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International audience; Drought severity has pervasive impacts on honey production via direct impacts on water resources and nectar availability. The current mega-drought in Chile has impacts on water resources and forest vigor, particularly in the Mediterranean and Temperate regions where honey production is concentrated. While honey production plays an important role in the local rural economy and providing pollination services to other agricultural activities, studies of the long-term impacts of the mega-drought on honey production are scarce. Here, we evaluate the impact of climate variability on historical changes in honey production in the Mediterranean (32°S–37°S) and Temperate (37°S–41°S) regions of Chile, using annual honey production records of beekeepers together with national records of honey exports. We also used questionnaires and interviews to evaluate beekeeper perceptions regarding the effects of climate change on honey production and adaptation practices in both regions. Results indicated a declining trend in honey production and exports in the last decade, largely related to changes in precipitation and temperature in both regions. Declines in honey production affected 82% of beekeepers, 80% of whom had employed adaptive measures, and 74% considered that these measures were effective. The drier, warmer Mediterranean region showed more severe declines in precipitation and honey production, which beekeepers reported as a main contributing factor to transhumance from the Mediterranean to the Temperate region. This is the first study to show the effects of drought on honey production in Chile, providing a foundation for future climate change adaptation strategies within apiculture.

Multiproxy reconstructions of fire regimes in forest ecosystems can provide a clearer understanding of past fire activity and circumvent some limitations of single proxy reconstructions. While inferring fire history from scars in trees is the most precise method to reconstruct temporal fire patterns, this method is limited in Araucaria araucana forests by rot after fire injuries, successive fires that destroy the evidence and the prohibition of sample extraction from living Araucaria trees. In this context, dendrochemical studies in Araucaria trees and charcoal analysis from sediment cores can complement and extend the time perspective of the fire history in the relictual Araucaria-Nothofagus forests of the coastal range. We used dendrochemical, fire scar and charcoal records from the Nahuelbuta Coastal Range (37.8° S; 73° W) spanning the last 1000 years to reconstruct the fire history. The results indicate that periods with higher fire activity occurred between 1400 and 1650 AD. Long-term changes in the fire regime are related to increased climate variability over the last 1000 years, and especially with the arrival of settlers to the area after 1860 CE. The most severe fire events in the Nothofagus and Araucaria forests occurred when suitable fire-prone conditions were superimposed with high human densities.

Regional teleconnections permit cross-continental modeling of hydroclimate throughout the world. Tree-rings are a good hydroclimatic proxy used to reconstruct drought and streamflow in regions that respond to common global forcings. We used a multi-species dataset of 32 tree-ring width chronologies from Chile and Uruguay as a climate proxy to infer annual streamflow (Q) variability in the Negro River basin, a grassland-dominated watershed of lowland Southeastern South America. A positive linear correlation between tree-ring chronologies from Central Chile and annual Negro River instrumental streamflow from 1957 to 2012 indicated a cross-continental teleconnection between hydroclimate variability in Central Chile and Northeastern Uruguay. This relationship was mediated in part by the El Niño Southern Oscillation (ENSO), whereby the El Nino 3.4 Index was positively correlated with regional rainfall, annual tree growth, and Q anomalies. Despite the proximity of Uruguayan tree-ring chronologies to Negro River hydrometric stations, the Chilean tree-ring chronologies best predicted annual streamflow. Thus, using tree-ring data from four long-term moisture-sensitive chronologies of the species Cryptocarya alba in Central Chile (32–34°S), we present the first streamflow reconstruction (1890–2009) in the lower La Plata Basin. The reconstruction supports regional evidence for increasing frequency of extreme flood years over the past century in Uruguay. We demonstrate how climate teleconnections that mediate local hydroclimate variability permit the cross-continental reconstruction of streamflow, filling a major geographical gap in historical proxies for flooding and drought in grassland biomes of the southern hemisphere.

