Browsing by Author "Garreaud, Rene D."

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    Agriculture Vulnerability to Climate Change in a Snowmelt-Driven Basin in Semiarid Chile
    (ASCE-AMER SOC CIVIL ENGINEERS, 2012) Vicuna, Sebastian; McPhee, James; Garreaud, Rene D.
    The Limari River basin is one of the most important watersheds in north-central Chile (30 S). Its headwaters lie at the top of the subtropical Andes (> 5; 000 m above sea level) and the river flows westward into the Pacific Ocean over a length of approximately 200 km. This basin has a marked snowmelt-driven hydrological regime and, in spite of the arid conditions that characterize this region, holds more than 50,000 ha of highly productive agricultural land thanks to its irrigation infrastructure and three interconnected reservoirs. Like many semiarid regions around the world, north-central Chile is expected to become warmer and drier during the 21st century as a consequence of ongoing anthropogenic climate change. The associated reduction in streamflow, changes in hydrograph timing, and enhanced evapotranspiration will undoubtedly threaten agriculture in the Limari basin and elsewhere in semiarid Chile. In this paper, the effect of temperature and precipitation on surface hydrology, performance of water infrastructure, and irrigation coverage in the Limari basin is investigated by using the water evaluation and planning (WEAP) model. WEAP was calibrated by using current climate and agriculture patterns, and then forced with a set of 30-year-long climate scenarios, each of them obtained by adding a temperature and precipitation perturbation to the historical time series. This delta approach allows (1) determination of the sensitivity of selected variables to climate change, and (2) obtaining a projection of the effects in irrigation coverage expected for the near and far future (2010-2040 and 2070-2100, respectively). Both aspects are investigated for agricultural districts with varying access to irrigation infrastructure and groundwater; this exercise highlights the relevance of added storage and innovative conjunctive use of surface and groundwater resources for improving the resilience and adaptability of irrigated agriculture in the face of a changing climate. DOI: 10.1061/(ASCE)WR.1943-5452.0000202. (C) 2012 American Society of Civil Engineers.
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    Diversifying Chile's climate action away from industrial plantations
    (2021) Hoyos-Santillan, Jorge; Miranda, Alejandro; Lara, Antonio; Sepulveda-Jauregui, Armando; Zamorano-Elgueta, Carlos; Gomez-Gonzalez, Susana; Vasquez-Lavin, Felipe; Garreaud, Rene D.; Rojas, Maisa
    As president of the Climate Change Conference of the Parties, Chile has advocated for developing ambitious commitments to mitigate greenhouse gas emissions to achieve carbon-neutrality by 2050. However, Chile's motivations and ambitious push to reach carbon-neutrality are complicated by a backdrop of severe drought, climate change impacts (i.e., wildfires, tree mortality), and the use of industrial plantations as a mitigation strategy. This has become more evident as widespread and severe wildfires have impacted large areas of industrial plantations, transforming the land-use, land-use change, and forestry sector from a carbon sink to a net carbon source. Consequently, Chile must diversify its climate actions to achieve carbon-neutrality. Nature-based solutions, including wetlands-peatlands and oceans, represent alternative climate actions that can be implemented to tackle greenhouse gas emissions at a national level. Diversification, however, must guarantee Chile's long-term carbon sequestration capacity without compromising the ecological functionality of biodiverse treeless habitats and native forest ecosystems.
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    Extreme Drought Affects Visitation and Seed Set in a Plant Species in the Central Chilean Andes Heavily Dependent on Hummingbird Pollination
    (2020) Arroyo, Mary T. K.; Robles, Valeria; Tamburrino, Italo; Martinez-Harms, Jaime; Garreaud, Rene D.; Jara-Arancio, Paola; Pliscoff, Patricio; Copier, Ana; Arenas, Jonas; Keymer, Joaquin; Castro, Kiara
    Rising temperatures and increasing drought in Mediterranean-type climate areas are expected to affect plant-pollinator interactions, especially in plant species with specialised pollination. Central Chile experienced a mega drought between 2010 and 2020 which reached an extreme in the austral summer of 2019-2020. Based on intensive pollinator sampling and floral studies we show that the subalpine form of Mutisia subulata (Asteraceae) is a specialised hummingbird-pollinated species. In a two-year study which included the severest drought year, we quantified visitation frequency, flower-head density, flower-head visitation rates, two measures of floral longevity, nectar characteristics and seed set and monitored climatic variables to detect direct and indirect climate-related effects on pollinator visitation. Flower-head density, nectar standing crop and seed set were significantly reduced in the severest drought year while nectar concentration increased. The best model to explain visitation frequency included flower-head density, relative humidity, temperature, and nectar standing crop with highly significant effects of the first three variables. Results for flower-head density suggest hummingbirds were able to associate visual signals with reduced resource availability and/or were less abundant. The negative effect of lower relative humidity suggests the birds were able to perceive differences in nectar concentration. Reduced seed set per flower-head together with the availability of far fewer ovules in the 2019-2020 austral summer would have resulted in a major reduction in seed set. Longer and more intense droughts in this century could threaten local population persistence in M. subulata.