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The spatial distribution of surface air temperatures is essential for understanding and modelling high‐relief environments. Good estimations of the surface temperature lapse rate (STLR) and the 0°C isotherm height (H0) are fundamental for hydrological modelling in mountainous basins. Although STLR changes in space and time, it is typically assumed to be constant leading to errors in the estimation of direct‐runoff volumes and flash‐floods risk assessment. This paper characterizes daily and seasonal temporal variations of the in‐situ STLR and H0 over the western slope of the subtropical Andes (central Chile). We use temperature data collected during 2 years every 10 min by a 16 sensors network in a small catchment with elevations ranging between 700 and 3,250 m. The catchment drains directly into Santiago, the Chilean capital with more than seven million inhabitants. Resulting values are compared against those obtained using off‐site, operational data sets. Significant intra‐ and inter‐day variations of the in‐situ STLR were found, likely reflecting changes in the low‐level temperature inversion during dry conditions. The annual average in‐situ STLR is −5.9°C/km during wet‐weather conditions. Furthermore, STLR and H0 estimations using off‐site gauges are extremely sensitive to the existence of gauging stations at high elevations. [ABSTRACT FROM AUTHOR]

Globally, treelines form a transition zone between tree‐dominated forest downslope and treeless alpine vegetation upslope. Treelines represent the highest boundary of "tree" life form in high‐elevation mountains and at high latitudes. Recently, treelines have been shifting upslope in response to climate warming, so it has become important to understand global tree diversity and treeline distributions. However, to the best of our knowledge, no global database on tree flora of treelines exists, which limits our capacity to undertake macroecological analyses. Here, for the first time, we present a global data set on the trees of the treeline ecotone, supported by an online ToTE database. We synthesized the database from 1202 studies published over the last 60 years (1962 to 2022) following the Preferred Reporting Items in Systematic Reviews and Meta‐Analysis (PRISMA) protocol. We classified the tree species in the database into three categories: treeline tree (TL) species, near to treeline (NTL) tree species, and tree species with an upper montane range limit (TUMR). The ToTE Version‐1 presents a total of 208 tree taxa, including 189 species, five subspecies, and 14 varieties, belonging to 54 genera and 26 families distributed across 34 mountain regions worldwide that either grow exactly at the treeline or have a range limit below the treeline. Of the total taxa, 155, 14, and 39 belong to TL, NTL, and TUMR, respectively. Genera such as Abies, Picea, Pinus, Larix, and Juniperus are more represented in the treeline tree category. On the other hand, Acer, Prunus, Populus, and Quercus have more representatives in the near to treeline category, whereas Erica, Nothofagus, and Polylepis contribute more tree species with an upper montane range limit. Furthermore, families such as Rosaceae and Pinaceae include trees that occur both at the treeline and with an upper montane range limit, whereas Sapindaceae includes trees that occur exclusively near to treeline. Our database also includes information on the global distribution patterns of treeline tree species richness across mountains and biomes. The mountains with the highest number of tree species are the Andes (39) followed by the Himalaya (37). Close to 67% of tree species show restricted distributions in different mountains, with the highest endemism in the Andes and the Himalaya. In terms of tree species distribution, Pinus sylvestris was widespread, with a distribution across nine mountain regions, followed by Picea glauca and Fagus sylvatica, both distributed across five mountain regions. In terms of species' distribution across biomes, the temperate biome harbors the highest treeline tree species richness (152 species), which may reflect the fact that the majority of studies are available from the temperate regions of the world. The remaining 56 species are distributed within five other biomes, with the least in dry tropical and subarctic (four species each). Furthermore, currently 40 treeline tree species fall under different International Union for Conservation of Nature threat categories. We anticipate that our database will help advance research on macroecological, biogeographic, evolutionary, climate‐change, and conservation aspects of the treeline on a global scale. The data are released under a Creative Commons Attribution 4.0 international license. Please cite this data paper when the data are reused. [ABSTRACT FROM AUTHOR]

Purpose – This paper aims to explore how Andean knowledge and culture have shaped mountain ecosystems by building cultural landscapes where agrobiodiversity is created and recreated, water is domesticated (seeded and harvested), and where a harmonious relationship with the Earth and the Universe is kept. Design/methodology/approach – Through the use of primary and secondary sources, the information is then organized detailing a synthesis of thoughts and joint research studies conducted by various authors regarding the valuable contributions made by the Andean culture. Findings – This paper finds that strategies for facing the ecological crisis affecting planet Earth are being developed: the Pleiades and the Andean Cross continue to be observed in order to predict the weather and climate and make decisions related to traditional agricultural systems; cultural landscapes are being created and maintained; and water continues to be domesticated. Originality/value – The tropical Andes of Peru would be in the third country most affected by global climate change worldwide. The severe impacts of the global phenomenon on mountain ecosystems and cultural landscapes are many, all of which are affecting food security of large human groups and traditional lifestyles of communities and farmers. [ABSTRACT FROM AUTHOR]

Warm and moist air masses, required to generate deep convection east of the Andes Cordillera, are generally the result of humidity transport by the so-called low-level jet (LLJ). In this paper, it is shown from detailed test cases that the eastern part of the continent and the adjacent Atlantic Ocean may constitute another source of moist, warm air, which could be of potential importance even in the presence of a southerly LLJ. The position of the anticyclones crossing South America from the Pacific Ocean to the Atlantic Ocean appears to be a key factor affecting the origin of moisture over the continent. In particular, the LLJ may weaken and even change its direction when the eastern side of the South Pacific anticyclone crosses the mountains; this wind reversal is generally associated with deep convection suppression. Thus, as a South Pacific anticyclone crosses the continent more to the east and its western side reaches the east coast of South America, deep convection can reappear east of the Andes, over the Mendoza region, although the LLJ is frequently suppressed. This is associated with a transport of warm and moist air from Uruguay, southeast Brazil, or even directly from the Atlantic Ocean. [ABSTRACT FROM AUTHOR]

The Special Collection of papers in this issue of Astrobiology provides an overview of the characteristics and potential for future exploration of the Ojos del Salado volcano, located in the Andes Mountains in front of the Atacama Desert in northern Chile. The main benefits of this site compared with others are the combination of strong UV radiation, the presence of permafrost, and geothermal activity within a dry terrain. The interaction between limited snow events and wind results in snow patches buried under a dry soil surface. This leads to ephemeral water streams that only flow during daytime hours. On this volcano, which has the highest located subsurface temperature monitoring systems reported to date, seasonal melting of the permafrost is followed by fast percolation events. This is due to the high porosity of these soils. The results are landforms, shaped by the strong winds. At this site, both thermal springs and lakes (the latter arising from melting ice) provide habitats for life; a 6480 m high lake heated by volcanic activity shows both warm and cold sediments that contain a number of different microbial species, including psychrophiles. Where the permafrost melts, thawing ponds have formed at 5900 m that are dominated by populations of Bacteroidetes and Proteobacteria, while in the pond sediments and the permafrost itself Acidobacteria, Actinobacteria, Bacteroidetes, Patescibacteria, Proteobacteria, and Verrucomicrobia are abundant. In turn, fumaroles show the presence of acidophilic iron-oxidizers and iron-reducing species. In spite of the extreme conditions reported at Ojos del Salado, this site is easily accessible. [ABSTRACT FROM AUTHOR]