[ES] Este estudio describe y analiza los principales cambios en las reglas oficiales de competición de judo entre 2010 y 2020,destacandoloscambiosenel tiempo de combate, puntuaciones y penalizaciones. En este estudio retrospectivo, se buscaron los documentos oficiales que regularon la s reglas de competición de judo entre 2010 y 2020 en las páginas web de la Federación Internacional de Judo y la Confederación Brasileña de Judo, así como los manuales de arbitraje de la Federación de Judo de Sergipe (Brasil), y en la plataforma Google. A lo largo de los años, el tiempo de combate se ha acortado (2015=5’→4’paramujeres;2017=5’→4’para hombres), así como el tiempo osaekomi (2013=25”→20”). Este cambio tuvo la intención de facilitar la comprensión del público sobre las puntuaciones de judo, así como de devaluar el uso de penalizaciones sobre el rival para lograr la victoria (2010= exclusión dekoka;2013 = penalización ya no equivalió a puntuaciones; 2017= exclusión de yuko, el shido ya no decidió el ganador en el tiempo reglamentario; 2018 = shido ya no decidió el ganador en la técnica de oro). Se fomentaron las acciones de ataque (prohibición de acciones para evitar el combate) y se pretendió reducir el riesgo de lesiones (prohibición de algunos tipos de acciones y agarres). En otras palabras, existió un intento por parte de la Federación Internacional de Judo de fomentar el judo positivo a través de las reglas de competición entre 2010 y 2020. Sin embargo, estos cambios constantes en las reglas hicieron que el contexto del entrenamiento de competición fuese inestable. Los entrenadores y atletas de judo deben estar atentos en el final de cada ciclo olímpico a los nuevos cambios que eventualmente se introducirán, y adaptarse a ellos rápidamente para lograr un alto rendimiento. [EN] This study aimed to describe and analyze the main changes in the official competitive rules of judo between 2010 and2020, highlighting changes in combat time, scores and penalties. In this retrospective study, a search was performed forofficial documents which regulated judo rules between 2010 and 2020 on the websites of the International JudoFederation and the Brazilian Judo Confederation, as well as refereeing manuals of the Sergipe Judo Federation (Brazil)and on the Google platform. Over the years, regular combat time has been shortened(2015=5’→4’ for women;2017=5’→4’for men), as well asosaekomitime(2013=25”→20”). This change was intended to facilitate the public’sunderstanding of judo scores, as well as to devalue the use of penalties to achieve the victory (2010=koka’s exclusion;2013=penalty was no longer worth scores; 2017=yuko’s exclusion,shido no longer decided the winner in regular time;2018=shido no longer decided the golden score winner). Attack actions were encouraged (ban on actions to flee combat)and there was an intention to reduce the risk of injuries in competitive judo (prohibition of some types of actions andgrips). In other words, there was an attempt by the International Judo Federation to encourage positive judo through therules from 2010 to 2020. However, these constant rule changes made the competitive training context unstable. Judocoaches and athletes must be aware at the end of each Olympic cycle for new changes which will eventually be introducedand adapt to them quickly to achieve high performance. [PT] Este estudo descreveu e analisou as principais mudanças nas regras oficiais da competição do judô ocorridas entre 2010 e 2020, destacando mudanças nos tempos de combate, pontuações e penalidades. Neste estudo retrospectivo buscou-se documentos oficiais, que regulamentaram as regras do judô entre 2010 e 2020, nos sites da Federação Internacional de Judô e da Confederação Brasileira de Judô, em manuais de arbitragem da Federação Sergipana de Judô (Brasil) e na Plataforma Google. Ao longo dos anos, o tempo de combate regular foi reduzido(2015=5’→4’ para mulheres; 2017=5’→4’ para homens), bem como o tempo de Osaekomi (2013=25"→20"). Essa mudança teve como objetivo facilitar a compreensão do público sobre as pontuações do judô, bem como desincentivar o uso de punições para obter a vitória (2010=exclusão de Koka; 2013=punição não vale mais pontuação; 2017=exclusão do Yuko, e Shido não decide mais o vencedor no tempo regular; 2018=Shidonão decide mais o vencedor do Golden Score). Ações de ataque foram incentivadas (proibição de ações para fugir do combate) e houve a intenção de reduzir o risco de lesões no judô competitivo (proibição de alguns tipos de ações e pegadas). Ou seja, houve uma tentativa da Federação Internacional de Judô de estimular um judô positivo por meio das regras de 2010-2020. No entanto, essas constantes mudanças nas regras tornaram o contexto de treinamento competitivo instável. Os treinadores e atletas de judô devem estar atentos ao final de cada ciclo olímpico para novas mudanças que eventualmente são introduzidas e devem adaptar-se a elas rapidamente para ter rendimento competitivo.

This study compared the time of female judo combat phases in international competitions between two Olympic cycles (2016; 2020) according to weight divisions (48 kg = 132; 52 kg = 72; 57 kg = 109; 63 kg = 96; 70 kg = 69; 78 kg = 106; >78 kg = 82; total = 666 combats/cycle). The behaviors of 1,332 high-level female judo combats were randomly observed over two Olympic cycles (2016 = 666; 2020 = 666) from the top 20 athletes in the world ranking by weight division. We performed time-motion analysis according to the combat phase and sequential judo actions (approach, gripping, attack, defense, groundwork, pause, and effort: pause ratio) considering the moment when the combat ended (Regular time = RT; Golden score = GS). The weight division groups were compared between Olympic cycles (2016; 2020), and p < 0.05 was defined as significant. The main results showed that 2020 athletes spent less time in the gripping (p = 0.005), attack (p < 0.001), defense (p < 0.001), groundwork (p<0.001) and pause (p = 0.002) phases than 2016 athletes. However, compared by the end-of-combat, 2020 female athletes spent less time in all combat phases for RT combats (p < 0.001), and more time in the approach phase for GS combats (p < 0.05) than in 2016. The 2016 weight divisions showed a higher diversity in the effort: pause ratio (2.5:1–3.4:1), whereas the 2020 weight divisions had values closer to each other (2.8,1–3:1). Analyzing each weight division separately and by the end-of-combat, the main results showed that (p < 0.05): 48, 63, 70, and 78 kg reduced the time in almost every phase of RT combat (except for: 63 kg = gripping and attack; 70 kg = approach and groundwork; 78 kg = approach); 48 and 57 kg increased the groundwork time in GS combats whereas 78 kg decreased; 52 kg and 78 kg increased the GS approach time. The temporal behavior of the combats changed between the Olympic cycles with different rules. These data must be considered to understand the characteristics of each group and to prescribe specialized training in female judo.

The worldwide production of vanilla, a native orchid from Mexico, is greatly affected by stem and root rot disease, typically associated with Fusarium oxysporum fungi. We hypothesized that the presence of Fusarium species in vanilla is not sufficient for the plant to express symptoms of the disease. We described the taxonomic composition of endophytic microbiomes in symptomatic, asymptomatic vanilla plants using 16S and ITS rDNA metabarcoding, and ITS Sanger sequences generated from fungal isolates. We compared the bacterial and fungal diversity in vanilla plants from a long-term plantation, and from feral plants found near abandoned plantations that did not present SRD symptoms. No significant differences were found in the species richness of the bacterial and fungal microbiome among feral, or asymptomatic and symptomatic cultivated vanilla. However, significant differences were detected in both fungal and bacterial diversity from different organs in the same plant, with roots being more diverse than stems. We found that Proteobacteria and Actinobacteria, as well as the fungal families Nectriaceae and Xylariaceae, constitute the core of the vanilla microbiome that inhabits the root and stem of both cultivated and feral plants. Our work provides information on the microbial diversity found in root and stem rot in vanilla and lays the groundwork for a better understanding of the role of the microbiome in fungal diseases in vanilla cultivation.

El presente ensayo crítico, aborda el ambiente que se vive en la educación superior, debido a los estragos provocados por la pandemia que ha paralizado al mundo COVID-19, debido a esto la manera de facilitar aprendizajes se ha tenido que redefinir en todas las áreas, y de forma particular en física y matemáticas, ya que ambas ciencias son necesarias para formar integralmente al hombre moderno, permitiéndole analizar y comprender el uso y significado de los números, realizar comparaciones de cantidades física y sistematizar la información. Es por ello que este ensayo fue realizado con el propósito de analizar desde ambientes semipresenciales la forma como se enseña y aprende física y matemática en la UNAN MANAGUA FAREM Estelí, durante primer semestre 2020.

