Elevation Mountain Research Articles

Chemical composition and diversity of the essential oils of Juniperus rigida along the elevations in Helan and Changbai Mountains and correlation with the soil characteristics

Essential oils obtained from Juniperus rigida Sieb. et Zucc. are potential natural sources for perfume and health products, and are considered as natural antimicrobial agents. This study used chromatographic fingerprint analysis and quantitative ecological methods to research essential oil composition diversity and the antibacterial activity and key soil factors affecting the synthesis of essential oils in J. rigida, which were from the different elevations in Helan Mountain (the arid hinterland) and Changbai Mountain (the humid region). Statistical results showed that the essential oil compounds of J. rigida in Helan Mountain were classified into 3 groups: germacrene D (2063 m, 2280 m, and 2340 m), β-caryophyllene (1568 m, 1883 m, and 2112 m), and α-pinene chemotype (1741 m, 1801 m, and 2182 m). While in Changbai Mountain, they can be classified into 2 major groups, the α-pinene chemotype (838 m and 1203 m) and the sylvestrene/β-myrcene chemotype (885 m, 1073 m, and 1170 m). The essential oils in middle-high elevations (2112−2280 m) in Helan Mountain were of higher yields, composition, chemical composition diversity, and antibacterial activity than low elevations. The essential oils of J. rigida needles in middle-high elevations (1073−1203 m) in Changbai Mountain had lower diversity chemical compositions but better antibacterial activity. The antibacterial activity was closely related to terpenoids in essential oils of J. rigida. Middle-high elevations in Helan and Changbai Mountains provided an excellent source of cosmetics, perfume, and industrial product development from J. rigida. Phosphorus and potassium fertilizers and water conditions should be considered first in the management of cultivation J. rigida. This study researched suitable elevations and cultivation management of J. rigida for the improvement of quality and biological activity of essential oil especially in the arid hinterland and gave insights into resource utilization, perfume and fragrance product development.

Direct observations of a Mt Everest snowstorm from the world's highest surface‐based radar observations

Direct observations of a Mt Everest snowstorm from the world's highest surface‐based radar observations

Floristics and soil characteristics of Ohud mountain, Al-Madinah Al-Munawarah, Western Saudi Arabia

Ohud mountain is one of the main important historic sites in the Arab Peninsula, and it is distinguishable over the rest of the mountains in the region. No extensive floristic survey has been carried out on Ohud mountain because of the rugged topography of this mountain. The current study investigates the floristic diversity and the correspondence of environmental factors of the phytogeographical distribution of plants, based on the floristic analysis of the present region. The research question is about the relationships between the species diversity and the human impacts of populated area at lowlands around Ohud mountain. A total of 59 species belonging to 56 genera and 28 families were recorded. Asteraceae had the highest contribution, about 12% of the total plant species. The analysis of the life forms demonstrated the prevalence of therophytes (68%) followed by chamaephytes (24%), indicating the adaptation of these life forms to hyperarid conditions. The chorological analysis indicated the predominance of the bi-regional taxa over the other phytochoria. Most of the recorded plant species belong to Saharo-Arabian and Sudano-Zambezian (24%) phytochoria. TWINSPAN analysis was performed to detect the indicator species of different vegetation groups and confirmed by detrended correspondence analysis (DCA or DECORANA). It is concluded that species richness and diversity revealed clear variation along the mountain and among the studied sites. Plant species diversity and richness were more pronounced in the intermediate portion of the elevation gradients across the mountain, with a decrease in the high altitudinal belts. The decrease was also recorded at the lower altitudes, where human impacts clearly affected vegetation; leading to a decrease in alpha diversity. In addition, the beta diversity among moderately highlands and lowlands was considerably high indicating the heterogeneous species composition among the studied sites along mountain elevations. The general pattern of vegetation groups distribution is controlled by a number of environmental factors; such as latitude, longitude, elevation, organic matter and some anions and cations. A Canonical Correspondence Analysis (CCA) ordination revealed that the vegetation structure has a strong association with the latitude of the mountain followed by organic matter and Magnesium. It is recommended that the populated area should be subjected to restoration of mountain ecosystem that might be degraded by human activities.

