Alpine Environments Research Articles

Role of phenotypic and transcriptomic plasticity in alpine adaptation of Arabidopsis arenosa.

Plasticity is an important component of the response of organism to environmental changes, but whether plasticity facilitates adaptation is still largely debated. Using transcriptomic and phenotypic data, we explored the evolution of ancestral plasticity during alpine colonization in Arabidopsis arenosa. We leveraged naturally replicated adaptation in four distinct mountain regions in Central Europe. We sampled seeds from ancestral foothill and independently formed alpine populations in each region and raised them in growth chambers under conditions approximating their natural environments. We gathered RNA-seq and genetic data of 48 and 63 plants and scored vegetative and flowering traits in 203 and 272 plants respectively. Then, we compared gene expression and trait values over two treatments differing in temperature and irradiance and elevations of origin and quantified the extent of ancestral and derived plasticity. At the transcriptomic level, initial plastic changes tended to be more reinforced than reversed in adapted alpine populations. Genes showing reinforcement were involved in the stress response, developmental processes and morphogenesis and those undergoing reversion were related to the stress response (light and biotic stress). At the phenotypic level, initial plastic changes in all but one trait were also reinforced supporting a facilitating role of phenotypic plasticity during colonization of an alpine environment. Our results contrasted with previous studies that showed generally higher reversion than reinforcement and supported the idea that ancestral plasticity tends to be reinforced in the context of alpine adaptation. However, plasticity may also be the source of potential maladaptation, especially at the transcriptomic level.

Application of hybrid intelligent algorithm for multi-objective optimization of high performance concrete in complex alpine environment highway

Concrete mix proportion affects concrete performance and cost. Therefore, it arouses an increase of interest in the research on performance improvements in concrete through the optimization of the raw material mix proportion, especially in the high cold, high-salinity and other complex environment. In this paper, an intelligent multi-objective optimization framework is constructed based on Bayesian optimization Random Forest (BO-RF) algorithm and fast non-dominated sorting genetic algorithm (NSGA-III). The key factors affecting concrete performance are taken as the input indexes, the freezing resistance, impermeability, carbonization depth and cost are taken as the evaluation indexes of concrete. Based on 400 groups of freeze–thaw cycle of salt invasion experiments in cold environment, the orthogonal experiment method is used to obtain the index system of the original data sets, then, the RF prediction algorithm is adopted to establish the key factors and performance index of a nonlinear mapping relationship and the Bayesian optimization random forest is used to establish a high-precision fitness function. Ultimately, the BO-RF-NSGA-III model is applied for multiobjective optimization. The results show that (1) Based on the proposed framework, the rapid prediction and optimization of concrete performance can be realized, which can well meet the needs of the complex alpine environment (2) Accurate model prediction can be made through BO-RF. The R2 values obtained at the time of prediction range from 0.944 to 0.998, the mean absolute error (MAE) range from 0.001 to 0.09. (3) Based on BO-RF-NSGA-III and grey correlation method, the comprehensive optimal mix proportion of concrete is obtained.

Analysis of Water Conservation Trends and Drivers in an Alpine Region: A Case Study of the Qilian Mountains

The water conservation service of an ecosystem reflects the sustainability of regional water resources and is significant to human survival and sustainable development. However, global climate warming and intensified human activities pose substantial challenges to regional water conservation services, especially in an alpine region with a fragile ecological environment, which is more sensitive to climate factors and land use pattern changes. In this study, the Qilian Mountains (QLM) region was chosen as the study area to investigate water conservation trends and drivers in an alpine region. The InVEST model was used to estimate water conservation in the QLM from 2000 to 2020. In addition, the characteristics of the spatiotemporal variation in the water conservation were analyzed using a combination of the Theil–Sen median trend and Mann–Kendall method, coefficient of variation, and Hurst exponent, and the main driving factors affecting these changes were determined using partial correlation analysis and contribution analysis. The main conclusions are as follows: (1) The predicted water conservation in the QLM based on the InVEST model’s water yield module had a relative inaccuracy of 5.96%, and the mean water conservation in the QLM from 2000 to 2020 was approximately 78.08 × 108 m3. (2) The water conservation showed a slight increase over the whole QLM region, with a change rate of 0.565 mm/a; yet, it showed a distinct spatial distribution pattern characterized by “more in the east than in the west”. (3) The contribution of the various land use categories to the total water conservation, from highest to lowest, was according to the following: grassland (62.44%) > unutilized land (15.99%) > forest (11.44%) > cultivated land (9.86%) > construction land (0.45%) > water (0.03%). (4) Precipitation exhibited a significant positive correlation, with contribution ratios of approximately 58.50% to the variation in the water content, whereas potential evapotranspiration and surface temperature showed a nonsignificant negative correlation with contribution ratios of approximately 2.17% and 2.08%, respectively. The results can provide scientific reference for ecological protection in the QLM and other similar alpine environment areas.