This study aimed to compare jump-related performance after plyometric training on harder vs. softer surfaces in rugby sevens players. Fourteen players were randomly assigned to the harder surface group (H-G, n = 7) and softer surface group (S-G, n = 7). Three times per week, in the morning, the players performed plyometric training on different surfaces and strength training. Before and after the 4-week intervention period, squat jump (SJ), countermovement jump (CMJ), and CMJ with arms (CMJA) tests were performed to measure vertical jump displacement (d), rate of force development (r), and power (p). The main results indicated a significant improvement in S-G for CMJd (∆% = +8.2%; p = 0.029; ES = 0.59) and for CMJAp (∆% = +8.7%; p = 0.035; ES = 0.44). These improvements were significant compared to H-G for CMJAd (F1,12 = 8.50; p = 0.013; ηp2 = 0.41; ES = 0.83) and CMJAp (F1,12 = 7.69; p = 0.017; ηp2 = 0.39; ES = 0.79). This study reveals that performance related to the counter movement jump with arms on softer surfaces after 4-week plyometric training improved vertical jump displacement and lower body power in rugby sevens players.

Objetivo: Revisar información actualizada sobre las adaptaciones cinéticas y cinemáticas que provoca la sentadilla sobre la articulación de la rodilla; incluyendo deportistas femeninos y masculinos, en un rango etario entre 18 y 45 años. Métodos: A partir de estudios publicados desde enero de 2010 hasta diciembre de 2020, se realizó una búsqueda en las bases de datos Pubmed, Medline, Scopus y SciELO. Las palabras claves se emplearon en tres idiomas; español, inglés y portugués; además se utilizaron términos booleanos distribuidos en distintas combinaciones: Sentadilla (AND) rodilla, knee joint (NOT) genu varum, squat (OR) knee, osteoartrite (AND) lesão. La selección, se realizó a través de los criterios establecidos por PRISMA. Para evaluar la calidad de los estudios, se aplicó la lista de verificación Downs & Black. Resultados: 22 publicaciones cumplieron con los criterios establecidos, luego de su análisis, surgen 3 clasificaciones biomecánicas: i) cinemática; la tibia al desplazarse genera rotación interna de cadera y valgo; ii) cinética: el momento neto máximo de flexión de rodilla se incrementa al aumentar la carga sobre el 85% de 1RM; iii) electromiografía: músculos con mayor activación: vasto lateral, vasto medial y recto femoral. Conclusión: El movimiento de sentadilla genera distintos patrones de movimiento como rotación interna de cadera, desplazando medialmente las rodillas, generando un valgo. Esta adaptación, predispone a la pérdida de la estabilidad en la base de apoyo y, por consecuencia, el desplazamiento del centro de gravedad.

Given the relevance of the effects that weight loss can generate on the physical performance in athletes, this study performed a systematic review with meta-analysis of the published literature on rapid weight loss (RWL) and examined its impact on the physical performance in Official Olympic combat sports athletes. The “Preferred Reporting Items for Systematic Reviews and Meta-Analysis” (PRISMA) guidelines were followed to ensure an ethical and complete reporting of the findings. PubMed, SPORT Discus, and EBSCO were the electronic databases explored for article retrieval and selection. The following string was applied: “RWL” OR “weight loss” OR “weight reduction” AND “judo” OR “wrestling” or “taekwondo” or “boxing” AND “performance.” Based on the quality analysis, conducted according to the “Tool for the assessment of study quality and reporting in exercise training studies” (TESTEX), ten articles achieved a score >6 points. The meta-analysis showed a significant difference in pre- vs. post-weight loss (p = 0.003) and no effects in pre- vs. post-power and strength performance analysis (p > 0.05 for both results). Based on our systematic review and meta-analysis of the literature, RWL up to ≤5% of the body mass in less than 7 days does not influence performance outcomes in Official Olympic combat athletes with weight classes, considering the strength and power measures.

To verify the effects of sodium bicarbonate (NaHCOA systematic review of articles indexed in three databases (PubMed, CAPES journal, and Google Scholar) was carried out until October 2020, using descriptors related to NaHCO

El cálculo ha sido el instrumento elegido desde el principio, porque el concepto de «pequeñas variaciones» se encuentra en el centro de muchos problemas económicos. Este ensayo fue realizado con el propósito de analizar el cómo aprenden los estudiantes con perfil económico, algunos de los conceptos más importantes relacionados al Cálculo Matemático en el aula de clase, es decir reflexionar sobre algunos aspectos de la tarea de enseñar Matemáticas que resulta fundamental e importante, para promover mejores aprendizajes, de modo de seguir construyendo un marco interpretativo compartido sobre las características que debe asumir el trabajo matemático en el aula. Por ende, se tomado como muestra el segundo año de la carrera de Contaduría Pública y Finanzas de la UNAN – Managua, FAREM - Estelí.

Este ensayo fue realizado con el propósito de describir las experiencias vividas en el aula de clase, así como la metodología implementada y dificultades presentadas durante todo el proceso de enseñanza - aprendizaje, en la asignatura Estadística I, con estudiantes de la carrera de segundo año de Administración de empresas del turno por encuentro (sabatino). Según lo observado, las metodologías de enseñanza permiten que los estudiantes relacionen la teoría con la práctica, faciliten la compresión de las temáticas abordadas, propicien curiosidad para realizar comprobaciones, investigaciones y aplicar los conocimientos adquiridos en la resolución de problemas.

