Browsing by Tema "Arid"

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A First Rock Glacier Inventory for the Bolivian Andes
(Wiley, 2014) Sally Rangecroft; Stephan Harrison; Karen Anderson; John R. Magrath; Ana Paola Castel; Paula Pacheco
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 km 2 , 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.
A Multidisciplinary Approach for Clarifying the Recharge Processes and Origin of Saline Water in the Semi-Arid Punata Alluvial fan in Bolivia
(Multidisciplinary Digital Publishing Institute, 2018) Andres Gonzales Amaya; Gerhard Barmen; G. Abad Muñoz
The analysis of stable isotopes assisted in identifying that groundwater in the Punata alluvial fan is mainly recharged by heavy flash floods, and the recharge from rainfall is of less importance. In addition, the hydrochemical analysis identified the Pucara River as the main source of recharge. Other streams in the north and northwest of the fan do not seem to contribute to the recharge. The hydrochemistry also shows that there is an increase of the Na+ and Cl− concentrations in the middle and distal part of the fan. The salinization of groundwater is most likely a result of the mixing of fresh water with residual saline pore water in the lacustrine deposits and/or ion exchange within these layers. Geophysical surveys assisted in describing the aquifer system layering, and indicated a fine-grained bottom layer where ion exchange might occur. This study demonstrates that the integration of several methods (e.g., hydrochemistry, hydrogeophysics, and stable isotopes) is valuable for clarifying ambiguities during the interpretation process and for characterizing hydrogeological processes in alluvial fans in general.
Aplicación de la hidrología isotópica en la gestión de las aguas transfronterizas: Conclusión del proyecto piloto en la Cuenca Transfronteriza Tierra de los Lípez (Proyecto de cooperación técnica BOL-7005 del Estado Plurinacional de Bolivia). Depósito Legal 4-1-637-2022 P.O.
(European Organization for Nuclear Research, 2022) FLORES AVILES, Gabriela Patricia
This publication presents the scientific results of the pilot study conducted in the Tierra de los Lípez Transboundary Basin, developed under the Technical Cooperation Project BOL-7005 of the Plurinational State of Bolivia and the International Atomic Energy Agency (IAEA). The study applies advanced isotope hydrology techniques to characterize groundwater dynamics in one of South America’s most arid high-altitude basins shared by Bolivia, Chile, and Argentina. The research integrates stable isotopes (δ¹⁸O, δ²H, δ¹³C), radioactive isotopes (³H, ¹⁴C, ²²²Rn), hydrochemistry, hydrogeology, lithology, geophysics, topography, and GIS analyses to reconstruct the hydrodynamic functioning of the transboundary aquifer system, particularly the Laguna Colorada sub-basin. The results provide evidence on recharge mechanisms, evaporation processes, groundwater residence times, mixing patterns between shallow and deep flow systems, and discharge pathways toward the endorheic depressions of the region. The publication also establishes a conceptual hydrogeological model of the Tierra de los Lípez Transboundary Aquifer, contributing baseline scientific information essential for transboundary water governance, early cooperative frameworks, and hydrodiplomacy between neighboring countries. This document was conceptualized, led, and written by Gabriela Patricia Flores Avilés (PhD), as part of the national scientific program on isotope hydrology implemented by the Bolivian Nuclear Energy Agency (ABEN). It represents one of the first comprehensive applications of nuclear techniques to transboundary aquifer assessment in Bolivia.
Aplicación de la hidrología isotópica en la gestión de las aguas transfronterizas: Conclusión del proyecto piloto en la Cuenca Transfronteriza Tierra de los Lípez (Proyecto de cooperación técnica BOL-7005 del Estado Plurinacional de Bolivia). Depósito Legal 4-1-637-2022 P.O.
