Megafauna in South America became extinct by the end of the Late Pleistocene and the relative role of human influence, climate, and other indirect factors in driving these population declines is still a matter of debate. The Campo Laborde archeological site (Pampas, Argentina) offers an exceptional opportunity to understand the complex interactions between climate, ecosystems, and human populations during that time. This study integrates biological proxies (pollen, diatoms, chrysophytes, silicophytoliths) within a stratigraphic framework (sedimentological and geochemical analyses) to reconstruct the paleoenvironmental conditions that prevailed before, during, and after the megamammal hunting and processing event. The results indicate a gradual environmental shift from a stable aquatic environment characterised by greater water availability to a more unstable, shallow and periodically desiccated aquatic environment. Particularly, during the human occupation of the site (similar to 12,600 cal years BP), the shallow and flooded areas acted as attractive zones due to the availability of vital resources such as water, vegetation, and fauna. This environmental evolution was primarily driven by local factors (e.g. topographic setting and hydrological dynamics) and secondarily by regional processes (seasonal precipitation). These results emphasise the importance of paleoecological studies to reconstruct detailed environmental histories at both local and regional scales.

To understand plant community succession; paleoenvironmental history, and to contribute to the regional knowledge base for the eastern area of the Southern Patagonian Icefield (SPIF), we present a paleoenvironmental reconstruction from the last glacial-interglacial transition to the early Holocene (18,500 to 9000 cal yr BP). This research was based on pollen and plant macrofossil analyses together with lithostratigraphy characterization from a sequence obtained at the Mallin Cipres wetland (49 degrees S; Southern Santa Cruz, Patagonia, Argentina). Between 18,500 and 16,000 cal yr BP, cold and arid conditions prevailed in the study area with dwarf-shrub communities dominated by Ephedra, likely under weakened Southern Westerly Winds (SWW). From 16,000 to 12,800 cal yr BP, a shift to grass-dwarf-shrub steppes occurred, along with increased moisture and expansion of Nothofagus, likely driven by stronger SWW contemporaneous with the Antarctic Cold Reversal. Between 12,800 and 9600 cal yr BP, we observe a western grass steppe with Nothofagus forest expansion, indicating warmer but relatively arid conditions under weaker westerly winds. Pilgerodendron began to establish at 10,500 cal yr BP, marking the onset of the wetland's modern dynamics. After 9600 cal yr BP, the significant spread of Nothofagus forest reflects increased moisture during early Holocene warming. This study addresses a critical gap in paleoecological knowledge of the eastern SPIF, providing insights into the influence of SWW variability, temperature fluctuations, and glacial dynamics on vegetation development between 48 degrees and 52 degrees S.

At 47° S in Argentine Patagonia, the interaction between the Southern Westerly Winds (SWW) and the Andean barrier generates a steep climatic gradient, providing an ideal setting to evaluate Holocene vegetation responses. This study focuses on the extra-Andean sector, where new pollen records from La Tapera (LTap) and Cisne 7 provide insights into steppe vegetation dynamics under dry conditions. These sequences are contrasted with previously studied records further west (LF, ZB, CMN1, CMN2, and COCU) to assess west–east gradients in vegetation change and moisture availability throughout the Holocene. Western records indicate that the Early Holocene was dominated by grass–dwarf-shrub steppe under arid conditions, followed by increased humidity around 7600 cal yr BP that promoted the development of forest–steppe ecotonal environments. The Middle Holocene was characterised by aridity, reflected in shrub dominance and reduced forest signals, whereas the Late Holocene included a humid pulse between ~1750 and 1000 cal yr BP, followed by renewed aridity over the last millennium. In contrast, eastern records show persistent shrub–dwarf-shrub steppes since ~4700 cal yr BP, with vegetation changes expressed mainly as shifts in the relative dominance of shrubs and dwarf–shrubs rather than floristic replacements. Archaeological sites corroborated and complemented the continuous records, strengthening the reconstruction of environmental variability across different temporal windows. Overall, this west–east comparison highlights the differential sensitivity of ecosystems to SWW fluctuations, reinforcing their role as an important forcing of hydrological balance and vegetation dynamics in mid-latitude Patagonia.