Soil moisture (SM) is a key variable in the earth surface dynamics; however, long-term in situ measurements at the global scale are scarce. In the Mediterranean Chilean Andes (MA; 30°-37°S), Sclerophyllous Forest tree species such as Belloto del Norte (BN; Beilschmiedia miersii) can grow for more than two centuries in very scarce humid lowland geographical zones. At the present work, we assess the linkages between two BN tree-ring chronologies (BML and AGU sites; 70 cores) and daily high-resolution satellite-based surface soil moisture product v201812.0 from ESA and to reconstruct past SM variations in the MA region. Our findings exhibit strong relationships between tree-growth from BML and AGU sites and the SM from 32°-34°S and 71°-73°W spatial domain, especially from February to September. We found significant r Pearson correlations of 0.85 and 0.68 during 1983-2014 (P-value < 0.001), respectively. Based on these results, we reconstructed the SM between 1800 - 2014 period using multiple linear regression. Our model retains 71.4% of the total variance and exhibits an unprecedented SM reduction since 2006 in the context of the past two centuries. This work constitutes the first reconstruction of surface soil moisture variability derived from remote sensing carried out in Chile, and can provide new information to understand current environmental changes related to the severe mega-drought period experienced in Chile since 2010, which has provoked water conflicts, the Sclerophyllous Forest decline and browning, and the intensification of climate extreme events such as heatwaves and wildfires in the MA. AcknowledgmentsÁlvaro González-Reyes wish to thank: ANID+PAI+CONVOCATORIA NACIONAL SUBVENCIÓN A INSTALACIÓN EN LA ACADEMIA CONVOCATORIA AÑO 2019 + PAI77190101. Ariel Muñoz and Isadora Schneider thanks to the FONDECYT 1201714 and the Center for Climate and Resilience Research (CR)2, FONDAP 15110009.

Mediterranean climate regions have become more vulnerable to fire due to the extreme weather conditions and numerous Eucalyptus globulus plantation areas. The aim of this study is to analyze the fire hazard related to E. globulus in a forest fire scenario, based on the contrast of thermochemical parameters and their relationship with chemical properties, considering the predominant exotic forest species (E. globulus, Pinus radiata, Acacia dealbata, and Acacia melanoxylon) present in the Valparaiso region, Chile. The results revealed that although all of the studied species were highly flammable, E. globulus was extremely flammable, as its leaves contain high concentrations of essential oils, monoterpenes, and sesquiterpenes, which can generate a flammable atmosphere due to their low flashpoint and the strong negative influence shown between the essential oils, volatile terpenes, and limonene concentration. Moreover, the heat of combustion of E. globulus was positively correlated with its high essential oil contents. Finally, all of the studied species had low flashpoints and high heating values; therefore, they are predisposed to ignite in the presence of a heat source, releasing high amounts of energy during combustion, which contributes to the risk of the formation and spread of canopy fires among these tree formations.

Significance The SADA is an annually-resolved hydroclimate atlas in South America that spans the continent south of 12°S from 1400 to 2000 CE. Based on 286 tree ring records and instrumentally-based estimates of soil moisture, the SADA complements six drought atlases worldwide filling a geographical gap in the Southern Hemisphere. Independently validated with historical records, SADA shows that the frequency of widespread severe droughts and extreme pluvials since the 1960s is unprecedented. Major hydroclimate events expressed in the SADA are associated with strong El Niño Southern Oscillation (ENSO) and Southern Annular Mode (SAM) anomalies. Coupled ENSO-SAM anomalies together with subtropical low-level jet intensification due to increasing greenhouse gas emissions may cause more extreme droughts and pluvials in South America during the 21st century., South American (SA) societies are highly vulnerable to droughts and pluvials, but lack of long-term climate observations severely limits our understanding of the global processes driving climatic variability in the region. The number and quality of SA climate-sensitive tree ring chronologies have significantly increased in recent decades, now providing a robust network of 286 records for characterizing hydroclimate variability since 1400 CE. We combine this network with a self-calibrated Palmer Drought Severity Index (scPDSI) dataset to derive the South American Drought Atlas (SADA) over the continent south of 12°S. The gridded annual reconstruction of austral summer scPDSI is the most spatially complete estimate of SA hydroclimate to date, and well matches past historical dry/wet events. Relating the SADA to the Australia–New Zealand Drought Atlas, sea surface temperatures and atmospheric pressure fields, we determine that the El Niño–Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) are strongly associated with spatially extended droughts and pluvials over the SADA domain during the past several centuries. SADA also exhibits more extended severe droughts and extreme pluvials since the mid-20th century. Extensive droughts are consistent with the observed 20th-century trend toward positive SAM anomalies concomitant with the weakening of midlatitude Westerlies, while low-level moisture transport intensified by global warming has favored extreme rainfall across the subtropics. The SADA thus provides a long-term context for observed hydroclimatic changes and for 21st-century Intergovernmental Panel on Climate Change (IPCC) projections that suggest SA will experience more frequent/severe droughts and rainfall events as a consequence of increasing greenhouse gas emissions.

We study a regional precipitation time series, built upon seven meteorological records from South Central Chile (SCC; 37° - 42°S), which together cover the period 1900 - 2019. As a first objective, we investigated changes in the return period (RP) of dry ( P80) seasonal extreme events of precipitation (SEE), for each season. We observed a reduction in the RP of wet SEE during 1900 - 1950 in all seasons. Contrarily, the dry SEE RP shows a reduction from 1950 to the present in all seasons. This phenomenon is noteworthy since 1900 for summer and winter, and since 1930 for autumn. Spring registers a constant RP value from 1990 onwards. As a second objective, we study possible relationships between seasonal precipitation variability and climate modes, such as the Southern Annular Mode (SAM) and the Tripolar Index (TPI) of sea surface temperature (SST) over the Pacific Ocean. Summer and autumn precipitation register a significant negative correlation with SAM activity at interannual and decadal scales, while winter and spring precipitation show a significant positive correlation with SST variability over multiple regions of the Pacific Ocean (including the tropics and New Zealand) and the Southern Ocean (Amundsen-Bellingshausen Sea). Finally, we confirm that SAM strongly modulates precipitation in SCC, especially in autumn, and that SEE variability in SCC is considerably characterized by climate modes of tropical and extra-tropical origin.