Estimating surface water availability in high mountain rock slopes using a numerical energy balance model

Abstract. Water takes part in most physical processes that shape mountainous periglacial landscapes and initiation of mass-wasting processes. An observed increase in rockfall activity in high mountain regions was previously linked to permafrost degradation, and water that infiltrates into rock fractures is one of the likely drivers of processes related to thawing and destabilization. However, there is very little knowledge of the quantity and timing of water availability for infiltration into steep rock slopes. This knowledge gap originates from the complex meteorological, hydrological, and thermal processes that control snowmelt, as well as challenging access and data acquisition in extreme alpine environments. Here we use field measurements and numerical modeling to simulate the energy balance and hydrological fluxes on a steep high-elevation permafrost-affected rock slope at Aiguille du Midi (3842 m a.s.l, France), in the Mont Blanc massif. Our results provide new information about water balance at the surface of steep rock slopes. Model results suggest that only ∼ 25 % of the snowfall accumulates in our study site; the remaining ∼ 75 % is likely transported downslope by wind and gravity. The snowpack thickness was found to decrease with surface slopes between 40 and 70∘. We found that among all water fluxes, sublimation is the main process of snowpack mass loss at our study site. Snowmelt occurs between spring and late summer, but most of it may not reach the rock surface due to refreezing and the formation of an impermeable ice layer at the base of the snowpack, which was observed at the field site. The annual snowmelt that is available for infiltration (i.e., effective snowmelt) is highly variable in the simulated years 1959–2021, and its onset occurs mostly between May and August and ends before October. By applying the model to a range of altitudes, we show that effective snowmelt is the main source of water for infiltration above 3600 m a.s.l.; below, direct rainfall on the snow-free surface is the dominant source. This change from snowmelt- to rainfall-dominated water input leads to an abrupt, nonlinear increase in water availability at altitudes below 3600 m a.s.l and may point to higher sensitivity of permafrost-affected rock slopes to climate change at these altitudes.

Participatory Geographic-Information-System-Based Citizen Science: Highland Trails Contamination due to Mountaineering Tourism in the Dolomites

Environmental pollution is a persistent problem in terrestrial ecosystems, including remote mountain areas. This study investigates the extent and patterns of littering on three popular hiking trails among mountaineers and tourists in the Dolomites range located in northeastern Italy. The data was collected adopting a citizen science approach with the participation of university students surveying the trails and recording the macroscopic waste items through a GPS-based offline platform. The waste items were categorized according to their material type, usage, and geographical location, and the sorted data was applied to Esri GIS ArcMapTM 10.8.1. Even though littering is found to be widespread all along the trails, the outcomes of the study reveal diverse patterns based on density (cigarette butts, napkins and wet wipes, and mountain equipment littering) while highlighting the prevalence of plastic pollution. The other patterns include voluntary and involuntary littering and different hot spots of contamination, with lodge, barn, and cableway effects. The implications of littering patterns for alpine environment sustainability are discussed, and recommendations are drawn indicating the need for increased supervision for waste management and maintenance on-site, GIS tech-based participatory awareness raising, and zippered clothing and equipment design for sustainable practices of mountaineering in the area.

