Search

Copyright of Antipode is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cetina et al. (2019) presented new geochronological, geochemical and isotopic data obtained from volcanic and sub-volcanic rocks exposed in the northern segment of the Western Cordillera of Colombia, which are interpreted as related to a Cretaceous island arc-plateau system. These data are used to come up with a paleogeographic model for the circum-Caribbean realm that may account for the presence of old (Paleozoic – Proterozoic) xenocrystic zircons in the analyzed units. Nevertheless, the authors ignored previously published geological, geochemical, geochronological, thermochronological and provenance constraints from Cretaceous rocks of northwestern Colombia, which refuse the plausibility of their proposed models. Particularly, the occurrence of Cretaceous subduction-related metamorphism, magmatism and construction of marginal sedimentary basins, documented by several published papers in the last decade, renders the paleogeographic reconstructions of Cetina et al. (2019) to be unlikely. We demonstrate that when considering the ignored geological evidences, alternative explanations for the origin of pre-Mesozoic xenocrystic zircons are required. • We comment the recently published paper by Cetina et al. (2019). • Several ignored geological evidences are recalled and discussed. • Paleogeographic models of Cetina et al. (2019) are not plausible. • Alternative explanations for the origin of pre-Mesozoic xenocrystic zircons are required. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the variability of the stable carbon and nitrogen isotope composition of herbivores -guanaco and huemul-in southern Patagonia. The study area extends from the eastern slopes of the Andes to the Atlantic Coast between 47° and 49° S. The ultimate aim of the research was to generate an isotopic ecology with an adequate spatial resolution that allows the incorporation and development of stable isotope studies in discussions of the population dynamics of hunter-gatherers in continental Patagonia. This paper presents the δ13C and δ15N values of 159 guanaco and huemul specimens, both modern and archaeological. This space was divided into three areas: Western area, Central Plateau and Eastern Area. Isotopic variability within groups was analyzed using the SIBER, from which the isotopic niches of the different groups are compared. The results show a spatial pattern of isotopic variability in herbivores, i.e. lower δ13C and δ15N values associated with forest environments in the western end of the transect and higher values, especially δ15N, towards the east, with maximum values observed near the Atlantic coast. Our results support the stated expectations on herbivore stable isotope composition variability and its association with environmental variables in a longitudinal transect across the southern Argentinean Patagonia. [ABSTRACT FROM AUTHOR]

This paper aims to determine the economic and technical feasibility of developing a thermally enhanced digester in the Andean area using solar collectors. Communities in the rural area of the Andes lack access to electricity and other basic services which impact negatively on their everyday life and exposes them to harmful and inefficient fuels. Several experiences with anaerobic digestion prove that this technology could be applied in the Andean area, although its performance is limited due to low temperatures. To overcome this constraint, an enhanced digester was modelled and simulated using TRNSYS Software. The system consisted of two solar collectors, a storage tank and a digester with a wrapped-around heat exchanger. The average digester temperature in the simulation was 30.7 °C. The enhanced temperature was used in a model to calculate the daily biogas production. The Net Present Value and Internal Rate of Return were calculated and confirm the economic viability of the project. The biogas production fully covers the requirements of the system for household cooking and lighting, making a significant social impact. This simulation indicates that it is technically possible to develop an enhanced digester in the Andean area that is economically viable as well. [ABSTRACT FROM AUTHOR]

Top-down processes of regional integration among the Andean countries of South America are occurring alongside bottom-up processes of Indigenous regionalism in Bolivia and Ecuador that weave together Indigenous peoples' territories across local administrative units and even national borders. In light of this dynamic, the study asks: What explains the new Indigenous regionalism in the Andes? And, what are its implications for formal processes of regional integration? The study examines the cases of the Coordinator of Indigenous Organizations of the Amazon River Basin (COICA) and the National Council of Ayllus and Markas of Qullasuyo (CONAMAQ) as examples of Indigenous regionalism in relation to the institutional innovations of the Andean Community of Nations (CAN) to incorporate Indigenous organizations into its structure and agenda. The article argues that the intersections of regional integration, the enactment of the plurinational state, and Indigenous autonomies have provided the necessary institutional space for expressions of Indigenous regionalism to flourish. [ABSTRACT FROM AUTHOR]

Abstract: Unravelling the spatiotemporal evolution of the Cenozoic Andean (Altiplano‐Puna) plateau has been one of the most intriguing problems of South American geology. Despite a number of investigations, the early deformation and uplift history of this area remained largely enigmatic. This paper analyses the Paleogene tectono‐sedimentary history of the Casa Grande Basin, in the present‐day transition zone between the northern sector of the Puna Plateau and the northern part of the Argentine Eastern Cordillera. Our detailed mapping of synsedimentary structures records the onset of regional contractional deformation during the middle Eocene, revealing reactivation of Cretaceous extensional structures and the development of doubly vergent thrusts. This is in agreement with records from other southern parts of the Puna Plateau and the Eastern Cordillera. These observations indicate the existence of an Eocene broken foreland setting within the region, characterized by low‐lying compressional basins and ranges with spatially disparate sectors of deformation, which was subsequently subjected to regional uplift resulting in the attainment of present‐day elevations during the Neogene. [ABSTRACT FROM AUTHOR]

The Salares Norte (SN) Au–Ag belt is here defined as an Upper Miocene-Pliocene metallogenic area, extending for nearly 200 km, located NE of the northern end of the Upper Oligocene-Lower Miocene Maricunga Belt in the central Andes of northern Chile. The belt is located just east of the main reverse NS fault systems which are part of the Sierra Castillo, Potrerillos Mine and Claudio Gay Cordillera faults, limited to the north and south by the NW-striking oblique to the arc Imilac and Wheelwright-Incahuasi regional faults systems. The epithermal deposits within the SN belt are intimately associated with the occurrence of Middle Miocene volcaniclastic basins and Middle to Upper Miocene phreatomagmatic vents and their related high-sulfidation hydrothermal systems. The volcanostratigraphy of the SN epithermal belt comprises volcaniclastic sequences, subvolcanic and volcanic rocks ranging between the Lower Miocene and the Pliocene. High-angle NS reverse faults involving Paleozoic and lower Cenozoic units form the western-southwestern limit of the belt. Folded and faulted Middle Miocene volcaniclastic and volcanic sequences form the main host rock of at least 4 phreatomagmatic events that generated maar-diatreme fields and discrete maar vents, with their related subvolcanic facies, within the widespread Upper Cenozoic volcanic arc, ranging in age between ca. 15 and ca. 4 Ma. These four phreatomagmatic events are spatially and temporarily associated to 4 main high-sulfidation hydrothermal events which have altered both the phreatomagmatic rocks and the Cenozoic country rock of the explosive activity. These hydrothermal systems have formed dozens of discrete hydrothermally altered areas where argillic, advance argillic, silicification and steam-heated alteration are common. Most of the maar fields and the hydrothermal alteration systems are emplaced within a strike-slip tectonic regime with NE-trending shortening which is accommodated in the NW-striking sinistral-normal faults and NE-striking extension structures. These fault systems crosscutting interaction favor the hydrothermal fluid circulation and migration, as well as mineral precipitation on structural and/or primary lithological traps and on NE-striking tension cracks. In summary, the SN epithermal belt is an almost 200 km long and 60 km wide area, mainly NNE-oriented, where epithermal deposits have formed during the Upper Miocene and Pliocene (ca. 13-4 Ma), emplaced within Middle to Upper Miocene volcanic and volcaniclastic sequences associated to small volcanotectonic basins oriented in NS, NE-SW and NW-SE directions, in which most of the high-sulfidation systems are associated to discrete or repetitive structurally-controlled Upper Miocene-Pliocene phreatomagmatic vents and maar fields. • This paper defines a new Au–Ag epithermal belt in the Central Andes of northern Chile. • Novel results in terms of age, volcanic stratigraphyand hydrothermal alteration. • The relationships between Upper Cenozoic HS epithermal areas, local tectonics and phreatomagmatic volcanism are discussed. [ABSTRACT FROM AUTHOR]

