events. Forests were the principal denning habitat and no dens were found in alpine areas. The Scandinavian brown bears have a history of intense harvest, including culling at the den. This may have exerted a selection pressure to avoid denning in open alpine habitat which compared to forests provide little cover. The bears denned away from main roads and in steep, rugged terrain, probably limiting human access. The odds for finding a bear den decreased with increasing distance to the population core where females could be found. Previous studies have documented directed movement of male brown bears from the male-biased population periphery toward the core areas during the mating season. In this way, denning males may be trading off between low resource competition and access to sheep in the low-density periphery, and mating opportunities in the higher-density population core.

Goodyera fusca (Lindl.) Hook. f. (Orchidaceae): a new record for Kashmir Himalaya, India

Goodyera fusca (Lindl.) Hook. f., a rare orchid species is reported for the first time from the Kashmir Himalaya, India. A brief description and photographs of diagnostic features are provided. Comparative characters are also provided to distinguish G. fusca from Goodyera repens (L.) R. Br. already reported from Kashmir Himalaya. This newly reported terrestrial orchid species occurs in alpine habitats of this Himalayan region.

La Sal Daisy,Erigeron mancus,Density and Associated Species from Treeline Ecotone and Alpine Habitats

The La Sal daisy, Erigeron mancus, is endemic to treeline ecotone and alpine meadow habitats of the La Sal Mountains in Utah, an insular, laccolithic mountain range on the Colorado Plateau in southeastern Utah. From 2009 to 2011 we established elevational transects through upper spruce-fir forest, treeline ecotone, and alpine meadow habitats on Laurel Ridge in the Middle Mountain group of the La Sal Mountains to measure (1) periodic changes in E. mancus population density, (2) changes in the elevation of the E. mancus population centroid, (3) changes in patch size occupied by E. mancus, and (4) changes in frequency of occurrence in herbaceous plant species associated with E. mancus along these transects. We measured both E. mancus density and vascular plant species composition within 1-m × 1-m square frames in mid-July, near peak alpine plant flowering time. The E. mancus population density on Mt. Laurel ridge did not significantly change from 2009 to 2015, but the species was most abundant in alpine meadow habitat for both years. Changes in patch width, centroid elevation, and frequency of occurrence of 30 associated plant species were also not statistically significant. Like E. mancus, most species show changes in frequency of occurrence between upper spruce-fir forest, treeline ecotone, and alpine meadow habitats. Individual plants of E. mancus are probably long-lived perennials, so changes in population density and distribution due to global warming are expected to be gradual and/or have an unknown lag time. Although there is no evidence of ongoing change in the Laurel Ridge population of E. mancus, having this information will provide a solid statistical basis for determining significant future changes.

Long-Term Changes in the Composition, Ecology, and Structure of Pinus mugo Scrubs in the Apennines (Italy)

Mountain ecosystems are vulnerable because of land-use and climate change. In this study, we performed a re-visitation study using historical and newly collected vegetation plots to explore the primary trends in the floristic, ecological, and structural features of Mediterranean Pinus mugo krummholz over past decades. The plant community composition over time (1992 vs. 2016–17) was analyzed by a detrended correspondence analysis followed by a statistical comparison of time steps and an analysis of the contribution of each species to temporal differences. Ecological and structural changes were analyzed by a permutational multivariate analysis of variance followed by a post hoc comparison. We observed relevant changes in the floristic composition, structure, and ecological characteristics of Pinus mugo scrub. Some subalpine and treeline species that characterize the early stages of Pinus mugo succession declined as several warm-adapted species increased. Furthermore, these changes were most likely due to the natural evolution of high-mountain krummholz combined with a thermophilization process occurring in alpine habitats. In contrast, a small group of cold-adapted species also increased, probably because the patchy spatial pattern of Pinus mugo scrubs gives rise to “mesic patches” in a matrix of arid grasslands. The re-visitation approach adopted for long-term analysis in this study can potentially be applied to other mountainous regions to better understand long-term ecological changes in high alpine vegetation.

Trends in Population Size of Rare Plant Species in the Alpine Habitats of the Ukrainian Carpathians under Climate Change

Population trends in rare alpine plant species in the high-mountain zone of the Ukrainian Carpathians are described with regard to the types of habitats where they occur. Populations of cold-adapted species confined to snowbeds, alpine screes, poorly vegetated rocks, and the highest ridges, as well as mires and springs, are very vulnerable to climate change, while their habitats tend to shrink. The direct impact of warming affects mainly the most cryophilic species. Another driver of changes is climate-induced succession that results in denser vegetation cover and encroachment of more thermophilic plants, which replace low-competitive rare alpine species. Their replacement is largely caused by the loss of open microsites suitable for seed recruitment. However, the climate-driven decrease of snow cover often leads to frost damage to vegetation that provides gaps appropriate for the establishment of many rare species. One of the groups of species that benefit from warming includes rather thermophilic tall herbs that are more common in the subalpine zone but have been actively spreading at higher altitudes lately.