Soil moisture is a key variable into the earth surface dynamics, however long-term in situ measurements are globally scarce. In the Mediterranean Andes of Chile (30° - 37°S) grow the long-lived conifer “Ciprés de la Cordillera” (Austrocedrus chilensis), which is a demonstrated hydroclimatic proxy capable to cover the last millennium. Previous paleoclimatic studies have documented a high sensitivity between tree species and several hydroclimatic variables such as precipitation, streamflow, snowpack and aridity indexes, but the lack of in situ soil moisture observations has precluded an assessment of the spatial growth responses to high-resolution soil moisture variability. Here, we use three A. chilensis chronologies to determine linkages with the satellite-based surface soil moisture product v04.5 generated by ESA. We found significant relationships between tree-growth an a soil moisture field across the 32° - 34°S spatial domain of western South America from January to September during 1985 – 2013 period (r = 0.65; P < 0.001). Temporal relationships between tree-growth and soil moisture satellite observations exhibit a significant spectral coherence associated to cycles around 7 years (P < 0.10) and a clear decadal variability. Based on our preliminary results and the present extensive network of A. chilensis tree-ring chronologies, this species appears as a promising proxy to reconstruct surface soil moisture variability derived from remote sensing over the last millennium in a topographically complex Andean region of South America.AcknowledgementsAlvaro Gonzalez-Reyes wish to thank: CONICYT+PAI+CONVOCATORIA NACIONAL SUBVENCIÓN A INSTALACIÓN EN LA ACADEMIA CONVOCATORIA AÑO 2019 + PAI77190101

Tree-ring research in the highland tropics and subtropics represents a major frontier for understanding climate-growth relationships. Nonetheless, there are many lowland regions – including the South American Pampa biome – with scarce tree ring data. We present the first two tree-ring chronologies for Scutia buxifolia in subtropical Southeastern South America (SESA), using 54 series from 29 trees in two sites in northern and southern Uruguay. We cross-dated annual rings and compared tree growth from 1950 to 2012 with regional climate variability, including rainfall, temperature and the Palmer Drought Severity Index – PDSI, the El Nino Southern Oscillation (ENSO) and the Southern Annular Mode (SAM). Overall, ring width variability was highly responsive to climate signals linked to water availability. For example, tree growth was positively correlated with accumulated rainfall in the summer-fall prior to ring formation for both chronologies. Summer climate conditions were key for tree growth, as shown by a negative effect of hot summer temperatures and a positive correlation with PDSI in late austral summer. The El Nino phase in late spring/early summer favored an increase in rainfall and annual tree growth, while the La Nina phase was associated with less rainfall and reduced tree growth. Extratropical climate factors such as SAM had an equally relevant effect on tree growth, whereby the positive phase of SAM had a negative effect over radial growth. These findings demonstrate the potential for dendroclimatic research and climate reconstruction in a region with scarce tree-ring data. They also improve the understanding of how climate variability may affect woody growth in native forests – an extremely limited ecosystem in the Pampa biome.

In January 2017, hundreds of fires in Mediterranean Chile burnt more than 5000 km(2), an area nearly 14 times the 40-year mean. We contextualize these fires in terms of estimates of global fire intensity using MODIS satellite record, and provide an overview of the climatic factors and recent changes in land use that led to the active fire season and estimate the impact of fire emissions to human health. The primary fire activity in late January coincided with extreme fire weather conditions including all-time (1979–2017) daily records for the Fire Weather Index (FWI) and maximum temperature, producing some of the most energetically intense fire events on Earth in the last 15-years. Fire activity was further enabled by a warm moist growing season in 2016 that interrupted an intense drought that started in 2010. The land cover in this region had been extensively modified, with less than 20% of the original native vegetation remaining, and extensive plantations of highly flammable exotic Pinus and Eucalyptus species established since the 1970s. These plantations were disproportionally burnt (44% of the burned area) in 2017, and associated with the highest fire severities, as part of an increasing trend of fire extent in plantations over the past three decades. Smoke from the fires exposed over 9.5 million people to increased concentrations of particulate air pollution, causing an estimated 76 premature deaths and 209 additional admissions to hospital for respiratory and cardiovascular conditions. This study highlights that Mediterranean biogeographic regions with expansive Pinus and Eucalyptus plantations and associated rural depopulation are vulnerable to intense wildfires with wide ranging social, economic, and environmental impacts, which are likely to become more frequent due to longer and more extreme wildfire seasons. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13280-018-1084-1) contains supplementary material, which is available to authorized users.

The Calbuco volcano ranks third in the specific risk classification of volcanoes in Chile and has a detailed eruption record since 1853. During 2015, Calbuco had a sub-Plinian eruption with negative impacts in Chile and Argentina, highlighting the need to determine the long-term history of its activity at a high-resolution time scale to obtain a better understanding of its eruptive frequency. We developed a continuous eruptive record of Calbuco for the 1514–2016 period by dendrochemical analysis of Fitzroya cupressoides tree rings at a biennium resolution using inductively coupled plasma–mass spectrometry. After comparing the chemical record of 20 elements contained in tree rings with historical eruptions, one group exhibited positive anomalies during (Pb/Sn) and immediately after (Mo/P/Zn/Cu) eruptions, with a Volcanic Explosivity Index (VEI) ≥ 3, and so were classified as chemical tracers of past eruptions (TPE). The tree-ring width chronology also exhibited significant decreases in tree growth associated with eruptions of VEI ≥ 3. According to these records, we identified 11 new eruptive events of Calbuco, extending its eruptive chronology back to the 16th century and determining a mean eruptive frequency of ~23 years. Our results show the potential to use dendrochemical analysis to infer past volcanic eruptions in Northern Patagonia. This information provides a long-term perspective for assessing eruptive history in Northern Patagonia, with implications for territorial planning.