High-altitude hypoxia is one of many environmental stressors affecting human populations in the highland Andes. Living highland Andeans show adaptive physiological responses to these conditions through both developmental plasticity and natural selection. Given the longevity of human settlement in this region, these same responses ought to have affected ancient Andeans. This paper tests whether developmental plasticity or natural selection best explains the morphological signatures of adaptations to high-altitude hypoxia in ancient highland Andeans. I compare four groups of skeletons: two groups from lowland regions and two groups from high elevations. Previous work shows that the two highland groups have small bodies and voluminous ribs compared with the lowland groups indicating morphological adaptations to high-altitude environments. This paper compares patterns of intrinsic variation and sexual dimorphism in body size, limb lengths, and rib morphology in highland and lowland groups to test if developmental plasticity or natural selection underlies these morphological differences. The four groups share similar patterns of sexual dimorphism and intrinsic variation in body size and limb lengths. The two highland samples show greater degrees of sexual dimorphism in rib morphology than the lowlanders. Patterns of intrinsic variation in rib morphology do not sort by altitude. Both natural selection and developmental plasticity in response to high-altitude hypoxia likely shaped skeletal morphology in ancient highland Andeans. [ABSTRACT FROM AUTHOR]

Understanding the spatio-temporal variability of the solar resource is crucial to effectively support solar power utilization. Unfortunately, long-term and high-resolved measurements of solar irradiance are generally scarce, challenging the characterization for larger areas. In this paper, we propose a methodology to characterize the spatio-temporal variability of global horizontal irradiance (GHI) at a regional scale using long-term satellite-derived data. Spatial functional data analysis (sFDA) is used to identify areas with similar intra-annual variability patterns. The methodology is applied to a 21-year period data on Ecuador retrieved from the National Solar Radiation Database. Being the first time that sFDA is used for this purpose, the results indicate that it provides an appropriate basis for the interannual variability and complementarity analyses. In Ecuador's mainland, twenty-two subregions with four seasonal patterns are identified. The highest GHI potential (5.4 kWhm−2d−1) with the lowest variability (3.4%) is found in the Inter-Andean valleys. Further, seasonal complementarities between the coast and western Andes are identified. In Galapagos, high values are found over all islands (≥4.8 kWhm−2d−1), characterized by three subregions with one seasonal pattern. Our findings provide the first comprehensive spatio-temporal characterization of GHI in Ecuador, which aims at supporting a sustainable energy transition in the country. •A new approach to analyze the spatio-temporal variability of GHI is demonstrated. •The GHI variabilities due to microclimate effects in complex terrain are captured. •The findings provide the first comprehensive characterization of GHI in Ecuador. •High solar potential with low variability is found in the Inter-Andean valleys. •Strong seasonal complementarity between the coast and western Andes is identified. [ABSTRACT FROM AUTHOR]

The present study aims to comprehensively assess the solar irradiance patterns in the western zone of the Mantaro Valley, a region of ecological and agricultural significance in the central Peruvian Andes. Leveraging radiation data from the Baseline surface Radiation Network (BSRN) sensors located in the Huancayo Geophysical Observatory (HYGO-12.04°S,75.32°W, 3350 masl) spanning from 2017 to 2022, the research delves into the seasonal variations and trends in surface solar irradiance components. Actually, the study investigates the diurnal and seasonal variations of solar irradiance components, namely diffuse (EDF), direct (EDR), and global (EG) irradiance. Results demonstrate distinct peaks and declines across seasons, with EDR and EDF exhibiting opposing seasonal trends, influencing the overall variability in, EG. Peaks of, EG occurred in spring (3.32 MJ m-2 h-1 at noon), particularly during October (24.14 MJ m-2 day-1), probably associated with biomass-burning periods and heightened aerosol optical depth (AOD). These findings highlight the impact of biomass-burning aerosols on solar radiation dynamics in the region. In general, the seasonal variability of, EG on the HYGO is lower than that observed in other regions of South America at higher latitudes and reach its maximums during spring months. Moreover, the research evaluates various irradiation models to establish correlations between sunshine hours, measured with a solid glass sphere heliograph, and, EG and EDF at different time scales, showing acceptable accuracy to predict. In addition, the sigmoid logistic function emerges as the most effective in correlating the hourly diffuse fraction (…) and the hourly clearness index (…), showcasing superior performance compared to alternative functions and exhibiting strong statistical significance and providing valuable insights for future solar radiation forecasting and modeling efforts. This study offers valuable insights for solar radiation forecasting and modeling efforts, emphasizing the importance of interdisciplinary research for solar power generation, sustainable development and climate resilience in mountainous regions like the Peruvian Andes. [ABSTRACT FROM AUTHOR]

Centrolenidae is a Neotropical family widely distributed in Central and South America, with its species richness concentrated in the tropical Andes. Several taxonomic problems have been identified within this family, mostly related to species with broad geographic distributions. In this study, we assessed and redefined the species boundaries of the Centrolene buckleyi species complex, and formally described two new species from the Andes of Ecuador. These new taxa are recognized by a combination of morphometric, osteological, acoustic, and genetic data. Following IUCN criteria, we propose that the two new species should to be considered as Endangered (EN), mainly because of their small distributions and habitat loss. The C. buckleyi complex provides insights into the biogeography of closely related Andean species. As in other glassfrogs, speciation in Centrolene seems to be mediated by the linearity of the Andes, where gene flow can be restricted by topography and, also, local extinctions. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Ingeniería Universidad de Antioquia is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study addresses the financial sustainability challenge of integrated watershed management (IWM) in regions with inadequate water service tariffs. A novel water service tariff model is proposed, incorporating supply costs, water loss reduction investments, and IWM expenses informed by user perceptions. The model is applied to an intermediate Andean city in southern Ecuador, where the current tariff impedes the financial viability of the water utility, reflecting a regional trend. The results indicate a necessary tariff increase exceeding 100% to cover the costs and support IWM. The economic value of watershed environmental services (WES) were estimated at USD 1,505,530.64 per year. This value translates to an average water consumption of 20 m3/user/month, equivalent to a WES of USD 2.60 per month. Despite the users' willingness to pay falling below the estimated economic value of WES, there is a clear need for implementing incentive programs to promote water conservation and policy adjustments that favor the financial sustainability of water supply companies in developing countries. [ABSTRACT FROM AUTHOR]

