Browsing by Author "Cuevas, Jaime G."

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    Improving the underground structural characterization and hydrological functioning of an Andean peatland using geoelectrics and water stable isotopes in semi-arid Chile
    (2021) Valois, Remi; Araya Vargas, Jaime; MacDonell, Shelley; Guzman Pinones, Camilo; Fernandoy, Francisco; Yanez Carrizo, Gonzalo; Cuevas, Jaime G.; Sproles, Eric A.; Maldonado, Antonio
    High altitude, Andean wetlands, or bofedales as they are locally known, are important regulators of the local water balance and also play a key role in sustaining biodiversity. Nevertheless, there is almost no information regarding their hydrogeological structure and functioning. This paper aims to characterize the thickness of the alluvial filling of one peat-accumulating wetland in North-Central Chile using Electrical Resistivity Tomography (ERT) to assess its role as a water reservoir. To develop a quasi-3D understanding of the peatland's structure, four ERT profiles were conducted. Results highlight a conductive basin shape of the peatland, with a thicker interface downstream than upstream between alluvial materials and the underlying bedrock or rock screes. Those results allow the estimate of the water column (1000-3400 mm) within the peatland alluvial filling. The second objective is to better understand the water exchanges between the peatland and the streamflow using discharge measurements and water stable isotopes. Water and isotopes budgets highlight a streamflow loss towards the peatland groundwater reservoir at the end of spring season. In addition, ten delta O-18 and delta H-2 surveys were used to characterize the distinct wetland water sources and their temporal variations. A peatland conceptual model is proposed to connect groundwater, rock glaciers, snowmelt, and hillslope flows. Andean peatlands provide a pivotal control on water delivery downstream, and therefore, understanding their structure and function is important, because they are unique structures providing ecological services at high elevations.
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    Nurse effect and herbivory exclusion facilitate plant colonization in abandoned mine tailings storage facilities in north-central Chile
    (2013) Cuevas, Jaime G.; Silva, Sergio I.; Leon-Lobos, Pedro; Ginocchio, Rosanna
    Positive interactions among plants, such as the nurse effect, can attenuate environmental stress (e.g., drought) or reduce the intensity of perturbations (e.g., herbivory), thus enhancing the possibility of regeneration in natural systems. This study analyses the potential use of nurse plants for restoring artificial environments, such as mine hard-rock dumps. We evaluated seedling recruitment and survival in open areas and beneath the canopy of nurse shrubs, with and without grazing exclusion, on an abandoned copper tailings storage facility in north-central Chile. The nurse species was Baccharis linearis (Asteraceae), and seedling species were B. linearis, Haplopappus parvifolius (Asteraceae), Schismus arabicus (Poaceae), and several forb/grass taxa. A field survey showed that seedlings of all species were more abundant beneath the Baccharis shrub canopy coverage than in the open spaces between shrubs. Only Baccharis seedlings produced a significant difference. We found a decreasing sequence of seedling survival under the following conditions: beneath the Baccharis canopy with herbivore exclusion, beneath the canopy without exclusion, in the open field with exclusion, and finally, in the open field without exclusion. Substrates beneath shrubs had higher P and K levels at depths < 10 cm than substrates in open areas. Water content, substrate compaction, and plant diversity did not differ between microenvironments. Our results demonstrate the importance of both the nurse effect and herbivore exclusion in enhancing seedling establishment on abandoned mine tailings storage facilities in semi-arid north-central Chile. Thus shedding light upon the ecological restoration possibilities in such disturbed environments.
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    Nurse effect and herbivory exclusion facilitate plant colonization in abandoned mine tailings storage facilities in north-central Chile
    (2013) Cuevas, Jaime G.; Silva, Sergio I.; León Lobos, Pedro; Ginocchio Cea, Rosanna