Search Results (43)

The occurrence of toxic metal(loid)s in surface freshwater is a global concern due to its impacts on human and ecosystem health. Conceptual and quantitative metal(loid) models are needed to assess the impact of metal(loid)s in watersheds affected by acid rock drainage. Few case studies have focused on arid and semiarid headwaters, with scarce hydrological and hydrochemical information. This work reports the use of WASP8 (US EPA) to model Al, Fe, As, Cu, and SO₄²⁻ concentrations in the Upper Elqui River watershed in north–central Chile. Calibrated model performance for total concentrations was “good” (25.9, RRMSE; 0.7, R²-d) to “very good” (0.8–0.9, R²-d). The dissolved concentrations ranged between “acceptable” (56.3, RRMSE), “good” (28.6, RRMSE; 0.7 d), and “very good” (0.9, R²-d). While the model validation achieved mainly “very good” (0.8–0.9, R²-d) predictions for total concentrations, the predicted dissolved concentrations were less accurate for all indicators. Sensitivity analysis showed that the partition coefficient is a sensitive constant for estimating dissolved concentrations, and that integrating sorption and sediment interaction reduces the model error. This work highlights the need for detailed and site-specific information on the reactive and hydrodynamic properties of suspended solids, which directly impact the partition coefficient, sedimentation, and resuspension velocity calibration. Full article

In the north and center of Chile, there has been a significant environmental contamination by copper due to natural factors, mining activities and use of agricultural fertilizers and pesticides. Copper (Cu) soil contamination is of important concern in agriculture, food safety, and human health. Soil copper concentrations higher than 100–150 mg/kg can be toxic for plants and other organisms. Therefore, identification of copper-tolerant crops is of great interest for sustainable cultivation purposes. Quinoa is a promising candidate as a copper-tolerant crop, owing to its wide genetic diversity, high adaptability to different environmental conditions, and tolerance to abiotic stresses. In this work, we evaluated the effect of copper on 21 accessions of quinoa (including 19 accessions from different geographical locations of Chile) in order to identify tolerant and sensitive accessions. Our results show that (1) Germination parameters of quinoa are negatively affected in the presence of increasing Cu concentrations, with differential inhibition values among accessions. (2) Early seedling growth of accessions was differentially affected in the presence of Cu. (3) Plant biomass production (relative fresh and dry weights) was also affected by Cu, with significant differences between accessions. A Principal Component Analysis (PCA) of these data identified accessions based on Cu tolerance. (4) A clear regional pattern was observed when comparing accessions from northern, central, and southern Chile, suggesting local adaptation to Cu-rich soils. Thus, significant differences in copper tolerance between accessions were observed, revealing genetic diversity in copper tolerance among quinoa accessions. Tolerant accessions of quinoa can have important applications in sustainable agriculture. Full article

The purpose of this study was to assess the methodology for selecting sports talent in the Chilean Promising Athletes Program (CPAP). Methods: The standing broad jump (SBJ), medicine ball chest throw (MBCT), thirty-meter running sprint (RS-30), Agility-T (T-test), and height were analyzed in 3060 schoolchildren from Chile, grouped by sex, age, geographical area (north, central and south) and maturity status at peak height velocity (PHV) in pre-, circa- and post-PHV. Results: Superior differences were found in boys for all age ranges in SBJ, RS-30, T-test, and MBCT (p < 0.05). Girls were taller than boys until the age of 12 years (p < 0.01) with a reversal of this trend after 13 years old (p < 0.001). In geographical grouping, higher scores in SBJ, RS-30, and T-test were found in the central zone for boys and girls (p < 0.05). In both sexes, higher scores for the northern zone in MBCT (p < 0.01) and height (p < 0.05) are observed. Among selected talents, when comparing post-PHV vs. pre-PHV the differences are superior in all tests for post-PHV in girls and for MBCT and height (p < 0.05) in boys. In circa-PHV vs. post-PHV in MBCT, T-test, and RS-30 only girls (p < 0.05) were superior in post-PHV. For pre-PHV vs. circa-PHV, RS-30, and height (p < 0.05), both sexes were superior in circa-PHV. There are differences between talents selected by physical tests and technical aspects (p < 0.05). Conclusions: The results show variations in physical and anthropometric tests in schoolchildren by age, sex, geography, and maturity status that should be considered for talent selection. Full article