(2022) Gabriela Patricia Flores Avilés
This publication presents the scientific results of the pilot study conducted in the Tierra de los Lípez Transboundary Basin, developed under the Technical Cooperation Project BOL-7005 of the Plurinational State of Bolivia and the International Atomic Energy Agency (IAEA). The study applies advanced isotope hydrology techniques to characterize groundwater dynamics in one of South America’s most arid high-altitude basins shared by Bolivia, Chile, and Argentina. The research integrates stable isotopes (δ¹⁸O, δ²H, δ¹³C), radioactive isotopes (³H, ¹⁴C, ²²²Rn), hydrochemistry, hydrogeology, lithology, geophysics, topography, and GIS analyses to reconstruct the hydrodynamic functioning of the transboundary aquifer system, particularly the Laguna Colorada sub-basin. The results provide evidence on recharge mechanisms, evaporation processes, groundwater residence times, mixing patterns between shallow and deep flow systems, and discharge pathways toward the endorheic depressions of the region. The publication also establishes a conceptual hydrogeological model of the Tierra de los Lípez Transboundary Aquifer, contributing baseline scientific information essential for transboundary water governance, early cooperative frameworks, and hydrodiplomacy between neighboring countries. This document was conceptualized, led, and written by Gabriela Patricia Flores Avilés (PhD), as part of the national scientific program on isotope hydrology implemented by the Bolivian Nuclear Energy Agency (ABEN). It represents one of the first comprehensive applications of nuclear techniques to transboundary aquifer assessment in Bolivia.
AREAS OF ENDEMISM IN THE SOUTHERN CENTRAL ANDES
(Museo Botánico Córdoba, 2012) Lone Aagesen; María Julia Bena; Soledad Nomdedeu; Adela M. Panizza; Ramiro Pablo López; Fernando O. Zuloaga
This paper analyzes the distribution of vascular plants species endemic to the southern central Andes (south-western Bolivia and north-western Argentina). All 540 species endemic to the study regions (approx. 720600 km2) have been included in the analysis. The main part of the endemic species is found in semiarid habitats between 1500-3500 m asl pointing to the topographically complex plateau, slope, and valley system of the southern central Andes as the main locations for its endemic flora. The distribution of the endemic species within arid sites is in contrast with that of vascular plant diversity in general, as the most diverse habitat of the region is the moist subtropical Tucumano-Bolivian Yungas forest of the eastern Andes slope. A total of 17 well defined and partly overlapping distribution patterns were indentified. The broadest distribution pattern defines a general area of endemism for the southern central Andes. This area extends through nearly the entire region and is defined by species that are widespread within the region in desert to sub-humid environments of the high Andes, slopes, or valleys. Nearly all other areas of endemism are nested within this broad distribution pattern as successively north-south overlapping areas along the slopes and valleys of the Andes and the Pampeanas Range. Despite the distributional bias of endemism towards the arid sites almost half of the endemic species are restricted to a few high endemic areas that lie in juxtaposition to the main rainfall zones. These areas contain the widest habitat ranges in terms of altitude and rainfall within the region with the endemic species being equally variable in altitude and moisture requirements. Previous defined phytogeographic units were not recognized among the distribution patterns. However, the northern part of the Prepuna can be defined as two partly overlapping distribution patterns.
Assessment of charcoal driven deforestation rates in a fragile rangeland environment in North Eastern Somalia using very high resolution imagery
(Elsevier BV, 2011) S.M. Oduori; Felix Rembold; O.H. Abdulle; Ricardo Vargas
Bird diversity of the Cúcuta valley (Colombia) and biogeographical affinities with dry forest avifaunas of northern South America
(Wilson Ornithological Society, 2018) Jorge Enrique Avendaño; JuanPablo López-O.; Oscar Laverde-R.
Seasonally dry tropical forest is the least known and most threatened ecosystem in the Neotropics. In December 2009, we surveyed 3 tropical dry forest remnants in the arid Cúcuta valley, northeast Colombia. We recorded 140 of the 171 maximum species expected for the study area. Another 20 species were observed outside the inventory, totaling 160 species for the whole region. Results of the similarity analysis showed that the Cúcuta valley avifauna is biogeographically more related to the arid inter-Andean river valleys than to the Caribbean plains of Colombia and the Caribbean lowlands of northern Venezuela. This pattern of biogeographical affinities of dry forest bird communities in northwestern South America seems to be explained by the effect of geographic distance rather than environmental differences shaping species composition (β-diversity) and phylogenetic relatedness (phyloβ-diversity) across space. Our results highlight the uniqueness and need to protect the topical dry forest remnants of the Cúcuta valley.