Soils are a valuable renewable resource on human timescales, and they interact with distinctive grassland ecosystems characterized by unique biodiversity and essential provision of ecosystem services, such as water supply and carbon sequestration. However, knowledge of the effects of wildfires on soil properties and nutrient availability in the Andes remains limited. Andean grasslands are currently one of the ecosystems of the Peruvian Andes most affected by wildfires. Our objective is to analyze the effect of fire activity on the physicochemical properties of soil and analyze its social context in Cusco, in the southern Andes of Peru. Soil samples were collected during five periods, spanning both the dry and rainy seasons, to characterize changes in soil properties and monitor vegetation recovery post-fire in two local communities dedicated to livestock activities. The vegetation restored after the wildfire was measured by the "step transect" method. Post-fire changes in soil properties indicate slight increases in pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium during the onset of the rainy season; thereafter, a gradual reduction in these values was observed. This reduction can be attributed to leaching associated with the seasonal rainfall and runoff regime. Our findings indicate that one-year post-fire, the biomass in burned areas is reduced to 30–46% of the biomass in unburned areas. A complete regeneration is likely to occur in up to 4 years; this assertion is supported by the perceptions of the affected population, as expressed in interviews conducted in the two farming communities. These results are significant for decision-makers formulation of policies and regulations regarding grasslands and their seasonal restoration. [ABSTRACT FROM AUTHOR]

Plants absorb nutrients and water through their roots and modulate soil biogeochemical cycles. The mechanisms of water and nutrient uptake by plants depend on climatic and edaphic conditions, as well as the plant root system. Soil solution is the medium in which abiotic and biotic processes exchange nutrients, and nutrient concentrations vary with the abundance of reactive minerals and fluid residence times. High-altitude ecosystems of the tropical Andes are interesting for the study of the association between vegetation, soil hydrology, and mineral nutrient availability at the landscape scale for different reasons. First of all, because of low rock-derived nutrient stocks in intensely weathered volcanic soils, biocycling of essential nutrients by plants is expected to be important for plant nutrient acquisition. Second, the ecosystem is characterized by strong spatial patterns in vegetation type and density at the landscape scale and hence is optimal to study soil-water–vegetation interactions. Third, the area is characterized by high carbon stocks but low rates of organic decomposition that might vary with soil hydrology, soil development, and geochemistry, all interconnected with vegetation. The páramo landscape forms a vegetation mosaic of bunch grasses, cushion-forming plants, and forests. In the nutrient-depleted nonallophanic Andosols, the plant rooting depth varies with drainage and soil moisture conditions. Rooting depths were shallower in seasonally waterlogged soils under cushion plants and deeper in well-drained soils under forest and tussock grasses (>100 cm). Vegetation composition is a relevant indicator of rock-derived nutrient availability in soil solutions. The soil solute chemistry revealed patterns in plant-available nutrients that were not mimicking the distribution of total rock-derived nutrients nor the exchangeable nutrient pool but clearly resulted from strong biocycling of cations and removal of nutrients from the soil by plant uptake or deep leaching. Soils under cushion plants showed solute concentrations of Ca, Mg, and Na of about 3 times higher than forest and tussock grasses. Differences were even stronger for dissolved Si with solute concentrations that were 16 times higher than forest and 6 times higher than tussock grasses. Amongst the macronutrients derived from lithogenic sources, P was a limiting nutrient with very low solute concentrations (<1 µ M) for all three vegetation types. In contrast K showed greater solute concentrations under forest soils with values that were 2 to 3 times higher than under cushion-forming plants or tussock grasses. Our findings have important implications for future management of Andean páramo ecosystems where vegetation type distributions are dynamically changing as a result of warming temperatures and land use change. Such alterations may lead not only to changes in soil hydrology and solute geochemistry but also to complex changes in weathering rates and solute export downstream with effects on nutrient concentrations in Andean rivers and high-mountain lakes. [ABSTRACT FROM AUTHOR]

In this study, we assess competing interpretations of a burnt ceremonial structure from the terminal Middle Formative period (ca. 300–100 BCE) by analyzing the stepped platform mound at Chiripa, Bolivia, through a systematic reconstruction of the fire that destroyed it. We developed a model of potential fire pathways, their social contexts, and material indicators. Our approach contrasts incipient fires from accident or arson to planned fires initiated for functional or social ends. We assessed these pathways for the Chiripa mound fire through experimental, geoarchaeological, faunal, and botanical data. Experiments were aimed at deducing the temperature, duration, and oxidation conditions of the fire. The fire temperature and duration were approximated from geoarchaeological analyses of construction materials in comparison with controls, and thermal alteration of faunal bone. Fuels were reconstructed through paleoethnobotanical analysis of charred remains from discrete areas within the burnt structure. We conclude that an intentional fire burned the structures on the Chiripa mound to temperatures of 700 °C or higher under oxidizing conditions for several hours. The pattern of heat-altered materials recovered would have required a substantial supplemental fuel load. At the 3840 masl elevation of Chiripa, the effective control of a high temperature oxidizing fire demonstrates technical expertise in fire management. Our findings indicate the fire appears intentional, likely a ritual event. We believe the structures were burned to facilitate a socio-political change during a period of social transition at the end of the Middle Formative period in Bolivia. [ABSTRACT FROM AUTHOR]

Paleomagnetic results obtained from 38 Pliocene—Pleistocene volcanic flows from the Knot of the Pastos and surroundings of Puracé volcano and Popayán (southwestern Colombia) are presented. Using stringent quality criteria and excluding sites that classify as representatives of transitional states of Earth's field, a selected group of 27 sites (16 with normal polarity and 11 with reversed polarity) was obtained with a mean direction (Dec = 357.8°, Inc = 6.4°, α95 = 7.5° and κ = 15) that coincides with the geocentric axial dipole field (GAD: Dec = 0o, Inc = 3.2o) and, unlike similar studies at similar latitudes, does not coincide with the GAD plus a 5% axial quadrupolar component (Dec = 0°, Inc = −1.08°). However, when serial correlation (SC) among several sites with high inclination anomalies is taken into consideration, the mean direction of two resulting groups of sites shows greater consistency with a field that includes a quadrupolar component. It is interpreted that the sites treated for SC record states of the field similar to today's field in the area of study, which is being affected by the South Atlantic Anomaly. Plain Language Summary: The only way to study Earth's magnetic field in the geologic past from experimental data is by studying the magnetization of rocks that record Earth's field in a way comparable to the way compasses point close to the geographic north. Earth's magnetic field changes are significant in relatively short time‐scales like years or centuries. In this study the paleomagnetic directions recorded in volcanic products from extinct volcanoes of the Colombian Andes were obtained. Most of the volcanic flows record paleomagnetic directions consistent with the ones obtained from previous studies, which in general differ from the present magnetic directions in the area by being less inclined downwards. However, some of the volcanic flows did record paleomagnetic directions that are similar to the present magnetic directions in the area, which have been linked to an ample low magnetic intensity area in the Atlantic Ocean called the South Atlantic Anomaly. So, as it has been pointed out in other studies, it is possible that this anomaly has acted recurrently during the geologic past. Key Points: The mean paleomagnetic direction among the selected sites from Colombia shows consistency with a geocentric axial dipole (GAD) fieldConsistency with a GAD field with a 5% quadrupolar component is obtained when serial correlation is appliedSerially correlated sites are probably affected by the South Atlantic Anomaly, in a way similar to the present field in the study area [ABSTRACT FROM AUTHOR]