In recent decades, global ecosystems have increasingly faced impacts from heightened precipitation variability. Specifically, water availability is an essential factor in wetland dynamics and has ecological importance in the high-Andean wetlands in both mountains and downstream ecosystems, particularly in semi-arid regions. This study focused on a chain of twelve high-Andean wetlands within the “Estero Derecho” nature sanctuary at the headwaters of the Elqui River in north-central Chile. The analysis of the spatiotemporal dynamics of precipitation and vegetation cover used the Landsat 5 and 8 Satellite imagery-derived normalized difference vegetation index (NDVI) and normalized difference moisture index (NDMI) time series during the austral summer (December–March). We employed time series, boxplots, and least-squares regression analyses to explore vegetation cover behavior in relation to precipitation, water quality, and vegetation indices. Precipitation had a marked influence on vegetation behavior, particularly during the Chilean “megadrought” phenomenon. For both the NDVI and NDMI indices and precipitation, negative trends in the time series were observed, along with a highly significant correlation with a one-year lag between both indices and precipitation. The analysis of the individual wetlands showed different vegetation cover behaviors, which were attributable to the altitude, terrain slope, and additional water inputs from streams that have also given rise to alluvial fans that exert a shaping influence on the wetlands. In addition, significant correlations between both indices and water quality parameters (CE, Cl, Mg, Na, and Fe) were identified. The findings of this study can be incorporated into the Sanctuary’s management plan and concretely assist communities involved with wetland conservation. Full article

Water is a fundamental resource for Chile’s productive structure, which is more important in arid areas, and especially with agricultural uses. This study was based on two basins (Cogotí and Illapel) located in the Coquimbo Region of north-central Chile. In this region, surface water rights were closed in 2002 and the only current option is the use of groundwater. These basins have high water demands due to the use of surface and groundwater for agricultural purposes, a fact that should influence the sustainability of groundwater reserves over time. The objective of this study was to determine how much agricultural use has affected the availability of groundwater in two basins. Under the previous context, the evolution of agricultural irrigation surfaces was evaluated using Landsat images and forest classifications. Similarly, groundwater reserves were evaluated using the recessive curves of hydrographs associated with the beginning of each hydrological year. The results show an increase in the agricultural area between 1996 and 2016, with a subsequent decrease, while groundwater reserves denoted significant decreases over time. In conclusion, a significant decrease in the volumes of groundwater reserves in both basins was observed, a decrease that is consistent with the increase in irrigated areas. Full article

The genus Elasmoderus belongs to the family Tristiridae, an orthopteran group that is distributed across the transitional region of South America and represented in the Andean areas of Peru, Argentina, and Chile. The species of Elasmoderus have morphological adaptations that make them especially suited for surviving in extreme arid environments and are an endemic and eremic group of the north-central region of Chile. On the basis of field samplings, direct observations, and a comprehensive literature review, we collected information about the genus Elasmoderus. The objectives of this research were: (i) to provide updated information on the geographical distribution range of the species of the genus Elasmoderus, and (ii) to collect and synthesize the most relevant information on the natural history and ecology of this orthopteran group as a basis for future long-term studies of its populations. Although this genus is underrepresented compared to other orthopteran families, it has developed interesting adaptations to extreme arid environments that remain unstudied to this date. E. lutescens is known to be one of the species with a wider latitudinal distribution, mostly on the coast and longitudinal valley of Atacama. E. minutus has a more restricted distribution, whereas E. wagenknechti is concentrated in coastal and interior environments of the Coquimbo region, an area where it reaches high population densities, thus affecting crops and natural vegetation and polluting water sources. Our findings underscore the importance of conducting comprehensive research on native insect groups that are poorly known but crucial for arid and semiarid ecosystems. These data will serve as a starting point for conducting long-term studies on this orthopteran group to gain a better understanding of the importance and role of these species in the semiarid ecosystems of northern Chile. Full article