In central Chile, increasing demand for water and decreasing runoff volumes due to drier conditions have placed catchments in this zone under water stress. However, scarcity of observed data records increases the difficulty of planning future water supply. Instrumental records suggest a reduction in streamflow over the last 56 years. However, this change is not statistically significant and the lack of meteorological stations with long records in this mountainous region hampers a deeper analysis, motivating the use of tree rings to analyse whether these changes are part of a long-term trend. This work represents the first high-elevation runoff reconstruction in Chile using 300 years of tree ring chronologies of Araucaria araucana and Astroceudrus chilensis. The upper part of Biobio river melting season runoff (October–March) and pluvial season runoff (April–September) was reconstructed and analysed to investigate the influence of large-scale climatic drivers on runoff generation, current drought trends and to improve the understanding of climate variability in this region. We obtained positive correlations between the 20-year moving average of reconstructed pluvial season runoff and reconstructed Pacific Decadal Oscillation (PDO), which is indicative of multi-decadal variability. We also found a negative correlation between the 11-year moving average of reconstructed melting season runoff and the PDO and positive correlations with the Southern Annular Mode (SAM). Important differences in the runoff variability of the upper and the lower part of the catchment were identified which are in part led by the influence of the large-scale climatic features that drive runoff generation in both regions. We found that the changes observed in the instrumental records are part of multi-decadal cycles led by the PDO and SAM for pluvial season runoff and melting season runoff, respectively.

In the Mediterranean Andes region (MA; 30°-37°S), the main rivers are largely fed by melting snowpack and provide freshwater to around 10 million people on both sides of the Andes Mountains. Water resources in the MA are under pressure because of the extensive development of industrial agriculture and mining activities. This pressure is increasing as the region faces one of its worst recorded droughts. Previous studies have pointed to El Niño-Southern Oscillation (ENSO) as the main climatic force impacting the MA. However, the role of decadal and multidecadal climate variability, their spatial patterns, and the recurrence of long-term droughts remains poorly studied. In an attempt to better understand these factors, spatial and temporal patterns of hydroclimatic variability are analyzed using an extensive database of streamflow, precipitation, and snowpack covering the period between 1910 and 2011. These analyses are based on the combination of correlation, principal components, and kernel estimation techniques. Despite a general common pattern across the MA, the results presented here identify two hydroclimatic subregions, located north and south of 34°S. While the interannual variability associated with ENSO is slightly stronger north of 34°S, the variability associated with the Pacific decadal oscillation (PDO) and/or the interdecadal Pacific oscillation (IPO) index shows similar patterns in both regions. However, variations produced by the IPO forcing seem to be greater in the southern subregion since 1975. The estimations presented here on drought recurrence reveal a generalized increase in dry extremes since the 1950s. These findings suggest that the northern MA is more vulnerable to changes in hydrology and climate than the southern MA. Fil: González Reyes, Álvaro. Universidad Austral de Chile; Chile Fil: McPhee, James. Universidad de Chile; Chile Fil: Christie, Duncan A.. Universidad de Chile; Chile. Universidad Austral de Chile; Chile Fil: Quesne, Carlos Le. Universidad Austral de Chile; Chile Fil: Szejner, Paul. University of Arizona; Estados Unidos Fil: Masiokas, Mariano Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Villalba, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Muñoz, Ariel A.. Pontificia Universidad Católica de Valparaíso; Chile Fil: Crespo, Sebastián Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina

Since 2010, Chile has experienced one of the most severe droughts over the last century, the so-called mega-drought (MD). The MD conditions, combined with intensive agricultural activities and the current water management system, have led to water scarcity problems in Mediterranean and Semi-arid regions of Chile. An emblematic case is the Petorca basin, where a water crisis is undergone. To characterize this crisis, we analyzed water provision by using tree-ring records, remote sensing, instrumental data, and allocated water rights within the basin. Results indicate that the MD is the most severe dry period over the last 700-years of streamflow reconstruction. During the MD, streamflow and water bodies of the upper parts of the basin have been less affected than mid and low areas of this valley, where consumptive withdrawals reach up to 18% of the mean annual precipitation. This extracted volume is similar to the MD mean annual precipitation deficits. The impacts of the current drought, along with the drier climate projections for Central Chile, emphasize the urgency for faster policy changes related to water provision. Climate change adaptation plans and policies should enhance the current monitoring network and the public control of water use to secure the water access for inhabitants and productive activities.

Almost half of the tributaries of the Amazon River originate in the tropical Andes and support large populations in mountain regions and downstream areas. However, it is difficult to assess hydroclimatic conditions or to evaluate future scenarios due to the scarcity of long, high-quality instrumental records. Data from the Global Precipitation Climatology Project (GPCP) provide a complete record since 1979 and offer a good representation of rainfall over the tropical Andes. Longer records are needed to improve our understanding of rainfall variability and summer monsoon behavior at various scales. We developed the first annually resolved precipitation reconstruction for the tropical Andes in Peru, based on tree-ring chronologies of Cedrela and Juglans species. The annual (November–October) reconstruction extends the short instrumental records back to 1817, explaining 68% of the total variance of precipitation over the 1979–2007 calibration period. The reconstruction reveals the well-documented influence of El Niño-Southern Oscillation (ENSO) on Amazon Rainfall at interannual scales (~19% of total variance) and significant multidecadal variability with alternating periods of about 40 years (~13% of rainfall variability) related to the Atlantic Multidecadal Oscillation (AMO). Both oscillatory modes can explain dry and humid periods observed within the reconstruction and are likely associated with the negative trends of rainfall in the short instrumental records and the increased drought recurrence in recent decades. Our results show that montane tropical tree rings can be used to reconstruct precipitation with exceptionally high fidelity, characterize the interannual to multidecadal variability, and identify remote forcings in the hydroclimate over the Andean Amazon Basin of Peru. Fil: Humanes Fuente, Victor. Pontificia Universidad Católica de Valparaíso; Chile Fil: Ferrero, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Muñoz, Ariel A.. Pontificia Universidad Católica de Valparaíso; Chile Fil: González Reyes, Álvaro. Universidad Mayor; Chile Fil: Requena Rojas, Edilson Jimmy. Universidad Austral de Chile; Chile Fil: Barichivich, J.. Universidad Austral de Chile; Chile. Laboratoire des Sciences du Climat et de l'Environnement; Francia Fil: Inga, J.G.. Universidad Continental; Perú Fil: Layme Huaman, Eva Trinidad. Instituto Nacional de Innovación Agraria; Argentina

