Lake Waiau is a tropical alpine lake situated near the summit of Mauna Kea on the Island of Hawai‘i at an elevation of 3969 m. The lake is a place of Hawaiian cultural practice that encompasses Hawaiian mythology, history, genealogy, and spirituality. Concern over declining lake levels has created the stimulus to examine methodologies to monitor lake levels without disturbance. The objective of this research study was to determine the most accurate and cost-effective combination of new approaches to enable long-term monitoring with minimal disturbance to the lake and its environs. Three strategies were used to construct 3D models of the lake: soft-copy stereo photogrammetry from aerial photography, image-based 3D reconstruction from overlapping photographs (Structure from Motion), and terrestrial laser scanning (TLS). To supplement these detection methods, side scan sonar was used to collect bathymetric data. The results were three high-resolution 3D models that were used to calculate volumetric and areal changes over time using Geographic Information Systems (GIS) to analyze and visualize the lake body. The methodologies used in this study are compared for the feasibility of long-term data collection based on variations in accuracy and the associated costs of data collection.

The goal of this research is to help develop a better understanding of the micro-meteorology of the Mauna Kea summit area and its relationship to the distribution and population health of the Wēkiu bug (Nysius wekiuicola). SnowModel, a spatially distributed snow-evolution model, is used to construct snowfall and summit eolian debris (known as bug fall throughout this study) accumulation maps across the summit. Eight weather stations associated with astronomical observatories on the summit ridges and four Davis weather stations located in various cinder cones (pu‘u in Hawaiian), provide the meteorological observations needed as input to run SnowModel. Snow depth observations taken after a passing cold front in January 2011 are used to help validate the model accumulation predictions prior to the climatological study. Observations from summit weather stations over a three-year period (2008, 2009, and 2010) are used as input for the modeled summit accumulations of snowfall and bug fall presented in this study. For the snowfall maps, only weather data from days during which snow fell are included. For the bug-fall estimates, all days where valid weather data are available are included in the model output. Since there are no comprehensive data available on the distribution of bug fall, the bug-fall maps only provide a climatological pattern, without reference to the magnitude of the bug fall.

The greatest modeled snow accumulations are found on Pu‘u Wēkiu and Pu‘u Haukea. Similar results are found in the climatological bug-fall accumulation pattern. Prevailing wind direction is most critical for the distribution of snowfall and bug fall, with maximum accumulations occurring on the lee side of ridges and crests. Favorable Wēkiu bug trapping sites in which bugs were found historically are spatially well collocated with snowfall and bug-fall accumulations, suggesting that the results of this study will be of interest to entomologists in locating Wēkiu bug populations.

We review some recent work regarding climatic changes in selected mountain regions, with particular attention to the tropics and the American Cordillera. Key aspects of climatic variability and trends in these regions are the amplification of surface warming trends with height, and the strong modulation of temperature trends by tropical sea surface temperature, largely controlled by changes in El Niño—Southern Oscillation on multiple time scales. Corollary aspects of these climate trends include the increase in a critical plant growth temperature threshold, a rise in the freezing level surface, and the possibility of enhanced subtropical drying. Anthropogenic global warming projections indicate a strong likelihood for enhancement of these observed changes.

Mountains of the tropical Pacific are influenced by synoptic-scale air subsidence, which causes a temperature inversion and a distinct dry meteorological condition above the inversion. The inversion appears at a lower altitude in the eastern Pacific where descending air of the Walker circulation prevails. On the other hand, if or how the alpine ecosystem of the tropical mountains of the western Pacific is influenced by dry synoptic-scale air subsidence is not well documented. We studied the vegetation and climate of the summit zone of Mount Kinabalu (4095 m) of Borneo. The leaf-size spectrum and physiognomy of forest community changed abruptly along the slope approximately at 3200 m from microphyll to leptophyll, suggesting that dry climatological conditions influence the vegetation above that altitude. Mean daily vapor pressure deficits (VPDs), estimated daily potential evapotranspiration (ET0), and the ratio of 30-day total ET₀ to 30-day total rainfall increased drastically during El Niño and the magnitude of the increase was greater in the summit zone than in the montane zones. Increased VPDs during El Niño were linked with katabatic winds in the summit zone. We suggest that such irregular dry spells caused by synoptic-scale air subsidence in El Niño years can be a major factor for the formation of xeromorphic vegetation of the summit zone of Mount Kinabalu.

