Rodrigo Vega

New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile

Questions surrounding the chronology, place, and character of the initial human colonization of the Americas are a long-standing focus of debate. Interdisciplinary debate continues over the timing of entry, the rapidity and direction of dispersion, the variety of human responses to diverse habitats, the criteria for evaluating the validity of early sites, and the differences and similarities between colonization in North and South America. Despite recent advances in our understanding of these issues, archaeology still faces challenges in defining interdisciplinary research problems, assessing the reliability of the data, and applying new interpretative models. As the debates and challenges continue, new studies take place and previous research reexamined. Here we discuss recent exploratory excavation at and interdisciplinary data from the Monte Verde area in Chile to further our understanding of the first peopling of the Americas. New evidence of stone artifacts, faunal remains, and burned areas suggests discrete horizons of ephemeral human activity in a sandur plain setting radiocarbon and luminescence dated between at least ~18,500 and 14,500 cal BP. Based on multiple lines of evidence, including sedimentary proxies and artifact analysis, we present the probable anthropogenic origins and wider implications of this evidence. In a non-glacial cold climate environment of the south-central Andes, which is challenging for human occupation and for the preservation of hunter-gatherer sites, these horizons provide insight into an earlier context of late Pleistocene human behavior in northern Patagonia.

Glacier expansion in southern Patagonia throughout the Antarctic cold reversal

Resolving debated climate changes in the southern middle latitudes and potential teleconnections between southern temperate and polar latitudes during the last glacial-interglacial transition is required to help understand the cause of the termination of ice ages. Outlet glaciers of the Patagonian Ice Fields are primarily sensitive to atmospheric temperature and also precipitation, thus former ice margins record the extent and timing of past climate changes. 38 10 Be exposure ages from moraines show that outlet glaciers in Torres del Paine (51°S, south Patagonia, Chile) advanced during the time of the Antarctic cold reversal (ACR; ca. 14.6– 12.8 ka), reaching a maximum extent by ~14,200 ± 560 yr ago. The evidence here indicates that the South Patagonian Ice Field was responding to late glacial climate change distinctly earlier than the onset of the European Younger Dryas stadial (ca. 12.9 ka). Major glacier recession and deglaciation in the Torres del Paine region occurred by 12.5 ka and thus early in the Younger Dryas. We provide direct evidence for extensive ice in Patagonia at the very start of the ACR that agrees with atmospheric and marine records from the Southern Ocean and Antarctica. Atmospheric conditions responsible for the early late glacial expansion at Torres del Paine resulted from a climate reorganization that prompted a northern migration of the south westerly wind belt to the latitude of Torres del Paine at the onset of the ACR chronozone.

Species catch composition, length structure and reproductive indices of swordfish (Xiphias gladius) at Easter Island zone

The species composition, size distribution, and gonadal index (GI) of swordfish (Xiphias gla- dius) are reported from catches obtained by longliners in the zone of Easter Island in the southeastern Pacific. Five cruises were made during the summer season between 2001 and 2006 completing a total of 150 fishing sets. A total of 3,781 fish belonging to 24 species were registered, of which 17 were commercial and 6 were bycatch. Of the total, 44.1% were swordfish, 28.3% sharks, 12.1% marlins, 8.4% tunas and 7.1% other teleosts. Amongst the sharks the most important species was the blue shark (Prionace glauca, 16.5%) fol- lowed by the brown shark (Carcharhinus spp., 6.9%). Amongst the tunas and istiophorids, striped marlin (Tetrapturus audax, 8.0%) and yellowfin tuna (Thunnus albacares, 4.9%) were also important (≥ 4% in num- ber). The number of units by species, the nominal yield in number and weight and the gutted average weight are reported in addition to size statistics. The population structure of swordfish was dominated by males and differences in the average length between sexes were not found. Individuals with high values of GI were ob- served during every survey, mainly during December-February which suggests a reproductive area for this species. The blue shark showed a predominance of males, and differences in the average length between sexes were observed, possibly due to a spatial and temporal segregation.

Environmental conditions associated with swordfish size compositions and catches off the Chilean coast

Multivariate analyses were applied to explore the relative influence of environmental factors on swordfish (Xiphias gladius) size compositions and catches off Chile. A first analysis was applied to a commercial fishing data base made up of biological-fishery and environmental records from 343 fishing sets performed between 2000 and 2002 by two longline vessels. Furthermore, a data base of fishing research cruises over the Cordillera de Nazca was analyzed; this set consisted of biological-fishery and environmental satellite information recorded for 43 fishing sets done in summer and winter 2003 and autumn and spring 2005. Principal component and hierarchical classification analyses were applied to seven environmental vari- ables (Latitude, Longitude, Sea surface temperature, Chlorophyll a concentration, Sea surface height, Sea sur- face salinity, Bathymetry), all of which may affect the distribution of swordfish size compositions and catches. The analyses indicate four spatial groups representing specific latitudinal locations and typologies of environmental conditions associated with the swordfish size compositions and catches in the study area. Swordfish were caught within a range of SST that varied from 16 to 22oC, with larger catches given smaller SSTs, greater chlorophyll concentrations, and higher latitudes. A latitudinal gradient in size composition is af- firmed, with juvenile specimens associated with warmer conditions, greater salinity, lower chlorophyll con- centrations, and lower latitudes. The geographic distribution of the recruitment zone is associated with the Cordillera de Nazca marine area.