Peatlands of the Central Andes Puna, South America

The Andean puna is the highest elevation mountain and plateau region in the western hemisphere, extending from northern Peru to central Chile and Argentina, with vast areas above 4,250 m elevation. The Atacama Desert on the western side of the Andes is the world’s most arid region, and this aridity extends across the mountains. The upland vegetation is mostly continuous in the more humid north but becomes more and more patchy and barren composed only of bunch grasses in the central and southern region. Extensive upland talus, moraines, and colluvial deposits of the mountains produces perennial ground water flow systems that support thousands of peatlands and other wetlands that are regionally termed “bofedales” or “vegas”. The peatlands are dominated by several species in the family Juncaceae, most famously Distichia muscoides, that forms dense clonal cushions that characterize the alpine peatlands and landscapes. Being close to the equator, the growing season extends across the entire year, and continuous growth of the cushion plants have produced high carbon accumulation rates and peat bodies 7-10 m thick in many areas. The region supports unique plants and animals, and ecosystems, and the wetlands are threatened by overuse for livestock grazing, and climate changes that could reduce water provision may lead to some bofedales completely drying.

Anthropogenic‐driven transformations of dragonfly (Insecta: Odonata) communities of low elevation mountain wetlands during the last century

Abstract Freshwater environments are experiencing high rates of species extinction due to human impacts, with aquatic insects thought to be strongly threatened by these changes; however, long‐term research on this topic is scant. Among aquatic insects, dragonflies are considered valuable indicators of human disturbance at multiple scales. This study addresses transformations of odonate communities of low elevation mountain wetlands in the Alps over the last century, comparing historical and present assemblages based on past records derived from scientific collections or literature and present data derived from site resurveys. About 32.6% of species have been extirpated or strongly declined in the area (mostly temporary lentic and lotic water specialists, or cold‐adapted species). Conversely, only 12.2% of species were new or considerably increased (mostly permanent lentic specialists and warm‐adapted species). Nearly half of historical populations have been lost. The great majority of species which disappeared from all the study sites also disappeared (or strongly declined) at the regional scale. Although gamma species richness was higher in the historical period compared with the present, mean alpha species richness does not significantly differ between the two, likely suggesting homogenisation of communities from historical to the present period. Present communities of dragonflies show a significantly higher community temperature index compared with historical ones. These patterns are putatively explained by the joint effects of land‐use change (drainage and reclamation), land‐use intensification or abandonment, environmental pollution, and anthropogenic‐driven climate warming.

Berit Dağları’nda (Kahramanmaraş) Litolojik ve Jeomorfolojik Faktörlerin Bitki Örtüsünün Dağılışına Etkisi

Bu çalışmanın amacı, Berit Dağları’nda litolojik ve jeomorfolojik faktörlerin bitki örtüsünün dağılışına etkisini açıklamaktır. Bu amaçla litolojik ve jeomorfolojik faktörlere ait alt kriterler ile bitki örtüsü katman haritaları oluşturulmuştur. Oluşturulan katman haritaları, Coğrafi Bilgi Sistemleri (CBS) teknikleriyle, ArcGIS 10.7 yazılımı kullanılarak çakıştırılmıştır. Çakıştırma işlemi sonunda her bir jeomorfolojik faktörün alt kriterinde bulunan bitki türü ve alanı tespit edilmiştir. Buna göre, Berit Dağları’nda 1600,01-1800 m yükseltileri arasındaki yüksek plato ve yamaçlarda şist anakayası üzerinde 45,01º> eğimli alanlarda kuzeydoğu, doğu ve güneydoğu yönlerde bitki çeşitliliği ve yoğunluğu fazladır. Buna karşılık 2400 m’den yüksek alanlardaki zirve düzlükleri üzerinde, ofiyolitik melanj ve 0-15ºeğimli güney ve güneybatı yönlü alanlarda bitki tür çeşitliliği ve yoğunluğu azdır. Çalışma sonucunda, Berit Dağları’nda litoloji, yerşekilleri, yükselti, eğim ve bakı gibi jeomorfolojik faktörlerin bitki örtüsü çeşitliliğini ve dağılışını etkileyen önemli unsurlar olduğu anlaşılmıştır.