Supergene Hydrous Sulfates in the Tuolugou Co-Au Deposit, Northern Qinghai–Tibet Plateau: Implications for Genetic Mechanism and Exploration

Supergene hydrous sulfate minerals form through the oxygenation and weathering of primary sulfides. In the Qinghai–Tibet Plateau region, with an alpine and dry environment, hydrous sulfate minerals oxidized from pyrite-bearing ore bodies provide important clues regarding the mineralization and environment. The Tuolugou sedimentary-exhalative (SEDEX) Co-Au deposit is located in the East Kunlun metallogenic belt of the northern Qinghai–Tibet Plateau in China. In the mining district, pyrite is the prevalent Co-hosting sulfide mineral, and is partially exposed on the surface to weathering and oxidation. Herein, we document the mineral assemblages in the supergene oxidation zone in the Tuolugou deposit, probe the genesis of supergene assemblage, and explore the implications for exploration. Three zones can be recognized in the oxidation zone of the Tuolugou deposit, including the outer zone (natrojarosite), intermediate zone (rozenite and aplowite), and inner zone (roemerite and melanterite). The mechanism of oxidation under aerobic and anaerobic conditions, as well as zoning with different oxidation degrees, are described in detail. Hydrous sulfates such as natrojarosite can be used as possible indicators of the exploration of albitite-related SEDEX deposit in this region.

Biodiversity and Indigenous Medicinal Knowledge of North-East India: Navigating Climate Change Impacts on Medicinal Plants for Conservation and Advancement -

The northeastern region of India holds the sixth position among the world's 25 biodiversity hotspots, covering approximately 8% of the nation's total land area, which amounts to 262,060 square kilometers. Situated in the eastern Himalayas, any alterations in this biodiversity-rich area can have significant and far-reaching consequences. Indigenous tribes of this region believe in the remarkable healing properties of certain medicinal plants, and within its diverse population of around 225 communities, each tribal and sub-tribal group possesses distinct traditional knowledge. Capturing and harnessing this indigenous wisdom by scientists and researchers could unlock new avenues for progress, particularly within the pharmaceutical sector. Climate change stands as one of the paramount global environmental challenges. Predictions indicate that by the close of the 21st century, the Earth's average temperature might rise by anywhere between 0.3 to 4.8 °C, accompanied by a potential sea level increase of 26 to 82 cm. These climate shifts could have adverse effects on the abundance and accessibility of medicinal plants, potentially leading to species extinction. Moreover, the impact of climate change could extend beyond availability to also encompass alterations in the pharmacological properties of various plants, particularly those found in alpine environments. This discussion underscores the importance of existing knowledge, critical analyses, challenges, opportunities, and the immense value of medicinal plants. It emphasizes the intersection of changing climate and the vulnerability of medicinal plant resources, necessitating a comprehensive understanding of these effects in the context of the North Eastern region of India. To address these challenges, there is a pressing need for in-depth research on the geographical distribution of plant communities and strategies to enhance the secondary synthesis of critically endangered medicinal plants under the current climate change scenarios.

Debris‐flow fan development and geomorphic effects in alpine canyons under a changing climate

AbstractDebris flows in alpine environments are prone to occur in the context of global climate change (i.e., elevated air temperature and higher frequency of strong precipitation events). (Alluvial) Fans often develop at the outlet of tributaries after high‐intensity debris flows. Most debris‐flow fans in alpine canyon areas extend directly to the main river channel and become the forefront of the interaction between the tributary gully and the main river channel. Clarifying the development processes/dynamics, evolutionary mechanisms and driving factors of alluvial fans would shed light on understanding the geomorphological effects and genesis of river valleys in alpine canyon areas. Here, we report the development of debris‐flow fan at the outlet of the Tianmo Gully, a formerly hazard‐free but currently hazard‐active tributary of the Parlung Tsangpo Basin, Southeast Tibet, where debris flows have occurred frequently in the last two decades. Combining remote‐sensing images, DEM data, UAV aerial photography, RTK topographic survey and other fieldwork, the development processes and morphological characteristics of the Tianmo fan under the influence of four large debris flows were analysed. Both primary events (described as episodic debris‐flow events characterized by high‐magnitude mass movement) and secondary events (corresponding to perennial stream flow processes with much lower sediment concentrations) affected the development of the Tianmo fan. Episodic debris‐flow events drastically shape the macroscopic morphology of the fan, with rapid deposition and expansion of the fan body, whereas perennial stream flow processes slowly modulate the fan during the intermittent period between debris flows, mainly with gradual retrogressive incision and lateral migration of flow channel on the fan body. Influenced by the strong sediment‐transport process of debris flows and the alluvial fan development, the planform of the Parlung Tsangpo River evolved from a relatively narrow and single‐thread pattern to an alternating‐wide‐and‐narrow pattern, with a corresponding staircase‐like longitudinal profile.