In this research, we reconstruct the paleoenvironmental conditions from a sedimentary record of a wetland (mallín) located in the Patagonian steppe near to the Subantarctic forest on the northeastern shore of the San Martín Lake basin (SW Santa Cruz, Patagonia, Argentina). The Mallín Ñire (49° 00’ 23.5” S; 72° 13’ 34.5” W) presents a basal age of 10,200 cal. years BP and its pollen content, carbon isotopes, and stratigraphy were analyzed. The relationship with modern pollen assemblages from surface sediment samples allows us to interpret changes in the fossil record. Between 10,200 and 9,000 cal. years BP, we can infer a grass-shrub steppe with dwarf-shrubs under arid conditions and between 9,000 and 6,500 cal. years BP, a grass steppe dominated under an increase of moisture availability. Conditions became drier until 4,000 cal. years BP; later, a grass-shrub steppe developed, which suggests an environmental transition like the modern ones. The last 1,400 cal. years BP present high paleoenvironmental variability. The integration with other sequences allowed us to interpret the regional changes during the Holocene related to moisture availability by precipitation changes related to the westerly variations.

In this research, we reconstruct the paleoenvironmental conditions from a sedimentary record of a wetland (mallín) located in the Patagonian steppe near to the Subantarctic forest on the northeastern shore of the San Martín Lake basin (SW Santa Cruz, Patagonia, Argentina). The Mallín Ñire (49° 00’ 23.5” S; 72° 13’ 34.5” W) presents a basal age of 10,200 cal. years BP and its pollen content, carbon isotopes, and stratigraphy were analyzed. The relationship with modern pollen assemblages from surface sediment samples allows us to interpret changes in the fossil record. Between 10,200 and 9,000 cal. years BP, we can infer a grass-shrub steppe with dwarf-shrubs under arid conditions and between 9,000 and 6,500 cal. years BP, a grass steppe dominated under an increase of moisture availability. Conditions became drier until 4,000 cal. years BP; later, a grass-shrub steppe developed, which suggests an environmental transition like the modern ones. The last 1,400 cal. years BP present high paleoenvironmental variability. The integration with other sequences allowed us to interpret the regional changes during the Holocene related to moisture availability by precipitation changes related to the westerly variations.

This paper reconstructs the vegetation history of the Lake Pueyrredón area during the Holocene and contextualizes the use of space and resources by hunter-gatherer groups according to palaeoenvironmental evolution. The pollen analysis of the Los Flamencos lake sequence is presented and integrated with local archaeological pollen data. Early Holocene vegetation consisted of a dwarf-shrub-grass steppe associated with cold conditions. From 7,600 cal bp a shrub vegetation with forest patches is inferred, suggesting a high moisture availability and possibly involving an eastwards displacement of the forest-steppe ecotone boundary. Human occupation, previously interrupted by the Hudson volcano eruption, and use of space is evident in this period. Between 6,600 and 5,400 cal bp an environmental change to drier conditions suggests a heterogeneous shrub steppe and the higher availability of floristic resources possibly used by hunter-gatherer groups. The predominance of shrub steppe with dwarf shrubs from 5,400 cal bp indicates more arid than current conditions, which correlates with a higher human-environment interaction related to changes in the lake configuration allowing new north–south circulation roads and vice versa, and major floristic resources availability. A decrease in dwarf-shrubs indicates a slight increase in moisture availability since 3,550 cal bp, suggesting a weakening of the westerly winds. The results indicate local and regional changes in vegetation linked mainly to moisture availability and Southern Westerly Winds fluctuations. The integration of pollen, archaeological and palaeogeographic information available and its comparison with other fossil records studied in Patagonia complement palaeoenvironmental reconstruction and explain the changes in a regional palaeoenvironmental framework.

Patagonian shrub and ecotonal communities were sensitive to past environmental changes and thus may also be affected by future ones. Therefore, their paleoecological study constitutes a valuable tool to understand the way in which these plant communities respond to the forcings responsible for environmental variability. The aim of this paper is to reconstruct the vegetation dynamics of the Pueyrredón Lake area (47°25′55′′ S; 72°0.7′7′′ W) for the last 3000 cal yr BP and to contextualize these changes in a regional paleoclimatic framework. The results indicate that at the beginning of the 2900 cal yr BP, the vegetation in the northwest of Santa Cruz, Argentinian Patagonia, was represented by a grass-shrub steppe associated with forest–shrub steppe ecotonal elements. This information correlates with the larger-scale environmental inferences described for the period, which indicate an increase in moisture availability due to the weakening of the westerly winds. A marked change to arid conditions is indicated in the last 1050 cal yr BP, with the establishment and development of different shrub steppe communities and the lack of ecotonal elements. Although vegetation was sensitive to changes in moisture conditions related to the variability of the westerly winds, there is evidence of differences in the composition of shrub vegetation regarding the sequences analyzed. Variations in pollen proportions of the shrub steppes in the Pueyrredón Lake area suggest that changes in vegetation are not only due to climate variability but also local factors in the areas where shrub communities grow. The integration of the information with other Patagonian sequences allowed to frame these changes in a regional context. The results obtained provide useful information to understand the way vegetation changed in the past and the manner in which it may respond to future changes.