Winter orographic precipitation over the Andes between 30° and 37°S is examined using precipitation gauges in the mountains and adjacent lowlands. Because of the limited number of precipitation gauges, this paper focuses on the large-scale variation in cross-barrier precipitation and does not take into account the fine ridge-valley scale. The maximum amount of precipitation was observed on the windward slope of the mountain range below the crest, which was twice that observed on the low-windward side between 32.5° and 34°S. Toward the east of the crest, precipitation amounts drop sharply, generating a strong cross-barrier gradient. The rain shadow effect is greater in the north (32°-34.5°S) than in the south (35°-36.5°S) of the low-lee side, which is probably due to more baroclinic activity in southernmost latitudes and a southward decrease in the height of the Andes enabling more spillover precipitation. The effect of the Andes on winter precipitation is so marked that it modifies the precipitation regimes in the adjacent windward and leeward lowlands north of 35°S. Based on the fact that ~75%% of the wintertime precipitation accumulated in the fourth quartile, through four or five heavy events on average, the synoptic-scale patterns of the heavy (into fourth quartile) orographic precipitation events were identified. Heavy events are strongly related to strong water vapor transport from the Pacific Ocean in the pre-cold-front environment of extratropical cyclones, which would have the form of atmospheric rivers as depicted in the reanalysis and rawinsonde data. The composite fields revealed a marked difference between two subgroups of heavy precipitation events. The extreme (100th-95th percentiles) events are associated with deeper cyclones than those for intense (95th-75th percentiles) events. These deeper cyclones lead to much stronger plumes of water vapor content and cross-barrier moisture flux against the high Andes, resulting in heavier orographic precipitation for extreme events. In addition, regional airflow characteristics suggest that the low-level flow is typically blocked and diverted poleward in the form of an along-barrier jet. On the lee side, downslope flow dominates during heavy events, producing prominent rain shadow effects as denoted by the domain of downslope winds extending to low-leeward side (i.e., zonda wind). [ABSTRACT FROM AUTHOR]

The Andes as mountain regions worldwide, provide fundamental resources, not only for the local population. Due to the topographic characteristics, the potential for natural hazards is higher than elsewhere. In these areas, assessments of climate change impacts and the development of adequate adaptation strategies therefore become particular important. The data basis, however, is often scarce. Moreover, perceptions of changes and needs are often divergent between national and local levels, which make the implementation of adaptation measures a challenge. Taking the Peruvian Andes as an example, this paper aims at initiating a discussion about scientific baseline and integrative concepts needed to deal with the adverse effects of climate change in mountain regions. [ABSTRACT FROM AUTHOR]

Tropical peatlands form in at least two distinct altitudinal zones, namely lowlands and high mountains. Unlike lowland tropical peatlands, which are typically forested, tropical mountain peatlands are dominated by cushion plants, bryophytes and herbaceous plants. Tropical mountain peatlands are poorly understood and little information is available on their ages, whether their peat bodies are relicts or actively accumulating carbon, the amount of carbon they contain, or the rate at which they can accumulate carbon. Our objective in this paper is to quantify carbon accumulation rates in two peatlands in the Andes Mountains of Ecuador, South America. At each site, we collected peat cores which were analysed for bulk density, mineral content and % C and we calculated the amount of carbon stored. Due to the high amount of mineral sediment in the Cotopaxi peatland, carbon dating was not done at this site. The Cayambre-Coca peat body was 4 m thick, ca. 3,000 years old, and had accumulated 140 kgC m-2. The approximate long-term rate of carbon accumulation (LARCA) is 46 gC m-2 yr-1. However, a significant part of the depth of accumulation is due to high levels of mineral sediment input from steep side slopes and volcanic ash input. [ABSTRACT FROM AUTHOR]

In this paper l want to present a synthesis of the ethnohistorical and archaeological data referring to the Chichas of the Southcentral Andes, offering an integral view of its territorial and temporal development. The main question that guides me throughout this article is the supposed continuity between the ethnohistoric Chichas group, known from written sources of the 16th century. and the archaeological "style" often associated with them and dated preliminary between 600 and 1500 A.D, To present a broader picture of the Chichas culture it is necessary to review both data sets and question this supposed "cultural continuity" which leads to the idea of a territory of Chicha influence which is characterized by its heterogenous relations between the different entities that habitated this area, relations which, far from being static during time and space. represent a diverse panorama of human interrelationships. [ABSTRACT FROM AUTHOR]

This paper explores the ways in which tourism development has resulted in new and competing forms of territoriality in the Peruvian Andes. In a predominantly subsistence economy, the income opportunities offered by tourism have intensified conflicts relating to territorial control. Analysis focuses on a dispute between the direction of the Lake Titicaca National Reserve and the Uros, an indigenous group living within the Reserve. Both have attempted to enforce their authority over the Reserve's territory in order to control tourism flows and revenues. The Uros strive for the establishment of their own Communal Reserve, creating a new territorial division based on ethnic criteria. The elaboration of contradicting tourism use plans has created multiple normative frameworks used by both parties to support their claims for authority over the contested territory. [ABSTRACT FROM AUTHOR]

Deep convection in the Tunuyán Valley region (33°–34°S, 69°–70°W) on the eastern side of the highest peaks of the Andes Mountains is sometimes associated with damaging hail. Understanding the physical mechanisms responsible for the occurrence of deep convection in that region is therefore a central part of the development of hail suppression projects. In this paper, a case of deep convection that occurred on 22 January 2001 is studied in detail through a combined analysis of radar, satellite, and radiosonde data and numerical simulations using a nonhydrostatic mesoscale atmospheric (Meso-NH) model. The time evolution and stability characteristics are first documented using the data. In order to get insight into the main causes for the deep convection event, numerical simulations of that day were performed. These results are compared with the results corresponding to conditions of 4 January 2001 when no deep convection occurred. The comparison between the 2 days strongly suggests that the deep convection event occurred because of the simultaneous presence of anabatic winds, accumulation of moist enthalpy, and the stability conditions. The present results should be helpful in designing future observational programs in the region. [ABSTRACT FROM AUTHOR]

This study documented land degradation resulting from initial trail development and further high‐intensity touristic activity in a high‐altitude setting (>4000 m a.s.l.) in the Andes. Peru's Rainbow Mountain (also named Vinicunca or Montaña de Siete Colores) only became a world‐renowned tourist destination in recent years (after 2015/2016). A high‐mountain setting as such is fragile and does not recover fast, meaning the rapid influx of visitors has caused severe landscape degradation from which it will take several decades to recover. The main objectives of the study were to (1) characterise and map different types of impacts related to direct visitor pressure, (2) document and evaluate activities aimed at limiting degradation while enhancing visitors' experience, and (3) propose a conceptual model of trail functioning in the tropical high‐mountain environment. Data were collected using ground‐based surveys, unmanned aerial vehicles and high‐resolution satellite images. We identified eight dominant morphogenetic processes responsible for the transformation of landscape surface: (1) trampling, (2) abrasion/shearing by visitors and service animals and (3) transformation of water and sediment circulation—these direct human activities can initiate and/or intensify further degradation by the following natural processes: (4) water erosion, (5) freeze–thaw cycles, (6) dry‐wet cycles, (7) aeolian activities and (8) mass movements. The five main trail impacts identified were: trail widening, trail incision, formation of braided trail networks, development of muddy sections and development of informal (visitor‐created) trails. These observed impacts have left a clear imprint on the landscape after just one to two seasons of intensive recreational use. [ABSTRACT FROM AUTHOR]

