Browsing by Author "Nunez-Hidalgo, Ignacio"

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    Andean peatlands at risk? Spatiotemporal patterns of extreme NDVI anomalies, water extraction and drought severity in a large-scale mining area of Atacama, northern Chile
    (2023) Chavez, Roberto O.; Meseguer-Ruiz, Oliver; Olea, Matias; Calderon-Seguel, Matias; Yager, Karina; Isela Meneses, Rosa; Lastra, Jose A.; Nunez-Hidalgo, Ignacio; Sarricolea, Pablo; Serrano-Notivoli, Roberto; Prieto, Manuel
    In the Andes, multiple human and climatic factors threaten the conservation of bofedales, a type of high altitude peat forming wetland widely distributed in the tropical and subtropical Andes. In northern Chile, climate change and water extraction for industrial activities are among the most significant threats to these relevant socio-hydrological systems hosting indigenous pastoral communities. In this study, we present an integrated anal-ysis of Normalized Difference Vegetation Index (NDVI) anomalies, drought severity and water rights granted to industry to provide insight on the conservation status of bofedales, historical drivers of their transformation, and current threats. Using Landsat satellite imagery from 1986 to 2018, we identify spatio-temporal NDVI changes of 442 bofedales in one of the leading copper producing regions of the world. The NDVI time series analysis over 32 growing seasons was used to detect extreme anomalies, i.e. values outside the 95 % of the reference frequency distribution, indicating periods of extreme changes in the productivity of these high Andes wetlands. To evaluate the relationship between bofedales NDVI extreme periods to drought and continued water extraction activities, we combine a climate-based multi-temporal-scale drought index (SPEI) with the geospatial latitudinal distri-bution of water rights granted for extractive industries in the study area. Over the time period of analysis, the total amount of granted water rights increased 465 % from 1,201 l/s recorded before 1985 to 5,584 l/s in 2018. In the areas where the highest amount of water rights are concentrated, i.e. between 21.3 degrees S and 22.1 degrees S, "green" bofedales (NDVI>=0.23) are practically absent. NDVI of the austral summer (JFM) was highly correlated with the severity of drought occurring during the three months of the growing season peak. While our findings show bofedal productivity is mostly influenced by precipitation and temperature of the wet season (JFM) during the study period, results also raise questions regarding possible bofedal loss occurring over the previous 80 years prior to the satellite record, wherein water extraction activities have significantly increased according to official records.
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    From risk assessment to land planning. The case of a trace element-contaminated area in Chile
    (2024) Mondaca, Pedro; Berasaluce, Maite; Larraguibel-Gonzalez, Cristian; Salazar, Andres; Nunez-Hidalgo, Ignacio; Diaz-Siefer, Pablo
    While abundant scientific literature focuses on diagnosing contaminated areas, solutions with a scientific base are far from balanced. This is the case of the Quintero-Puchuncavi Bay, a widely known contaminated area in the central coast of Chile. Here, arsenic in soils surrounding the industrial complex has been reported as a threat to human health. However, land planning based on As contamination becomes a challenge since the whole area is identified as contaminated. Such a lack of land-planning constrains the occupation and remediation of contaminated soil leading to a brownfield-like landscape. To face this challenge, we proposed using a geospatial decision support system (S-DSS) to integrate the contamination assessment, health and ecosystem risks, and potential land uses. When characterizing soil arsenic concentration thresholds for different land uses in a S-DSS, we could categorize the land in suitable, caution, and unsuitable areas (based on human health risks). This way, we unravel areas with potential use in the current condition while also discerning caution and unsuitable categories, that can undergo extensive and intensive remediation techniques. Similarly, we took a conservational approach to estimate emerging risk from the industrial complex associated to explosions. Altogether, it highlights the potential of S-DSS to integrate different geographic information. We finally feature two APPs regarding current land-use suitability and a modeled one considering future arsenic emissions.