Evolution, Diversification, and Biogeography of Grasshoppers (Orthoptera: Acrididae)

AbstractThe grasshopper family Acrididae is one of the most diverse lineages within Orthoptera, including more than 6,700 valid species distributed worldwide. Grasshoppers are dominant herbivores, which have diversified into grassland, desert, semi-aquatic, alpine, and tropical forest habitats, and exhibit a wide array of morphological, ecological, and behavioral diversity. Nevertheless, the phylogeny of Acrididae as a whole has never been proposed. In this study, we present the first comprehensive phylogeny of Acrididae based on mitochondrial genomes and nuclear genes to test monophyly of the family and different subfamilies as well as to understand the evolutionary relationships among them. We recovered the monophyletic Acrididae and identified four major clades as well as several well-characterized subfamilies, but we also found that paraphyly is rampant across many subfamilies, highlighting the need for a taxonomic revision of the family. We found that Acrididae originated in the Paleocene of the Cenozoic period (59.3 million years ago) and, because the separation of South America and Africa predates the origin of the family, we hypothesize that the current cosmopolitan distribution of Acrididae was largely achieved by dispersal. We also inferred that the common ancestor of modern grasshoppers originated in South America, contrary to a popular belief that they originated in Africa, based on a biogeographical analysis. We estimate that there have been a number of colonization and recolonization events between the New World and the Old World throughout the diversification of Acrididae, and, thus, the current diversity in any given region is a reflection of this complex history.

Comparative research of photosynthetic processes in selected poikilohydric organisms from Mediterranean and Central-European alpine habitats

Dehydration-induced decrease in photosynthetic activity was investigated in five poikilohydric autotrophs using chlorophyll fluorescence parameters recorded during controlled desiccation. For the study, two representatives of mosses from alpine zone (Rhizomnium punctatum, Rhytidiadelphus squarrosus) of the Jeseníky Mts. (Czech Republic) were used. Other two experimental species were mediterranean habitats liverwort (Pellia endiviifolia) and moss (Palustriella commutata), collected from under Woodwardia radicans canopy in the Nature Reserve Valle delle Ferriere (Italy). The last species was a liverwort (Marchantia polymorpha) collected from lowland site (Brno, Moravia, Czech Republic). We investigated the relationship between relative water content (RWC) and several chlorophyll fluorescence parameters evaluating primary photochemical processes of photosynthesis, such as effective quantum yield of photosynthetic processes in photosystem II (ΦPSII), and non-photochemical quenching (qN). With desiccation from fully wet (RWC = 100%) to dry state (RWC = 0%), ΦPSII exhibited a rapid (R. punctatum) and slow decline of ΦPSII (R. squarrosus, P. endiviifolia, M. polymorpha, and P. commutata). Shapes of dehydration-response curves were species-specific. RWC0.5, i.e. the RWC at which the sample showed half of maximum ΦPSII, reflected the species-specificity. It reached 65% in desiccation sensitive (R. punctatum), 53% and 43% in semi-tolerant (P. commutata and R. squarrosus), 24% and 18% in desiccation-tolerant species (P. endiviifolia and M. polymorpha). In all experimental species, non-photochemical quenching (qN) of absorbed light energy showed high values at RWC = 100% and a slight increase with desiccation. Steady state chlorophyll fluorescence (FS) remained high during desiccation and was not correlated with ΦPSII.

Local adaptation and ecological differentiation under selection, migration, and drift in Arabidopsis lyrata.

How the balance between selection, migration, and drift influences the evolution of local adaptation has been under intense theoretical scrutiny. Yet, empirical studies that relate estimates of local adaptation to quantification of gene flow and effective population sizes have been rare. Here, we conducted a reciprocal transplant trial, a common garden trial, and a whole-genome-based demography analysis to examine these effects among Arabidopsis lyrata populations from two altitudinal gradients in Norway. Demography simulations indicated that populations within the two gradients are connected by gene flow (0.1<4Ne m<11) and have small effective population sizes (Ne< 6000), suggesting that both migration and drift can counteract local selection. However, the three-year field experiments showed evidence of local adaptation at the level of hierarchical multiyear fitness, attesting to the strength of differential selection. In the lowland habitat, local superiority was associated with greater fecundity, while viability accounted for fitness differences in the alpine habitat. We also demonstrate that flowering time differentiation has contributed to adaptive divergence between these locally adapted populations. Our results show that despite the estimated potential of gene flow and drift to hinder differentiation, selection among these A. lyrata populations has resulted in local adaptation.

Alpine soil microbial ecology in a changing world.