The role of topography in determining water transit times and pathways through catchments is unclear, especially in mountainous environments – yet these environments play central roles in global water, sediment, and biogeochemical fluxes. Since the vast majority of intensively monitored catchments are at northern latitudes, the interplay between water transit, topography, and other landscape and climatic characteristics is particularly underexplored in tropical environments. To address this gap, here we present the results of a multiyear hydrologic sampling campaign (twice-monthly and storm sampling) to quantify water transit in seven small catchments (<1.3 km 2 area) across the transition from the Andes mountains to the Amazon floodplain in southern Peru. We use the stable isotope composition of water (δ18 O) to calculate the fraction of streamflow comprised of recent precipitation ("young water fraction") for each of the seven small catchments. Flow-weighted young water fractions (Fyw) are 5 %–26 % in the high-elevation mountains, 22 %–52 % in the mid-elevation mountains, and 7 % in the foreland floodplain. Across these catchments, topography does not exert a clear control on water transit; instead, stream Fyw is apparently controlled by a combination of hydroclimate (precipitation regime) and bedrock permeability. Mid-elevation sites are posited to have the highest Fyw due to more frequent and intense rainfall; less permeable bedrock and poorly developed soils may also facilitate high Fyw at these sites. Lowland soils have low Fyw due to very low flow path gradients despite low permeability. The data presented here highlight the complexity of factors that determine water transit in tropical mountainous catchments, particularly highlighting the role of intense orographic precipitation at mountain fronts in driving rapid conveyance of water through catchments. These results have implications for the response of Earth's montane "water towers" to climate change and for water–rock reactions that control global biogeochemical cycles. [ABSTRACT FROM AUTHOR]

Reconstructions of motions of the Nazca, South American, and Indian plates record short‐duration (≲10 Myr) variations in angular velocity, which enable a vector‐based test of the hypothesis that mountain uplift can cause changes in plate motion. Reductions in velocity of Nazca and South America between ∼12 and 6 Ma coincide with a phase of rapid surface uplift in the Central Andes. Decrease in the rate of India's convergence with Eurasia between ∼20 and 10 Ma corresponds to an increase in gravitational potential energy per unit area (GPE) within Tibet, marked by a transition from crustal thickening to thinning. The vectorial test shows that, in each case, the only change in driving force capable of balancing the change in basal drag is an increased resistance along the convergent boundary to the plate. Changes in GPE associated with mountain uplift provide a calibration for basal drags on plates. Basal tractions of ∼0.1–1 MPa provide resisting forces comparable in magnitude to driving forces from GPE variation in ocean lithosphere. The rapid change in motion of the Indian plate between about 48 and 41 Ma is explained by the juxtaposition of the Indian continent against the Andean‐type margin of the Transhimalaya and reduction in driving force due to loss of the slab. The net slab driving force lost was ∼2–4 TN m−1, in agreement with previous studies suggesting that forces resisting slabs' penetration into the mantle largely offset their negative buoyancy. Key Points: Calculation of forces required to cause rapid changes in plate motion test the hypothesis that some stem from increase in gravitational potential energy (GPE) of mountainsRapid decreases in velocity of Nazca, South American, and Indian plates require increases in resistance at their convergent boundariesGeological evidence shows that the Miocene decreases in velocity were contemporaneous with increases in GPE of the Andes and Tibet [ABSTRACT FROM AUTHOR]

We have discovered a spectacular new species of frog in the genus Hyloscirtus, belonging to the H. larinopygion species group. The adult female is characterized by a mostly black body with large bright red spots on the dorsal and ventral surface, extremities, and toe pads. The adult male is unknown. Small juveniles are characterized by a yellow body with variable black markings on the flanks; while one larger juvenile displayed irregular orange or yellow marks on a black background color, with light orange or yellow toe pads. Additional distinctive external morphological features such as cloacal ornamentation are described, and some osteological details are imaged and analyzed. The performed phylogeny places the new species as the sister to a clade consisting of ten taxa, all of which are part of the H. larinopygion group. We use genetic distances to fit the new species into a published time-calibrated phylogeny of this group; our analysis based on the published chronology suggests that the divergence of the new species from its known congeners pre-dates the Quaternary period. The new species is currently only known only from Cerro Mayordomo, in Fundación EcoMinga's Machay Reserve, at 2,900 m in the eastern Andes of Tungurahua province, Ecuador, near the southern edge of Los Llanganates National Park, but its real distribution may be larger. [ABSTRACT FROM AUTHOR]

The present work focuses on the study of the environmental conditions preceding the development of a group of subtropical mesoscale convective systems over central and northern Argentina on 6–7 February 2003 during the South American Low Level Jet Experiment. This period was characterized by an extreme northerly low-level flow along the eastern Andes foothills [South American low-level jet (SALLJ)]. The entire studied episode was dominated by the presence of a very unstable air mass over northern Argentina and a frontal zone near 40°S. The SALLJ generated an important destabilization of the atmosphere due to the strong humidity and differential temperature advection. Orography provided an extra lifting motion to the configuration of the regional wind field, which was efficient in forcing the initiation of convection. Once convection developed, it moved and regenerated in regions where the convective instability was horizontally homogeneous and stronger. [ABSTRACT FROM AUTHOR]

Abstract: South America delivers more freshwater runoff to the ocean per km2 land area than any other continent, and much of that water enters the fluvial system from headwaters in the Andes Mountains. This paper reviews ways in which human occupation of high mountain landscapes in the Andes have affected the delivery of water and sediment to headwater river channels at local to regional scales for millennia, and provides special focus on the vulnerability of páramo soils to human impact. People have intentionally altered the fluvial system by damming rivers at a few strategic locations, and more widely by withdrawing surface water, primarily for irrigation. Unintended changes brought about by human activities are even more widespread and include forest clearance, agriculture, grazing, road construction, and urbanization, which increase rates of rainfall runoff and accelerate processes of water erosion. Some excavations deliver more sediment to river channels by destabilizing slopes and triggering processes of mass-movement. The northern and central Andes are more affected by human activity than most high mountain regions. The wetter northern Andes are also unusual for the very high water retention characteristics of páramo (high elevation grass and shrub) soils, which cover most of the land above 3000 m. Páramo soils are important regulators of headwater hydrology, but human activities that promote vegetation loss and drying cause them to lose water storage capacity. New data from a case study in southern Ecuador show very low bulk densities (median 0.26 g cm−3), high organic matter contents (median 43%), and high water-holding capacities (12% to 86% volumetrically). These data document wetter soils under grass than under tree cover. Effects of human activity on the fluvial system are evident at local scales, but difficult to discern at broader scales in the regional context of geomorphic adjustment to tectonic and volcanic processes. [Copyright &y& Elsevier]

The article presents a study on the light reaching the ground vegetation in the high forest phase and its relation on the differences in forest structure of two selected sites, where one is on the slopes of Mount Andes and the other is at the extreme western edge of the Amazon basin. The authors state that their observations and analysis have enabled them to associated some of the differences between the two forests with differences in light climate. They mention that the interactions between light and other factors, specially root competition, may be very important. They believe that future studies on light as an ecological factor in tropical forests will most productively be aimed to the reaction of individual species to light at various stages of growth.

