The Magallanes–Tierra del Fuego region, Southern Patagonia (53–56° S) features a plethora of fjords and remote and isolated islands, and hosts several thousand glaciers. The number of investigated glaciers with respect to the multiple Neoglacial advances is based on a few individual studies and is still fragmentary, which complicates the interpretation of the glacial dynamics in the southernmost part of America. Schiaparelli Glacier (54°24′ S, 70°50′ W), located at the western side of the Cordillera Darwin, was selected for tree-ring-based and radiocarbon dating of the glacial deposits. One focus of the study was to address to the potential dating uncertainties that arise by the use of Nothofagus spp. as a pioneer species. A robust analysis of the age–height relationship, missing the pith of the tree (pith offset), and site-specific ecesis time revealed a total uncertainty value of ±5–9 years. Three adjacent terminal moraines were identified, which increasingly tapered towards the glacier, with oldest deposition dates of 1749 ± 5 CE, 1789 ± 5 CE, and 1867 ± 5 CE. Radiocarbon dates of trunks incorporated within the terminal moraine system indicate at least three phases of cumulative glacial activity within the last 2300 years that coincide with the Neoglacial phases of the Southern Patagonian Icefield and adjacent mountain glaciers. The sub-recent trunks revealed the first evidence of a Neoglacial advance between ~600 BCE and 100 CE, which so far has not been substantiated in the Magallanes–Tierra del Fuego region.

Registros de precipitación instrumental extensos y continuos son escasos en América del Sur, y aún más en altas latitudes. Estos registros son útiles para contrastar reconstrucciones climáticas del pasado y calibrar modelos climáticos regionales. Pocas ciudades de Chile (e.g. Santiago, Concepción, Valdivia, Punta Arenas), poseen observaciones meteorológicas extensas desde mediados del siglo XIX o principios del siglo XX. El análisis de estos registros es también fundamental para evaluar los cambios recientes en el clima respecto de períodos previos, información especialmente útil para delinear políticas de adaptación. Este trabajo analizó la pluviometría de Punta Arenas y tuvo como objetivos: i) evaluar los cambios mensuales, estacionales y anuales de la precipitación en los períodos 1900-2014 y 1990-2014, ii) evaluar la recurrencia de eventos de sequías, y iii) analizar la relación entre la precipitación y el Modo Anular del Sur (SAM). Los resultados evidenciaron una fuerte variabilidad decadal a multi-decadal en la precipitación anual y en cada estación del año. Reducciones significativas se observaron en la precipitación anual durante el período 1900 -2014, siendo más acentuadas entre 1990 -2014. En este último período, la precipitación de primavera y verano presentó una reducción significativa, sugiriendo una extensión de las condiciones estivales. En invierno, un significativo incremento fue observado desde el año 1990. La recurrencia de eventos extremos de sequías severas también se incrementó posterior al año 1990. Relaciones negativas y significativas entre la actividad SAM y la precipitación anual se observaron en marzo y en el intervalo septiembre- diciembre. La reducción en la precipitación de la ciudad de Punta Arenas estaría estrechamente relacionada con la actividad SAM, el cual modularía la variabilidad de las precipitaciones a escalas temporales interanuales e interdecadales.

Spatio-temporal patterns of climatic variability have effects on the environmental conditions of a given land territory and consequently determine the evolution of its productive activities. One of the most direct ways to evaluate this relationship is to measure the condition of the vegetation cover and land-use information. In southernmost South America there is a limited number of long-term studies on these matters, an incomplete network of weather stations and almost no database on ecosystems productivity. In the present work, we characterized the climate variability of the Magellan Region, southernmost Chilean Patagonia, for the last 34 years, studying key variables associated with one of its main economic sectors, sheep production, and evaluating the effect of extreme weather events on ecosystem productivity and sheep production. Our results show a marked multi-decadal character of the climatic variables, with a trend to more arid conditions for the last 8 years, together with an increase in the frequency of extreme weather events. Significant percentages of aboveground net primary productivity (ANPP) variance is explained by high precipitation, mesic temperatures, and low evapotranspiration. These conditions are, however, spatially distributed in the transition zone between deciduous forests and steppe and do not represent a general pattern for the entire region. Strong precipitation and wind velocity negatively affect lamb survival, while temperature and ANPP are positively correlated. The impact of extreme weather events on ANP and sheep production (SP) was in most of the cases significantly negative, with the exception of maximum temperature that correlated with an increase of ANPP, and droughts that showed a non-significant negative trend in ANPP. The examination of these relationships is urgent under the current scenario of climate change with the acceleration of the environmental trends here detected.

The lack of long and complete instrumental records hampers the study of climatic variability in remote regions of the Earth. Alternatively, paleoenvironmental sources of information such as tree rings provide valuable information on climate variations. In the context of this study, four new tree-ring width chronologies were developed from Nothofagus betuloides in Cordillera Darwin, southern Chile. The main goal of this study is to estimate the influence of the Antarctic Oscillation (AAO) and changes in temperature and rainfall on Nothofagus betuloides tree growth. New tree-ring chronologies were developed from samples collected at Glaciar Schiaparelli valley (54°25' S, 70°54' W) and Valle de los Divorcios (54°36' S, 69°03' W). Four already published tree-ring width chronologies from Nothofagus betuloides in the region were also included in the analysis. Using Principal Component Analysis (PCA) on the eight tree-ring width chronologies, two main growth patterns were identified: PC1 or eastern tree-growth mode, and PC2 or western tree-growth mode. Both components showed significant correlations with air temperature and AAO. PC1 presented significant negative correlations with summer rainfall, temperature and AAO index. On the contrary, PC2 showed significant positive correlations with air temperatures, rainfall and AAO index. Significant growth responses to climate variability indicate that N. betuliodes records could be considered a reliable proxy of environmental fluctuations during the last few centuries in Cordillera Darwin, Chile.

The South American Dendroecological Fieldweek (SADEF) associated with the Third American Dendrochronology Conference was held in El Bolsón, Argentina, in March 2016. The main objective of the SADEF was to teach the basics of dendrochronology while applying specific knowledge to selected research questions. The course included participants and instructors from six different countries. This report describes activities of the course and briefly summarizes exploratory group projects. The Introductory Group developed an Austrocedrus chilensis chronology from 1629–2015 and documented a persistent decline in growth since 1977 which supports the fact that the current severe drought is the most severe in the 386-year record. Based on regional A. chilensis chronologies from 32° to 39°S Latitude, the Stream Flow Reconstruction Group developed a regional 525 year-long reconstruction from Río Chubut and found the most severe drought episodes from 1490 to the present occurred from 1680–1705, 1813–1828, 1900–1920, 1993–2002, and from 2011 to the present. The Drought Reconstruction Group used A. chilensis annual tree-ring width chronologies to develop preliminary spatial field reconstructions of the Palmer Drought Severity Index spanning the Central Andes region. The reconstructions explain up to 81% of the 1907–1975 PDSI variance, indicating this tree species is powerful for informing on historical drought especially in very arid domains. The Dendroecology Group documented three spreading fires since the 1850s with a 12-year return interval but lack of fire for the last 94 years; they also documented a persistent decline in their chronologies in recent years, dating back to 1965.