Seamounts in the southeastern Pacific Ocean and biodiversity on Juan Fernandez seamounts, Chile

Seamounts are vulnerable marine ecosystems. In Chile, information on these ecosystems is quite scarce; thus, a compilation of information on their geographical distribution and biodiversity is presented herein. A total of 118 seamounts distributed in the Chilean EEZ are identified and characterized. Additionally, an in situ assessment was carried out on the Juan Fernandez seamounts 1 and 2 (JF1 and JF2), which were also oceanographically characterized. Phytoplankton, zooplankton, and marine invertebrate samples were collected and an exploratory fishing survey was executed using different gears. According to the bibliographical review, a total of 82 species have been collected on the JF1 and JF2 seamounts, highlighting findings of black coral species caught in lobster traps at the Juan Fernandez Archipelago. Submarine images of the marine substrate at JF1 and JF2 reveal characteristics attributable to the impact of bottom dredges, coinciding with the information obtained from the trawling fleet. The fishing activity was carried out primarily at JF2 (4,667 km of trawling). The monthly fishing effort increased considerably in 2002, 2003, and 2005, reaching values above 500 km of trawling and, thus, modifying the spatial structure of the resource aggregates on the JF2 seamount.

An integrated conceptual approach to study the swordfish (Xiphias gladius Linnaeus, 1758) fishery in the eastern South Pacific

espanolSe analizo la informacion disponible sobre el entorno ambiental, biologico, ecologico y pesquero asociado a la explotacion de la unidad de stock de pez espada (Xiphias gladius) del Pacifico suroriental, ademas de una revision bibliografica de modelos que orientan una aproximacion ecosistemica en la administracion de pesquerias. De esta forma, se establecio un modelo conceptual que incorpora procesos definidos en tres planos, con tres escalas espaciales (Oceano Pacifico, Pacifico suroriental y area de la pesqueria) y tres escalas temporales (interanual, estacional e intraestacional). La distribucion geografica, su historia de vida y la actividad migratoria que desarrolla el pez espada, implicaron considerar en el modelo, los estados de huevos y larvas, juveniles y adultos, en las zonas de reproduccion, crianza y alimentacion de adultos. Sin desconocer la investigacion pesquera operativa que se realiza actualmente, el modelo conceptual propone la dimension de trabajo para el desarrollo de un manejo pesquero integrador. EnglishThe available environmental, biological, ecological, and fishery data associated with the exploitation of swordfish (Xiphias gladius) in the eastern South Pacific were analyzed and the literature on models aiming at an ecosystem approach to fisheries management was reviewed. The conceptual model set forth in this work incorporates three planes with processes defined on three spatial (Pacific Ocean, eastern South Pacific, fishing area) and three temporal (interannual, seasonal, intraseasonal) scales. Because of the swordfish�s geographic distribution, life history, and migratory activity, the model must consider several developmental states (eggs and larvae, juveniles, adults) inhabiting different grounds (spawning, breeding, adult feeding). The conceptual model presented herein, without detracting from current operational fisheries research, suggests what must be done to develop integrated fishery management.

Identification of the spatial-temporal distribution pattern of swordfish (Xiphias gladius) in the southeastern Pacific

The pattern of the spatial-temporal distribution of the fishing yields (catch rates) of swordfish (Xiphias gladius) from the Chilean industrial longline fleet it was determined using generalized additives models, autocorrelation analysis and Fourier spectral analysis. The basic information came from fishing log- book recorded by scientific observers between January 2001 and December 2005. The generalized additives models included five physical variables (latitude, longitude, date, lunar index and sea surface temperature (SST)), which affect the availability and vulnerability of swordfish, and two operational variables (length of the vessel and type of longline), which are directly associated with the effectiveness of the fishing system. The non-linear effects were established significantly (p < 0.01) for each of the independent variables. There was a typical annual cycle in the catch rates, with high values from March to July/August, and displacement of the fishing operation northward from the 38° to 32°S, in a SST range of 17° to 19°C. Subsequently, catch rates decrease in a northerly direction from 32°S in SST higher than 20°C. This spatial-temporal pattern was determinates with a high square coherency (79%) in the time series of nominal catch rates and latitudinal component analyzed in the Fourier spectral analysis. It also established for the time series of swordfish nomi- nal catch rates, low-frequency fluctuations with periods of 28, 38 and 59 days. This intraseasonal variability in swordfish catch rates coincides with changes in mesoscale oceanographic conditions in the area where the fishery is developed off the coast of Chile.

Correction: New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile

The images for Figs ​Figs77 and ​and88 have been incorrectly swapped. Please view the correct Figs ​Figs77 and ​and88 here. Fig 7 Serpentine pebble tool from Unit 17, MV-I, showing bifacially knapped and retouched edge. Serpentine is a raw material available in the coastal cordillera west of Monte Verde. Fig 8 Basalt wedge showing seven facets on obverse face (one of which is cortex) and three on the reverse face.

Environmental Responses to Climatic and Cultural Changes

Geological sediment cores from the Puren-Lumaco Valley are analyzed for the sedimentological, geochemical, pollen, chironomids, diatoms, and charcoal patterns during the last 26 years.

Stratigraphy and sedimentology of a late Pleistocene incised valley fill: a depositional and paleogeographic model for “Cancagua” deposits in north-western Patagonia, Chile

Late Pleistocene sedimentary deposits outcropping around Valdivia city, locally known as Cancagua, have been subject of contrasting interpretations, from glacial to interglacial sediments. Opposing views emerge from focusing on upstream or coastal sedimentary controls, within a zone were these potentially overlap through a full glacial cycle. Here we present the first detailed facies analysis and a broad chronological framework, reconciling previous interpretations in a single paleogeographic model that encompasses the last glacial cycle. Seven facies associations are described, interpreted as an estuarine complex developed primarily during the last glacial cycle’s highstand, yet accumulating sediments during a substantial part of the falling stage. These results offer the opportunity to extend paleoenvironmental records through a full glacial cycle in northern Patagonia.