Geographic turnover in community composition is created and maintained by eco-evolutionary forces that limit the ranges of species. One such force may be antagonistic interactions among hosts and parasites, but its general importance is unknown. Understanding the processes that underpin turnover requires distinguishing the contributions of key abiotic and biotic drivers over a range of spatial and temporal scales. Here, we address these challenges using flexible, nonlinear models to identify the factors that underlie richness (alpha diversity) and turnover (beta diversity) patterns of interacting host and parasite communities in a global biodiversity hot spot. We sampled 18 communities in the Peruvian Andes, encompassing ~1,350 bird species and ~400 hemosporidian parasite lineages, and spanning broad ranges of elevation, climate, primary productivity, and species richness. Turnover in both parasite and host communities was most strongly predicted by variation in precipitation, but secondary predictors differed between parasites and hosts, and between contemporary and phylogenetic timescales. Host communities shaped parasite diversity patterns, but there was little evidence for reciprocal effects. The results for parasite communities contradicted the prevailing view that biotic interactions filter communities at local scales while environmental filtering and dispersal barriers shape regional communities. Rather, subtle differences in precipitation had strong, fine-scale effects on parasite turnover while host-community effects only manifested at broad scales. We used thesemodels tomap bird and parasite turnover onto the ecological gradients of the Andean landscape, illustrating beta-diversity hot spots and their mechanistic underpinnings. [ABSTRACT FROM AUTHOR]

Three new species of Luticola are described from lotic ecosystems in Andakí Municipal Natural Park, located in the Andean-Amazon region on the eastern flank of the eastern Andes mountain range in Colombia. Size and morphological features of the three new species, L. caquetensis Kociolek, Simonato & Núñez-Avellaneda sp. nov., L. andakiesiorum Simonato, Kociolek & Plata Díaz sp. nov., and L. sinchii Sala, Kociolek & Simonato sp. nov. are provided, based on light and scanning electron microscopical observations, and compared with similar congeners. Species of the genus are organized into groups depending upon whether they possess or lack marginal channels and/or pseudosepta. All the new species possess pseudosepta and L. caquetensis and L. andakiesiorum lack marginal channels. The two latter species share this combination of features with Luticola affinis Levkov et al., a species described from Brazil. These species thus form a unique group within the genus, offering additional evidence for the unique biodiversity found in this region. [ABSTRACT FROM AUTHOR]

Satellite-based estimates of rainfall are frequently used to complement scarce networks of gauges. Understanding uncertainties is an important step, but it is often hindered by a lack of validation data or misrepresented by spatial-scale-related uncertainties, which are especially important in spatially variable regions such as mountains. This study evaluates the Integrated Multisatellite Retrievals for GPM (IMERG) V05B 30-min estimates for all three runs (Early, Late, Final) over the high tropical Andes. A unique dataset containing 15 rain gauges located within one IMERG grid at elevations ranging from 3800 to 4600 m provides a first evaluation opportunity in this topographical context. The evaluation was based on categorical, statistical, and graphical methods. Error dependencies on precipitation characteristics and data source of the IMERG estimate were investigated. We show that IMERG severely underdetects precipitation events, thus underestimating precipitation depths. Poor detection is partially attributable to the low-intensity nature of precipitation over the region. However, tracing the error to the data source highlights limitations in passive microwave retrievals over the full range of intensities. No IMERG run has best overall performance, emphasizing that run suitability is application specific. The impact of gauge density on performance metrics was also evaluated and showed that subdaily IMERG accuracy is overestimated by sparse networks. A minimum of six gauges was required at the 30-min increment so that performance metrics are within 0.1 points of their true scores. We provide the first comprehensive assessment of 30-min IMERG in a mountainous setting, highlighting the importance of high-density networks for accurate subdaily evaluations. [ABSTRACT FROM AUTHOR]

Like other aspiring geologists in the 1830s, Darwin focused heavily on the rising and falling of the earth's crust. I use his time in the Andes to underscore the importance he placed on larger questions of vertical movement, which mountains helped to solidify in his mind. His most impressive ramblings occurred in 1835 on two high passes in the Andes. Prior to his upland journey, he was well prepared to see the gradual movement of the earth's crust, but his time in the mountains honed his vertical vision. His actual travels up and over enabled him to think more clearly about rise and fall, and how corresponding geographies could link the past to the present. Mountains were instructive backdrops to his theorizing, partly because he traveled through them, but also because his time there, linked with other geographies, became a means to foster his thinking both spatially and temporally. He did not think about mountains, but with them and through them. He is a good example of the broader vertical consciousness that directed many sciences at this time. [ABSTRACT FROM AUTHOR]

Hosting the flattest sedimentary plains and highest Andean range of the continent, southern South America faces hydrological transformations driven by climate and land use changes. Although water stable isotopes can help understand these transformations, regional synthesis on their composition is lacking. We compiled for the first time a dataset of H and O isotopic composition for 1659 samples (precipitation, rivers, groundwater and lakes) along latitude (22.4°S to 41.6°S), longitude (55.3°W to 71.5°W), elevation (1–4700 m) and precipitation (∼50 to ∼1500 mm/a) gradients encompassing the Chaco-Espinal-Pampas plains, their adjacent Andean Cordillera and smaller mountain ranges in-between. Emerging patterns reveal (i) only slight seasonal isotope trends in precipitation with no effects of event size, (ii) Atlantic/Amazonian vs. Pacific moisture supply to rivers north and south of the 'arid diagonal' of the continent, respectively, (iii) uniform isotopic composition in Atlantic/Amazonian-fed rivers vs. poleward isotope enrichment in Pacific-fed rivers caused by the elevation decline of the Andes, (iv) strong direct evaporation effect in rivers and shallow (<1 m) phreatic groundwater of the plains. We provide the first integrated water isotope geographical patterns of southern South America helping to improve our understanding of its water cycling patterns at the atmosphere and the land. [ABSTRACT FROM AUTHOR]

Volcanic eruptions often modify the structure and function of ecosystems at large geographical scales. However, the extent to which species diversity patterns respond to these major natural disturbances is still poorly known. We tested the shape of the species richness – elevation relationship (SRER) and its environmental correlates (thermal environment at ground level, vegetation structure and soil attributes) before and 6 months after (in the first summer) the most recent eruption of the Puyehue Cordon Caulle volcanic complex (PCCVC), which caused an extensive ash accumulation in northwestern Patagonia, Argentina.We re‐established 32, 100‐m2 sampling plots of nine pitfall traps, placed every 100 m of altitude from the base to the summit of three mountains differentially affected by ash deposition, and from which we had pre‐eruption data on richness and environmental variables.Coverage‐based rarefaction/extrapolation curves showed a local post‐eruptive decrease in richness on only one mountain. Generalised additive models (GAMs) showed no significant differences between pre‐ and post‐eruptive SRER shapes. Partial least squares structural equation modelling (PLS‐SEM) showed that woody vegetation and the thermal environment accounted for most of the variation in richness before and after the eruption. Soil attributes were only indirectly associated with beetle richness and the association was mediated by woody vegetation. Ash accumulation ameliorated the thermal environment, promoting a local increase in beetle richness.The rapid recovery of the SRER shape and its environmental correlates suggest that the structuring of local diversity patterns at temperate latitudes of the southern hemisphere is resilient to major volcanic eruptions. [ABSTRACT FROM AUTHOR]

Aim: The climate variability hypothesis (CVH) predicts that locations with reduced seasonal temperature variation select for species with narrower thermal ranges. Here we (a) test the CVH by assessing the effect of latitude and elevation on the thermal ranges of Andean vascular plant species and communities, and (b) assess tropical alpine plants vulnerability to warming based on their thermal traits. Location: High tropical Andes. Taxon: Vascular plants. Methods: Temperature data for 505 vascular plant species from alpine communities on 49 summits, were extracted from 29,627 georeferenced occurrences. Species thermal niche traits (TNTs) were estimated using bootstrapping for: minimum temperature, optimum (mean) temperature and breadth (maximum‐minimum). Plant community‐weighted scores were estimated using the TNTs of their constituent species. CVH was tested for species, biogeographical species groups and communities. Vulnerability to global warming was assessed for species, biogeographical species groups and communities. Results: Species restricted to the equator showed narrower thermal niche breadth than species whose ranges stretch far from the equator, however, no difference in niche breadth was found across summits' elevation. Biogeographical species groups distributed close to the equator and restricted to alpine regions showed narrower niche breadth than those with broader ranges. Community‐weighted scores of thermal niche breadth were positively related to distance from equator but not to elevation. Based on their TNTs, species restricted to equatorial latitudes and plant communities dominated by these species were identified as the most vulnerable to the projected 1.5°C warming, due to a potentially higher risk of losing thermal niche space. Main conclusions: Our study confirms that the CVH applies to high tropical Andean plant species and communities, where latitude has a strong effect on the thermal niche breadth. TNTs are identified as suitable indicators of species' vulnerability to warming and are suggested to be included in long‐term biodiversity monitoring in the Andes. [ABSTRACT FROM AUTHOR]