Megathrust shear force controls mountain height at convergent plate margins

The shear force along convergent plate boundary faults (megathrusts) determines the height of mountain ranges that can be mechanically sustained1-4. However, whether the true height of mountain ranges corresponds to this tectonically supported elevation is debated4-7. In particular, climate-dependent erosional processes are often assumed to exert a first-order control on mountain height5-12, although this assumption has remained difficult to validate12. Here we constrain the shear force along active megathrusts using their rheological properties and then determine the tectonically supported elevation using a force balance model. We show that the height of mountain ranges around the globe matches this elevation, irrespective of climatic conditions and the rate of erosion. This finding indicates that mountain ranges are close to force equilibrium and that their height is primarily controlled by the megathrust shear force. We conclude that temporal variations in mountain height reflect long-term changes in the force balance but are not indicative of a direct climate control on mountain elevation.

Glaciimonas soli sp. nov., a soil bacterium isolated from the forest of a high elevation mountain.

A Gram-negative, psychrophilic bacterium, designated strain GS1T, was isolated from a forest soil sample collected from the West Peak of Mt. Yushan, Yushan National Park, Taiwan. Cells grown in broth cultures were mostly non-motile and non-flagellated, whereas motile cells with monotrichous, subpolar flagella were also observed. The novel strain grew over a temperature range of 4-25°C with optimum growth at 10-15°C. It grew aerobically and was not capable of anaerobic growth by fermentation of D-glucose or other carbohydrates. Ubiquinone 8 was the predominant isoprenoid quinone. The major polar lipids comprised phosphatidylethanolamine, diphosphatidylglycerol and dimethylaminoethanol. Cellular fatty acids were dominated by C16:1ω7c (35.2%), C16:0 (19.5%), C18:1ω7c (18.8%) and C17:0ω7c cyclo (15.5%). The DNA G + C content was 49.2mol% evaluated according to the genomic sequencing data. Strain GS1T shared more than 96.5% 16S rRNA gene sequence similarities with type strains of four Collimonas species (97.2-97.5%), three Glaciimonas species (97.3% for each of the three) and Oxalicibacterium solurbis (96.5%). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain GS1T formed a stable genus-level clade with type strains of species in the genus Glaciimonas in the family Oxalobacteraceae and GS1T was an outgroup with respect to these Glaciimonas species. Characteristically, strain GS1T could be easily distinguished from the recognised Glaciimonas species by exhibition of swimming motility with monotrichous, subpolar flagellum in some of the cells, ability to grow in NaCl at 2% but not at 3% and the distinguishable fatty acid profiles. On the basis of the polyphasic taxonomic data from this study, strain GS1T is considered to represent a novel species of the genus Glaciimonas, for which the name Glaciimonas soli sp. nov. is proposed. The type strain is GS1T (= JCM 33275T = BCRC 81091T).

Evaluating rainfall datasets to reconstruct floods in data-sparse Himalayan region

Floods are widespread natural disasters having significant socio-economic impacts and require appropriate modelling and management strategies. Flood modelling is an enduring challenge, especially over the data-sparse mountainous regions such as the Himalayas, due to the lack of accurate rainfall measurements. Global datasets are often employed for flood modelling; however, their applicability over the Himalayan terrain is still uncertain. In this regard, the Weather Research and Forecasting (WRF) numerical weather prediction model is increasingly used to obtain reliable rainfall estimates. This work aims at evaluating the performance of different reanalysis datasets, satellite product, and the WRF model to represent heavy rainfall over the Himalayan terrain. Further, these datasets are used to drive the Variable Infiltration Capacity (VIC) hydrologic model to assess their ability to reconstruct floods in the Himalayan region. A Rainfall-Flood Skill Score (RFSS) is proposed in this work to rank different rainfall datasets in the order of their ability to represent flooding in the region. The range of RFSS can vary from -∞ to 1, with positive values as the desired value. The analysis is conducted over the upstream part of the Upper Ganga Basin, spanning from high elevation mountains to the foothills of the Himalayas for three heavy rainfall events that caused flooding in the region. Quantitative evaluation of rainfall datasets in terms of bias, RMSE, and scale errors shows high spatial variability with different datasets performing differently over various regions of the study area. The topography is observed to influence the performance of rainfall datasets. Based on the error metrics, it is found that the rainfall simulated using the WRF model exhibits least error in high elevation and valley regions of the Himalayas, whereas, Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) and Climate Forecast System Reanalysis (CFSR, in some cases) datasets can capture the rainfall in the foothills of the Himalayas. On forcing the VIC model with these datasets, the WRF model with a moderate resolution of 9 km is found to have an overall highest RFSS score of 0.97 among all the datasets and, therefore, considered most suitable for simulating floods in the study region.

