Universidad de Magallanes
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Valoración de servicios ecosistémicos vinculados al recurso hídrico de los glaciares de las cuencas Olivares-Colorado, Andes de Chile Central
No full textAn assessment of the ecosystem services of water storage and continuous water supply was carried out in the Olivares and Colorado River basins, Maipo River basin, Metropolitan Region, Chile. To carry out the assessment of the ecosystem service of water stor-age, the indirect market method "avoided cost" was used, and to estimate the value of continuous water supply, a direct market valuation was used. The results showed that the Olivares-Colorado basins together contain 29.2% of glaciers, 46.2% of the ice surface and 55.7% of the water in the form of ice in the Maipo River basin. The sum of both ecosystem service values for both basins resulted in an annual value of USD 902 million, and a projected present value of USD 14,224 million over 50 years. This annual value exceeds by 32 times the budget for the entire National System of State Protected Wild Areas (SNASPE) for the year 2022, so its high associated value amply justifies the protection of these glaciers
Social-ecological filters influence plant and invertebrate diversity in educational gardens in a South American metropolis
No full textEducational gardens are green areas in schools that are cultivated with vegetables and are at least partially under the care of students. Although they are usually small in size, they can be biodiversity refuges and act as stepping stones for the flow of species within cities. Biodiversity in educational gardens may be "filtered" by social-ecological processes occurring within the garden, around the garden, and by management practices. This study analyzed species richness and the social-ecological filters that may influence plants and invertebrates in school gardens in the Metropolitan Area of Santiago (MAS), Chile. We sampled 33 vegetable gardens in municipal schools, identifying vascular plants (cultivated and spontaneously growing) and invertebrate morphospecies richness in gardens. We further measured the area of the garden, classified the garden's ground cover and the land cover around the garden's buffer zone, and conducted an interview with the main gardener. A total of 362 plant species and 127 invertebrate morphospecies were recorded. The most influential social-ecological filters of plant richness were garden area (m2), percentage of cultivated ground cover, and irrigation during the summer. The most influential factors influencing invertebrate richness were plant species richness, bare ground cover (with a negative effect) and, to a lesser extent, tree cover in the garden's buffer zone and irrigation during the summer. We conclude that the biodiversity of school gardens in the MAS is more related to social-ecological filters within the garden and management practices than to filters within the garden's buffer zone
Enhancing cardiovascular monitoring: a non-linear model for characterizing RR interval fluctuations in exercise and recovery
No full textThis work aimed to develop and validate a novel non-linear model to characterize RR interval (RRi) time-dependent fluctuations throughout a rest-exercise-recovery protocol, offering a more precise and physiologically relevant representation of cardiac autonomic responses than traditional HRV metrics or linear approaches. Using data from a cohort of 272 elderly participants, the model employs logistic functions to capture the non-stationary and transient nature of RRi time-dependent fluctuations, with parameter estimation achieved via Hamiltonian Monte Carlo. Sobol sensitivity analysis identified baseline RRi (alpha) and recovery proportion (c) as the primary drivers of variability, underscoring their critical roles in autonomic regulation and resilience. Validation against real-world RRi data demonstrated robust model performance (R2 = 0.868, CI95%[0.834, 0.895] and Root Mean Square Error [RMSE] = 32.6 ms, CI95%[30.01, 35.77]), accurately reflecting autonomic recovery and exercise-induced fluctuations. By advancing real-time cardiovascular assessments, this framework holds significant potential for clinical applications in rehabilitation and cardiovascular monitoring in athletic contexts to optimize performance and recovery. These findings highlight the model's ability to provide precise, physiologically relevant assessments of autonomic function, paving the way for its use in personalized health monitoring and performance optimization across diverse populations
Linking habitat preferences and fitness across scales for a relict bird species of the southern Andes