Supported by a National Science Foundation, Pan-American Advanced Studies Institute (PASI) grant and the Smithsonian Institute, two expeditions were made by teams of multidisciplinary researchers to the Andes Mountains of Peru to study the design and construction methods used to build the great Inca Road. The objectives of the study were to identify sustainable engineering practices used by the Inca, determine which practices can apply to modern design and construction, and share findings with visitors at the National Museum of the American Indian and others throughout the world through live interactive satellite broadcasts. This paper focuses on the technologies that were used to accomplish the broadcasts and used to support the engineering and construction analysis of the Inca Road. Each technology used on these expeditions provided a unique opportunity to learn about the road and disseminate findings with others. The technologies utilized included communication equipment (e.g., satellite router and dish, Wi-Fi, and mobile portable video equipment), location and mapping technologies [e.g., geographic information system (GIS) and global positioning system (GPS)], photogrammetric techniques for three-dimensional modeling, laser range finding for precision measurement of the road features, and ground-penetrating radar (GPR) for use in nondestructive testing and evaluation of subsurface conditions. The technologies are explained in this paper along with the challenges of implementing them in such harsh and extreme conditions. In addition, some of the more salient engineering and construction discoveries are included. This information can be useful for others who are interested in implementing a similar approach for studying ancient civil infrastructure in other remote locations. [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]

Many efforts are made to promote soil conservation in developing countries. This paper compares the effect of two programs promoting soil conservation in Peru on the adoption decision of households. One program applies a top-down approach with soil conservation as its core activity. The other program applies a participatory approach, offering a portfolio of activities in order to improve rural livelihoods. The decisions on participation and adoption are estimated with a trivariate probit model. The results show that each program attracts different types of households and achieves different outcomes in terms of soil conservation. [ABSTRACT FROM AUTHOR]

Copyright of Población & Sociedad is the property of Población & Sociedad and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One of the main problems of teachers aiming to teach the construction techniques used in to build a building is the lack of practical examples to show to their students. In order to be useful, these examples must come from real projects or even better the teachers may take their students to constructions sites, but this latter option is not always available and may be dangerous. To deal with this problem, Los Andes University has committed the construction of a knowledge repository containing information gathered from real projects and semantically described, in order to provide easy access to its content and in the language of people of construction. This project is called KOC, standing for Knowledge Objects of Construction, which uses an ontology to describe semantically the data contained in the repository. Being the pedagogical objective of the project, it is important to provide the teachers with additional tools to generate new knowledge objects, based on existing knowledge objects in the repository. This paper presents three composition tools for KOC: a complex objects composer issued from structured searches, a constructive processes composer and a case study composer, all of them aiming the improvement of learning quality in the technical area of building construction at the architecture and engineering schools. The paper also shows some examples of knowledge objects and how KOC is been used in the courses of the Architecture Department of Los Andes University. [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]

One of the main problems in climate reconstruction from documentary sources is the evaluation of the quality of non instrumental meteorological records in absence of instrumental observations to perform a calibration. In these cases it is mandatory to envision different approaches to assess the climatic signal in a reconstruction. This work is aimed to test the consistency of a snow frequency reconstruction in the central Argentinean Andes by studying the synoptic patterns related to the occurrence of precipitation in this area. While the original reconstruction covers the period between 1885 and 1996, the insufficiency of overlapping instrumental data limited the calibration to a short 15-year interval. In this paper we evaluate the performance of the reconstructed series for the entire 45-year period between 1958 and 1996 by analyzing the displacement in the jet stream and the patterns of geopotential height related to anomalies in the reconstructed snow frequency series. Previous works have linked the precipitation in the central Andes to the ENSO through the Pacific South American mode. We also have found this connection between ENSO and the reconstructed precipitation. Finally, it is shown that the ENSO relationship is the cause of a significant link between the precipitation anomalies in the central Argentinean Andes and the ice extent around the Antarctic Peninsula. [ABSTRACT FROM AUTHOR]

Education was an essential ingredient of the state strategy to address the so-called 'Indian question' in the Americas throughout the first half of the twentieth century. In the 1930s, Bolivian intellectuals promoted a new educational policy inspired by indigenismo, a trend of thought that sought to solve the problems faced by indigenous people concerning welfare, hygiene, agricultural techniques, and land issues; it also sought, to some extent, to teach them to value their own culture. The educational experience, originally conducted in the village of Warisata and then spread across the Andes, has merited special attention from historiography. However, very little is known about Warisata's replication in the country's lowlands. This paper explores the originality, scope, and limitations of the first project of socialization of 'non-subjected' societies of the Amazon Basin. That project was inspired by the postulates of the innovative Warisateño model, which aimed to give birth to a "new Indian" who would contribute actively and voluntarily to the progress of the nation. The categories adopted in that project, and the practices carried out, were inscribed in the positivists' thought, based on their view of the alleged "wild nature" and "savagery" of the groups with whom educators would interact. This study aims to contribute to the debate on the 'Indian question' in the Americas by highlighting the contradictions faced by intellectuals when designing projects for the "integration" of otherness into the nation. [ABSTRACT FROM AUTHOR]

Background: Climate change is arguably a major threat to biodiversity conservation and there are several methods to assess its impacts on species potential distribution. Yet the extent to which different approaches on species distribution modeling affect species richness patterns at biogeographical scale is however unaddressed in literature. In this paper, we verified if the expected responses to climate change in biogeographical scale—patterns of species richness and species vulnerability to climate change—are affected by the inputs used to model and project species distribution. Methods: We modeled the distribution of 288 vertebrate species (amphibians, birds and mammals), all endemic to the Amazon basin, using different combinations of the following inputs known to affect the outcome of species distribution models (SDMs): 1) biological data type, 2) modeling methods, 3) greenhouse gas emission scenarios and 4) climate forecasts. We calculated uncertainty with a hierarchical ANOVA in which those different inputs were considered factors. Results: The greatest source of variation was the modeling method. Model performance interacted with data type and modeling method. Absolute values of variation on suitable climate area were not equal among predictions, but some biological patterns were still consistent. All models predicted losses on the area that is climatically suitable for species, especially for amphibians and primates. All models also indicated a current East-western gradient on endemic species richness, from the Andes foot downstream the Amazon river. Again, all models predicted future movements of species upwards the Andes mountains and overall species richness losses. Conclusions: From a methodological perspective, our work highlights that SDMs are a useful tool for assessing impacts of climate change on biodiversity. Uncertainty exists but biological patterns are still evident at large spatial scales. As modeling methods are the greatest source of variation, choosing the appropriate statistics according to the study objective is also essential for estimating the impacts of climate change on species distribution. Yet from a conservation perspective, we show that Amazon endemic fauna is potentially vulnerable to climate change, due to expected reductions on suitable climate area. Climate-driven faunal movements are predicted towards the Andes mountains, which might work as climate refugia for migrating species. [ABSTRACT FROM AUTHOR]