Rain-induced flash floods are common events in regions near mountain ranges. In peri-urban areas near the Andes the combined effects of the changing climate and El Niño–Southern Oscillation (ENSO) have resulted in an alarming proximity of populated areas to flood-prone streams, increasing the risk for cities and infrastructure. Simulations of rapid floods in these watersheds are particularly challenging, due to the complex morphology, the insufficient hydrometeorological data, and the uncertainty posed by the variability of sediment concentration. High concentrations produced by hillslope erosion and rilling by the overland flow in areas with steep slopes and low vegetational covering can significantly change the dynamics of the flow as the flood propagates in the channel. In this investigation, we develop a two-dimensional finite-volume numerical model of the nonlinear shallow water equations coupled with the mass conservation of sediment to study the effects of different densities, which include a modified version of the quadratic stress model to quantify the changes in the flow rheology. We carry out simulations to evaluate the effects of the sediment concentration on the floods in the Quebrada de Ramón watershed, a peri-urban Andean basin in central Chile. We simulate a confluence and a total length of the channel of 10.4 km, with the same water hydrographs and different combinations of sediment concentrations in the tributaries. Our results show that the sediment concentration has strong impacts on flow velocities and water depths. Compared to clear-water flow, the wave-front velocity slows down more than 70 % for floods with a volumetric concentration of 60 % and the total flooded area is 36 % larger when the sediment concentration is equal to 20 %. The maximum flow momentum at cross sections in the urban area increases 14.5 % on average when the mean concentration along the main channel changes from 30 % to 44 %. Simulations also show that other variables such as the arrival time of the peak flow and the shape of the hydrograph at different locations along the channel are not significantly affected by the sediment concentration and depend mostly on the steep channel morphology. Through this work we provide a framework for future studies aimed at improving hazard assessment, urban planning, and early warning systems in urban areas near mountain streams with limited data and affected by rapid flood events. [ABSTRACT FROM AUTHOR]

The genus Isostenosmylus Krüger, 1913 (Neuroptera: Osmylidae) is the most species-rich genus of lance lacewings in the Neotropical region. Seven species are newly described here (Isostenosmylus angustipennis , sp. nov., Isostenosmylus apaapensis sp. nov., Isostenosmylus barbatus , sp. nov., Isostenosmylus inca , sp. nov., Isostenosmylus jaguar , sp. nov., Isostenosmylus penai , sp. nov., Isostenosmylus triangulatus , sp. nov.). A neotype of Oedosmylus morenoi Navás, 1928 is proposed, the male of Isostenosmylus irroratus Ardila-Camacho et al., 2016 is newly described, and identification keys to males and females of Isostenosmylus species are provided. A morphological phylogeny and biogeographical analysis of the genus are also presented. Isostenosmylus is recovered as a monophyletic genus and species are divided in two main clades (named here as 'bifurcatus' and 'pulverulentus' clades); the greatest diversity of this genus is located in the Andean mountain range, where new studies should be focused on. http://zoobank.org/urn:lsid:zoobank.org:pub:7AA1CED6-D30D-4DE5-A45A-86C2F038B915 Isostenosmylus Krüger, 1913 is recognised as the most diverse lance lacewings (Neuroptera: Osmylidae) genus in the Neotropical region. Its highest diversity is found throughout the mountain chains of the Andes. In the past 4 years, the number of species classified in the genus has doubled. In this article, we describe seven new species, the male of a species that was only known by the female, and a neotype is designated. Phylogenetic and biogeographic analyses based on parsimony and morphology were performed for the first time to the Isostenosmylus species, representing the first analyses of the whole family in the Neotropical region. [ABSTRACT FROM AUTHOR]

Aim: To quantify the effect of Pleistocene climate fluctuations on habitat connectivity across páramos in the Northern Andes. Location: Northern Andes. Methods: The unique páramos habitat underwent dynamic shifts in elevation in response to changing climate conditions during the Pleistocene. The lower boundary of the páramos is defined by the upper forest line, which is known to be highly responsive to temperature. Here, we reconstruct the extent and connectivity of páramos over the last 1 million years (Myr) by reconstructing the upper forest line from the long fossil pollen record of Funza09, Colombia, and applying it to spatial mapping on modern topographies across the Northern Andes for 752 time slices. Data provide an estimate of how often and for how long different elevations were occupied by páramos and estimate their connectivity to provide insights into the role of topography in biogeographical patterns of páramos. Results: Our findings show that connectivity amongst páramos of the Northern Andes was highly dynamic, both within and across mountain ranges. Connectivity amongst páramos peaked during extreme glacial periods but intermediate cool stadials and mild interstadials dominated the climate system. These variable degrees of connectivity through time result in what we term the 'flickering connectivity system'. We provide a visualization (video) to showcase this phenomenon. Patterns of connectivity in the Northern Andes contradict patterns observed in other mountain ranges of differing topographies. Main conclusions: Pleistocene climate change was the driver of significant elevational and spatial shifts in páramos causing dynamic changes in habitat connectivity across and within all mountain ranges. Some generalities emerge, including the fact that connectivity was greatest during the most ephemeral of times. However, the timing, duration and degree of connectivity varied substantially among mountain ranges depending on their topographical configuration. The flickering connectivity system of the páramos uncovers the dynamic settings in which evolutionary radiations shaped the most diverse alpine biome on Earth. [ABSTRACT FROM AUTHOR]

Native Nothofagus forests in the midlatitude region of the Andes Cordillera are notorious biodiversity hot spots, uniquely situated in the Southern Hemisphere such that they develop in snow‐dominated reaches of this mountain range. Spanning a smaller surface area than similar ecosystems, where forests and snow coexist in the Northern Hemisphere, the interaction between vegetation and snow processes in this ecotone has received lesser attention. We present the first systematic study of snow–vegetation interactions in the Nothofagus forests of the Southern Andes, focusing on how the interplay between interception and climate determines patterns of snow water equivalent (SWE) variability. The Valle Hermoso experimental catchment, located in the Nevados de Chillán vicinity, was fitted with eight snow depth sensors that provided continuous measurements at varying elevations, aspect, and forest cover. Also, manual measurements of snow properties were obtained during snow surveys conducted during end of winter and spring seasons for 3 years, between 2015 and 2017. Each year was characterized by distinct climatological conditions, with 2016 representing one of the driest winters on record in this region. Distance to canopy, leaf area index, and total gap area were measured at each observational site. A regression model was built on the basis of statistical analysis of local parameters to model snow interception in this kind of forest. We find that interception implied a 23.2% reduction in snow accumulation in forested sites compared with clearings. The interception in these deciduous trees represents, on average, 23.6% of total annual snowfall, reaching a maximum measured interception value of 13.8‐mm SWE for all snowfall events analysed in this research. [ABSTRACT FROM AUTHOR]