No full textAnimals select their habitats from available resources in a way that should maximize fitness, and thus habitat preferences are generally predicted to be adaptive. However, there may be a mismatch between habitat preferences and fitness due to factors such as limited availability or disturbance of nesting habitats. In this study, we examine whether preferred nesting habitat attributes are linked to fitness (nest survival and number of fledglings) of the White-throated Treerunner (Pygarrhichas albogularis), an obligate excavator and tree cavity nester, across four spatial scales: (1) cavity -for fitness influence only-, (2) nest-tree, (3) forest-stand, and (4) landscape. During eight breeding seasons (October to February), between 2010 and 2018, we found and monitored 65 Treerunner nests in Andean temperate forests, Chile. We obtained four main results. First, we found a multiscale response for both habitat preferences and fitness: variables at both nest-tree and landscape scales were the most influential for nesting habitat preferences, while variables at both cavity and nest-tree scales were the most influential for fitness. Second, the probability that a given habitat is used for nesting increased with larger trees, advanced tree decay classes, and forest cover. Third, nest survival was positively related with cavity entrance diameter, height, and distance from the forest edge. Fourth, the number of fledglings increased with south-oriented cavities and decay class, excepting for old dead trees where the breeding outcomes decreased. Combined, our results suggest a general match between habitat preferences and fitness, with a mismatch occurring with trees in advanced decay. The fact that the match occurs in areas with live unhealthy trees and recently dead trees, and a high forest cover, highlight the importance of (a) old-growth forests, as they comprise the best integration of multiscale habitat attributes for this species, and (b) maintaining the continuity of forest cover together with both live unhealthy and recently dead trees in managed and/or second-growth forests
Bryophyte literature records database of Aysén, Chilean sub-Antarctic ecoregion
No full textThe Chilean sub-Antarctic ecoregion hosts the largest expanse of temperate forests, wetlands and peatlands, as well as the largest proportion of protected areas in the southern hemisphere. Bryophytes are highly diverse and ecologically essential in sub-Antarctic ecosystems and are considered as biodiversity loss indicators caused by the current socio-ecological crisis. However, knowledge about their biodiversity is rather limited. Integrating the available information on bryophyte diversity in regional platforms such as SIB-Aysén can be useful to acknowledge their ecological importance and remarkable biodiversity. This article integrates 345 records of 273 bryophyte taxa known in the region of Aysén and emphasizes the need to include citizen science as a tool to increase observations in lesser-known taxonomic groups
Marine Biodiversity in Inútil Bay (Tierra del Fuego): Patterns of Zooplanktonic and Benthic Assemblages
No full textSouthern Patagonian ecosystems are characterized by high environmental heterogeneity. Within this context, Inútil Bay exhibits a complex geomorphology and only fragmentary information on its biodiversity, despite a long history of resource exploitation and increasing human pressures. The objective of this study was to establish a baseline of biodiversity focusing on three key trophic components: zooplankton, megabenthos, and macrobenthos. Samples were collected using both traditional and non-invasive methods, including a bongo net, ROV, and Van Veen grab. A total of 239 taxa were identified, comprising 32 zooplankton species, 61 megabenthic taxa, and 146 macrobenthic taxa. Alpha diversity indices revealed a spatial gradient, with higher mixed-level taxonomic richness near the Whiteside Channel. In contrast to patterns observed in zooplankton and megabenthos, the macrofauna showed significant differences between assemblages at stations located inside and outside the bay. Moreover, a low representation of meroplankton was recorded compared to the high abundance of adult benthic invertebrates. Overall, these results provide a biodiversity baseline, underscore the ecological vulnerability of Inútil Bay, and support its recognition as a priority area for conservation
Validity and reliability of the step test to estimate maximal oxygen consumption in pediatric population