How Climate Shapes the Functioning of Tropical Montane Cloud Forests

Tropical Montane Cloud Forest (TMCF) is a highly vulnerable ecosystem, which occurs at higher elevations in tropical mountains. Many aspects of TMCF vegetation functioning are poorly understood, making it difficult to quantify and project TMCF vulnerability to global change. We compile functional traits data to provide an overview of TMCF functional ecology. We use numerical models to understand the consequences of TMCF functional composition with respect to its responses to climate and link the traits of TMCF to its environmental conditions. TMCF leaves are small and have low SLA but high Rubisco content per leaf area. This implies that TMCF maximum net leaf carbon assimilation (An) is high but often limited by low temperature and leaf wetting. Cloud immersion provides important water and potentially nutrient inputs to TMCF plants. TMCF species possess low sapwood specific conductivity, which is compensated with a lower tree height and higher sapwood to leaf area ratio. These traits associated with a more conservative stomatal regulation results in a higher hydraulic safety margin than nearby forests not affected by clouds. The architecture of TMCF trees including its proportionally thicker trunks and large root systems increases tree mechanical stability. The TMCF functional traits can be conceptually linked to its colder and cloudy environment limiting An, growth, water transport and nutrient availability. A hotter climate would drastically affect the abiotic filters shaping TMCF communities and potentially facilitate the invasion of TMCF by more productive lowland species.

Spatial variations of hydrochemistry and stable isotopes in mountainous river water from the Central Asian headwaters of the Tajikistan Pamirs

Water resources in Central Asia from the mountainous headwater catchments is changing due to the shrinkage of glaciers in the Tian Shan and Pamir mountain systems. In order to predict future changes in water quality, it is crucial to understand what factors are governing the spatial variations of water chemistry and hydrological processes in mountainous headwater catchments. In this study, water chemistry including major ions and stable isotopes in the headwaters of major Tajikistan rivers was studied. Results showed that Tajikistan river water had an alkaline pH value (mean: 8.2) and total dissolved solids (mean: 368.5mg/L) were higher than the global average value. Ca2+, Na+, HCO3−, and SO42− in the rivers were the most abundant cations and anions, controlled by the rock weathering process and evaporation-crystallization processes. The hydrochemical facies of river water was dominated by Ca-HCO3 (71.7%) and exhibited spatial heterogeneity, which was related to the lithologic compositions and water source across Tajikistan. A significant negative correlation of river water δ18O with elevation was observed with a vertical lapse rate of 0.17‰/100 m. The more negative δ18O values in rivers from eastern Tajikistan were scattered in the lower left corner of the δ18O-δ2H plot, implying that the rivers were primarily supplied by snow/glacier meltwater because of the substantial number of glaciers and high elevation mountain in eastern regions. The drinking and irrigation suitability from ionic compositions revealed that the water quality of Tajikistan rivers was naturally good, though some sites posed a safety concern. These findings can provide new insights into sustainable management of water quality in the climatically and lithologically distinct segments of headwater regions in the Tajikistan Pamirs.