Archaeological GIS is moving towards increasingly detailed, embodied, multidimensional simulations and analyses of human experience in the past. Most of the emerging GIS research synthesizing spatial modeling and subject-centered approaches has been concerned with practices and perceptions of landscape. This paper tightens the analytical focus to the more intimate scale of a single settlement, combining models of movement and visual experience within a planned colonial town in highland Peru. Such a rendering is important, since controlling movement and visual experience were central to the colonial project that built this and other such towns in the Viceroyalty of Peru. This study centers on an exceptionally well-preserved, relict planned colonial town in highland Peru to investigate affordances of movement and visibility within it. Several GIS-based simulations and analytical techniques are brought together, including drone-based high resolution three dimensional modeling, spatial network analysis, walking models, and cumulative viewshed analysis, to simulate aggregate visual experience as people moved through the town. The results are suggestive of how the layout of the town specifically routed transit to facilitate the visual prominence of the church and original Inka plaza of the reducción, as well as the prominence of indigenous elite households. Both continuities and discontinuities of movement and visual experience relative to Inkaic and Spanish colonial spaces are evident. By extension, this paper also provides a pathway for quantitative and reproducible modeling of site-scale movement and visual affordances as dimensions of subject and community formation in other global contexts. [ABSTRACT FROM AUTHOR]

This paper presents a political ecological framework for Geographic Information Systems (GIS) analysis to examine changes in agricultural land in ancient and early historical contexts. It raises several issues pertinent to archaeological epistemology and science, with a particular focus on the limitations of using fixed data categories to examine fluid environmental processes and ecological relationships. The paper draws on political ecological theories that define land as a social process, moving beyond economic conceptions of agricultural land that rest on productive capacity and phenomenological theories that examine the physical environment in terms of cultural perception. It combines qualitative (archival) and quantitative (archaeological) data in a GIS methodology to address how linked changes in physical land attributes and labor routines can affect regional ecologies and foment social conflict. In empirical terms, the paper traces changes from maize to wheat fields during Spanish colonization (ca. 1533-1670) in Ollantaytambo, Peru, a monumental Inca town near the capital of their empire. It reveals how ecological transformations that occurred during this century–widespread deaths throughout, abandonment of Inca fields, and introduction of European biota–in part framed conflicts between Andean people and the colonial regime, and also empowered local farmers to claim land in previously undeveloped areas. [ABSTRACT FROM AUTHOR]

Global climate model simulations project that the tropical Andes Mountains of South America, which are particularly vulnerable to climate change because of a reliance on snow and glacial melt for freshwater resources, will experience enhanced warming in the near future, with both higher rates of warming at higher elevations within the mountain range itself and localized enhancement of warming exceeding surrounding areas of the globe. Yet recent surface temperature changes in the tropical Andes do not show evidence for either elevation-dependent warming or regional enhancement of warming on average. However, it remains a possibility that the expected warming trends in this region have begun to manifest in other ways (e.g., in the free atmosphere or at intermediate mountain elevations). This paper proposes evidence from several reanalysis products that there has indeed been a regional enhancement of midtropospheric warming around the central Andes over the past few decades that makes this region stand out as a hot spot within the broader pantropics. This trend is generally not reproduced by historical AMIP climate model simulations, which suggests that the mechanisms through which the atmosphere is warming over the central Andes are not adequately captured by climate models. Possible explanations for localized enhancement of warming in this region are considered. On the other hand, reanalysis products do not consistently exhibit enhanced warming at intermediate mountain elevations in the central Andes as evidenced by the generally moderate rates of change in the freezing-level height, except perhaps in the highest-resolution reanalysis product. [ABSTRACT FROM AUTHOR]

In this paper I examine how Christian priests in the early colonial period in the Andes tried to communicate the Christian concept of the Trinity to the indigenous population, mainly through textual but also through visual means. On the basis of these sources, I will address the following questions: how did the priests present the concept in Quechua, one of the general languages of the Andes, in morphological, lexico-semantic and argumentative terms; how was the Trinity represented in painting and, could the Indians relate these explanations to something they were familiar with in their own religion? Answering these questions will provide us with hypotheses as to how the indigenous population might have understood this Christian concept, which, in turn may enable us to better understand modern Andean belief forms with respect to the Trinitarian concept, which I shall briefly discuss in the final section. On the whole, the evidence suggests that, whilst the Christians may have thought that they could explain their Trinity to the Andean people better by using the Quechua language, the adoption of Andean concepts and language resources resulted in different reception strategies, such as the accommodation of Christian beliefs in the Andean religious system, but also the creation of new hybrid concepts based on Amerindian as well as Christian belief forms. [ABSTRACT FROM PUBLISHER]

[Display omitted] • The prevalence and diversity were higher for Haemoproteus than Plasmodium in Passeriformes. • The haplotype diversity was higher for Plasmodium than Haemoproteus. • Plasmodium and Haemoproteus prevalence were associated with higher avian diversity in the Chilean ecoregions. • Haemoproteus presented more specialist lineages than Plasmodium. • Haemoproteus presented greater genetic differentiation than Plasmodium between the east and west of the Andes mountains. The specialist versus generalist strategies of hemoparasites in relation to their avian host, as well as environmental factors, can influence their prevalence, diversity and distribution. In this paper we investigated the influence of avian host species, as well as the environmental and geographical factors, on the strategies of Haemoproteus and Plasmodium hemoparasites. We determined prevalence and diversity by targeting their cytochrome b (Cytb) in a total of 2,590 passerine samples from 138 localities of Central and South America, and analysed biogeographic patterns and host-parasite relationships. We found a total prevalence of 23.2%. Haemoproteus presented a higher prevalence (15.3%) than Plasmodium (4.3%), as well as a higher diversity and host specificity. We determined that Plasmodium and Haemoproteus prevalences correlated positively with host diversity (Shannon index) and were significantly influenced by bird diversity, demonstrating a possible "amplification effect". We found an effect of locality and the avian family for prevalences of Haemoproteus and Plasmodium. These results suggest that Haemoproteus is more specialist than Plasmodium and could be mostly influenced by its avian host and the Andes Mountains. [ABSTRACT FROM AUTHOR]