Climatic influences on interannual variability in regional burn severity across western US forests
(CSIRO Publishing, 2017) John T. Abatzoglou; Crystal A. Kolden; Park Williams; James A. Lutz; Alistair M. S. Smith
Interannual variability in burn severity is assessed across forested ecoregions of the western United States to understand how it is influenced by variations in area burned and climate during 1984–2014. Strong correlations (|r| &gt; 0.6) between annual area burned and climate metrics were found across many of the studied regions. The burn severity of individual fires and fire seasons was weakly, but significantly (P &lt; 0.05), correlated with burned area across many regions. Interannual variability in fuel dryness evaluated with fuel aridity metrics demonstrated weak-to-moderate (|r| &gt;0.4) relationships with regional burn severity, congruent with but weaker than those between climate and area burned for most ecoregions. These results collectively suggest that irrespective of other factors, long-term increases in fuel aridity will lead to increased burn severity in western United States forests for existing vegetation regimes.
Co-occurrence Patterns along a Regional Aridity Gradient of the Subtropical Andes Do Not Support Stress Gradient Hypotheses
(Public Library of Science, 2013) Ramiro Pablo López; Sergio Valdivia; Mónica L. Rivera; Rodrigo S. Ríos
The stress gradient hypothesis posits that facilitation and stress are positively correlated. The hump-shaped hypothesis, on the contrary, proposes that facilitation is greater at intermediate stress levels. The relationship between facilitation and environmental stress is commonly studied at small spatial scales and/or considering few species; thus, the implications of facilitation at a community level remain poorly understood. Here, we analyzed local co-occurrence patterns of all plant species at 25 sites within the subtropical Andes to evaluate the role of facilitation and competition as drivers of community structure. We considered a wide latitudinal gradient (19-26°S) that incorporates great variation in aridity. No previous studies have attempted to study these patterns across such a broad scale in warm deserts. Each locality was sampled at two scales (quadrat and patch), and co-occurrence was analyzed via null models. Furthermore, we tested for a relationship between plant co-occurrences and environmental aridity. Resulting patterns depended on life form. When all species were considered, negative associations were found, indicating competition. Woody/cactus life forms tended to be associated across communities, suggesting that there is facilitation between these life forms. Additionally, and unlike previous studies, we found positive associations among shrubs. The strength of the association between woody species changed non-monotonically with aridity. Herbs showed an inverted hump-shaped relationship, albeit ranging mostly among neutral values. Independent of the association type exhibited by different life forms, our community level results do not support current stress gradient hypotheses.
Comparative Assessments of the Latest GPM Mission’s Spatially Enhanced Satellite Rainfall Products over the Main Bolivian Watersheds
(Multidisciplinary Digital Publishing Institute, 2017) Frédéric Satgé; Alvaro Xavier; Ramiro Pillco Zolá; Yawar Hussain; F. Timouk; Jérémie Garnier; Marie‐Paule Bonnet
The new IMERG and GSMaP-v6 satellite rainfall estimation (SRE) products from the Global Precipitation Monitoring (GPM) mission have been available since January 2015. With a finer grid box of 0.1°, these products should provide more detailed information than their latest widely-adapted (relatively coarser spatial scale, 0.25°) counterpart. Integrated Multi-satellitE Retrievals for GPM (IMERG) and Global Satellite Mapping of Precipitation version 6 (GSMaP-v6) assessment is done by comparing their rainfall estimations with 247 rainfall gauges from 2014 to 2016 in Bolivia. The comparisons were done on annual, monthly and daily temporal scales over the three main national watersheds (Amazon, La Plata and TDPS), for both wet and dry seasons to assess the seasonal variability and according to different slope classes to assess the topographic influence on SREs. To observe the potential enhancement in rainfall estimates brought by these two recently released products, the widely-used TRMM Multi-satellite Precipitation Analysis (TMPA) product is also considered in the analysis. The performances of all the products increase during the wet season. Slightly less accurate than TMPA, IMERG can almost achieve its main objective, which is to ensure TMPA rainfall measurements, while enhancing the discretization of rainy and non-rainy days. It also provides the most accurate estimates among all products over the Altiplano arid region. GSMaP-v6 is the least accurate product over the region and tends to underestimate rainfall over the Amazon and La Plata regions. Over the Amazon and La Plata region, SRE potentiality is related to topographic features with the highest bias observed over high slope regions. Over the TDPS watershed, the high rainfall spatial variability with marked wet and arid regions is the main factor influencing SREs.