Climate change-driven elevational changes among boreal nocturnal moths

Climate change has shifted geographical ranges of species northwards or to higher altitudes on elevational gradients. These changes have been associated with increases in ambient temperatures. For ectotherms in seasonal environments, however, life history theory relies largely on the length of summer, which varies somewhat independently of ambient temperature per se. Extension of summer reduces seasonal time constraints and enables species to establish in new areas as a result of over-wintering stage reaching in due time. The reduction of time constraints is also predicted to prolong organisms’ breeding season when reproductive potential is under selection. We studied temporal change in the summer length and its effect on species’ performance by combining long-term data on the occurrence and abundance of nocturnal moths with weather conditions in a boreal location at Värriötunturi fell in NE Finland. We found that summers have lengthened on average 5 days per decade from the late 1970s, profoundly due to increasing delays in the onset of winters. Moth abundance increased with increasing season length a year before. Most of the species occurrences expanded upwards in elevation. Moth communities in low elevation pine heath forest and middle elevation mountain birch forest have become inseparable. Yet, the flight periods have remained unchanged, probably due to unpredictable variation in proximate conditions (weather) that hinders life histories from selection. We conclude that climate change-driven changes in the season length have potential to affect species’ ranges and affect the structure of insect assemblages, which may contribute to alteration of ecosystem-level processes.

Description of <I>Nanorana conaensis</I> (Fei and Huang, 1981) (Amphibia: Anura: Dicroglossidae) reported from Arunachal Pradesh, India

The dicroglossid frog Nanorana conaensis was described from the high elevation mountain ranges of Tibet about three decades ago. Recently this species was reported from India as a first record for India. In the present account, detailed morphological data, genetic data and phylogenetic status has been provided with a photograph of live animal in order to facilitate easy identification of the species from India.

The potential sensitivity to climate change of selected endangered and important Natura 2000 Habitats and plants from Bucegi Natural Park, Romania

This study was carried out in the Bucegi Natural Park, a protected area of the Romanian Carpathians. It aims at documenting the potential sensitivity of six widespread Natura 2000 habitat types and of all plants with conservative value (200 taxa) in the mountain area, to the changes in temperature and humidity, predicted for this century. Regional expert knowledge and environmental indicator values were considered in assessing the potential habitat’s sensitivity. The results support the evidence that sensitivity to temperature may be potentially higher for habitats at alpine and subalpine levels (bushes and grasslands) and medium for forest habitats. Sensitivity to moisture was detected as potentially high for forest habitats and as medium for bushes and grasslands at high mountain elevation. Microthermophilic plants have shown a greater share (76-79%) in alpine and subalpine communities, and the hydrophilic plants (86-96%) in forest communities. About 80% of plants of conservation value (microthermophilic or hydrophilic plants) may be potentially sensitive to predicted warming and drought and 44% of them (microthermophilic and hydrophilic plants) to the changes of both parameters. Climate scenarios (2011-2100) and sensitivity maps (Sat – image interpretation with GIS for the whole mountain area) are included.

Seed testing of foliar-fertilised red clover crops after various periods of storage

This study was carried out in the Bucegi Natural Park, a protected area of the Romanian Carpathians. It aims at documenting the potential sensitivity of six widespread Natura 2000 habitat types and of all plants with conservative value (200 taxa) in the mountain area, to the changes in temperature and humidity, predicted for this century. Regional expert knowledge and environmental indicator values were considered in assessing the potential habitat’s sensitivity. The results support the evidence that sensitivity to temperature may be potentially higher for habitats at alpine and subalpine levels (bushes and grasslands) and medium for forest habitats. Sensitivity to moisture was detected as potentially high for forest habitats and as medium for bushes and grasslands at high mountain elevation. Microthermophilic plants have shown a greater share (76-79%) in alpine and subalpine communities, and the hydrophilic plants (86-96%) in forest communities. About 80% of plants of conservation value (microthermophilic or hydrophilic plants) may be potentially sensitive to predicted warming and drought and 44% of them (microthermophilic and hydrophilic plants) to the changes of both parameters. Climate scenarios (2011-2100) and sensitivity maps (Sat – image interpretation with GIS for the whole mountain area) are included.

