Variations in rodent fecal pellet sizes from fossil middens reveal past rainfall episodes in the central Atacama Desert.

High-altitude peatlands in the Andes, i.e., bofedales, play an essential role in alpine ecosystems, regulating the local water balance and supporting biodiversity. This is particularly true in semiarid Chile, where bofedales develop near the altitudinal and hydrological limits of plant life. The subterranean geometry and stratigraphy of one peatland was characterized in north-central Chile using Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR) and core extraction. Two sounding locations, two transversal and one longitudinal profile allowed a 3D interpretation of the bofedal’s internal structure. A conceptual model of the current bofedal system is proposed. Geophysical results combined with porosity measurements were used to estimate the bofedal water storage capacity. Using hydrological data at the watershed scale, implications regarding the hydrological role of bofedales in the semiarid Andes were then briefly assessed. At the catchment scale, bofedal water storage capacity, evapotranspiration losses and annual streamflow are on the same order of magnitude. High-altitude peatlands are therefore storing a significant amount of water and their impact on basin hydrology should be investigated further.

En este trabajo se describen las relaciones que las sociedades humanas establecieron con su entorno durante el período Formativo (3000-1000 aP) en la Pampa del Tamarugal, Desierto de Atacama, desde una perspectiva teórico-metodológica que pone el acento en el potencial del registro ecofactual. Éste, al mediar entre lo cultural y lo ambiental, proporciona información vital para una mejor comprensión de la relación entre naturaleza y cultura construida por estas sociedades. Queremos demostrar que este proceso forma parte de una larga historia de racionalización del desierto y de sus recursos silvestres, locales e introducidos, así como de la vivencia particular que tuvieron estas comunidades andinas. Por consiguiente, proponemos que la intervención humana en la Pampa del Tamarugal puede ser entendida como un cambio no sólo ecológico y económico, sino también cosmológico.

The European conquest of the New World produced major socio-environmental reorganization in the Americas, but for many specific regions and ecosystems, we still do not understand how these changes occurred within a broader temporal framework. In this paper, we reconstruct the long-term environmental and vegetation changes experienced by high-altitude wetlands of the southcentral Andes over the last two millennia. Pollen and charcoal analyses of a 5.5-m-long core recovered from the semi-arid puna of northern Chile indicate that while climatic drivers influenced vegetation turnaround, human land use and management strategies significantly affected long-term changes. Our results indicate that the puna vegetation mostly dominated by grasslands and some peatland taxa stabilized during the late Holocene, xerophytic shrubs expanded during extremely dry events, and peatland vegetation persisted in relation to landscape-scale management strategies by Andean pastoralist societies. Environmental changes produced during the post-conquest period included the introduction of exotic taxa, such as clovers, associated with the translocation of exotic herding animals (sheep, cattle, and donkeys) and a deterioration in the management of highland wetlands.

This review paper compiles research related to debris flows and hyperconcentrated flows in the central Andes (30°–33° S), updating the knowledge of these phenomena in this semiarid region. Continuous records of these phenomena are lacking through the Andean region; intense precipitations, sudden snowmelt, increased temperatures on high relief mountain areas, and permafrost degradation are related to violent flow discharges. Documented catastrophic consequences related to these geoclimatic events highlight the need to improve their understanding in order to prepare the Andean communities for this latent danger. An amplified impact is expected not only due to environmental changes potentially linked to climate change but also due to rising exposure linked to urban expansion toward more susceptible or unstable areas. This review highlights as well the need for the implementation of preventive measures to reduce the negative impacts and vulnerability of the Andean communities in the global warming context.

Este trabajo pretende introducir a los usos e imaginarios relacionados con las plantas en las aldeas formativas de la Pampa del Tamarugal, Tarapacá (Chile). Se estudiaron los restos vegetales recuperados de las excavaciones de los sitios Pircas y Caserones, en la quebrada de Tarapacá, así como de Guatacondo 1 y Ramaditas, en la de Guatacondo. Estas aldeas poseen contextos domésticos, ceremoniales, mortuorios y de almacenaje, asociados a alimentos silvestres y cultivados, así como un amplio universo artefactual, principalmente en madera, que incluye materias primas, instrumentos y desechos de talla. Se concluye que, si bien las cuatro aldeas comparten aspectos significativos como su orientación agrícola y forestal, las ocupaciones de ambas cuencas expresan situaciones disímiles que permiten cuestionar la noción evolucionista que se ha tenido del período Formativo como una sucesión unilineal de etapas de progreso.