Landslide susceptibility evaluation in Alpine environment: 2. Thermo-hydro-mechanical modeling for the response to climate-related variables

This paper is Part 2 of two companion papers, proposing a multidisciplinary approach to assess stability and velocity evolution of a large landslide located in the Central Italian Alps (upper Valtellina region): the Ruinon landslide. Part 1 of this work presented a 3D stress–strain finite element analysis, which assessed the morphological and geomechanical predisposition of the slope to gravitational instabilities and defined the current stress state along the slope. In this paper, a thermo-hydro-mechanical (THM) numerical analysis is applied to the landslide shear zone, to assess the link between landslide driving factors and the shear band material response. Data used as input for the model were pore pressure, reference stresses and initial temperature at the sliding surface, as well as the monitored velocity of the landslide body, assumed to move as a rigid block. The shear band material was modeled as a visco-plastic medium with thermal softening and velocity hardening, thus thermal- and load-rate sensitivity of the material were estimated through laboratory testing. To this end, triaxial compression tests with thermal control were performed on rock samples representative of the shear band. To constrain the model, results of the analysis presented in Part 1 were used to define the stress state at the sliding surface and the relationship between pore pressure and shear stresses. Then, pore pressure data from in-situ piezometers relevant to the period 2014–2018 were introduced and a best fitting between modeled and monitored landslide velocities was obtained. Finally, velocities were forecasted for the period 2018–2020​ and a process of validation was performed using field displacement data. The outputs of the model adequately simulate the measured landslide velocity, reproducing the sliding behavior and its relationship with pore pressure. The presented approach may be applied to further case studies, aimed at defining a novel physics based early warning strategy for landslides.

Patchy and Pink: Dynamics of a Chlainomonas sp. (Chlamydomonadales, chlorophyta) algal bloom on Bagley Lake, North Cascades, WA.

Snow algal blooms frequently occur throughout alpine and polar environments during spring and summer months; however, our understanding of bloom dynamics is limited. We tracked a recurrent bloom of Chlainomonas sp. on Upper Bagley Lake in the North Cascade Mountains, USA, to assess the spatiotemporal dynamics in bloom color intensity, community photophysiology, and community composition over eight weeks. We found that the algae biomass had a dynamic patchy distribution over space and time, which was decoupled from changes in community composition and life-cycle progress averaged across the bloom. The proportional representation of Chlainomonas sp. remained consistent throughout the study while the overall community composition shows a progression through the bloom. We found that community photophysiology, measured by the maximum quantum yield of PSII (Fv/Fm), decreased on average throughout the bloom. These findings suggest that the Chlainomonas sp. community on Bagley Lake is not simply an algal bloom with rapid increase in biomass followed by a population crash, as is often seen in aquatic systems, though there is a physiological trajectory and sensitivity to environmental stress. These results contribute to our understanding of the biology of Chlainomonas sp. and its response to environmental stress, specifically an extreme warming event.