Palaeoecological reconstructions document past vegetation distribution with estimates of the communities boundaries shifts. This work presents a compilation of palaeoecological studies from southern Patagonia Argentina as a contribution to a better understanding of the composition and distribution of Andean and extra-Andean plant communities. Paleoenvironmental reconstructions are based on pollen sequences from different types of deposits located in the forest, forest-steppe ecotone and steppes between 46° and 51°S. The comprehension of modern pollen and its relation with the actual vegetation is a critical component of palaeoecological research. Models of the current relationship pollen-vegetation-climate were applied to interpret these sequences. Their integration made it possible to reconstruct the spatio-temporal patterns of vegetation and past climatic changes since the Late Glacial-Holocene transition. Four areas were selected to map past vegetation communities; three lake basins: Pueyrredón, San Martín and Argentino, and the Deseado Massif. The local conditions given by the geomorphology of each site were also taken into account. The vegetation reconstruction during the Pleistocene-Holocene transition came from records located in the Deseado Massif only, and indicated steppes, without modern analogues, linked to arid and cold conditions. During the Holocene, plant communities were sensitive to moisture conditions related to westerly winds or Atlantic-derived precipitation events. Taxa related to the anthropogenic impact of the past centuries were found at all sites, both in Andean and extra-Andean Patagonia.

This work presents the first Monte desert palaeofire record from an ephemeral northern Patagonia pond called Bajo de la Quinta (40 55' 42 "S; 64 20' 19''W). The aims of this study are (1) to reconstruct past fire regime changes related to vegetation variability during the last 4000 cal yrs BP for the southern Monte region; (2) to discuss the importance of climatic versus anthropogenic control of fire regime at different periods; and (3) to integrate these results with other fossil pollen sequences located in North Patagonia (between 39 and 43S), to infer centennial to millennial-scale changes in vegetation, linked to major palaeoclimatic variability. Long-scale fire-vegetation changes have characterised the southern Monte desert modifying vegetation intra-community patches distribution. The heterogeneous two-phase mosaic shrubland distribution is more resilient to fire at centennial to millennial scales than homogeneous high vegetation coverage. Southern Monte desert presents current fire regime characteristics since the last two centuries, which may be related to livestock introduction and the subsequent increase in human -induced-fires and changes in biomass availability. Also, the use of the composite Nothofagus pollen abundance index and the comparison between sequences located along the west -east precipitation gradient of North Patagonia (between 39 and 43S), suggests synchronous but in opposite direction humidity availability long term changes affecting vegetation and fire behavior in Northern Patagonia during the Late Holocene.

Fil: Marcos, Maria Alejandra. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biologia. Laboratorio de Paleoecologia y Palinologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Paleoecological studies in Patagonia provide information about vegetation and climate changes occurred during the Holocene. The climatic evolution of this region offers a unique opportunity to study the environmental variability as well as the ecosystem variations. The dynamic of the forest ecosystems is modulated by the occurrence of disturbances. Fires are one of the most important disturbances in temperate forest ecosystems, and its study allows contrasting independently about the changes experienced by ecosystems. In addition, in Patagonia, environmental and postglacial vegetation changes have been determined by variations in the temperature and westerlies winds. In order to reconstruct changes experienced by the forest ecosystem and patterns of plant diversity during the Holocene, in relation to Postglacial dynamics, natural and anthropic disturbances in the Lake Argentino, pollen and charcoal were studied in a sedimentary sequence at Peninsula Avellaneda. Pollen assemblages suggest non-cyclic changes in plant diversity during the Holocene. The highly diverse cold grass-shrub communities dominated the area up to the Early Holocene, when they were displaced upland by less diverse forest and steppes. Also, The Early and Midd-Holocene was characterized by opposite variations of hydric balance between Andean and extra-andean plant communities present between 48 degrees and 50 degrees S, whereas fire activity occurs synchronously between forest (Andean) and steppe communities (Extra-andean). Late Holocene is characterized by different proxy signals depending on the geographical location of the paleoecological records. To conclude, this work provides a better understanding of the fossil pollen record by its comparison with modern surface pollen samples along an altitudinal vegetation gradient.

