Evidence of moist niches in the Bolivian Andes during the mid-Holocene arid period

Ledru, Marie‐Pierre; Jomelli, Vincent; Brémond, Laurent; García-Ortuño, Teresa; Cruz, Pablo; Bentaleb, I.; Sylvestre, Florence; Kuentz, Adèle; Beck, Stephan; Martin, Céline; Paillès, Christine; Subitani, Sandrine

doi:10.1177/0959683613496288

Cited by 27 publications

(46 citation statements)

References 87 publications

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“…Paleorecords located on both sides of the Central Andes point to dry conditions during the mid-Holocene, with greater drying towards the tropics than the subtropics (e.g. Pueyo et al, 2011;Ledru et al, 2013;Tchilinguirian and Morales, 2013).…”

Section: Mid-holocenementioning

confidence: 99%

Late Quaternary environmental dynamics in the Atacama Desert reconstructed from rodent midden pollen records

Porras

Maldonado

Pol‐Holz

et al. 2017

J Quaternary Science

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In the past two decades, much has been learned about the late Quaternary climate history of the Atacama Desert with some details still unclear about the seasonality, timing and extent of wet and dry phases. Modern climate studies reveal that, far from exhibiting a unique pattern, seasonal precipitation originates from many sources and mechanisms. For the last 16 ka, we attempt to sort out these complexities in pollen records from four fossil rodent midden series spanning 22°–25°S in northern Chile. Widespread wet conditions prevailed during the late Pleistocene and early Holocene, particularly between 13 and 9 ka, evidenced by <400 m lowering of pollen zones (plant communities) compared to today. Regional differences in the timing and magnitude of this displacement may be related to the prevailing source (tropical/extra‐tropical) or mode (NNW/SE) of tropical precipitation through time. Wet conditions persisted well into the early Holocene, lasting ∼1–1.5 ka longer than previously suggested. The pollen record suggests extreme drying ∼8 ka, possibly associated with a northward shift of the Inter Tropical Convergence Zone, tracking minimum insolation values at subtropical latitudes during the austral summer. The establishment of conditions similar to today happened ∼4 ka. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Mid-holocenementioning

confidence: 99%

Late Quaternary environmental dynamics in the Atacama Desert reconstructed from rodent midden pollen records

Porras

Maldonado

Pol‐Holz

et al. 2017

J Quaternary Science

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“…(Figures 1 and 2). Due to limited water availability, indigenous communities have depended on the extensive high Andean peatland network, locally known as "bofedales", as water reservoirs and livestock forage resources for thousands of years [6][7][8]. The high Andean peatlands have the highest primary productivity among the distinct terrestrial ecosystems of the Altiplano region, with average carbon accumulation rates at least an order of magnitude higher than Northern Hemisphere peatlands [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

A Multiscale Productivity Assessment of High Andean Peatlands across the Chilean Altiplano Using 31 Years of Landsat Imagery

et al. 2019

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The high Andean peatlands, locally known as “bofedales”, are a unique type of wetland distributed across the high-elevation South American Altiplano plateau. This extensive peatland network stores significant amounts of carbon, regulates local and regional hydrological cycles, supports habitats for a variety of plant and animal species, and has provided critical water and forage resources for the livestock of the indigenous Aymara communities for thousands of years. Nevertheless, little is known about the productivity dynamics of the high Andean peatlands, particularly in the drier western Altiplano region bordering the Atacama desert. Here, we provide the first digital peatland inventory and multiscale productivity assessment for the entire western Altiplano (63,705 km2) using 31 years of Landsat data (about 9000 scenes) and a non-parametric approach for estimating phenological metrics. We identified 5665 peatland units, covering an area of 510 km2, and evaluated the spatiotemporal productivity patterns at the regional, peatland polygon, and individual pixel scales. The regional assessment shows that the peatland areas and peatlands with higher productivity are concentrated towards the northern part of our study region, which is consistent with the Altiplano north–south aridity gradient. Regional patterns further reveal that the last seven years (2011–2017) have been the most productive period over the past three decades. While individual pixels show contrasting patterns of reductions and gains in local productivity during the most recent time period, most of the study area has experienced increases in annual productivity, supporting the regional results. Our novel database can be used not only to explore future research questions related to the social, biological, and hydrological influences on peatland productivity patterns, but also to provide technical support for the sustainable development of livestock practices and conservation and water management policy in the Altiplano region.

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“…Ecuador is also well known for its very active volcanic region. Two eruptions of the Guagua Pichincha and one of the Quilotoa were seen at pollen site Papallacta (Ledru et al, 2013b). Thanks to four radiometric 40 Ar-39 Ar dates from tephra deposits, the chronology of the Erazo pollen record was placed within the middle Pleistocene period (Cardenas et al, 2011).…”

Section: Tephrochronometrymentioning

confidence: 99%

“…The development of such freely available Bayesian age-modelling packages as "OxCal" (Bronk Ramsey, 1995), "BCal" (Buck et al, 1999), "Bchron" (Parnell et al, 2008), "BPeat" (Blaauw and Christen, 2005) and "Bacon" (Blaauw and Christen, 2011), has greatly advanced the science. To our knowledge, however, so far there has been only a single application of Bayesian methods for age modelling in South America, namely at Papallacta 1-08 (Ledru et al, 2013b). The authors included a priori information on sedimentation rates and tephra layers to construct the age model and consequently derive the best age for an uncertain tephra deposition.…”

Section: Current Age Models and Calibration Curvesmentioning

confidence: 99%

Geochronological database and classification system for age uncertainties in Neotropical pollen records

2016

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Abstract. The newly updated inventory of palaeoecological research in Latin America offers an important overview of sites available for multi-proxy and multi-site purposes. From the collected literature supporting this inventory, we collected all available age model metadata to create a chronological database of 5116 control points (e.g. 14C, tephra, fission track, OSL, 210Pb) from 1097 pollen records. Based on this literature review, we present a summary of chronological dating and reporting in the Neotropics. Difficulties and recommendations for chronology reporting are discussed. Furthermore, for 234 pollen records in northwest South America, a classification system for age uncertainties is implemented based on chronologies generated with updated calibration curves. With these outcomes age models are produced for those sites without an existing chronology, alternative age models are provided for researchers interested in comparing the effects of different calibration curves and age–depth modelling software, and the importance of uncertainty assessments of chronologies is highlighted. Sample resolution and temporal uncertainty of ages are discussed for different time windows, focusing on events relevant for research on centennial- to millennial-scale climate variability. All age models and developed R scripts are publicly available through figshare, including a manual to use the scripts.

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Evidence of moist niches in the Bolivian Andes during the mid-Holocene arid period

Abstract: International audienc

Cited by 27 publications

References 87 publications

Late Quaternary environmental dynamics in the Atacama Desert reconstructed from rodent midden pollen records

Late Quaternary environmental dynamics in the Atacama Desert reconstructed from rodent midden pollen records

A Multiscale Productivity Assessment of High Andean Peatlands across the Chilean Altiplano Using 31 Years of Landsat Imagery

Geochronological database and classification system for age uncertainties in Neotropical pollen records

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