Landslide susceptibility evaluation in Alpine environment: 1. 3D Finite Element modeling of the Ruinon (IT) case study

This manuscript is Part 1 of two companion papers that explore a multidisciplinary approach to predict velocity and stability of a large landslide located in the Central Italian Alps: the Ruinon landslide. The area is of high geological interest due to the presence of numerous shallow and deep gravitational instability processes that affect valley flanks, mainly driven by unfavorable morphological conditions and geomechanical properties of rock masses. In this manuscript, a 3D finite element model (FEM) was implemented in order to analyze the stress–strain distribution along the Ruinon rock-slope. Goals are to define the relation between morphological factors, mechanical parameters and the development of irreversible strains. The model was defined based on morphological features and mechanical properties detected along the slope, as well as on piezometric data from the landslide monitoring system. In a first step of the analysis, a static simulation was carried out under dry conditions. Then, a validation process was performed by comparing numerical outputs with geomorphological field observations. Finally, a parametric analysis was carried out where different piezometric level scenarios were evaluated in order to assess the influence of both mechanical parameters and pore pressure on the distribution of high sliding susceptibility areas. By overlaying satellite images with the model outputs, results were shown to accurately reproduce the extent of the slope areas subject to active gravitational instability. Parametric analyses showed a clear relationship between the input factors and the magnitude of strain, while the extension of areas subject to irreversible deformation did not change significantly. Stress distribution and stress–strain relations defined in this article are subsequently introduced in a thermo-hydro-mechanical (THM) numerical model presented in Part 2 of this work, where the evolution of the Ruinon landside is simulated.

Genome assembly of the snow lotus species Saussurea involucrata provides insights into acacetin and rutin biosynthesis and tolerance to an alpine environment.

Genome assembly of the snow lotus species Saussurea involucrata provides insights into acacetin and rutin biosynthesis and tolerance to an alpine environment.

Oxidant and Antioxidant Profiling in Viscaria alpina Seed Populations Following the Temporal Dynamics of an Alpine Climate

The adaptability of seed metabolism to different environmental conditions represents a crucial aspect to understand the effects of climate change on plant populations in wild environments. Among the indicators of stress and repair in seeds, tocopherols and malondialdehyde have been related to membrane stability in seed deterioration. Alpine plants constitute an interesting system to understand stress response dynamics because of the relevant climate variations challenging seed viability in alpine environments. This study considered five accessions of Viscaria alpina seeds collected over five years, highlighting significant correlations between environmental parameters such as precipitations and temperature, and several indicators of the oxidative stress response. These provide new insights on how changes in indicators of the seed stress response can reflect annual variations in temperature and precipitations affecting their parental plants, with possible implications on the current understanding of seed persistence in alpine environments threatened by climate change and on the effects of seed storage.

Historical and projected evolutions of glaciers in response to climate change in High Mountain Asia

Glacier changes are regarded as the conspicuous icon of climate change in High Mountain Asia (HMA) alpine environments. Multi-temporal glacier coverage is essential for mass balance estimations and understanding glacial changes in response to climate variability. However, consistent multi-temporal glacier area datasets across the HMA are limited due to challenges posed by seasonal snow and cloud cover in remote sensing satellite images. In this study, a new method is proposed to estimate glacier and nonseasonal snow (GNS) areas by combining the normalized difference snow index (NDSI) and bright temperature bands from Landsat remote sensing images in 1990s, 2000s, 2010s and 2020s. Meanwhile, the integrated ice dynamic Open Global Glacier Model (OGGM) is applied to simulate nine typical glaciers and project their changes using 15 general circulation models (GCMs) under four shared socioeconomic pathways (SSPs). The results showed that total GNS areas in HMA were estimated at 71.26 × 103 km2 in the 1990s, and decreased to 53.17 × 103 km2 in the 2020s. Massive proportions of GNS were mainly distributed in the southeast and northwest region. Tipping points of GNS indicating a transition from mass balance gain to loss during four periods were detected in the Upper Tarim basin, Inner Tibetan Plateau, Upper Yangtze river basin, Upper Brahmaputra river basin, and Upper Salween river basin. The reduction of total GNS area was attributed to significantly rising temperature and decreasing solid precipitation. The projections indicate that glacier shrinkages will be the dominant trend in the future, and most typical glaciers will experience a mass loss of 60% under SSP245 (SSP2-RCP4.5) and over 90% under SSP585 (SSP5-RCP8.5) by the end of the century. The response of glaciers to climate change is also found to be influenced by factors including local topography and elevation ranges. The findings of this study provides a better understanding of glacial dynamics in response to climate change and highlights the importance of making water resources management strategies to mitigate the influence of glacier retreat.