A new species of Ladenbergia (Rubiaceae) has been found in the Cordillera de Sira in the eastern Andes of central Peru. It is here described as Ladenbergia siranensis, and it is morphologically similar to L. acutifolia, L. graciliflora and L. shawistigma. It differs from these by a shrubby habit, coriaceous, narrowly elliptic leaves, few-flowered inflorescences, the hypanthium hirtellous outside, small and deeply lobed calyx, a glabrous style, and fruits with reddened hirtellous pubescence. A key to these four species is provided. [ABSTRACT FROM AUTHOR]

Environmental limits of animal life are invariably revised when the animals themselves are investigated in their natural habitats. Here we report results of a scientific mountaineering expedition to survey the high-altitude rodent fauna of Volcán Llullaillaco in the Puna de Atacama of northern Chile, an effort motivated by video documentation of mice (genus Phyllotis) at a record altitude of 6,205 m. Among numerous trapping records at altitudes of >5,000 m, we captured a specimen of the yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) on the very summit of Llullaillaco at 6,739 m. This summit specimen represents an altitudinal world record for mammals, far surpassing all specimen-based records from the Himalayas and other mountain ranges. This discovery suggests that we may have generally underestimated the altitudinal range limits and physiological tolerances of small mammals simply because the world's high summits remain relatively unexplored by biologists. [ABSTRACT FROM AUTHOR]

We evaluated if two sigmodontine rodent taxa (Abrothrix olivacea and Phyllotis darwini) from the Andes and Coastal mountaintops of central Chile, experienced distributional shifts due to altitudinal movements of habitat and climate change during and after the Last Glacial Maximum (LGM). We tested the hypothesis that during LGM populations of both species experienced altitudinal shifts from the Andes to the lowlands and the coastal Cordillera, and then range retractions during interglacial towards higher elevations in the Andes. These distributional shifts may have left remnants populations on the mountaintops. We evaluated the occurrence of intraspecific lineages for each species, to construct distribution models at LGM and at present, as extreme climatic conditions for each lineage. Differences in distribution between extreme climatic conditions were interpreted as post-glacial distributional shifts. Abrothrix olivacea displayed a lineage with shared sequences between both mountain systems, whereas a second lineage was restricted to the Andes. A similar scenario of panmictic unit in the past was recovered for A. olivacea in the Andes, along with an additional unit that included localities from the rest of its distribution. For P. darwini, both lineages recovered were distributed in coastal and Andean mountain ranges at present as well, and structuring analyses for this species recovered coastal and Andean localities as panmictic units in the past. Niche modeling depicted differential postglacial expansions in the recovered lineages. Results suggest that historical events such as LGM triggered the descending of populations to Andean refuge areas (one of the A. olivacea’s lineages), to the lowlands, and to the coastal Cordillera. Backward movements of populations after glacial retreats may have left isolates on mountaintops of the coastal Cordillera, suggesting that current species distribution would be the outcome of climate change and habitat reconfiguration after LGM. [ABSTRACT FROM AUTHOR]

The glacial morphology of southern South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. Here we present the first geomorphological record for the Sierra Baguales Mountain Range (SBMR), forming the eastern foothills of the Southern Patagonian Andes 200 km from the Pacific coast. This area is topographically isolated from the Southern Patagonian Ice Field (SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Andean uplift, which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum (LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower elevations. This can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26 m Equilibrium Line Altitude (ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio (AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography. [ABSTRACT FROM AUTHOR]

Deformation and uplift in the Andes are a result of the subduction of the Nazca plate below South America. The deformation shows variations in structural style and shortening along and across the strike of the orogen, as a result of the dynamics of the subduction system and the features of the upper plate. In this work, we analyse the development of thin-skinned and thick-skinned fold and thrust belts in the Southern Central Andes (30–36°S). The pre-Andean history of the area determined the formation of different basement domains with distinct lithological compositions, as a result of terrane accretions during Palaeozoic time, the development of a widespread Permo-Triassic magmatic province and long-lasting arc activity. Basin development during Palaeozoic and Mesozoic times produced thick sedimentary successions in different parts of the study area. Based on estimations of strength for the different basement and sedimentary rocks, calculated using geophysical estimates of rock physical properties, we propose that the contrast in strength between basement and cover is the main control on structural style (thin- v. thick-skinned) and across-strike localization of shortening in the study area. [ABSTRACT FROM PUBLISHER]

We present the first large-scale assessment of vascular epiphyte mortality in the neotropics. Our goals were to explore the primary types of vascular epiphyte death and to identify local and regional determinants of epiphyte mortality in natural forests located 60 to 2900 m a.s.l. in the Colombian Andes., Based on two consecutive annual surveys, we followed the fate of 4247 epiphytes to estimate the epiphyte mortality rate on 116 host trees at nine sites. A logistic regression analysis for proportional data with a binomial distribution of the error was applied to determine the probability of epiphyte death in relation to local and regional explanatory variables., The overall epiphyte mortality rate was 7.5 ± 1.1% year−1 (mean ± standard error). Non-mechanical factors, such as desiccation, accounted for a mortality rate of 1.9 ± 0.3% year−1. Mechanical factors, such as falling branches, accounted for a mortality rate of 5.6 ± 1.1% year−1. According to generalized linear modelling analyses, both local and regional factors played key roles in determining epiphyte mortality. The actual evapotranspiration (regional factor) and the mean epiphyte attachment height (local factor) were both consistently positively associated with the probability of epiphyte death. Additional variables identified as possible determinants of the epiphyte mortality were the temperature seasonality, annual temperature range, the height and number of branches of the tree and the abundance of large trees ( DBH ≥10 cm)., Synthesis. The recorded high mortality rate indicates that natural epiphyte assemblages must be highly dynamic to avoid local extinction of species. Our study identifies actual evapotranspiration as an important driver of epiphyte mortality, and we highlight its importance in determining the fate tropical epiphyte communities may experience if evapotranspiration increases due to climate change. We hope our study addresses the paucity of research on non-tree growth forms, typically ignored in vegetation dynamics, and encourages their inclusion in future studies that investigate the function of tropical ecosystems. [ABSTRACT FROM AUTHOR]

Here we review the literature preferentially concerned with modern glacier-climate modeling along the Andes. We find a diverse range of modeling approaches, from empirical/statistical models to relatively complex energy balance procedures. We analyzed these models at three different spatial scales. First, we review global approaches that have included the Andes. Second, we depict and analyze modeling exercises aimed at studying Andean glaciers as a whole. Our revision shows only two studies dealing with glacier modeling at this continental scale. We contend that this regional approach is increasingly necessary because it allows for connecting the 'average-out' tendency of global studies to local observations or models, in order to comprehend scales of variability and heterogeneity. Third, we revise small-scale modeling, finding that the overwhelming number of studies have targeted glaciers in Patagonia. We also find that most studies use temperature-index models and that energy balance models are still not widely utilized. However, there is no clear spatial pattern of model complexity. We conclude with a discussion of both the limitations of certain approaches, as for example the use of short calibration periods for long-term modeling, and also the opportunities for improved understanding afforded by new methods and techniques, such as climatic downscaling. We also propose ways to future developments, in which observations and models can be combined to improve current understanding of volumetric glacier changes and their climate causes. [ABSTRACT FROM AUTHOR]