A relationship between forest vegetation patterns and climate has been proposed for Caribbean mountains, but mesoscale temperature, precipitation (PPT), humidity, and cloud formation patterns are poorly documented. Half-hourly temperature and humidity observations were obtained from 2001 to 2011 from a network of 10 data-logging instruments ranging in elevation from 1500 to 2800 m on the windward slopes of the Cordillera Central, Dominican Republic. We report diurnal, seasonal, and annual patterns in temperature, PPT, humidity, and the trade wind inversion (TWI) along the elevation gradient. The elevational gradient in mean air temperature was non-linear during the dry season, with lapse rates decreasing to -0.5 °C km^-1 between 1500 and 1900 m and -0.8 °C km^-1 between 2100 and 2400 m. Relative humidity reached a maximum at 2100 m (mean of 91%), but remains above 85% over the entire gradient until 2600 m, above which it drops steeply. Relative humidity also showed marked seasonality but only at the highest elevations, dropping markedly above 2400 m and especially above 2600 m in the dry season, while remaining high at lower elevations throughout the year. PPT declined only slightly with elevation on windward slopes, but was markedly lower in leeward areas. Dry season PPT was lower on windward and leeward slopes at all elevations, except at ∼2400 m on windward slopes where it remained nearly as high as the rest of the year. Sub-zero temperatures occurred at elevations ≥2325 m and increased markedly in frequency ≥2600 m. These observations support the hypothesis that the discrete vegetation ecotone between the cloud forest and subalpine pine forest at ∼2200 m on windward slopes results from climatic discontinuities, especially during the dry season. In particular, the TWI effect on mesoclimatic patterns (especially moisture) regulates the elevational maximum of cloud forest flora and likely will represent a strong barrier to the future migration of cloud forest flora to higher elevations in response to warmer temperatures. Together with increased moisture stress due to higher temperatures, climate change in the high elevations of tropical mountains is therefore likely to disrupt the dynamics and distributions of tropical montane forests.

Hurricanes are intense, frequent disturbances of Caribbean ecosystems and are important agents in structuring the region's ecological patterns and processes. The rugged topography and diverse vegetation of Caribbean tropical montane forests interact with hurricane forces to create complex disturbance patterns. In this study, we used a 158-yr historical database of hurricane tracks to calculate fine-scale hurricane return intervals across the Caribbean, and Landsat imagery and field inventory to reconstruct wind and rain disturbance from Hurricane Georges in the Cordillera Central, Dominican Republic. Spatial patterns of disturbance from Georges and the relationship of disturbance with hurricane meteorology, topography, and vegetation were analyzed for the landscape. The long-term hurricane return interval for the Cordillera Central was 14.4 yrs. Damage from hurricane Georges was distributed over a small portion of the study area (∼330 km² study area); only 11.3% of the study area was disturbed by wind and 4.3% by flooding. Multiple logistic regression showed that hurricane meteorology, topography, and vegetation were all significant predictors of patterns of wind disturbance. In particular, wind disturbance was concentrated in high-elevation forest types, with 12% of the total disturbed area in cloud forest and 82% in pine forest. Within the wind-disturbed areas, the degree of mortality varied markedly by forest type, with the proportion of dead basal area 9.8% higher in cloud forest, 11.4% higher in transitional pine, and 50.5% higher in pine forest compared to controls. Although much of the landscape was undisturbed by Georges, the regularity of hurricanes in the region and the magnitude of change in disturbed patches suggest that hurricanes are an important driver of forest dynamics and demonstrates the importance of sampling across gradients of disturbance severity.