Compared cytogenetic of Drosophila starmeri (Díptera: Drosophüidae) of two Colombian isolated arid ecosystems
(2003) Carlos Fernando Prada G; Ma. Magdalena Echeverry de Polanco; Marina Ordóñez
Concentration of Traces Metals in Underground Dams in the Semi-Arid of the Rio Grande do Norte State, Brazil: Case Study of the Sub-Basin of the Cobras River
(Springer Science+Business Media, 2020) Alexandre de Oliveira Lima; Nildo da Silva Dias; Cleyton dos Santos Fernandes; Francisco Pinheiro Lima‐Filho; René Chipana Rivera; Yago Leopoldo Eleuterio Gurgel de Sousa; Líssia Letícia de Paiva Oliveira; José Dárcio Abrantes Sarmento; Hozano de Souza Lemos Neto
Cross‐cultural variation in thirst perception in hot‐humid and hot‐arid environments: Evidence from two small‐scale populations
(Wiley, 2021) Asher Y. Rosinger; Hilary J. Bethancourt; Zane S. Swanson; Kaylee Lopez; W. Larry Kenney; Tomás Huanca; Esther Conde; Rosemary Nzunza; Emmanuel Ndiema; David R. Braun
Our findings suggest hydration status is not a reliable predictor of thirst perceptions in extreme-hot environments with ad libitum drinking. Rather, our findings, which require additional confirmation, point to the importance of water availability during gestation in affecting thirst sensitivity to heat and water feedback mechanisms, particularly in arid environments. Thirst regulation will be increasingly important to understand given climate change driven exposures to extreme heat and water insecurity.
Diverse dinosaur tracks from the Upper Jurassic – Lower Cretaceous Chacarilla Formation of Quebrada de Arcas, northeast Chile: Evidence of high ichnodiversity in an arid palaeoenviroment
(Elsevier BV, 2025) Vincenzo Gesualdi; Matteo Belvedere; Marko Yurac; Dorothee Hippler; Nejla Hurem; Christian Salazar; Jose Nicanor Mendez; Christian A. Meyer
We report diverse dinosaur tracks from siltstone to fine-grained sandstone facies of the Chacarilla Formation, Quebrada de Arcas of northeast Chile. Track-bearing surfaces were studied using 3D modelling and false-colour depth maps, derived from UAV photographs. Five morphotypes are identified based on morphology and morphometric criteria. Morphotype I comprises rounded tracks with a consistent narrow-gauge and resembles the sauropod ichnogenus, Parabrontopodus ; diplodocids or titanosaurids are probable trackmakers. Morphotype II is assigned to the theropod ichnotaxon Abelichnus astigerrae and comprises some of the largest theropod tracks ever recorded from South America with a maximum footprint length of 51 cm; the trackmaker was most likely a large carcharodontosaurid, such as Giganotosaurus carolinii . Morphotype III is an indeterminate theropod track, which shows a distinctive and prominent metatarsal impression, but does not closely match any ichnotaxon although it bears some morphometrical affinity to Changpeipus carbonicus . The Morphotypes IV and V both belong to small-sized theropod trackmakers, and resemble Grallatoridae and Kayentapus -like forms, respectively. Additional theropod material cannot be assigned to specific morphotypes or trackmakers, due to poor preservation. Our findings show the existence of three distinct size classes (small, medium and large) of theropod morphotypes and point to a high ichnodiversity at the Jurassic-Cretaceous transition in the subtropical arid environments of Gondwana. • New track-bearing surfaces are found in the Chacarilla Fm. in Quebrada des Arca. • Five morphotypes: one of sauropod and four for different size theropod tracks are defined. • Huge theropod tracks have been found and identified.