The Andes/Amazon transition is among the rainiest regions of the world and the interactions between large-scale circulation and the topography that determine its complex rainfall distribution remain poorly known. This work provides an in-depth analysis of the spatial distribution, variability, and intensity of rainfall in the southern Andes/Amazon transition, at seasonal and intraseasonal time scales. The analysis is based on comprehensive daily rainfall data sets from meteorological stations in Peru and Bolivia. We compare our results with high-resolution rainfall TRMM-PR 2A25 estimations. Hotspot regions are identified at low elevations in the Andean foothills (400-700 masl) and in windward conditions at Quincemil and Chipiriri, where more than 4000 mm rainfall per year are recorded. Orographic effects and exposure to easterly winds produce a strong annual rainfall gradient between the lowlands and the Andes that can reach 190 mm/km. Although TRMM-PR reproduces the spatial distribution satisfactorily, it underestimates rainfall by 35% in the hotspot regions. In the Peruvian hotspot, exceptional rainfall occurs during the austral dry season (around 1000 mm in June-July-August; JJA), but not in the Bolivian hotspot. The direction of the low-level winds over the Andean foothills partly explains this difference in the seasonal rainfall cycle. At intraseasonal scales in JJA, we found that, during northerly wind regimes, positive rainfall anomalies predominate over the lowland and the eastern flank of the Andes, whereas less rain falls at higher altitudes. On the other hand, during southerly regimes, rainfall anomalies are negative in the hotspot regions. The influence of cross-equatorial winds is particularly clear below 2000 masl. [ABSTRACT FROM AUTHOR]

ABSTRACT Rock glaciers in the arid Bolivian Andes are potentially important water sources, but little is known about their spatial distribution and characteristics. We provide the first rock glacier inventory for the region (15-22°S), based on mapping using remote sensing data in Google Earth, supported by field validation. Of the 94 rock glaciers identified, 57 per cent were classified as active (containing ice) and the remaining as relict (not containing ice). The majority (87%) have a southerly aspect (SE, S and SW), and the rock glacier length and area averages were 500 m and 0.12 km2, respectively. We approximate the lower limit of permafrost to be at 4700 m in the Bolivian Andes, with the mean minimum altitude of rock glacier fronts estimated to be 4980 m for active rock glaciers, and about 100 m lower for relict rock glaciers. The inventory provides an important first step towards assessing the spatial distribution of regional permafrost as well as information to allow permafrost-based water resources in the Bolivian Andes to be understood against a backdrop of severe glacier recession. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A detailed geomorphological map is presented for a portion of a poorly investigated mountainous region of the Dry Frontal Andes and Western Pre-Andes of San Juan province around 30°S latitude. This map shows the presence and extension of landforms and geomorphic processes in an area of 2175.9 km2and is the result of detailed aerial photograph and remotely sensed data interpretation, including digital elevation models, supported by field survey. The landforms have been distinguished according to morphogenetic criteria, into: (i) glacial landforms; (ii) periglacial landforms; (iii) mass movement landforms; (iv) fluvial landforms: (v) polygenic landforms and (vi) neotectonic landforms. The objective of this map is to provide information on the landforms present in the selected area, allowing it to be used as a baseline for the study of landscape evolution or support guidelines for territorial management and planning. [ABSTRACT FROM AUTHOR]

In the Southern Hemisphere, a relatively well-known preferential pathway along which cold air surges equatorward is situated to the east of the Andes Mountains. In this study, a second preferred pathway is identified to the east of the African Highlands, with additional minor pathways identified east of the Brazilian Highlands and Madagascar. The primary objective of this study is to compare climatological and synoptic characteristics of extreme cold events (ECEs) along the Andes and African Highlands pathways. ECEs are defined as the top 1% coldest 925-hPa temperatures within the Andes and the African Highlands pathways using the 1977-2001 subset of the 2.5° × 2.5° 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40). ECEs within the Andes and African Highlands pathways are associated with dynamically forced anticyclogenesis and have low-level characteristics that vary substantially. Along the Andes pathway, ECEs feature 925-hPa temperatures as much as 17°C below normal, with 925-hPa southerly winds ranging from 0 to 10 m s−1 and 925-700-hPa lapse rates as low as −3°C km−1. In contrast, ECEs along the African Highlands pathway feature 925-hPa temperatures up to 10°C below normal, with 925-hPa southerly winds ranging from 5 to 15 m s−1, and 925-700-hPa lapse rates generally between 2° and 5°C km−1. Composite analyses reveal that despite stronger southerly winds, ECEs along the African Highlands pathway are typically not as cold or stable as those along the Andes pathway because cold air from Antarctica must traverse a longer distance over water to reach Africa. [ABSTRACT FROM AUTHOR]

The article discusses the effect of climatic change on mountain ecosystems and reflects the concerns of environmental justice. The vulnerabilities of indigenous communities and mountain ecosystems to climate change along with the protection of fundamental human rights are also discussed. It depicts the re-categorization of environmental justice as a civil rights issue. It uses the example of the Bolivian Andes to demonstrate the climate change impacts on high-altitude indigenous communities.

In an attempt to estimate the spatial and temporal behaviour of rainfall over the mountainous areas of the Peruvian Andes, a new in situ monthly rainfall dataset has been collected (1998-2007) and compared with Tropical Rainfall Measuring Mission (TRMM) 3B43 monthly precipitation data for regions located above 3000 m. The reliability of the TRMM 3B43 data varies depending on the root mean squared error ratio (%RMSE) and correlation coefficient. Because of the discrepancy between the two datasets, the use of additive and multiplicative correction models is proposed for the TRMM 3B43 data. In the Peruvian mountain ranges, these correction models better approximate TRMM rainfall monthly values, as already verified for annual values. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Thermal modelling of new fission-track and (U–Th–Sm)/He data from the Fuegian Andes reveals rapid cooling (∼12–48 °C Ma−1) during the middle and late Eocene followed by slow cooling ( ∼1.5 °C Ma−1) to the Recent. We interpret the rapid cooling as a result of exhumation from contractional uplift within the crystalline interior of the orogen. This interpretation is consistent with independent evidence of Eocene shortening, flexural subsidence and provenance changes in the study area, and is approximately coeval with marine geochemical evidence of the onset of Drake Passage opening. In light of the Palaeogene history of Nazca-South American plate convergence and the differences in shortening magnitudes and exhumation histories between the Fuegian and Patagonian Andes, our data support Eocene development of the Patagonian orocline, which also provides a plausible explanation for early opening of Drake Passage. [ABSTRACT FROM AUTHOR]

The height of mountain ranges reflects the balance between tectonic rock uplift, crustal strength and surface denudation. Tectonic deformation and surface denudation are interdependent, however, and feedback mechanisms—in particular, the potential link to climate—are subjects of intense debate. Spatial variations in fluvial denudation rate caused by precipitation gradients are known to provide first-order controls on mountain range width, crustal deformation rates and rock uplift. Moreover, limits to crustal strength are thought to constrain the maximum elevation of large continental plateaus, such as those in Tibet and the central Andes. There are indications that the general height of mountain ranges is also directly influenced by the extent of glaciation through an efficient denudation mechanism known as the glacial buzzsaw. Here we use a global analysis of topography and show that variations in maximum mountain height correlate closely with climate-controlled gradients in snowline altitude for many high mountain ranges across orogenic ages and tectonic styles. With the aid of a numerical model, we further demonstrate how a combination of erosional destruction of topography above the snowline by glacier-sliding and commensurate isostatic landscape uplift caused by erosional unloading can explain observations of maximum mountain height by driving elevations towards an altitude window just below the snowline. The model thereby self-consistently produces the hypsometric signature of the glacial buzzsaw, and suggests that differences in the height of mountain ranges mainly reflect variations in local climate rather than tectonic forces. [ABSTRACT FROM AUTHOR]