The New Guinea alpine-subalpine zone is the highest, largest, and wettest such region on any tropical island and it preserves great variations in biodiversity between the individual mountain areas. Relatively few plant species are confined to the alpine zone and this may reflect a limited time for adaptation by herbaceous species arriving in the formerly extensive alpine-subalpine biome. In the Pleistocene a zone above 3400 m was affected by glaciation while open subalpine habitat was greatly expanded by cooler climates and low levels of CO₂ which hindered the formation of subalpine forest. With post-glacial warming, the subalpine contracted and open areas were invaded by shrublands and forest. Early to late Holocene opening out of the subalpine forest and shrublands is associated with fire that was a result of hunting by humans. This process starts early in some areas but is late or absent on more remote areas.

The alpine is threatened by increased warming and potential invasion by emergent shrubs but is likely to prove resilient to extinction provided that wet conditions continue to prevail. Changing cultural use of high altitudes suggests that the subalpine shrublands are recovering in some areas. However, some mammals and bird species seem to have been lost or become restricted on mountains that are accessible from population centers at lower altitude. With few exceptions, management consists of benign neglect although widespread fires in 1997–1998 point to continuing human impacts linked to drought events. The large mine on Mount Jaya influences subalpine usage over a large area. Tourism is very minor and unlikely to expand while political problems affect both Papua New Guinea and Papua province and logistics remain a severe difficulty. However, locally managed tourism on Mount Wilhelm provides a good model for future development.

We assessed tropical montane cloud forest (TMCF) sensitivity to natural disturbance by drought, fire, and dieback with a 7300-year-long paleorecord. We analyzed pollen assemblages, charcoal accumulation rates, and higher plant biomarker compounds (average chain length [ACL] of n-alkanes) in sediments from Wai'ānapanapa, a small lake near the upper forest limit and the mean trade wind inversion (TWI) in Hawai‘i. The paleorecord of ACL suggests increased drought frequency and a lower TWI elevation from 2555–1323 cal yr B.P. and 606–334 cal yr B.P. Charcoal began to accumulate and a novel fire regime was initiated ca. 880 cal yr B.P., followed by a decreased fire return interval at ca. 550 cal yr B.P. Diebacks occurred at 2931, 2161, 1162, and 306 cal yr B.P., and two of these were independent of drought or fire. Pollen assemblages indicate that on average species composition changed only 2.8% per decade. These dynamics, though slight, were significantly associated with disturbance. The direction of species composition change varied with disturbance type. Drought was associated with significantly more vines and lianas; fire was associated with an increase in the tree fern Sadleria and indicators of open, disturbed landscapes at the expense of epiphytic ferns; whereas stand-scale dieback was associated with an increase in the tree fern Cibotium. Though this cloud forest was dynamic in response to past disturbance, it has recovered, suggesting a resilient TMCF with no evidence of state change in vegetation type (e.g., grassland or shrubland).

Summit ecosystems of oceanic islands constitute one of the most ephemeral and isolated ecosystems existing, harboring specific features that confer on their biota an outstanding distinctness. Summits are short-lived entities, being the last ecosystems to be constructed during the growth of the new oceanic island, and the first to vanish due either to island subsidence, island erosion, or both. Whereas their geological emergence/disappearance is controlled by the volcanic/erosion activity, Pleistocene glaciations in the past million years, by forcing the altitudinal shift of the timberline, have also likely created or destroyed summit ecosystems, enabling the appearance of alpine ecosystems during glacial maxima where they were not present in interglacial periods and vice versa.

On the other hand, summit ecosystems constitute islands within islands, being more isolated from climatically similar ecosystems than the coastlines of the islands containing them. Thus summit biota, frequently displaying a high endemicity, may originate either through dispersal from other close summit ecosystems during peak periods, or from the colonization of the summits and later evolution to the new conditions from mid-altitude species of the same island. Conversely, if peak periods are absent, the disappearance of summit ecosystems implies the extinction or extirpation of their constitutive species. Current summit species have likely occupied a much larger area during glacial periods. Thus the summits may be classified as climatic refuges. This is especially the case if glacial periods were associated with much drier conditions on oceanic islands as is the case on continents.