Despite ongoing efforts to document the use of khipus (Andean knotted-string recording devices) in the decades following the Spanish conquest, the scenes in which former Inka-era khipukamayuqs (cord keepers) rendered their cords for colonial observers remain unclear. This study confronts this historical blind spot, endeavouring to reconstruct early colonial khipu 'readings' by way of a heretofore unexplored occurrence: scribal modifications entered in transcriptions of khipu-based testimonies before the colonial high courts. Following an overview of evidentiary cord readings and previous treatments of scribal emendations, the prevalence of visible markings is assessed in the largest compilation of khipu transcriptions. Legal proceedings between 1558–1568 before the Audiencias of Lima and La Plata form two case studies. The documents are representative of other khipu transcriptions in lacking an exhaustive description of their own preparation; as such, the possibility that one or more is a secondary copy cannot be entirely excluded. Scribal modifications in three testimonies from the proceedings are deployed as heuristic devices to probe the presentation of ethnocategories and chronology by the cord keepers within this fraught documentary space. Despite the possibility of unattested documentary interference, the case studies attest to slippages in khipu reading that, in their sum, enable the proposal of punctuated narrative cadence, reversions to verbal shorthand, and relational discourse as recurring qualities of early colonial khipu readings. It is argued that this interpretive exercise enables closer study of the relationship between khipus and their written colonial references, serving other inquiries into 'lost' historical scenes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soils under anthropic uses showed more remarkable changes in soil properties with rainfall seasonality than soils under natural páramo. • Land-use change from natural vegetation to potato and onion crops followed by fallow reduces soil organic matter and water content and increases bulk density. • Land-use change could impair the ability of páramo catchments for streamflow buffering and this could increase surface runoff and reduce base flow. High-Andean páramos deliver essential ecosystem hydrological services from a combination of soil, vegetation, and climate characteristics, particularly in their natural state. However, agricultural activities considerably affect the páramo's ability to store, regulate, and supply water. Although there is information on the effect of potato crops (Solanum tuberosum) on páramo soils' properties, the effect of spring onion (Allium fistulosum) crops has been studied less. In addition, dry páramos are underrepresented in existent páramoś research. This study assessed the effect of rainfall seasonality (RS) and land-use change (transformation from páramo vegetation to crops) on soil hydrophysical properties associated with hydrological services (streamflow buffering) in a dry páramo in the Eastern range in Colombia. Six dominant land uses were studied: natural páramo vegetation (low slope, steep slope, and dense shrublands) and anthropic use (onion crops, potato crops, and fallow). An in-depth random stratified discrete design (0–5, 10–15, and 20–25 cm) was used to collect samples for analysis of soil organic matter (SOM), bulk density (BD), pH, and electrical conductivity (EC). Hydrophysical properties were measured at the soil surface: water retention capacity (WRC), structural stability (SS), and infiltration capacity (IC). Soils under anthropic uses showed more remarkable changes in soil properties with RS than soils under natural páramo. On the other hand, land-use change from natural vegetation to potato and onion crops followed by fallow leads to a reduction in SOM (9.8 %) and an increase in BD (0.19 gcm−3), especially at the surface level. In addition, this leads to a loss of WRC (20 % at field capacity), an increase in unstable aggregates (13 %), water erosion, and a loss of IC (44 mmh−1). This paper demonstrates the impact of land use on soil hydrophysical properties that compromise the maintenance of hydrological services and contributes to a better understanding of the complexity of Andean páramos. [ABSTRACT FROM AUTHOR]

The Amazon River Basin's extraordinary social-ecological system is sustained by various water phases, fluxes, and stores that are interconnected across the tropical Andes mountains, Amazon lowlands, and Atlantic Ocean. This "Andes-Amazon-Atlantic" (AAA) pathway is a complex hydroclimatic system linked by the regional water cycle through atmospheric circulation and continental hydrology. Here, we aim to articulate the AAA hydroclimate pathway as a foundational system for research, management, conservation, and governance of aquatic systems of the Amazon Basin. We identify and describe the AAA pathway as an interdependent, multidirectional, and multiscale hydroclimate system. We then present an assessment of recent (1981 to 2020) changes in the AAA pathway, primarily reflecting an acceleration in the rates of hydrologic fluxes (i.e., water cycle intensification). We discuss how the changing AAA pathway orchestrates and impacts social-ecological systems. We conclude with four recommendations for the sustainability of the AAA pathway in ongoing research, management, conservation, and governance. [ABSTRACT FROM AUTHOR]

Recordings of earthquakes by a temporary deployment of 84 short period seismometers in northern Chile were used to derive regional 3D seismic velocity models for the Taltal segment. We used the Regressive ESTimator (REST) package for event detection and automatic onset estimation of P‐ and S‐wave arrival times to create an earthquake catalog with 23,985 hypocenters. We followed standard acceptability criteria (i.e., azimuthal gap and residual cutoff) to create a high‐quality data set and inverted for 3D Vp, Vs and Vp/Vs models using local earthquake tomography. Plots of hypocenters from the catalog, comprising 16,349 earthquakes, reveal active structures in the upper crust, dip changes along the slab and fracturing within the oceanic crust. Moreover, the wavespeed models illuminate anomalies in both the Nazca and South American plates that correlate with the observed seismicity distribution, including variations from low (1.75) to high (>1.80) Vp/Vs near the Atacama fault system on the coastline and the Domeyko Fault System in the forearc. The seismic velocity models also provide evidence for fluid circulation caused by the subducting Taltal ridge on the coast and partial melting feeding a volcanic complex close to the Andes. Finally, the observed low Vp/Vs ratios (∼1.75) are associated with copper mining operations in the area, suggesting that this kind of imaging can be used to characterize the distribution of potential ore deposits in the area. Plain Language Summary: We recorded earthquakes in northern Chile with a network of 84 seismometers and used the arrival times of P and S waves to generate 3D wavespeed models of the region. These models reveal several structures in the area, including changes in the angle of the subducting Nazca plate and fractures in the oceanic crust. Among features observed in both the Nazca and South American plates are the Atacama and Domeyko fault systems. We also infer fluid circulation caused by the subducting Taltal ridge and partial melting that feeds a volcanic complex near the Andes. Low values of the Vp/Vs ratio are associated with copper mining operations in the area and could be used to identify new ore deposits. Key Points: Seismic catalog reveals forearc activity and slab dip variations. Vp anomalies in the oceanic plate are related to mid‐depth seismic eventsVelocity models uncover anomalies in Salar de Atacama and Taltal ridge that might influence seismicity distribution and hydration changesShallow low Vp/Vs (<1.75) correlate with ore deposits; deep high Vp/Vs (>1.80) suggest fluids and melting for the Lastarria volcanic complex [ABSTRACT FROM AUTHOR]

This study provides a comprehensive characterization of various hydrothermal systems in Southern Peru ranging from the faulted Precordillera's steep topography up to the volcanic High Cordillera (>4,000 m asl). The objective is to investigate thermal anomalies that may potentially serve as new geothermal resources. Our integrated approach combines: (a) geochemistry from 14 hot springs sampled throughout the Tacna region, and (b) 3D numerical modeling of coupled groundwater and heat transfer considering topography and faults embedded in homogeneous permeability. Water and gas analysis indicates that the springs located near volcanoes discharge Na‐K‐Cl waters with high temperatures (>87°C), high Total Dissolved Solid concentrations (TDS >3,452 mg/L), and free gases dominated by CO2 (>90 vol%). Springs located along the regional faults in the Precordillera discharge Ca‐SO4 and Na‐K‐Cl waters with moderate temperatures (27–53°C), intermediate TDS concentrations (464–2,458 mg/L), radiocarbon ages between 1.4 and 7.9 kyr, and free gases dominated by N2 (>95 vol%). The Aruma springs, which are located at the transition between the High and the Precordillera, display intermediate characteristics. Numerical models accurately replicate the locations and temperatures of the fault‐related springs only for permeable faults (>10−14 m2), revealing the creation of 100‐km long thermal plumes along faults, locally rising up the 150°C‐isotherm to about ∼1,000 m below the surface. This approach clearly distinguishes the spring origins, which are volcanic in High Cordillera and tectonic in Precordillera. Moreover, we highlight that steep topographic gradient and permeable reverse faults in the Andean forearc may generate considerable thermal anomalies, opening perspectives for the geothermal exploration. Plain Language Summary: Geothermal energy is an essential part of the transition to green energies. It consists of using the Earth' natural heat to generate electricity or provide direct heating. In the Peruvian Andes there is significant geothermal potential near volcanoes that constitute an efficient heat source. However, these are distant from many of the population hubs, mostly located along the Pacific Coast. In the Tacna region, Southern Peru, we observe hot springs aligned along faults near the city. We hypothesize that these faults act as pipes for the hot fluids making them suitable for geothermal energy extraction. The geochemical compositions of various hot springs in the region are compared with 3D numerical models simulating hydrothermal flows. We found that springs along volcanoes and those along faults have different geochemical signatures, evidencing different subsurface pathways. Numerical models accurately replicate the positions and temperatures of the observed and sampled hot springs and reveal significant thermal anomalies around compressional faults. Our findings open up promising perspectives for the geothermal exploration in the Andean forearc. Key Points: The geochemical properties of Southern Peru's hot springs are influenced by their spatial correlation with volcanic or tectonic featuresBy combining permeable faults and topography, 3D hydrothermal modeling replicates the temperatures and locations of observed springsDetection of regional topography‐driven thermal plumes along faults in the Andean forearc opens perspectives for geothermal exploration [ABSTRACT FROM AUTHOR]