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    General dry trends according to the standardized precipitation evapotranspiration index in mainland Chile
    (2024) Meseguer-Ruiz, Oliver; Serrano-Notivoli, Roberto; Nunez-Hidalgo, Ignacio; Sarricolea, Pablo
    Droughts are one of the main challenges affecting humanity in a global change context. Due to its spatial configuration, Chile experiences droughts of different severities, from arid to humid climates, ranging from sea level to elevations above 6,000 m above sea level (a.s.l.), but it is still unknown how this phenomenon behaves in distribution, duration and intensity. The goal of this study is to identify how droughts have affected the different climate regions of the country between 1979 and 2019. The Standardized Precipitation Evapotranspiration Index (SPEI), calculated for March and September, at the end of the humid season in the north and center-south of the country, respectively, and calculated at 3-, 6-, 9-, 12- and 24-month, allowed to determine the trends of the drought severity in a 5 x 5 km grid between 1979 and 2019. We found that negative and significant trends, indicating dry conditions, appear mainly in the Andes above 2,000 m a.s.l., where the main water reservoirs are located, affecting all climate types, except Mediterranean ones between 33 degrees S and 38 degrees S. The SPEI indicates general trends towards drier conditions across various elevations and climate types, with more pronounced negative trends in the north and central regions and some positive trends in the south. These trends suggest a significant impact on water availability, and highlight the need for focused policy initiatives to combat drought effects and manage water resources effectively. These findings are of main interest to Chile, one of the world's leading producers of lithium and copper, with both industries requiring substantial amounts of water for extraction and processing, demanding high water availability in a drier territory.
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    Niche models as a tool to inform restoration and conservation strategies: the case of Jubaea chilensis (palm, Arecaceae) and its seed disperser Octodon degus (rodent, Octodontidae)
    (2023) Nunez-Hidalgo, Ignacio; Fleury, Marina; Bustamante, Ramiro O.
    IntroductionBiotic interactions are a crucial component of the plant regeneration process, which has been traditionally studied at more local scales, providing the tools for planning and decision-making. Studies showing the signature of species interactions at coarser spatial scales contrasting with animal-plant interactions at fine scales have been scarce. This study aimed at integrating an approach, over both biogeographic and local scales, by testing two endemic species of Mediterranean central Chile: the relict and southernmost threatened Chilean palm Jubaea chilensis (Chilean palm; Molina; Baillon) and the caviomorph scatter-hoarding rodent Octodon degus (Degu; Molina), on which this palm currently relies for seed dispersal. MethodsIntegrating Geographic Information Systems and Ecological Niche Modeling, the intensity of seed-rodent interactions from a territorial perspective was evaluated in the range of the palm, at a biogeographic scale, identifying areas with greater or lesser potential for seed-rodent interactions; and in local populations, incorporating a variety of environmental factors that might affect palm regeneration. ResultsThe present results show that the rodent (Octodon degus) may play a role in Chilean palm (Jubaea chilensis) seed dispersal and seed establishment, since; Chilean palm regeneration is higher in areas where both species co-occur. At a local scale, a prominent overlap between palm seedlings and degu burrows was also found, which, allied with other abiotic variables such as altitude and topographic humidity, are crucial for successful palm regeneration. DiscussionUnderstanding the full extent of animal-plant interactions and how they are affected by habitat perturbation in a wide range will provide essential information for the design of effective conservation and management strategies, such as rewilding based on plant species.
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    Population dynamics shifts by climate change: High-resolution future mid-century trends for South America
    (2023) Nunez-Hidalgo, Ignacio; Meseguer-Ruiz, Oliver; Serrano-Notivoli, Roberto; Sarricolea, Pablo
    Population dynamics and climate change are the main challenges for the 21st century, especially in South America. Human populations will increase their exposure to novel climatic conditions in their territories, entangling and complicating health and social problems. We analyze how socioeconomic and climatic future pathways will evolve in South America, a land with high climatic and social heterogeneity. We use the Koppen-Geiger climate classification, population growth, and climate projections for the most likely climate change scenarios for the 2050s based on the CHELSA dataset. We found that tropical and arid climates extend between 4.2%-2.5% and 2.6%-3.9%, replacing temperate climate zones, which will be reduced between 5.3%-4.5% for the Representative Concentration Pathways (RCP) 4.5 and 8.5 respectively. This implies a reduction of the Mediterranean, oceanic and polar climates. Population growth shows a significant relationship to increasing tropical and arid climates extension in almost all countries, meaning a higher exposure to more severe conditions for humans. This work opens up the chance of using possible guidelines to assist environmental management with key background information on expected climate types and population changes and address the potential effects of climate change on human settlements in the near future.