Pastoralists of the high Andes Mountains raise mixed herds of camelids and sheep. This study evaluates the land use of herdsmen who are confronted by both socioeconomic and climate changes in Huancavelica, central Peru. Land use/ land cover change (LULCC) was measured through satellite imagery, and pastoralists’ capacity to adapt to socioenvironmental changes was evaluated through interviews and archival research. The most dynamic LULCCs between 1990 and 2000 were large increases in wetlands and a loss of permanent ice. We conclude that the people’s responses to these changes will depend on availability of institutions to manage pastures, other household resources, and perceptions of these biophysical changes. Socioenvironmental change is not new in the study area, but current shifts will likely force this community to alter its rules of access to pastures, its economic rationales in regards to commodities produced, and the degree of dependence on seasonal wage labor. In this scenario, households with a greater amount of livestock will fare better in terms of assets and capital that will allow them to benefit from the increasing presence of a market economy in a landscape undergoing climate change. [ABSTRACT FROM AUTHOR]

The climate of the last glacial maximum (LGM) is simulated with a high-resolution atmospheric general circulation model, the NCAR CCM3 at spectral truncation of T170, corresponding to a grid cell size of roughly 75 km. The purpose of the study is to assess whether there are significant benefits from the higher resolution simulation compared to the lower resolution simulation associated with the role of topography. The LGM simulations were forced with modified CLIMAP sea ice distribution and sea surface temperatures (SST) reduced by 1°C, ice sheet topography, reduced CO2, and 21,000 BP orbital parameters. The high-resolution model captures modern climate reasonably well, in particular the distribution of heavy precipitation in the tropical Pacific. For the ice age case, surface temperature simulated by the high-resolution model agrees better with those of proxy estimates than does the low-resolution model. Despite the fact that tropical SSTs were only 2.1°C less than the control run, there are many lowland tropical land areas 4–6°C colder than present. Comparison of T170 model results with the best constrained proxy temperature estimates (noble gas concentrations in groundwater) now yield no significant differences between model and observations. There are also significant upland temperature changes in the best resolved tropical mountain belt (the Andes). We provisionally attribute this result in part as resulting from decreased lateral mixing between ocean and land in a model with more model grid cells. A longstanding model-data discrepancy therefore appears to be resolved without invoking any unusual model physics. The response of the Asian summer monsoon can also be more clearly linked to local geography in the high-resolution model than in the low-resolution model; this distinction should enable more confident validation of climate proxy data with the high-resolution model. Elsewhere, an inferred salinity increase in the subtropical North Atlantic may have significant implications for ocean circulation changes during the LGM. A large part of the Amazon and Congo Basins are simulated to be substantially drier in the ice age—consistent with many (but not all) paleo data. These results suggest that there are considerable benefits derived from high-resolution model regarding regional climate responses, and that observationalists can now compare their results with models that resolve geography at a resolution comparable to that which the proxy data represent. [ABSTRACT FROM AUTHOR]

Changes in lake and stream habitats during the growth and retreat of Pleistocene glaciers repeatedly altered the spatial distributions and population sizes of the aquatic fauna of the southern Andes. Here, we use variation in mtDNA control region sequences to infer the temporal dynamics of two species of southern Andean fish during the past few million years. At least five important climate events were associated with major demographic changes: (i) the widespread glaciations of the mid-Pliocene ( c. 3.5 Ma); (ii) the largest Patagonian glaciation (1.1 Ma); (iii) the coldest Pleistocene glaciation as indicated by stacked marine δ18O ( c. 0.7 Ma); (iv) the last southern Patagonian glaciation to reach the Atlantic coast (180 ka); and (v) the last glacial maximum (LGM, 23–25 000 years ago). The colder-water inhabitant, Galaxias platei, underwent a strong bottleneck during the LGM and its haplotype diversity coalesces c. 0.7 Ma. In contrast, the more warm-adapted and widely distributed Percichthys trucha showed continuous growth through the last two glacial cycles but went through an important bottleneck c. 180 000 years ago, at which time populations east of the Andes may have been eliminated. Haplotype diversity of the most divergent P. trucha populations, found west of the Andes, coalesces c. 3.2 Ma. The demographic timelines obtained for the two species thus illustrate the continent-wide response of aquatic life in Patagonia to climate change during the Pleistocene, but also show how differing ecological traits and distributions led to distinctive responses. [ABSTRACT FROM AUTHOR]

The article discusses space-time rainfall variability in the Paute Basin, Ecuadorian Andes. The author states that although the importance of mountain ranges as water providers is known, knowledge of their climate variability is limited. The author explains that this limitation is because of a combination of lack of data and heterogeneous orography. The article states that the tropical Andes shares many of the main features of mountain ranges and are subject to several climatic influences that have an effect on rainfall variability. The aim of the study was to acquire a better understanding of rainfall variability in the tropical Andes using the Paute River basin of southern Ecuador as a case study.

The climatological nature of orographic precipitation in the southern Andes between 40° and 48°S is investigated primarily using stable isotope data from streamwater. In addition, four precipitation events are examined using balloon soundings and satellite images. The Moderate Resolution Imaging Spectroradiometer (MODIS) images taken during precipitation events reveal complex patterns of upstream open-cell convection over the ocean, stratus and/or convective clouds over the mountains, and sharp leeside clearing and roll convection over the steppe. Using the water vapor bands on MODIS reveals a sharp drop in column water vapor from about 1.4 to 0.7 cm across the mountain range. Seventy-one water samples from streams across the southern Andes provide deuterium and oxygen-18 isotope data to determine the drying ratio (DR) of airstreams crossing the mountain range and to constrain free parameters in a mathematical model of orographic precipitation. From the strong isotope fractionation associated with orographic precipitation, it is estimated that DR is ∼50%, the highest value yet found for a mountain range. The cloud delay parameters in a high-resolution linear precipitation model were optimized to fit the streamwater isotope data. The model agrees well with the data when the cloud delay time (i.e., elapsed time from condensation to precipitation) is about 1700 s. The tuned model is used to discuss the small-scale spatial pattern of precipitation. The isotope data from streams are also compared with data from sapwater. The good agreement suggests that future isotope mapping could be done using trees. [ABSTRACT FROM AUTHOR]

Where high species richness and high human population density coincide, potential exists for conflict between the imperatives of species conservation and human development. We examine the coincidence of at-risk bird species richness and human population in the countries of the tropical Andes. We then compare the performance of the expert-driven Important Bird Areas (IBA) scheme against a hypothetical protected-areas network identified with a systematic reserve selection algorithm seeking to maximize at-risk bird species representation. Our aim is to assess the degree to which: IBAs contain a higher richness of at-risk species than would be expected by chance, IBAs contain more people than would be expected by chance, and IBAs are congruent with complementary areas that maximize species representation with an equivalent number of sites. While the correlation of richness and population was low for the region as a whole, representation of all at-risk bird species required many sites to be located in areas of high human population density. IBA sites contained higher human population densities than expected by chance ( P < 0.05) and were markedly less efficient in representing at-risk bird species of the region than sites selected using the reserve selection algorithm. Moreover, overlap between IBAs and these latter sites was very limited. Expert-driven selection procedures may better reflect existing sociopolitical forces, including land ownership and management regimes, but are limited in their ability to develop an efficient, integrated network of sites to represent priority species. Reserve selection algorithms may serve this end by optimizing complementarity in species representation among selected sites, whether these sites are adopted independently or as a supplement to the existing reserve network. As tools of site selection, they may be particularly useful in areas such as the tropical Andes where complex patterns of species disjunction and co-occurrence make the development of representative reserve networks particularly difficult. Furthermore, they facilitate making spatially explicit choices about how reserve sites are located in relation to human populations. We advocate their use not in replacement of approaches such as the IBA initiative but as an additional, complementary tool in ensuring that such reserve networks are developed as efficiently as practically possible. [ABSTRACT FROM AUTHOR]