Establishment of SV40 Large T-Antigen-Immortalized Yak Rumen Fibroblast Cell Line and the Fibroblast Responses to Lipopolysaccharide.

The yak lives in harsh alpine environments and the rumen plays a crucial role in the digestive system. Rumen-associated cells have unique adaptations and functions. The yak rumen fibroblast cell line (SV40T-YFB) was immortalized by introducing simian virus 40 large T antigen (SV40T) by lentivirus-mediated transfection. Further, we have reported the effects of lipopolysaccharide (LPS) of different concentrations on cell proliferation, extracellular matrix (ECM), and proinflammatory mediators in SV40T-YFB. The results showed that the immortalized yak rumen fibroblast cell lines were identified as fibroblasts that presented oval nuclei, a fusiform shape, and positive vimentin and SV40T staining after stable passage. Chromosome karyotype analysis showed diploid characteristics of yak (n = 60). LPS at different concentrations inhibited cell viability in a dose-dependent manner. SV40T-YFB treated with LPS increased mRNA expression levels of matrix metalloproteinases (MMP-2 and MMP-9), inflammatory cytokines (TNF-α, IL-1β, IL-6), and urokinase-type plasminogen activator system components (uPA, uPAR). LPS inhibits the expression of tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), plasminogen activator inhibitor-2 (PAI-2), fibronectin (FN), anti-inflammatory factor IL-10, and collagen I (COL I) in SV40T-YFB. Overall, these results suggest that LPS inhibits cell proliferation and induces ECM degradation and inflammatory response in SV40T-YFB.

Case study of the market situation of calves from Alpine dairy farms and the effect of dams’ grazing during the last three months of gestation on auction parameters

The main aim of the study was to assess the recent evolution of cattle breeding in Alpine areas based on the number, quality and price of calves sold at local auctions in the South Tyrol region over the last decade, as case study. In addition, the effect of grazing during dam’s late gestation on calves’ auction quality was investigated to assess whether the inclusion of pasture in Alpine production system has an impact on auction parameters of calves beside its well-known positive effects on cattle welfare and the environment. Similarly, to other geographical areas, the study revealed that the numbers of crossbred calves (especially from specialised dairy breeds) has increased over the last years also in the Alpine area, because of more targeted breeding plans with an intensive use of beef bulls’ semen. Further, purebred calves from dual-purpose breeds (Simmental, Alpine Grey, Pinzgauer) received a higher remuneration in terms of price and market value at auction than purebred calves from specialised Holstein Friesian and Brown Swiss cows. A part of these animals could be available to support an innovative alpine meat supply chain which, if grass-fed, could further strengthen the current landscape maintenance service provided by the mountain livestock husbandry. Dams grazing during the last 90 days of gestation had a limited negative effect on calves’ liveweight and quality traits at auctions. All these results provide useful technical insights to support the switch from dairy to suckler herd system as future productive alternative for some small-scale mountain cattle farms whose viability is essential for the provision of several ecosystem services in the fragile Alpine environment.

“The forests are dirty”: Effects of climate and social change on landscape and well-being in the Italian Alps

Over the course of the last several decades, climate and social changes have fundamentally altered Alpine environments, landscapes, and weather patterns. While environmental changes are well-documented by natural science studies, the human dimensions of change remain understudied. Existing in-depth studies of the impact of climate and environmental changes on emotional well-being have revealed cross-cultural similarities in responses to change, but studies of the impact of such changes on the well-being of residents of the European Alps are needed. Through interviews, participant observation, and a questionnaire, the study identified two pathways through which changes to Alpine environments are affecting the well-being of mountain residents in the Lombardy region of the Italian Alps. The landscape and ecosystem changes caused by social changes are affecting well-being through disrupting connections to place and affecting people's sense of identity as tied to an agricultural past. The weather changes caused by climate change are increasing anxiety and worry linked to feelings of unpredictability, uncertainty, and loss of control. There is also overlap. Both the changes caused by climate change and by social changes are affecting well-being by disrupting the reliability of place-based knowledge.