Mammals in drylands face environmental challenges exacerbated by climate change. Currently, human activity significantly impacts these environments, and its effects on the energy demands experienced by individuals have not yet been determined. Energy demand in organisms is managed through elevations in glucocorticoid levels, which also vary with developmental and health states. Here, we assessed how anthropization, individual characteristics, and seasonality influence hair glucocorticoid concentration in the Darwin’s leaf-eared mouse (Phyllotis darwini) inhabiting two areas with contrasting anthropogenic intervention in a semi-arid ecosystem of northern Chile. Hair samples were collected (n = 199) to quantify hair corticosterone concentration (HCC) using enzyme immunoassays; additionally, sex, body condition, and ectoparasite load were recorded. There were no differences in HCC between anthropized areas and areas protected from human disturbance; however, higher concentrations were recorded in females, and seasonal fluctuations were experienced by males. The results indicate that animals inhabiting semi-arid ecosystems are differentially stressed depending on their sex. Additionally, sex and season have a greater impact on corticosterone concentration than anthropogenic perturbation, possibly including temporal factors, precipitation, and primary production. The influence of sex and seasonality on HCC in P. darwini make it necessary to include these variables in future stress assessments of this species. Full article

The Humboldt Archipelago, situated on Chile’s north-central coast, is renowned for its exceptional biodiversity. However, lizards of the Liolaemus genus are a particularly understudied group in this archipelago. Liolaemus genus is divided into two clades: chiliensis and nigromaculatus. Within the nigromaculatus clade the zapallarensis group is restricted to the semi-arid and arid coastal habitats of the Atacama Desert in north-central Chile. While it has been reported that lizards from the zapallarensis group inhabit various islands within the Humboldt Archipelago, there has been limited knowledge regarding their specific species identification. To identify the lizard species inhabiting these islands, we conducted phylogenetic analyses using a mitochondrial gene and examined morphological characteristics. Our findings reveal that lizards from the Damas, Choros, and Gaviota islands belong to Liolaemus silvai. In contrast, the lizards on Chañaral Island form a distinct and previously unrecognised group, clearly distinguishable from Liolaemus silvai. In conclusion, our study not only confirms the presence of L. silvai on the Damas, Choros, and Gaviota islands but also describes a new lizard species on Chañaral Island named Liolaemus carezzae sp. nov. These findings contribute valuable insights into the biodiversity of these islands and introduce a newly discovered endemic taxon to the region, enriching our understanding of Chile’s unique island ecosystems. Full article

The influenza A virus (IAV) poses a significant global threat to public health and food security. Particularly concerning is the avian influenza virus (AIV) subtype H5N1, which has spread from Europe to North and Central/South America. This review presents recent developments in IAV evolution in birds, mammals, and humans in Chile. Chile’s encounter with IAV began in 2002, with the highly pathogenic avian influenza (HPAI) H7N3 virus, derived from a unique South American low pathogenic avian influenza (LPAI) virus. In 2016–2017, LPAI H7N6 caused outbreaks in turkey, linked to wild birds in Chile and Bolivia. The pandemic influenza A (H1N1) 2009 (H1N1pdm09) virus in 2009 decreased egg production in turkeys. Since 2012, diverse IAV subtypes have emerged in backyard poultry and pigs. Reassortant AIVs, incorporating genes from both North and South American isolates, have been found in wild birds since 2007. Notably, from December 2022, HPAI H5N1 was detected in wild birds, sea lions, and a human, along Chile’s north coast. It was introduced through Atlantic migratory flyways from North America. These findings emphasize the need for enhanced biosecurity on poultry farms and ongoing genomic surveillance to understand and manage AIVs in both wild and domestic bird populations in Chile. Full article