Temperature trends and elevation dependent warming during 1965–2014 in headwaters of Yangtze River, Qinghai Tibetan Plateau

The understanding of temperature trends in high elevation mountain areas is an integral part of climate change research and it is critical for assessing the impacts of climate change on water resources including glacier melt, degradation of soils, and active layer thickness. In this study, climate changes were analyzed based on trends in air temperature variables (Tmax, Tmin, Tmean), and Diurnal Temperature Range (DTR) as well as elevation-dependent warming at annual and seasonal scales in the Headwaters of Yangtze River (HWYZ), Qinghai Tibetan Plateau. The Base Period (1965-2014) was split into two subperiods; Period-I (1965-1989) and Period-II (1990- 2014) and the analysis was constrained over two subbasins; Zhimenda and Tuotuohe. Increasing trends were found in absolute changes in temperature variables during Period-II as compared to Period-I. Tmax, Tmin, and Tmean had significant increasing trends for both sub-basins. The highest significant trends in annual time scale were observed in Tmin (1.15°C decade−1) in Tuotuohe and 0.98°C decade−1 in Zhimenda sub-basins. In Period-II, only the winter season had the highest magnitudes of Tmax and Tmin 0.58°C decade−1 and 1.26°C decade−1 in Tuotuohe subbasin, respectively. Elevation dependent warming analysis revealed that Tmax, Tmin and Tmean trend magnitudes increase with the increase of elevations in the middle reaches (4000 m to 4400 m) of the HWYZ during Period-II annually. The increasing trend magnitude during Period-II, for Tmax, is 1.77, 0.92, and 1.31°C decade−1, for Tmin 1.20, 1.32 and 1.59°C decade−1, for Tmean 1.51, 1.10 and 1.51°C decade−1 at elevations of 4066 m, 4175 m and 4415 m respectively in the winter season. Tmean increases during the spring season for > 3681 m elevations during Period-II, with no particular relation with elevation dependency for other variables. During the summer season in Period- II, Tmax, Tmin, Tmean increases with the increase of elevations (3681 m to 4415 m) in the middle reaches of HWYZ. Elevation dependent warming (EDW), the study concluded that magnitudes of Tmin are increasing significantly after the 1990s as compared to Tmax in the HWYZ. It is concluded that the climate of the HWYZ is getting warmer in both sub-basins and the rate of warming was more evident after the 1990s. The outcomes of the study provide an essential insight into climate change in the region and would be a primary index to select and design research scenarios to explore the impacts of climate change on water resources.

Spatial and temporal characteristics of rainfall over a forested river basin in NW Borneo

The spatial and temporal patterns of rainfall over the Baram River Basin (BR) in Sarawak (Malaysian Borneo) were characterised through cluster analysis and multivariate statistics for the 25 year period from 1990 to 2014. Baram River Basin recorded an average annual rainfall of 3654 mm with high spatial and temporal variations. Ward’s method based analytical hieratical clustering (AHC) identified three homogeneous clusters (HC’s) of rain gauging stations (HC-I, HC-II, and HC-III). Rain gauges in HC-I are located in high rainfall domain, HC-II gauges are in moderate rainfall domain and HC-III gauges are in low rainfall domains. The moderate elevation regions in the Baram basin recorded the highest amounts of rainfall compared to lower and upper elevated regions. Multivariate statistics show variation in the distribution of monthly and annual rainfall within and between individual HC’s. Mean annual rainfall recorded at individual HC’s varies by around 1000 mm. Though the mean monthly rainfall distribution in HC’s varies by more than 70 mm, all clusters show a common pattern of high and low rainfall seasons related to monsoon characteristics of the region. The northeast monsoon (NEM) is the wettest period with highest mean rainfall falling in the months of November and December at all stations. In comparison, the southwest monsoon (SWM) is the driest season with the lowest mean rainfall falling in July. It was also noted that the inter-monsoon periods are actually wetter than the SWM season. Overall, rainfall in the Baram shows high inter-annual variability with dominant low rainfall domain in the lower (coastal) and upper (plateau) reach with highly localised high rainfall domain surrounded by fluctuating moderate rainfall areas in the middle reaches of the river basin. The localised nature of high rainfall domain in the central (south and southwest) part of the basin suggests that the surrounding elevated mountains and hills in that region influence the high rainfall recorded. The findings of the present research will aid in formulating water resource management plans, large scale plantation and agricultural practices and any other hydrological development projects in the region.

Powerhouses in the cold: mitochondrial function during thermal acclimation in montane mayflies.