Men Somatic Types and Body Mass Composition Living in the Alpine Environment (22-35 Years)

For the first time, using bioimpedancemetry and Heath-Carter physique schemes, somatic types and body mass composition were established in healthy men of the 1st period of adulthood living in high mountains (h 2469-3325 m above sea level). Somatotypological features of body composition were revealed. An intertype analysis of body composition in individuals of different body types was carried out. Research objectives: to study the somatic types and composition of body mass in healthy men of the first period of adulthood permanently residing in highlands. The object of the study were healthy men aged 22-35 years old permanently residing at an altitude of 2469-3325 m above sea level. Alpine research was carried out on the basis of the medical and preventive institution Chon-Alai and Alai regions in compliance with the principles of ethics. A total of 208 mountaineers were examined. Among the subgroups of somatotypes, mesectomorphy, endectomorphy and meso-endomorphy prevail. Somatotypological features of the body composition of highlanders of different somatotypes were revealed.

Molecular phylogeny of mega-diverse Carabus attests late Miocene evolution of alpine environments in the Himalayan–Tibetan Orogen

The timing, sequence, and scale of uplift of the Himalayan–Tibetan Orogen (HTO) are controversially debated. Many geoscientific studies assume paleoelevations close to present-day elevations and the existence of alpine environments across the HTO already in the late Paleogene, contradicting fossil data. Using molecular genetic data of ground beetles, we aim to reconstruct the paleoenvironmental history of the HTO, focusing on its southern margin (Himalayas, South Tibet). Based on a comprehensive sampling of extratropical Carabus, and ~ 10,000 bp of mitochondrial and nuclear DNA we applied Bayesian and Maximum likelihood methods to infer the phylogenetic relationships. We show that Carabus arrived in the HTO at the Oligocene–Miocene boundary. During the early Miocene, five lineages diversified in different parts of the HTO, initially in its southern center and on its eastern margin. Evolution of alpine taxa occurred during the late Miocene. There were apparently no habitats for Carabus before the late Oligocene. Until the Late Oligocene elevations must have been low throughout the HTO. Temperate forests emerged in South Tibet in the late Oligocene at the earliest. Alpine environments developed in the HTO from the late Miocene and, in large scale, during the Pliocene–Quaternary. Findings are consistent with fossil records but contrast with uplift models recovered from stable isotope paleoaltimetry.

Plant-symbiotic fungal diversity tracks variation in vegetation and the abiotic environment along an extended elevational gradient in the Himalayas.

Arbuscular mycorrhizal (AM) fungi can benefit plants under environmental stress, and influence plant adaptation to warmer climates. However, very little is known about the ecology of these fungi in alpine environments. We sampled plant roots along a large fraction (1941-6150m asl) of the longest terrestrial elevational gradient on Earth and used DNA metabarcoding to identify AM fungi. We hypothesized that AM fungal alpha and beta diversity decreases with increasing elevation, and that different vegetation types comprise dissimilar communities, with cultured (putatively ruderal) taxa increasingly represented at high elevations. We found that alpha diversity of AM fungal communities declined linearly with elevation, whereas within-site taxon turnover (beta diversity) was unimodally related to elevation. Composition of AM fungal communities differed between vegetation types and was influenced by elevation, mean annual temperature and precipitation. In general, Glomeraceae taxa dominated at all elevations and vegetation types, however, higher elevations were associated with increased presence of Acaulosporaceae, Ambisporaceae and Claroideoglomeraceae. Contrary to our expectation, the proportion of cultured AM fungal taxa in communities decreased with elevation. These results suggest that, in this system, climate-induced shifts in habitat conditions may facilitate more diverse AM fungal communities at higher elevations but could also favour ruderal taxa.