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High‐Andean peatlands are high‐altitude wetland ecosystems found throughout the arid central Andes of South America. They form through the establishment of specialized grasses and cushion sedges that are well‐adapted to cold temperatures, in areas where groundwater emerges. The Silala River is a groundwater‐fed high‐Andean fluvial system, which emerges in various springs that generate wetlands, the Cajones and Orientales (Bolivia), the river's headwater sources, and the Quebrada Negra (Chile) being the most important. This article reviews detailed monitoring undertaken in the undisturbed Quebrada Negra wetland to provide insights into wetland processes, and to compare its functioning to that of the Bolivian wetlands, which were channelized a century ago. Vegetation composition was found to be similar among the three wetlands, and their spatiotemporal vegetation cover distribution showed strong seasonal and interannual variability. The channelized Bolivian wetlands have the highest annual actual evapotranspiration values (~700 mm, due to their higher vegetation vigor), as estimated using remote sensing, ~10% greater than that obtained in the undisturbed Quebrada Negra wetland. For the Quebrada Negra wetland, groundwater monitoring revealed that hydraulic head contours are consistent with the topography, although water sources to the wetland are complex to identify. While significant groundwater inflows arise at the wetland edges, upwelling and downwelling conditions are observed at various locations within the wetland, similar to other high‐Andean wetlands. The observations suggest that while the underlying groundwater discharge sustains the saturated conditions of the wetland, the spatial variability of groundwater inputs results in a negligible impact of channelization on wetland evapotranspiration. This article is categorized under:Water and Life > Stresses and Pressures on EcosystemsScience of Water > Hydrological Processes [ABSTRACT FROM AUTHOR]

Current scientific evidence shows that humans colonized South America at least 15,000 years ago, but there are still many unknown aspects of this process, including the major and minor migratory routes involved, and the pattern of successive occupation of a diverse continental mosaic of ecosystems. In this context, the role of the Andean highlands (≥3400 meters above sea level) has been neglected, because of the supposedly harsh conditions for humans including hypoxia and cold climate. Nevertheless, the environmental and cultural resources available in the high Andes constitutes an important “megapatch” that should be assessed in terms of human settlement patterns. We review the evidence for late Pleistocene/early Holocene hunter-gatherer occupation of one part of this megapatch, the northern Chilean Dry Puna, in its palaeoecological context. We focus on lithic technology, faunal remains, radiocarbon dates, and other archaeological materials related to different social activities, which allow us to suggest that groups of hunter-gatherers organized and adapted their way of life to highland ecosystems through logistical mobility, and curatorial strategies for lithic tool kits that included projectile points and other formalized tools. The morphology and technological processes involved are recognized over vast territories along the high Andes. We identify this material expression as the high south central Andean Archaic hunter-gatherer tradition, which also featured long distance mobile settlement systems and communication processes over this broad and distinct megapatch. More speculatively, we outline the hypothesis that these highland ecosystems constituted a suitable migratory route that may have been key for the early peopling of the continent, and contrast it with the alternative hypothesis of the initially secondary and seasonally intermittent exploitation of this habitat by hunter-gatherers dispersing along the Pacific coastal corridor. [ABSTRACT FROM AUTHOR]