Paleoecological studies in Patagonia provide information about vegetation and climate changes occurred during the Holocene. The climatic evolution of this region offers a unique opportunity to study the environmental variability as well as the ecosystem variations. The dynamic of the forest ecosystems is modulated by the occurrence of disturbances. Fires are one of the most important disturbances in temperate forest ecosystems, and its study allows contrasting independently about the changes experienced by ecosystems. In addition, in Patagonia, environmental and postglacial vegetation changes have been determined by variations in the temperature and westerlies winds. In order to reconstruct changes experienced by the forest ecosystem and patterns of plant diversity during the Holocene, in relation to Postglacial dynamics, natural and anthropic disturbances in the Lake Argentino, pollen and charcoal were studied in a sedimentary sequence at Peninsula Avellaneda. Pollen assemblages suggest non-cyclic changes in plant diversity during the Holocene. The highly diverse cold grass-shrub communities dominated the area up to the Early Holocene, when they were displaced upland by less diverse forest and steppes. Also, The Early and Midd-Holocene was characterized by opposite variations of hydric balance between Andean and extra-andean plant communities present between 48° and 50° S, whereas fire activity occurs synchronously between forest (Andean) and steppe communities (Extra-andean). Late Holocene is characterized by different proxy signals depending on the geographical location of the paleoecological records. To conclude, this work provides a better understanding of the fossil pollen record by its comparison with modern surface pollen samples along an altitudinal vegetation gradient.

Los sitios arqueológicos presentes en Santa Cruz han brindado importante información sobre los cambios de la vegetación y del clima en diferentes escalas espaciales y temporales. En este trabajo presentamos ejemplos metodológicos para analizar los datos polínicos actuales y del registro fósil de cuatro secuencias arqueológicas (CMN1 y COCU a los 47°S; 71°O y B1Oq y CPD a los 49°S; 72°O) ubicadas al oeste de Santa Cruz. A partir de estos resultados se discuten los alcances y los límites interpretativos de los datos utilizados. Nuestros resultados indican que los análisis polínicos actuales han permitido diferenciar con significancia estadística las unidades de vegetación a escala local y regional para ambas áreas. Las secuencias estudiadas han permitido estimar la representación espacial de los registros fósiles mediante un análisis de correspondencia destendenciado. CMN1 y CPD reflejan cambios en la vegetación a mesoescala y a escala regional verificables con otras secuencias continuas de lagos y mallines (47°-49º; 50°S), mientras que COCU y B1Oq indican una señal local de la vegetación. Si bien debe considerarse cuidadosamente el alcance de los datos para abordar la pregunta paleoambiental, las secuencias arqueológicas brindan valiosa información y son muy importantes en aquellos ambientes donde no hay disponibilidad de secuencias naturales continuas (como lagos, mallines, lagunas). En este trabajo concluimos que los análisis estadísticos son una herramienta importante que complementan nuestros análisis. Además, es necesario conocer las particularidades de las áreas de estudio, la vegetación circundante, su geomorfología, y la representación espacial de los registros actuales y fósiles para reflejar con mayor fidelidad los estudios polínicos.

Fil: Marcos, Maria Alejandra. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The Medieval Climate Anomaly (MCA) is a climatic perturbation with a core period of 1000-1200 AD that is well-recognized in the Northern Hemisphere (NH). Its existence in the Southern Hemisphere (SH) and the level of synchronicity with the NH is still a matter of debate. Here we present a palaeotemperature synthesis for South America encompassing the past 1500 years based on multiproxy data from 76 published land and marine sites. The data sets have been thoroughly graphically correlated and the MCA trends palaeoclimatologically mapped. The vast majority of all South American land sites suggest a warm MCA. Andean vegetation zones moved upslope, glaciers retreated, biological productivity in high altitude lakes increased, the duration of cold season ice cover on Andean lakes shortened, and trees produced thicker annual rings. Similar MCA warming occurred in coastal seas, except in the year-round upwelling zones of Peru, northern Chile and Cabo Frio (Brazil) where upwelling processes intensified during the MCA due to changes in winds and ocean currents. MCA warming in South America and the NH appears to have occurred largely synchronous, probably reaching comparable intensities. Future studies will have to address major MCA data gaps that still exist outside the Andes in the central and eastern parts of the continent. The most likely key drivers for the medieval climate change are multi-centennial Pacific and Atlantic ocean cycles, probably linked to solar forcing.