No full textCardiorespiratory fitness is the most important variable related to health and a strong predictor of mortality. However, it is rarely used in clinics due to costs, specialized equipment, space needs, and the requirements of expert staff such as an exercise physiologist, physician, or other health professional. This work aims to validate and test the reliability of a submaximal step test to estimate VO(2)max of 8-to 16-year-old pediatric populations as a simple and low-cost tool for clinical practice. A cross-sectional study included 242 children and adolescents (42.1% girls) aged 8-16. Cardiorespiratory fitness was determined by a maximal incremental test on a treadmill until exhaustion. The step test entailed maintaining a steady pace of 22 steps per minute for 3 min (60 bpm), with the heart rate being recorded at the end of the test. Nutritional status was computed through BMI z-score. A multiple linear regression model validated the step test and developed a new equation to predict VO(2)max, including the third-minute heart rate, weight, and height. The reliability among predicted and measured VO(2)max was assessed by Bland-Altman analysis. The mean age was 12.5 +/- 2.6; 51.6% were overweight or obese. The cardiorespiratory fitness measured as VO(2)max was 35.01 +/- 0.58 mlmin-(1)kg(-1). A robust correlation was observed between the predicted VO(2)max from the step test and the measured VO(2)max (r = 0.86, p < 0.001). Bland-Altman analysis indicated statistical concordance between predicted and measured VO(2)max. Our findings indicate that the step test protocol is valid and reliable for estimating VO(2)max in children and adolescents. Furthermore, the predictive equation is suitable for application among children aged 8-16
Monitoring the physical processes driving the mass loss of Tapado Glacier, Dry Andes of Chile
No full textWe summarise 15 years of field and remote monitoring of Tapado Glacier in north-central Chile (30 degrees S). Observations include meteorological records, direct mass balance measurements, uncrewed aerial vehicle surveys and tri-stereo satellite imagery for deriving high-resolution elevation changes. Frequent droughts and a significant warming trend of 0.29 degrees C decade-1 since 1974 have caused a decrease in glacier surface albedo and an accelerated loss of glacier area and mass, particularly since the onset of the Chilean Megadrought in 2010, associated here with a 43% winter precipitation deficit. Geodetic estimates indicate increasingly more negative mass balance, varying from slightly negative before 2000 to -0.18 +/- 0.35 m w.e. a-1 in 2000-12, -0.44 +/- 0.11 m w.e. a-1 in 2012-20 and -0.75 +/- 0.12 m w.e. a-1 after 2020. Glacier mass loss is associated with several morphological changes, such as increased penitente height, a larger total surface area of ice cliffs and supraglacial ponds over the debris-covered section and more frequent falls of snow and ice from marginal ice surrounding a steep area of exposed bedrock. Tapado Glacier exemplifies how glacier mass loss is driven by various processes, requiring multiple monitoring techniques, and highlights the accelerated changes of the Andes cryosphere
Heavy metal imprints in Antarctic snow from research and tourism
No full textAntarctica, long regarded as one of the last pristine environments on Earth, is increasingly affected by human activity. As tourism surges and scientific operations expand, air pollution from local emissions is raising new environmental concerns. Here we analyse surface snow samples collected along a similar to 2,000-km transect, from the South Shetland Islands (62 degrees S) to the Ellsworth Mountains (79 degrees S), to map the geochemical fingerprints of aerosol deposition. We identify distinct spatial patterns shaped by crustal, marine, biogenic and anthropogenic sources. Notably, we detect heavy metal imprints in the snow chemistry of the northern Antarctic Peninsula, where major research stations are concentrated and marine tourism traffic is most intense. Our findings shed light on the extent of the impacts from energy-intensive local activities in Antarctica, underscoring the need for enhanced environmental monitoring and sustainable management strategies in this fragile region
Breaking the Cycle of Echinococcosis: A Mathematical Modeling Approach
No full textThis study presents a mathematical model of the transmission and spread of the Echinococcus granulosus parasite. The model incorporates host mobility, laws governing the dynamics of Echinococcosis transmission between hosts, and control and prevention measures. The basic reproductive number of the proposed model is calculated, and a sensitivity analysis is performed to identify the parameters that most influence the dynamics of transmission and spread of the disease among its hosts. The study evaluates two control strategies-dog deworming and sheep vaccination-based on their respective target reproductive numbers. The impact of these control and prevention measures is investigated through numerical simulations, which reveal that the dog deworming strategy consistently reduces infections in humans. In contrast, the sheep vaccination strategy demonstrates a more favorable scenario for disease eradication in both hosts. In addition, simulations show a close relationship between the early detection of the disease and the recovery of the patient