The Complejo Volcánico Doña Juana – Cascabel National Natural Park is located between the departments of Cauca and Nariño in the southern Andean Region of Colombia. Due to the country's social challenges and the difficult access to the Doña Juana – Cascabel National Natural Park the biological knowledge concerning groups such as mammals, is based on studies prior to the park's declaration, reports from park rangers and residents. Between October 2017 and February 2018, eight trail cameras were set up in the Doña Juana – Cascabel National Natural Park and its buffer zone. We reviewed the information captured in these cameras and identified eight mammal species, three of which are new reports for the park. In total, 24 species were reported, including charismatic Andean species such as the spectacled bear (Tremarctos ornatus), and the Andean tapir (Tapirus pinchaque). The mammal diversity documented for the park is low (24 species) compared to other Andean areas. Further field work is necessary to complete the species inventories. Nevertheless, this research, to our knowledge is the first effort to study the medium and large mammals of the Doña Juana – Cascabel National Natural Park since its establishment in 2008. [ABSTRACT FROM AUTHOR]

The Andean swamp rat Neotomys ebriosus is a sigmodontine rodent restricted to the Central Andes of South America. A distribution map of the species in Peru have been previously drawn based on few of the localities where the species has been captured and collected. I update the distribution of the species in Peru based on new records from three different areas surveyed by the author, specimens at Museum collections in the United States and France from VertNet webpage, localities from the collection at the Natural History Museum of Universidad Nacional Mayor de San Marcos, and localities from the collection at the Natural History Museum of the Universidad Nacional San Agustín. The northern limit of the species distribution is increased based on new localities with collected individuals. Habitat used by N. ebriosus is mainly high Andean bogs; most individuals caught adjacent to the borders of Andean bogs and along streams near the bogs. Collected individuals leave unclear subspecies division and identity. [ABSTRACT FROM AUTHOR]

This article discusses the impact of anthropogenic greenhouse gases and aerosols on the 2022 Central Andes spring drought. Climate models suggest that human activity has a weak contribution to the drought, with compensating effects between greenhouse gases and aerosols. The Central Andes region is vulnerable to hydroclimatic extremes, and this study aims to assess the anthropogenic contribution to the drought and provide information for climate change mitigation and adaptation strategies. The study finds that the observed drought frequency has been increasing since 2010, with aerosol forcing having a marginal contribution to droughts in 2022, while greenhouse gas forcing has likely decreased the probability of droughts. Further research is needed to understand the combined impact of aerosol and greenhouse gas forcing under different sea surface conditions. The document is a list of references that cover various topics related to climate change, drought, and precipitation in South America, particularly in the Andean region. [Extracted from the article]

This study investigated lead (Pb) and cadmium (Cd) transfer in three dairy farming areas in the Mantaro river headwaters in the central Peruvian Andes and at varying distances from the mining complex at La Oroya. At each of these sites, the transfer of trace metals from the soil to raw milk was estimated, and a hazard assessment for lead and cadmium was carried out in scenarios of minimum, average, and maximum milk consumption in a Peruvian population aged 2–85. Pb and Cd were quantified by flame atomic absorption spectrometry. Significantly, the concentrations of lead and cadmium were found to exceed the maximum limits recommended by the World Health Organization, with a positive geospatial trend correlated with the distance from mining activity. Both Pb and Cd were found to be transferred through the soil–pasture–milk pathway, with the primary source of Cd being phosphate-based fertilizers used in pasture improvement. Pb was found to be the most significant contributor to the Hazard Index (HI) with those under 19 years of age and over 60 recording an HI of >1, with infants being the most vulnerable group due to their greater milk consumption in relation to their body weight. A marginal increase in contamination was observed in the dry season, indicating the need for studies to be expanded over several annual cycles. [ABSTRACT FROM AUTHOR]

Summary: Quinoa is an agriculturally important crop species originally domesticated in the Andes of central South America. One of its most important phenotypic traits is seed colour. Seed colour variation is determined by contrasting abundance of betalains, a class of strong antioxidant and free radicals scavenging colour pigments only found in plants of the order Caryophyllales. However, the genetic basis for these pigments in seeds remains to be identified. Here we demonstrate the application of machine learning (extreme gradient boosting) to identify genetic variants predictive of seed colour. We show that extreme gradient boosting outperforms the classical genome‐wide association approach. We provide re‐sequencing and phenotypic data for 156 South American quinoa accessions and identify candidate genes potentially controlling betalain content in quinoa seeds. Genes identified include novel cytochrome P450 genes and known members of the betalain synthesis pathway, as well as genes annotated as being involved in seed development. Our work showcases the power of modern machine learning methods to extract biologically meaningful information from large sequencing data sets. [ABSTRACT FROM AUTHOR]

The striped catfish Pseudoplatystoma magdaleniatum is a large-sized migratory species from the north Andes region, endemic to Magdalena basin and one of the major fishery resources. Despite the estimated reduction of over 80% of the fisheries production of this species throughout the basin in recent decades, its population in the lower Magdalena-Cauca basin showed healthy genetics after molecular analyses. However, the current conservation status of this species and several habitat disturbances demand the re-evaluation of its population genetics to infer evolutionary risks and assess potential changes. This work analyzed a total of 164 samples from the Cauca River collected downstream the Ituango Dam between 2019–2021 using species-specific microsatellite markers to compare the genetic diversity and structure in samples collected between 2010–2014 from the lower Magdalena-Cauca basin, previously analyzed. Our results showed a relatively stable panmictic population over time (4 to 10 years), with high genetic diversity and evidence of recent bottleneck. Promoting habitat connectivity to conserve gene flow, characterizing diversity and genetic structure over the entire basin, and integrating the results with future monitoring are important aspects for the management planning for P. magdaleniatum in the Magdalena-Cauca basin. [ABSTRACT FROM AUTHOR]

An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes where glacial–interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene. The Last Glacial Maximum (LGM) was reached ∼26000 yr BP (years before present). Significant deglaciation onsets between 21 000 and 17 000 yr BP were subject to an acceleration since the Little Ice Age (LIA), which was ∼400 yr BP. Fast uplift rates of up to 41±3 mm yr -1 are measured by global navigation satellite system (GNSS) around the Southern Patagonian Icefield and are currently ascribed to post-LIA lithospheric rebound, but the possible longer-term post-LGM rebound is poorly constrained. These uplift rates, in addition, are 1 order of magnitude higher than those measured on other glaciated orogens (e.g. the European Alps), which raises questions about the role of the asthenospheric window in affecting the vertical surface displacement rates. Here, we perform geodynamic thermo-mechanical numerical modelling to estimate the surface uplift rates induced by post-LIA and post-LGM deglaciation, accounting for temperature-dependent rheologies and different thermal regimes in the asthenosphere. Our modelled maximum post-glacial rebound matches the observed uplift rate budget only when both post-LIA and post-LGM deglaciation are accounted for and only if a standard continental asthenospheric mantle potential temperature is increased by 150–200 °C. The asthenospheric window thus plays a key role in controlling the magnitude of presently observed uplift rates in the southern Patagonian Andes. [ABSTRACT FROM AUTHOR]