Climate change has a disproportionally large impact on alpine soil ecosystems, leading to pronounced changes in soil microbial diversity and function associated with effects on biogeochemical processes at the local and supraregional scales. However, due to restricted accessibility, high-altitude soils remain largely understudied and a considerable heterogeneity hampers the comparability of different alpine studies. Here, we highlight differences and similarities between alpine and arctic ecosystems, and we discuss the impact of climatic variables and associated vegetation and soil properties on microbial ecology. We consider how microbial alpha-diversity, community structures and function change along altitudinal gradients and with other topographic features such as slope aspect. In addition, we focus on alpine permafrost soils, harboring a surprisingly large unknown microbial diversity and on microbial succession along glacier forefield chronosequences constituting the most thoroughly studied alpine habitat. Finally, highlighting experimental approaches, we present climate change studies showing shifts in microbial community structures and function in response to warming and altered moisture, interestingly with some contradiction. Collectively, despite harsh environmental conditions, many specially adapted microorganisms are able to thrive in alpine environments. Their community structures strongly correlate with climatic, vegetation and soil properties and thus closely mirror the complexity and small-scale heterogeneity of alpine soils.

Genetic integrity, diversity, and population structure of the Cascade red fox

The Cascade red fox (CRF) occurred historically throughout subalpine and alpine habitats in the Cascade Range of Washington and southernmost British Columbia, but now appears to be extremely rare. Causes for its apparent decline are unknown, as is the current distribution and connectivity of its populations. Additionally, the introduction of nonnative (fur-farm) red foxes to surrounding lowland areas during the past century raises concerns about their expansion to higher elevations and potential hybridization with the CRF. We conducted noninvasive genetic sampling and analyses of CRFs in a 5575 km2 region in the southern portion of its range, which is thought to contain a significant proportion of the current population. We obtained 154 mitochondrial DNA sequences and microsatellite genotypes for 51 individuals to determine trends in genetic diversity, assess evidence for nonnative introgression, and describe population structure. Although heterozygosity (He = 0.60, SE = 0.03) was only slightly lower than an estimate obtained from samples collected during the 1980s (He = 0.64, SE = 0.05), genetic effective size of the current population based on a one-sample estimate was very small (Ne = 16.0, 95% CI 13.3–19.4), suggesting a loss of genetic diversity and the potential for inbreeding depression in future decades. Genetic connectivity was high and we found no evidence for hybridization with nonnative lowland red foxes. Thus, although a small effective population size indicates the possibility of inbreeding depression and loss of evolutionary potential, high connectivity and genetic integrity could mitigate this to some extent, indicating that the population could respond to conservation efforts. Ultimately, successful conservation of this species depends on a better understanding of the factors that originally contributed to its decline and that currently limit its growth.

The lifestyle of lichens in soil crusts

AbstractLichens are one of the common dominant biota in biological soil crusts (biocrusts), a community that is one of the largest in extent in the world. Here we present a summary of the main features of the lifestyle of soil crust lichens, emphasizing their habitat, ecophysiology and versatility. The soil crust is exposed to full light, often to high temperatures and has an additional water source, the soil beneath the lichens. However, despite the open nature of the habitat the lichens are active under shady and cooler conditions and avoid climate extremes of high temperature and light. In temperate and alpine habitats they can also be active for long periods, several months in some cases. They show a mixture of physiological constancy (e.g. similar activity periods and net photosynthetic rates) but also adaptations to the habitat (e.g. the response of net photosynthesis to thallus water content can differ for the same lichen species in Europe and the USA and some species show extensive rhizomorph development). Despite recent increased research, aspects of soil crust ecology, for example under snow, remain little understood.

Glacial loss and its effect on riparian vegetation of alpine streams

Abstract Rising global temperature is expected to increase alpine glacier mass loss with cascading effects on alpine habitats and biota. Currently, there is limited information on the effects of climate change on alpine riparian vegetation including quantitative assessments of geophysical habitat context. We measured geomorphic conditions and riparian vegetation composition of alpine streams across a chronosequence of sites supported hydrologically by glaciers, permanent snowfields (PS) and seasonal snowfields (SS) in Glacier National Park (GNP), Montana, USA. Responses in the system to possible climate‐driven shifts in hydrologic regime were identified using multivariate analyses. Glacier‐fed streams had higher discharge and stream power and lower substrate stability than streams fed by PS and SS. Streams fed by PS supported a higher number of species than other stream types. Glacier‐fed streams were characterised by higher abundance of disturbance‐adapted shrub species than PS and SS. By applying projections from climate models that forecast total glacial loss in GNP by 2030 to our data, we predict that stream geophysical conditions will shift, resulting in a loss of physical habitat for shrub species, an increase in habitat for herbaceous species, and ultimately a homogenisation of riparian communities in the alpine zone. Our study identifies glaciers as drivers of alpine riverine ecosystems and highlights the importance of examining geophysical habitat linked to hydrologic regimes and glaciers to better understand the impacts to biota under future climate scenarios. We provide a framework for relating fluvial biological and hydrogeomorphic processes in the context of alpine glacial recession.