In recent years, a new discipline known as Explainable Artificial Intelligence (XAI) has emerged, which has followed the growing trend experienced by Artificial Intelligence over the last decades. There are, however, important gaps in the adoption of XAI in hydrology research, in terms of application studies in the southern hemisphere, or in studies associated with snowmelt-driven streamflow prediction in arid regions, to mention a few. This paper seeks to contribute to filling these knowledge gaps through the application of XAI techniques in snowmelt-driven streamflow prediction in a basin located in the arid region of north-central Chile in South America. For this, two prediction models were built using the Random Forest algorithm, for one and four months in advance. The models show good prediction performance in the training set for one (RMSE:1.33, R²: 0.94, MAE:0.55) and four (RMSE: 5.67, R²:0.94, MAE: 1.51) months in advance. The selected interpretation techniques (importance of the variable, partial dependence plot, accumulated local effects plot, Shapley values and local interpretable model-agnostic explanations) show that hydrometeorological variables in the vicinity of the basin are more important than climate variables and this occurs both for the dataset level and for the months with the lowest streamflow records. The importance of the XAI approach adopted in this study is discussed in terms of its contribution to the understanding of hydrological processes, as well as its role in high-stakes decision-making. Full article

This study utilized the Random Forest (RF) algorithm to assess groundwater potential (GWP) in the mid-mountain region of the Coquimbo region, north-central Chile. A comprehensive evaluation of twenty-one factors, primarily derived from Digital Elevation Models (DEM) and satellite data, was conducted against a database of 3822 groundwater discharge points. The majority of them consisted of shallow wells with relatively low yields. The main objective was to develop a groundwater potential (GWP) map for the study area. Among the factors considered, six variables, including two anthropogenic factors (distance to roads and presence of agricultural communities) and four natural factors (slope, elevation, concavity, and ruggedness index), were identified as the most influential indicators of GWP. The RF approach demonstrated excellent performance, achieving an Area Under the Curve (AUC) value of 0.95, sensitivity of 0.88, specificity of 0.86, and kappa coefficient of 0.74 in the test set. The majority of the study area exhibited low GWP, while only 14% of the area demonstrated high or very high GWP. In addition to providing valuable guidance for future hydrogeological investigations in the region, the GWP map serves as a valuable tool for identifying the areas that are most vulnerable to water shortages. This is particularly significant, as the region has been severely affected by extended drought, making water supply a critical concern. Full article

The tribe Astereae (Asteraceae) displays an American Amphitropical Disjunction. To understand the eco-evolutionary dynamics associated with a long-distance dispersal event and subsequent colonization of extratropical South America, we compared the climatic and geographic distributions of South American species with their closest North American relatives, focusing on the diverse South American Astereae genus, Haplopappus. Phylogenetic analysis revealed that two South American genera are closely related to seven North American genera. The climatic niche overlap (D = 0.5) between South and North America exhibits high stability (0.89), low expansion (0.12), and very low unfilling (0.04). The distribution of the North American species predicted the climatic and geographic space occupied by the South American species. In central Chile, Haplopappus showed a non-random latitudinal gradient in species richness, with Mediterranean climate variables mainly explaining the variation. Altitudinal patterns indicated peak richness at 600 m, declining at lower and higher elevations. These findings support climatic niche conservatism in shaping Haplopappus species distribution and diversity. Two major endemism zones were identified in central Chile and the southern region, with a transitional zone between Mediterranean and Temperate macro-bioclimates. Our results indicate strong niche conservatism following long-distance dispersal and slight niche expansion due to unique climatic variables in each hemisphere. Full article