Alpine areas of the tropical Andes constitute the largest of all tropical alpine regions worldwide. They experience a particularly harsh climate, and they are fragmented into tropical alpine islands at various spatial scales. These factors generate unique patterns of continental insularity, whose impacts on biodiversity remain to be examined precisely. By reviewing existing literature and by presenting unpublished data on beta-diversity and endemism for a wide array of taxonomic groups, we aimed at providing a clear, overall picture of the isolation-biodiversity relationship in the tropical alpine environments of the Andes. Our analyses showed that (1) taxa with better dispersal capacities and wider distributions (e.g., grasses and birds) were less restricted to alpine areas at local scale; (2) similarity among communities decreased with spatial distance between isolated alpine areas; and (3) endemism reached a peak in small alpine areas strongly isolated from main alpine islands. These results pinpoint continental insularity as a powerful driver of biodiversity in the tropical High Andes. A combination of human activities and warming is expected to increase the effects of continental insularity in the next decades, especially by amplifying the resistance of the lowland matrix that surrounds tropical alpine islands.

Treeline expansion is reported as a widespread response to rising temperatures, yet few studies have considered the impact of treeline advance on the diversity and function of high altitude systems. Evidence suggests that climate change is already having a negative impact on alpine diversity and is modifying functions such as carbon sequestration and nutrient cycling. Treeline advance is likely to further affect diversity and function, yet our understanding of the processes involved is limited. Here we review and synthesize literature that assesses the impact of treeline advance into treeless ecosystems. Using published literature, we explore to what extent treeline advance will lead to the displacement of alpine species and the fragmentation of alpine habitats. While large changes will be observed in the ecosystems above the current treeline as trees migrate, it is likely that these newly forested areas will deviate substantially from the established forests from which they have developed. Consequently, at the forest community level we investigate the potential for differential response speeds of typical forest plant species, and the potential for treeline advance to lead to community disassembly. Given that changes in species presence and abundance can alter the functional composition of plant communities, we explore the potential for shifts in tree distribution to lead to changes in carbon storage, nutrient cycling, and hydrological properties of ecosystems. Despite typically being intensively studied regions, the likely impact of forest expansion above the current mountain treeline has received relatively little attention and so we identify key knowledge gaps that should act as priorities for future research in mountain systems.

Increasing temperature imperils worldwide tropical subalpine and alpine ecosystems with the threat of mountaintop extinctions and a subsequent loss of biodiversity and ecosystem functions. This paper provides a first assessment of functional diversity along a high climatic gradient for bryophytes, which represent a major plant compartment in these ecosystems. The present study takes place on the highlands of the Piton des Neiges volcano, the highest summit of La Réunion Island (Western Indian Ocean). We find a relatively high species richness of bryophytes in these subalpine habitats, with a peak of diversity at 2750 m for the ground-dwelling community. We report a strong linear relationship between functional diversity and species richness for epiphytes. Within the same plant group, the relationship between functional richness, based on eight traits, and elevation differed between the ground-dwelling and epiphytic communities, suggesting that different processes may structure bryophyte species assemblages along this short subalpine climatic gradient. Higher functional redundancy in ground-dwelling bryophyte assemblages indicates that this community may be more robust than epiphytic bryophytes to disturbances in these subalpine ecosystems.

As a working hypothesis, we examined evidence for the former presence of a climacic woodland of Juniperus cedrus above the pine forest in the high elevation area of Tenerife (Canary Islands), which would indicate that the current dominant vegetation (endemic Spartocytisus supranubius scrub) may not be pristine. The main causes of the great regression of this woodland were caused by human activities (timber harvesting, herbivory by goats, and fires). The main support for this hypothesis is the survival of a presumably relict seed dispersal system of the endangered endemic J. cedrus, which relies mainly on the wintering thrush Turdus torquatus. The fact that genetic factors are directly involved in the control of bird migration routes strongly supports the idea that this interaction could be remnant of an older system, probably more widespread in the past. To test this hypothesis, we propose that a paleoecological approach could reconstruct the vegetation dynamics in the Teide National Park (Tenerife) and the past presence of this seed disperser migratory thrush. The analysis of plant microfossils in sediments (e.g., pollen, spores, phytoliths, coprolites, and charcoal) would allow us to evaluate whether the current vegetation is the same as that which naturally existed in the past, and assess the impact of the anthropogenic and natural factors to which it has been subjected during history. The results of these analyses will be useful for future management policies and practices aimed at restoring the pristine landscape and biotic interactions of the Teide National Park. To our knowledge, the case presented in this contribution, based on the high dependence of the seed dispersal of an endemic tree (J. cedrus) on a migratory bird, is the only reported in the context of oceanic islands.