Ferns are known to have a lower incidence of mycorrhization than angiosperms. It has been suggested that this results from carbon being more limiting to fern growth than nutrient availability, but this assertion has not been tested yet. In the present study, we took advantage of a fertilization experiment with nitrogen and phosphorus on cloud forest plots of the Ecuadorean Andes for 15 years. A previous analysis revealed changes in the abundances of fern species in the fertilized plots compared to the control plots and hypothesized that this might be related to the responses of the mycorrhizal relationships to nutrient availability. We revisited the plots to assess the root‐associated fungal communities of two epiphytic and two terrestrial fern species that showed shifts in abundance. We sampled and analyzed the roots of 125 individuals following a metabarcoding approach. We recovered 1382 fungal ASVs, with a dominance of members of Tremellales (Basidiomycota) and Heliotales (Ascomycota). The fungal diversity was highly partitioned with little overlap between individuals. We found marked differences between terrestrial and epiphytic species, with the latter fundamentally missing arbuscular mycorrhizal fungi (AMF). We found no effect of fertilization on the diversity or relative abundance of the fungal assemblages. Still, we observed a direct impact of phosphorus fertilization on its concentration in the fern leaves. We conclude that fern–fungi relationships in the study site are not restricted by nutrient availability and suggest the existence of little specificity on the fungal partners relative to the host fern species. [ABSTRACT FROM AUTHOR]

Changes in land-use practices have been a central element of human adaptation to Holocene climate change. Many practices that result in the short-term stabilization of socio-natural systems, however, have longer-term, unanticipated consequences that present cascading challenges for human subsistence strategies and opportunities for subsequent adaptations. Investigating complex sequences of interaction between climate change and human land-use in the past—rather than short-term causes and effects—is therefore essential for understanding processes of adaptation and change, but this approach has been stymied by a lack of suitably-scaled paleoecological data. Through a high-resolution paleoecological analysis, we provide a 7000-year history of changing climate and land management around Lake Acopia in the Andes of southern Peru. We identify evidence of the onset of pastoralism, maize cultivation, and possibly cultivation of quinoa and potatoes to form a complex agrarian landscape by c. 4300 years ago. Cumulative interactive climate-cultivation effects resulting in erosion ended abruptly c. 2300 years ago. After this time, reduced sedimentation rates are attributed to the construction and use of agricultural terraces within the catchment of the lake. These results provide new insights into the role of humans in the manufacture of Andean landscapes and the incremental, adaptive processes through which land-use practices take shape. [ABSTRACT FROM AUTHOR]

Enhanced anthropogenic climatic variability challenges small farmers. In the Sumapaz páramo (Colombia), higher irregularity in precipitation and temperature reduces the quality of pasture and cattle health. Data from surveys, semi-structured interviews, and focus groups were analyzed to understand livestock farmers' responses to the impacts of climatic variability. To estimate the communities' resilience in the páramo, we used the capitals framework, the Baseline Resilience Indicator for Communities (BRIC), and cluster analysis. The responses of most households aim to reduce the impacts of climatic variability on the production system, chiefly intensifying practices such as the rotation of paddocks, livelihood diversification, purchase of grass, and buying and selling livestock. Interestingly, farmers did not recognize the value of the types of capital for responding to climatic variability. Results showed that the use of available physical, social, and economic capitals render the farming system resilient. Our probit model estimated that economic and human capitals are the largest and most significant contributors to communities' capacity to respond to climatic variability. However, pre-existing non-climatic vulnerabilities are also important. For example, poverty hinders farmers from using their income in response to climatic variability. The place-based measurements used in this research are easily understood and applicable by local policy makers to address increasing climate variability. [ABSTRACT FROM AUTHOR]

The extratropical west coast of South America has one of the largest frequencies of landfalling atmospheric rivers (ARs), with dozens of events per season that account for ~50% of the annual precipitation and can produce extreme rainfall events in south-central Chile. Most ARs form an acute angle with the Andes, but, in some cases, the moist stream impinges nearly perpendicular to the mountains, referred to as zonal atmospheric rivers (ZARs). Enhanced surface-based and upper-air measurements in Concepcion (36.8° S), as well as numerical simulations, were used to characterize a ZAR and a meridionally oriented AR in July 2022. They represent extremes of the broad distribution of winter storms in this region and exhibit key features that were found in a composite analysis based on larger samples of ZARs and tilted ARs. The latter is associated with an upper-level trough, broad-scale ascent, extratropical cyclone, and cold front reaching southern Chile. Instead, ZARs are associated with tropospheric-deep, strong zonal flow and a stationary front across the South Pacific, with ascent restricted upstream of the Andes. Consequently, ZARs have minimum precipitation offshore but a marked orographic precipitation enhancement and exhibit relatively warm temperatures, thus resulting in an augmented risk of hydrometeorological extreme events. [ABSTRACT FROM AUTHOR]

The South American central Andes have a great richness of Asteraceae, where the genus Stevia (Eupatorieae, Piqueriinae) is also especially diverse. The taxonomy of Stevia species in the southern part of the central Andes pose a challenge because of the unclear delimitation among the species and overlap of morphological characters. Two species complexes were identified for the region comprising north Argentina and southern Bolivia. In this study, our objectives were to employ morphometric analyses to assess the delimitation of taxa within the Stevia alpina Griseb. and Stevia chamaedrys Griseb. complexes. We aimed to identify informative morphological characters and gain insight into the identity of species in each group. To accomplish this, we utilised cluster analysis, principal-component analysis, non-metric multidimensional scaling and univariate analyses to evaluate 37 morphological traits. In total, 200 specimens were examined, covering the entire geographic distribution of each species complex. We found support for the recognition of nine species: Stevia alpina, S. breviaristata Hook. & Arn., S. chamaedrys, S. mandonii Sch. Bip., S. mercedensis Hieron., S. minor Griseb., S. potrerensis Hieron., S. procumbens Hieron. and S. vaga Griseb. A new combination and status is proposed for S. tarijensis Hieron., incorporating it as a variety of S. mandonii, and S. centinelae Cabrera and S. crassicephala Cabrera are merged as synonyms under the name S. alpina. Two neotypes are designated for the names S. mercedensis and S. potrerensis. [ABSTRACT FROM AUTHOR]

Orthotrichum camanchacanum is presented as a newly described species from Chile. The species is primarily distinguished by its emergent capsule with cryptoporous stomata, a double peristome, linear-lanceolate stem leaves with a long hyaline aristae in apex, conspicuously differentiated perichaetial leaves, and a densely hairy vaginula. The species was discovered in the mountain massif of the Andes in the Coquimbo region, notable for its unique climatic conditions. Molecular data and a brief discussion comparing the newly described species with the most closely related taxa are also provided. [ABSTRACT FROM AUTHOR]