Natural hydrogen is known to be generated in the crust by water/rock interactions, especially the oxidation of iron-rich rock or radiolysis. However, other sources, especially deeper ones, exist. In the context of subduction, the dehydration of the slab, the destabilization of the NH₄, and the hydration of the mantle wedge above the subducting lithosphere may generate H₂. We present here a compilation of the known gases in the central part of the Pacific subduction and the results of a first field acquisition dedicated to H₂ measurements in Bolivia between La Paz and South Lipez. Various zones have been studied: the emerging thrust faults of the western borders of the Eastern Cordillera, the Sajama area that corresponds to the western volcanic zone near the Chile border northward from the Uyuni Salar, and finally, the Altiplano-Puna Volcanic Complex in South Lipez. Soil gas measurement within and around the Salar itself was not fully conclusive. North of the Uyuni Salar, the gases are very rich in CO₂, enriched in N₂ and poor in H₂. On the opposite, southward, all the samples contain some H₂; the major gas is nitrogen, which may overpass 90% after air correction, and the CO₂ content is very limited. On the western border of the Cordillera, the δC13 isotope varies between −5 and −13‰_, and it is not surprisingly compatible with volcanic gas, as well as with asthenospheric CO₂. The methane content is close to 0, and only a few points reach 1%. The isotopes (−1‰) indicate an abiotic origin, and it is thus related to deep H₂ presence. The high steam flow in the geothermal area of South Lipez combined with the H₂ content in the water results in at least 1 ton of H₂ currently released per day from each well and may deserve an evaluation of its economic value. The nitrogen content, as in other subduction or paleo-subduction areas, questions the slab alteration. Full article

The European rabbit (Oryctolagus cuniculus) is one of the main invasive species in Chile, where it became naturalized ca. 150 years ago. Their high reproductive capacity, lack of specialist predators, and great adaptability favored the settlement of rabbits in diverse mainland and island ecosystems of the country. Recently, rabbits have become central players in semi-arid ecosystems, such as those represented in Las Chinchillas National Reserve in north-central Chile. We undertook to analyze the place and role of rabbits in the food web of that Reserve, based on a bibliographic review and long-term annual data gathered from 1987 until 2022 (36 years). Results showed that the network comprised 77 species, where 69% were primary producers (plants), 18% were mid-level consumers (herbivores), and 13% were top-level consumers (predators). The most connected species in the food web was the rabbit, which positively or negatively affected the species interacting with it. Predators such as Galictis cuja, Geranoaetus polyosoma, Leopardus colocolo, and Puma concolor, and the scavenger Vultur gryphus, could be negatively affected by an eventual decrease (natural or human-caused) in the rabbit population of the Reserve. To the contrary, primary producers such as Oxalis perdicaria, Plantago hispidula, Schizanthus parvulus, Senna cumminggi, and Tropaeolum azureum could be positively affected by an increase in their biomass in response to a decrease in rabbits, favoring native rodents. We consider that analyzing the rabbit-centered food web and its impacts on native interacting species allows a better understanding of the relevance of invasive species in the local community, providing conceptual tools for rabbit management. Full article

Agricultural activity is a key strategic sector for countries, particularly for food production. One way to strengthen the sector is through the use of technology. However, while integrating new technologies, challenges have emerged in the sector with regard to incorporating workers. Thus, one way to resolve this workforce shortfall could be through labour commutation, which consists of people living in one territory but working in another. Therefore, this study aims to analyse the likelihood of agricultural workers becoming worker commuters. Chile is used as a case study, drawing on the Chilean National Employment Survey of 2018 to analyse differences among the five largest regions in the country: Great North, Small North, Central Zone, South, and Chilean Patagonia. Each zone possesses different characteristics, and a propensity score matching process was carried out within the data. The results indicate that agricultural workers with a higher education level, full-time jobs, working in the formal sector, and younger workers are more likely to commute. Different impacts of variables were found across the zones. However, most of the variables have similar impact on the likelihood to commute in different areas. Thus, from a labour perspective, public policies can create general incentives to attract a new workforce to strengthen the agricultural sector. Full article