Forests play an important role in water and carbon cycles in semiarid regions such as the Mediterranean ecosystems. Previous research in the Chilean Mediterranean forests revealed a break point in 1980 in regional tree-ring chronologies linked to climate change. However, it is still unclear which populations and age classes are more affected by recent increases in drought conditions. In this study, we investigated the influence of recent variations in precipitation, temperature, and CO2 concentrations on tree growth of various populations and age classes of Nothofagus macrocarpa trees in Central Chile. We sampled 10 populations from five sites of N. macrocarpa through its whole geographic distribution in both Coastal and Andes ranges. We used standard dendrochronological methods to (i) group populations using principal component analysis, (ii) separate age classes (young, mature, and old trees), (iii) evaluate linear growth trends based on the basal area increment (BAI), and (iv) analyze the link between BAI and atmospheric changes using linear mixed-effects models. Results showed that young trees are more sensitive to climate variability. Regarding population grouping, we observed that all population clusters were sensitive to winter-spring precipitation, but only the Andes and Coastal populations were negatively correlated with temperature. The results of CO2 fertilization analyses were controversial and unclear. Since young trees from all population clusters reacted positively in the phase with an increase of atmospheric CO2 between 1980 and 2014, this behavior was not translated into growth for the last 15 years (2000-2014). However, it should be noted that the young trees of the highest elevation populations did not have a negative growth trend, so it seems that CO2 counteracted the negative effect of recent regional climate change (increase in temperature and precipitation decrease) in these population trees. Further studies are needed to assess the effects of climate variability over other ecological and physiological processes. Fil: Venegas González, Alejandro. Universidad Mayor.; Chile Fil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Peña Rojas, Karen. Universidad de Chile; Chile Fil: Hadad, Martín Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentina Fil: Aguilera Betti, Isabella. Pontificia Universidad Católica de Valparaíso; Chile. Universidad Austral de Chile; Chile Fil: Muñoz, Ariel A.. Pontificia Universidad Católica de Valparaíso; Chile

Forest fires are one of the main environmental threats in Chile. Fires in this Mediterranean climate region frequently affect native forests and exotic plantations, including in several cases urban and rural settlements. Considering the scarcity of information regarding the fire response dynamics of tree species that are frequently affected by fires, this study aims to establish a flammability classification according to the evolution of the fire initiation risk presented by the most affected forest species in the Valparaíso region. Three exotic species, Eucalyptus globulus, Pinus radiata, and Acacia dealbata, and two native species, Cryptocarya alba and Quillaja saponaria, were studied. Flammability assays indicate that E. globulus, A. dealbata, and C. alba are extremely flammable, whereas P. radiata and Q. saponaria are flammable. Furthermore, E. globulus and A. dealbata have the highest heating values while Q. saponaria has the lowest values. The extreme flammability of E. globulus, A. dealbata, and C. alba indicates a high susceptibility to ignite. Furthermore, the high heat of combustion of E. globulus and A. dealbata can be associated with a high energy release, increasing the risk of fires spreading. In contrast, Q. saponaria has the lowest predisposition to ignite and capacity to release heat. Accordingly, this work shows that all studied tree species contain organic metabolites that are potentially flammable (sesquiterpenes, aliphatic hydrocarbons, alcohol esters, ketones, diterpenes, and triterpenes) and can be considered as drivers of flammability in vegetation. Finally, these preliminary results will aid in the construction of more resilient landscapes in the near future.

Global Climate Models project that observed climate trends are likely to be preserved and the number of extreme events will be increasing during the rest of the 21st century, which may have a detrimental impact on forest ecosystems. These impacts may include forest decline and widespread dieback of the most vulnerable biomes, such as the Mediterranean Forest of Central Chile (MFCC). Nothofagus macrocarpa and Austrocedrus chilensis are two canopy-dominant, endangered tree species in the mountains of MFCC. Here, we project tree growth of these species based on tree-ring width chronologies, a simplified version of a process-based model, and climate change projections. We used the tree ring information derived from ~400 trees from 12 sites distributed across MFCC in combination with the simplified version of process-based Vaganov-Shashkin tree-growth model (VS-Lite) to forecast changes in tree growth for the next four decades. Tree growth projections were made on the basis of monthly values of temperature and precipitation from the output of 35 climate models based on two ensembles of CO2 emission scenarios of the IPCC AR5 (RCP 8.5: higher-emission scenario, and RCP 2.6: lower-emission scenario). For the MFCC region these scenarios result in temperature rise ranging between 0.5 °C and 2.0 °C, and a precipitation decrease between 5% and 20% by the year 2065, as related to historical conditions. Our results showed that the VS-Lite model is capable of reproducing tree growth decline during the recent extreme dry period, i.e. 2010–2018, which supports its use for tree growth projections in the MFCC region. According to the modeling results, we find that tree growth in both N. macrocarpa and A. chilensis forests distributed in the MFCC region will be adversely affected by future climate changes, mainly starting from the year 2035, under both scenarios. Our work provides evidence of the degree of vulnerability of Mediterranean mountain forests in central Chile according to current climate change projections. The projected decline in tree growth indicates serious risks in the dynamics and survival of these forests relatively soon, so alerts are given about this situation which may require to counteract the deleterious effects of global change on vegetation in this region.

Questions Increasing climate variability has major effects on forest productivity, as well as transitions between forest and savanna ecosystems. While drought-induced declines in tropical forest productivity and forest loss is a global concern, forest expansion in subtropical South America predicted by climate models has received little attention. In the forest–grassland transition zone encompassing Uruguay, we ask: (1) how does climate variability affect woodland productivity and at what time scales; and (2) how do different woodland types (riparian, hillside and wooded savanna) differ in their sensitivity to climate variability? Location Forests and wooded savanna in Uruguay, subtropical southeast South America. Methods Primary productivity was measured as the fraction of photosynthetically active radiation (fPAR) based on monthly normalized difference vegetation index (NDVI) from multitemporal (1998–2012) SPOT imagery at a 1 km × 1 km resolution, covering 19% of Uruguayan woodlands. The effects of accumulated rainfall and mean temperature on the productivity of riparian and hillside forests and wooded savanna were evaluated using correlations and time series analysis over multiple time windows ranging from 1–24 mo. Results Inter-annual rainfall variability and seasonal temperatures affected forest productivity even though average conditions were largely non-limiting. Periods of exceptionally high rainfall and warm winters had positive effects on forest productivity, but hot summers had a negative effect on all woodland productivity. Riparian and hillside forest productivity was equally susceptible to drought, showing similar relationships to accumulated rainfall over multiple time periods, as well as similar susceptibility to high summer temperatures. Wooded savanna – a composite cover of trees and a grass/forb understorey – productivity was linked to seasonal rainfall over 3–6 mo, and in general showed the lowest correlation with inter-annual variability in rainfall. Conclusions Results suggest functional convergence in the response of riparian and hillside forests to water deficit and hot summers. The increases in forest productivity with increasing rainfall and declining drought risk – as predicted by the IPCC for this region – are a potential mechanism for increased growth and future expansion of forests in this biogeographic transition zone.