Novel disturbance regimes (e.g., introduced herbivores and fire) are among the major drivers of degradation in island ecosystems. High-elevation ecosystems (HEEs) on islands might be especially vulnerable to these disturbances due to high endemism. Here, data from an 11-year exclosure experiment in the HEE of La Palma (Canary Islands) are presented where mammalian herbivores have been introduced. We investigate the combined effect of herbivory and fire on total species richness, seedling richness, and seedling establishment on the whole system and a subset of highly endangered species (target species). Total species richness, seedling species richness, and seedling establishment decreased with herbivory. Five out of eight target species were exclusively found inside the exclosures indicating the negative impact of introduced herbivores on endemic high elevation flora. Target species were generally affected more negatively by introduced herbivores and were subject to significantly higher browsing pressure, probably owing to their lack of defense strategies. A natural wildfire that occurred six years before data sampling substantially increased total species richness and seedling richness in both herbivory exclosure and reference conditions. We conclude that species composition of the HEE has been severely altered by the introduction of non-native herbivores, even though fire seems to have a positive effect on this system.

Under the multiple-use paradigm, conflicts may arise when protection of an endangered species must compete with other management objectives. To resolve such a conflict in the Critical Habitat of the endangered Hawaiian honeycreeper, palila (Loxioides bailleui), federal courts ordered the eradication of introduced ungulates responsible for damaging the māmane (Sophora chrysophylla) forest on which palila depend. During 1980–2011, a total of 18,130 sheep (Ovis aries and O. gmelini musimon) and 310 goats (Capra hircus) were removed from Palila Critical Habitat (PCH) primarily by public hunters (54%) and secondarily by aerial shooting. Nevertheless, our analysis indicates that ungulates have increased over time. Palila numbers have declined sharply since 2003 due to long-term habitat degradation by ungulates and drought. Although culling ungulate populations has allowed some habitat improvement, their complete removal is necessary for palila to recover, especially given the potential for continued drought. Introduced predators are being controlled to reduce palila mortality, māmane and other native trees are being planted to restore some areas, and fencing is being constructed to prevent ungulate immigration. Funds are recently available for more effective eradication efforts, which are urgently needed to eliminate browsing damage in PCH and protect the palila from extinction.

Mount Cameroon (4095 m), the highest peak and only active volcano in West Africa, is located in the center of the Gulf of Guinea Pleistocene refugium. The associated forests and highlands along the southern Nigerian-Cameroon border and on the island of Bioko, known as the Biafran forests and highlands, are important formations of the Cameroon Volcanic Line owing to their wide elevational range, and on Mount Cameroon, a continuous gradient of unbroken vegetation from sea level to over 4000 m. The montane zones in the region begin 800 m above sea level forming the critically endangered Mount Cameroon and Bioko Montane Forests ecoregion.

The broad elevational gradient of the region has resulted in high habitat diversity, leading the region to be a center for species endemism and richness across many taxa. Some of the densest human populations in Africa also occur in this region, putting intense pressure on the forests and highlands mostly due to overexploitation and habitat loss. The governments of Nigeria, Cameroon, and Equatorial Guinea have designated protected areas in the region, but coverage is inadequate, especially for the rare montane ecosystems and endemic taxa. More importantly, protected areas are often not accompanied by effective management and regulatory enforcement. We recommend improved law enforcement and an expansion of the protected area network, as well as stronger commitments of institutional, financial, and technical support from governments and non-governmental organizations, in order to move conservation in the region in a positive direction. Without significant and immediate conservation progress, increasing anthropogenic pressure and systemic ineffectiveness of protected area management represent major concerns for the future of this important area.