Resumen. En este trabajo se discuten los diferentes aspectos metodológicos a tener en cuenta en los estudios paleoecológicos. Las consideraciones teóricas y metodológicas discutidas incluyen los siguientes aspectos: tipos de depósitos, procesos tafonómicos, representación polínica actual a partir de muestras de sedimento y registro de la vegetación, suma polínica representativa de la composición de la comunidad vegetal, productividad polínica diferencial y dispersión de taxones y su representación espacial, precisión taxonómica y la comparación con la vegetación en cada área, y análisis de múltiples indicadores. Las investigaciones realizadas por los autores en distintas áreas y depósitos de Patagonia, basadas principalmente en el análisis polínico, se utilizaron para ejemplificar y sintetizar estos diferentes aspectos y su importancia en la reconstrucción de ambientes del pasado. La integración de datos provenientes de múltiples sitios permitió reducir las limitaciones impuestas por las incertidumbres contenidas en el conjunto de datos de un único sitio, por ejemplo, discontinuidades, sesgos, sobre o subrepresentaciones de taxones. Esta integración también permitió poner a prueba hipótesis sobre cambios en el clima a escala regional a partir de los cambios en la vegetación. Palabras clave. Análisis polínico. Aspectos metodológicos. Tipos de depósitos. Tafonomía. Relación polen-vegetación. Múltiples indicadores. Abstract. PALEOECOLOGICAL ANALYSES AND METHODS FOR FOREST AND STEPPE COMMUNITIES RECONSTRUCTION IN PATAGONIA, ARGENTINA. In this paper we discuss the different methodological aspects to be taken into account in paleoecological studies. The theoretical-methodological considerations discussed include the following aspects: deposit types, taphonomic processes, pollen representation from modern sediment samples and vegetation records, pollen sum representative of the plant community composition, differential productivity and dispersion of taxa and their spatial representation, taxonomic precision and comparison with vegetation in each area, and multiproxy analysis. The investigations carried out by the authors in different areas and deposits of Patagonia, based mainly on palynological analysis, were applied to exemplify and synthesize these different aspects and their importance in the environmental reconstruction of the past. The data set integration from multi-site allowed us to overcome limitations contained in a single site data set, such as discontinuities, biases, or taxa overrepresentations. This integration also allowed us to test climate change hypotheses at a regional scale based on vegetation changes. Key words. Pollen analysis. Methodology. Deposit types. Taphonomy. Pollen- vegetation relationship. Multiproxies.

Resumen. La palinología de sitios arqueológicos o arqueopalinología ha sido frecuentemente utilizada en la Argentina tanto para reconstruir la vegetación y los ambientes desde el final del Pleistoceno Tardío hasta tiempos recientes, como para inferir ciertas actividades culturales desarrolladas dentro de los sitios arqueológicos. En el presente trabajo se realizó una revisión de los análisis polínicos realizados a partir de depósitos sedimentarios en sitios arqueológicos en cuevas, aleros y en contextos abiertos correspondientes a sociedades de cazadores-recolectores de la Argentina (32º–52º S), independientemente del periodo cronológico o cultural. Se explican las metodologías aplicadas y los resultados obtenidos y se discuten (1) las limitaciones del análisis polínico; (2) las diferentes formas en que los datos de polen son útiles en este tipo de sitios arqueológicos, y (3) los procesos tafonómicos tales como dispersión, depositación y preservación polínica en estos ambientes depositacionales. La potencialidad y aplicación del análisis polínico en arqueología de sitios cazadores-recolectores se ejemplificó con trabajos representativos en la región pampeana y patagónica, donde se han realizado la mayoría de los estudios arqueopalinológicos. Estos estudios, aunque complejos, ofrecen oportunidades únicas para comprender los entornos y las actividades humanas del pasado. Palabras clave. Palinología. Arqueología. Tafonomía polínica. Abstract. ARCHEOPALYNOLOGY: A REVIEW OF POLLEN ANALYSIS IN CAVES, SHELTERS AND OPEN CONTEXTS OCCUPIED BY HUNTERGATHERER SOCIETIES OF ARGENTINA (32º–52º S). Archeopalynology has been frequently used in Argentina to reconstruct vegetation and environments since the end of Late Pleistocene to the present, and to infer different cultural activities developed into the archaeological sites. The present paper presents a review of pollen analysis of sedimentary sequences from archaeological sites located in caves, shelters and open contexts occupied by hunter-gatherer societies of Argentina (32º–52º S), regardless the chronological or cultural period. The methodologies applied and results obtained are explained and the following topics are discussed (1) the limitations of the pollen analysis; (2) the different ways in which pollen data are useful in this type of archaeological sites; and (3) the taphonomic processes such as pollen dispersal, deposition and preservation in these depositational environments. The potentiality and application of pollen analysis in archaeology of hunter-gatherer sites were exemplified by representative works in the Pampa and Patagonia regions, where most of the archeopalynology studies have been carried out. These studies, often complex, offer unique opportunities to understand the environments and human activities of the past. Key words. Palynology. Archaeology. Pollen taphonomy.