Mitochondria provide the vast majority of cellular energy available to eukaryotes. Therefore, adjustments in mitochondrial function through genetic changes in mitochondrial or nuclear-encoded genes might underlie environmental adaptation. Environmentally induced plasticity in mitochondrial function is also common, especially in response to thermal acclimation in aquatic systems. Here, we examined mitochondrial function in mayfly larvae (Baetis and Drunella spp.) from high and low elevation mountain streams during thermal acclimation to ecologically relevant temperatures. A multi-substrate titration protocol was used to evaluate different respiratory states in isolated mitochondria, along with cytochrome oxidase and citrate synthase activities. In general, maximal mitochondrial respiratory capacity and oxidative phosphorylation coupling efficiency decreased during acclimation to higher temperatures, suggesting montane insects may be especially vulnerable to rapid climate change. Consistent with predictions of the climate variability hypothesis, mitochondria from Baetis collected at a low elevation site with highly variable daily and seasonal temperatures exhibited greater thermal tolerance than Baetis from a high elevation site with comparatively stable temperatures. However, mitochondrial phenotypes were more resilient than whole-organism phenotypes in the face of thermal stress. These results highlight the complex relationships between mitochondrial and organismal genotypes, phenotypes and environmental adaptation. This article is part of the theme issue 'Linking the mitochondrial genotype to phenotype: a complex endeavour'.

Sensing Area‐Average Snow Water Equivalent with Cosmic‐Ray Neutrons: The Influence of Fractional Snow Cover

AbstractCosmic‐ray neutron sensing (CRNS) is a promising non‐invasive technique to estimate snow water equivalent (SWE) over large areas. In contrast to preliminary studies focusing on shallow snow conditions (SWE 130 mm), more recently the method was shown experimentally to be sensitive also to deeper snowpacks providing the basis for its use at mountain experimental sites. However, hysteretic neutron response has been observed for complex snow cover including patchy snow‐free areas. In the present study we aimed to understand and support the experimental findings using a comprehensive neutron modeling approach. Several simulations have been set up in order to disentangle the effect on the signal of different land surface characteristics and to reproduce multiple observations during periods of snow melt and accumulation. To represent the actual land surface heterogeneity and the complex snow cover, the model used data from terrestrial laser scanning. The results show that the model was able to accurately reproduce the CRNS signal and particularly the hysteresis effect during accumulation and melting periods. Moreover, the sensor footprint was found to be anisotropic and affected by the spatial distribution of liquid water and snow as well as by the topography of the nearby mountains. Under fully snow‐covered conditions the CRNS is able to accurately estimate SWE without prior knowledge about snow density profiles or other spatial anomalies. These results provide new insights into the characteristics of the detected neutron signal in complex terrain and support the use of CRNS for long‐term snow monitoring in high elevated mountain environments.

Modeling visitor use on high elevation mountain trails: An example from Longs Peak in Rocky Mountain National Park, USA

Increasing use on mountain summits has both social and ecological implications. High numbers of visitors climbing mountain summits can be a safety issue, particularly in areas where terrain or elevation leads to queueing that may cause time delays. Estimating visitor use levels at site specific locations en route to summits is needed to understand the potential benefits and impacts of visitor use in these locations. However, it can be difficult to obtain reliable and robust data to estimate use and develop statistical relationships because of the remote and harsh climates on mountain summits, as well as the financial and personnel requirements involved to collect the data in remote locations. In 2015, data were collected on the higher stretches of the Keyhole Route on Longs Peak in Rocky Mountain National Park, USA (RMNP) to better understand use levels near the summit and to explore potential statistical relationships to trailhead use data that are relatively easy to collect. Strong statistical relationships from robust regression analyses were found between trailhead use counts and daily and hourly use totals on the “Homestretch” which is a final section of the Keyhole Route. Additionally, a strong statistical relationship was found between total daily use and maximum hourly use on the Homestretch. The results suggest that trailhead counts are an accurate and reliable means from which to estimate use levels on upper portions of the Keyhole route. Moreover, this research demonstrates the usefulness of an approach using proxy variables to estimate visitor use along remote peaks where data collection can be difficult. These types of data can elucidate various options and decisions for park management teams who are charged with deciding if and how to manage high use areas.