Terrestrial laser-scanning surveys of the south-facing cliff of the northern Ice Field on the summit crater of Kilimanjaro were taken on three occasions, in September 2004, January 2006, and August 2008. By comparing the three scans, the rates of lateral cliff retreat and surface lowering can be assessed. During 2004–2006, the mean lateral retreat was 1.39 m yr^-1, falling to 0.89 m yr^-1 during 2006–2008. These rates are broadly comparable with previous work using ablation stakes. Surface lowering is much less rapid, at 0.65 and 0.25 m yr^-1, respectively. Analysis of seasonal forcings (radiation on a south-facing cliff, radiation on a flat surface, surface vapor pressure, and relative humidity) shows that most of the lateral retreat occurs during the austral summer, when direct radiative input is considerably higher on the south-facing ice cliff. On the ice surface, however, high-sun periods around the equinoxes dominate the surface lowering. Lowering is more during the wet than the dry seasons, which suggests that the current moisture availability on Kilimanjaro is not frequent enough to prevent lowering year round.

Ka Roimata o Hine Hukatere (Franz Josef Glacier) is a fast-flowing maritime glacier and its climatological and hydrological drivers are different from those of many previously studied alpine glaciers. The glacier tongue has recently advanced as well as retreated, remains largely snow free, has significant volumes of melt and rainwater inputs throughout the year, and experiences small radiation and air temperature fluctuations over diurnal to seasonal time scales. We discuss measurements of surface velocity made between 2000 and 2012 at annual, seasonal, weekly, and daily time scales together with measurements of glacier geometry change, and calculations of surface water inputs and subglacial water pressure variations derived from a distributed surface mass balance model and a one-dimensional conduit hydrology model, respectively. Annual velocity variations are linked to changes in glacier geometry and advance/retreat cycles with accelerations during thickening and advance and decelerations during thinning and retreat. At seasonal, weekly and daily time scales, velocities are correlated with water input variations and with rates of water pressure fluctuation rather than absolute magnitudes of water pressure.

In view of the rapid and accelerating glacier retreat observed in the European Alps during the last decades, the repeated creation of glacier inventories is important to understand the spatio-temporal variability of glacier changes and to support modeling studies. This article presents the latest glacier inventory for the entire Swiss Alps (SGI2010) derived by manual digitization from high-resolution (25 cm) aerial orthophotographs acquired between 2008 and 2011. Its accuracy is assessed by comparing the extents of clean, snow-and/or debris-covered glaciers derived from multiple digitization by several experts. The potential of more precise mapping of debris-covered glaciers is pointed out through the combination of aerial orthophotos with Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques. In order to investigate the accuracy of glacier outlines obtained from medium-resolution satellite remote sensing imagery, a Landsat derived 2003 inventory is directly compared to all glaciers of the eastern Swiss Alps mapped with 2003 aerial orthoimagery. For the Swiss Alps, the total glacierized area mapped for 2010 is 944.3 ±24.1 km². Resulting area changes are -362.6 km² (-27.7%, or -0.75% a^-1) between 1973 and 2010. It is shown that satellite remote sensing techniques using medium-resolution source data misclassified more than 25% in area of very small glaciers (<0.5 km²). Therefore, use of high-resolution satellite or airborne imagery for future inventory creation in areas dominated by very small glaciers is recommended.

Gravel highways in the continuous permafrost zone provide critical transportation links that are increasingly vulnerable to the impacts of climate warming and permafrost thaw. To examine if the physical effects associated with the construction, maintenance, and use of gravel roads alter vegetation and permafrost conditions, we measured vegetation, soils, and near-surface ground temperatures at tall and dwarf shrub tundra sites adjacent to and distant from the Dempster Highway in the Northwest Territories of Canada. We found that alder growth and recruitment were significantly enhanced adjacent to the highway. Where alder shrubs had formed closed canopies, we observed dramatic alterations to plant community composition, soil properties, and ground temperatures. Tall shrub sites adjacent to the road exhibited less understory vegetation, greater litter and organic layer thickness, higher nutrient availability, and thicker snowpack than all other site types. Our results show that in shrub tundra ecosystems the conditions generated by the maintenance and use of a gravel road can drive ecological feedbacks that magnify changes to vegetation communities and soils. We found that where the road facilitated shrub dominance, feedbacks were initiated that enhanced snow accumulation and altered ground temperatures and soil chemistry. In turn, these changes likely promoted enhanced shrub recruitment and growth. Shrub proliferation adjacent to highways is an important consideration for the planning and maintenance of this form of infrastructure. To improve our understanding of the spatial heterogeneity of shrub proliferation, research exploring the relationships between biophysical landscape features and shrub development is also needed.