The Aconcagua river basin (Chile, 32 &deg, S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The &delta, 18O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing &ldquo, simmr&rdquo, model revealed that snowmelt input accounted 52% in spring and only 22&ndash, 36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15&ndash, 20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14&ndash, 21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water security in this territory.

Tree-ring research (TRR) in South America (SA) continues to make important contributions in multiple sub-disciplines, including dendrochemistry and dendrohydrology. This report describes some of the advances in TRR in SA presented in a two-day International Meeting Research entitled “An International Network to Promote Advances in Dendrochronology in South America”, organized by the Laboratory of Dendrochronology and Environmental Studies of the Pontifical Catholic University of Valparaiso in Valparaiso, Chile, on January 21–22, 2019. The objective of the meeting was to communicate recent advances in TRR within a network of laboratories in Argentina, Brazil, Chile, Peru, and Uruguay. Novel methodologies and results in dendrochemistry and wood anatomy were also presented by collaborating researchers from German institutions. This report describes some of the research within the subdisciplines of tree-ring science, including dendrochemistry, anatomy and dendrohydrology, and their application to understanding spatio-temporal variability in heavy metal contamination, climate, hydrology, fire regimes and other critical components of South American forest and woodland ecosystems. The meeting demonstrated expansion and diversification of inquiry and applications of TRR in SA, whereby collaboration across research centers has been critical for the advances made in broad-scale comparative studies as well as multi-proxy approaches and the study of global and hemisphere-scale climate phenomena.

Since 1981, water allocation in Chile has been based on a water use rights (WURs) market, with limited regulatory and supervisory mechanisms. The volume to be granted as permanent and eventual WURs is calculated from streamflow records, if stream gauge data are available, or from hydrologic parameter transfer from gauged to ungauged catchments, usually with less than 50 years of record. To test the performance of this allocation system, while analyzing the long-term natural variability in water resources, we investigated a 400 year-long (1590–2015) tree-ring reconstruction of runoff and historical water rights for Perquilauquén at Quella catchment, a tributary to the Maule River in Central Chile (35°S–36°30S). Furthermore, we assess how the current legislation would perform under a projected climate scenario, based on historical climate simulations of runoff calibrated against observed data, and future projections. Our analyses indicate that the allocation methodology currently applied by the Water Authority in Chile is very sensitive to the time window of data used, which leads to an underestimation of variability and long-term trends. According to the WURs database provided by the Chilean Water Directorate, WURs at Perquilauquén at Quella are already over-allocated. Considering regional climate projections, this condition will be exacerbated in the future. Furthermore, serious problems regarding the access and quality of information on already-granted WURs and actual water usage have been diagnosed, which further encumber environmental strategies to deal with and adapt to climate change. We emphasize the urgent need for a review and revision of current water allocation methodologies and water law in Chile, which are not concordant with the dynamics and non-stationarity of hydrological processes. Water scarcity and water governance are two of the key issues to be faced by Chile in the Anthropocene.

Streamflow in south-central Chile (SCC, ∼ 37–42∘ S) is vital for agriculture, forestry production, hydroelectricity, and human consumption. Recent drought episodes have generated hydrological deficits with damaging effects on these activities. This region is projected to undergo major reductions in water availability, concomitant with projected increases in water demand. However, the lack of long-term records hampers the development of accurate estimations of natural variability and trends. In order to provide more information on long-term streamflow variability and trends in SCC, here we report findings of an analysis of instrumental records and a tree-ring reconstruction of the summer streamflow of the Río Imperial (∼ 37∘ 40′ S–38∘ 50′ S). This is the first reconstruction in Chile targeted at this season. Results from the instrumental streamflow record (∼ 1940 onwards) indicated that the hydrological regime is fundamentally pluvial with a small snowmelt contribution during spring, and evidenced a decreasing trend, both for the summer and the full annual record. The reconstruction showed that streamflow below the average characterized the post-1980 period, with more frequent, but not more intense, drought episodes. We additionally found that the recent positive phase of the Southern Annular Mode has significantly influenced streamflow. These findings agree with previous studies, suggesting a robust regional signal and a shift to a new hydrological scenario. In this paper, we also discuss implications of these results for water managers and stakeholders; we provide rationale and examples that support the need for the incorporation of tree-ring reconstructions into water resources management. Fil: Fernández, Alfonso. Universidad de Concepción; Chile Fil: Muñoz, Ariel. Pontificia Universidad Católica de Valparaíso; Chile Fil: González Reyes, Álvaro. Universidad Austral de Chile; Chile Fil: Aguilera Betti, Isabella. Pontificia Universidad Católica de Valparaíso; Chile Fil: Toledo, Isadora. Pontificia Universidad Católica de Valparaíso; Chile Fil: Puchi, Paulina. Pontificia Universidad Católica de Valparaíso; Chile Fil: Sauchyn, David. University of Regina; Canadá Fil: Crespo, Sebastián Andrés. Pontificia Universidad Católica de Valparaíso; Chile Fil: Frene, Cristian. Pontificia Universidad Católica de Chile; Chile Fil: Mundo, Ignacio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: González, Mauro. Universidad Austral de Chile; Chile Fil: Vignola, Raffaele. Cátedra Latinoamericana en Decisiones Ambientales para el Cambio Global; Costa Rica