The core of the storm track flow intersects the landmass of Southern Patagonia providing a unique opportunity for palaeo-reconstructions. Most of the palaeo-reconstructions are based on records from sites where the relationship between precipitation and wind flow intensity, can be reconstructed from the impact on vegetation communities. Seven sites were selected for this study. The importance relies on their location in relation to vegetation communities; two sites lie within forest communities, two are from the forest-steppe ecotone and the other three from steppe communities in Southern Patagonia, Argentina, between 48° and 52.5° S and between 70° and 72° W. To compare the past palaeohydric balance based on the seven pollen records from these different vegetation communities along the precipitation gradient, we constructed a Palaeohydric Balance Index (PBI). The PBI is based on the water requirement of the main plant taxa represented by the pollen types analyzed in the records. The information provided by this index improves the understanding of the hydric balance variability in relation to the storm track behavior. During the last 8000calyrsBP we observed out-of-phase behavior in PBI variations between forest, forest-steppe ecotone and steppe PBIs, a greater amplitude of forest versus steppe environments and low amplitude of the forest-steppe ecotone variability. This out-of-phase behavior appears to have been replaced by in-phase palaeohydric changes between 700 and 500calyrsBP interpreted as related to an equatorward migration of the storm tracks.

Abstract. The Southern Hemisphere Westerly Winds (SWW) constitute an important zonal circulation system that dominates the dynamics of Southern Hemisphere mid-latitude climate. Little is known about climatic changes in the Southern South America in comparison to the Northern Hemisphere due to the low density of proxy records, and adequate chronology and sampling resolution to address environmental changes of the last 2000 years. Since 2009, new pollen and charcoal records from bog and lakes in northern and southern Patagonia at the east side of the Andes have been published with an adequate calibration of pollen assemblages related to modern vegetation and ecological behaviour. In this work we improve the chronological control of some eastern Andean previously published sequences and integrate pollen and charcoal dataset available east of the Andes to interpret possible environmental and SWW variability at centennial time scales. Through the analysis of modern and past hydric balance dynamics we compare these scenarios with other western Andean SWW sensitive proxy records for the last 2000 years. Due to the distinct precipitation regimes that exist between Northern (40–45° S) and Southern Patagonia (48–52° S) pollen sites locations, shifts on latitudinal and strength of the SWW results in large changes on hydric availability on forest and steppe communities. Therefore, we can interpret fossil pollen dataset as changes on paleohydric balance at every single site by the construction of paleohydric indices and comparison to charcoal records during the last 2000 cal yrs BP. Our composite pollen-based Northern and Southern Patagonia indices can be interpreted as changes in latitudinal variation and intensity of the SWW respectively. Dataset integration suggest poleward SWW between 2000 and 750 cal yrs BP and northward-weaker SWW during the Little Ice Age (750–200 cal yrs BP). These SWW variations are synchronous to Patagonian fire activity major shifts. We found an in phase fire regime (in terms of timing of biomass burning) between northern Patagonia Monte shrubland and Southern Patagonia steppe environments. Conversely, there is an antiphase fire regime between Northern and Southern Patagonia forest and forest-steppe ecotone environments. SWW variability may be associated to ENSO variability especially during the last millennia. For the last 200 cal yrs BP we can concluded that the SWW belt were more intense and poleward than the previous interval. Our composite pollen-based SWW indices show the potential of pollen dataset integration to improve the understanding of paleohydric variability especially for the last 2000 millennial in Patagonia.