In order to determine the distribution and morphometric characteristics of thermokarst lakes on the Qinghai-Tibet Plateau, SPOT-5 satellite images were acquired from the Chumaerhe High Plateau to Beiluhe Basin within a 10-km-wide corridor along the Qinghai-Tibet Railway. A total of 2163 water bodies, having a total area of 1.09 × 10⁷ m², were identified in the study area using unsupervised classification and image interpretation. Several shape metrics (area, perimeter, circularity index, elongation index, orientation of major axis, and curvature of lake shoreline) were determined for lakes from the imagery, and bathymetric profiles of lake bottoms were derived using ground-penetrating radar. The results highlighted significant morphometric differences between lakes larger than 5000 m² among three subregions: the Chumaerhe High Plain (CHP), the Hoh Xil Hill region (HXR), and the Beluhe Basin region (BBR). The lakes in CHP usually have a more regular outline and smooth lake bottoms, while the lakes in HXR often have the greatest depths and the most complex shorelines. The most elongated and largest lakes were typically in BBR. Other than a minor NE-SE peak in HXR and BBR, the major axis orientation for lakes in the three subregions is mostly ENE-WSW. The differences in lake morphology between the three subregions are associated with differences in ground-ice content, local relief, and topography. The dominant factors controlling the development of orientated thermokarst lakes in the region are the prevailing summer wind direction and solar insolation.

This study aimed at investigating the vegetation pattern associated with the transition from upper northern Andean cloud forest to páramo grassland in a relatively unmodified area in Ecuador's Eastern Cordillera. Single 20 × 10 m plots were randomly placed in representative sites along an altitudinal gradient from continuously wet Andean montane cloud forest at 3400–3700 m to páramo grassland at 3900–4000 m. Also sampled was a disjunct stand of the stem-rosette Espeletia pycnophylla var. llanganatensis, some 200 km south of the limit of the otherwise continuous distribution of this genus. Several physical and chemical soil factors, including temperature at -30 cm, were determined. Visual estimates of cover in four life-form classes (trees, shrubs, herbs, ground cover) at each site revealed similarities related to their relative proximity along an elevation gradient. Stands with a tree cover were more species-rich than those without, due largely to the differential distribution of the woody flora. No abrupt discontinuity occurred in the mix of species along this gradient. Soil temperature and altitude were the most important factors of those measured to explain the variability in plant community structure and composition. There was no clear zonation evident along the altitudinal gradient, with vegetation structure and floristics displaying continuous variation. No clear upper forest limit was differentiated. The isolated presence of Espeletia in the area is discussed, but the theory about its origin remains speculative.

Soils with mountain permafrost occupy 3.5 million km² worldwide, with 70% in central Asia. High-mountain environments have “warm” permafrost, with surface permafrost temperatures of -0.5 to -2 °C and deep active layers (2 to 8 m). From a global database of 41 sites and 312 pedons, alpine soils with permafrost are strongly acid (pH = 5.0 to 5.5), have intermediate cation-exchange capacities (20 to 25 cmol_c/kg) and base saturation (44% to 85%), and commonly have an isotic mineral class. Soil organic carbon is concentrated in the upper 30 to 40 cm, with profile density averaging 15.2 ± 1.3 kg m^-2 (range = <1.0 to 88.3 kg m^-2), which is comparable to temperate grasslands (13 kg m^-2) but substantially less than moist arctic tundra (32 kg m^-2). Mountain soils with permafrost contain 66.3 Pg of soil organic carbon (SOC), which constitutes 4.5% of the global pool. In contrast, the SOC pool in the Arctic is 496 Pg (33% of the global pool). Alpine soils with deep active layers contrast strongly with high-latitude soils in areas of continuous permafrost. Permafrost in the upper 2 m induces cryoturbation in the profile, acts as a barrier to water movement, and generates cooler temperatures resulting in greater SOC levels. High-elevation and high-latitude soils are experiencing warming of air temperature and permafrost and a thickening of the active layer.