Diversity-multifunctionality relationships shift with increasing aridity in grasslands
(2026) Weiling Niu
Data related to the study of biodiversity and ecosystem functions in dryland grasslands.
Diversity-multifunctionality relationships shift with increasing aridity in grasslands
(2026) Weiling Niu
Data related to the study of biodiversity and ecosystem functions in dryland grasslands.
Drying has limited effects on the composition of invertebrate communities across a river network of the arid Bolivian Andes
(European Organization for Nuclear Research, 2025) Nabor Moya; Mathis Messager; Beymar Fernandez Rodriquez; Florentino Saigua; Ariel Angel Cespedes Llave; N. Bonada; Thibault Datry
This dataset consists of an Excel file with two sheets. The first sheet contains environmental data and invertebrate abundance data, while the second sheet provides explanations for each column. Specifically, the environmental variables recorded in the first sheet are described in the second sheet. ‘N/A’ (not applicable) indicates missing information in environmental variables or metadata, which may vary depending on whether the data were not collected or were lost.
Drying has limited effects on the composition of invertebrate communities across a river network of the arid Bolivian Andes
(European Organization for Nuclear Research, 2025) Moya, Nabor; Messager, Mathis Loïc; Fernandez Rodriquez, Beymar; Saigua, Florentino; Cespedes Llave, Ariel Angel; Bonada, Núria; Datry, Thibault
This dataset consists of an Excel file with two sheets. The first sheet contains environmental data and invertebrate abundance data, while the second sheet provides explanations for each column. Specifically, the environmental variables recorded in the first sheet are described in the second sheet. ‘N/A’ (not applicable) indicates missing information in environmental variables or metadata, which may vary depending on whether the data were not collected or were lost.
Drying has limited effects on the composition of invertebrate communities across a river network of the arid Bolivian Andes
(European Organization for Nuclear Research, 2025) Moya, Nabor; Messager, Mathis Loïc; Fernandez Rodriquez, Beymar; Saigua, Florentino; Cespedes Llave, Ariel Angel; Bonada, Núria; Datry, Thibault
This dataset consists of an Excel file with two sheets. The first sheet contains environmental data and invertebrate abundance data, while the second sheet provides explanations for each column. Specifically, the environmental variables recorded in the first sheet are described in the second sheet. ‘N/A’ (not applicable) indicates missing information in environmental variables or metadata, which may vary depending on whether the data were not collected or were lost.
Effect of shade and precipitation on germination and seedling establishment of dominant plant species in an Andean arid region, the Bolivian Prepuna
(Public Library of Science, 2021) Natalio Roque Marca; Ramiro Pablo López; Kazuya Naoki
Germination and seedling establishment are two critical processes in the life cycle of plants. Seeds and seedlings must pass through a series of abiotic and biotic filters in order to recruit as members of their communities. These processes are part of the regeneration niche of the species. In arid regions, the regeneration niche is frequently associated to facilitation by shade. Facilitation is a positive interaction between plants, in which one of them acts as a benefactor (the nurse) of the other (the beneficiary). The result of this interaction can be reflected in the increased growth, survival, and/or reproduction of the beneficiary plant. In this study, we determined experimentally the effect of shade and irrigation on the germination and early survival of dominant species of a semi-arid Andean region, the Bolivian Prepuna. An experiment with Acacia feddeana, Prosopis ferox, Cercidium andicola (woody species), Parodia maassii, and Oreocereus celsianus (cactus species) was carried out at an experimental garden in La Paz, Bolivia, with a bifactorial design, considering shaded and unshaded pots, subjected to two irrigation treatments (≈50 and 80 mm of rainfall during the whole study period). Microenvironmental conditions did not affect the seed germination of the woody species. However, they showed differences in seedling survival: A. feddeana survived better under shade, whereas P. ferox and C. andicola survived better without shade. Cercidium andicola, compared to P. ferox, was more affected by shade and low irrigation. Although germination success of cacti was low, both species germinated better under shade and with high irrigation. These results showed differences in the regeneration niche of dominant species of the Prepuna which may favor their coexistence and which may be characteristic of other dry Andean regions.