Updated site compilation of the Latin American Pollen Database

Flantua, S.G.A.; Hooghiemstra, H.; Grimm, Eric C.; Behling, Hermann; Bush, Mark B.; González‐Arango, Catalina; Gosling, William D.; Ledru, Marie‐Pierre; Lozano‐García, Socorro; Maldonado, Antonio; Prieto, Aldo R.; Rull, Valentı́; Boxel, J.H. van

doi:10.1016/j.revpalbo.2015.09.008

Cited by 78 publications

(86 citation statements)

References 121 publications

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“…Likewise, there is no guarantee that the change in vegetation cover in response to climate change will result in a change across all biotic components, but validation by fossil pollen may allow extrapolations. Future fossil pollen sampling in the core of the biomes may add relevant contributions to our model, because the currently exploited areas are mostly located in ecotonal regions (see Flantua et al, ). However, the findings at the available sites were consistent with the models proposed here, which enabled us to contribute to the discussion on biogeographical hypotheses, for example on the hypothesis of Amazonian refugia, which, unlike the statements by Colinvaux et al () and Bush and De Oliveira (), is not yet concluded.…”

Section: Discussionmentioning

confidence: 99%

Vegetation cover of Brazil in the last 21 ka: New insights into the Amazonian refugia and Pleistocenic arc hypotheses

Arruda

Schaefer

Fonseca

et al. 2017

Global Ecol Biogeogr

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Aim: The two main hypotheses about the Neotropical palaeovegetation, namely that of Amazonian refugia by Haffer and of the Pleistocene arc by Prado and Gibbs, are still constantly debated. We offer new insights on this debate using ecological niche modelling with combined climate-soil predictors to test both hypotheses, reconstruct the palaeovegetation of the Last Glacial Maximum (LGM; 21 ka) and Mid-Holocene (Mid-H; 6 ka) and indicate the configuration of refugia areas. Location: Brazil.Time period: Last 21 ka.Major taxa studied: Biomes. Methods:We modelled the environmental space of the 10 most representative biomes with the RandomForest classifier, using climate predictors from three atmospheric general circulation models (CCSM4, MPI-ESM-P and MIROC-ESM) and soil predictors, the same for the different situations. Based on the consensus among the models, we reconstructed the palaeovegetation cover for LGM and Mid-H and used fossil pollen sites to validate the reconstructions in a direct comparison.Results: The climate in the past was cooler and wetter throughout most of the territory. The Amazon basin region was the most affected by climate change in the last 21 ka, with equatorial rain forest retracting to refugia areas, while the tropical rain forest (with climatic preferences similar to the Atlantic forest) expanded in the basin. In southern Brazil, the mixed forest (Araucaria forest) shifted to lower latitudes, while the grasslands expanded. In most biomes, the greatest changes occurred in the ecotonal zones, supported by pollen fossils.Main conclusions: With regard to Haffer's hypothesis, the forests of the Amazonian lowlands retreated to refugia areas, while the colder and wetter climate of the basin created a favourable niche for another type of forest, instead of savanna. The advance of dry vegetation was restricted to ecotonal conditions, preventing the formation of a continuous Pleistocene arc, predicted by

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Section: Discussionmentioning

confidence: 99%

Vegetation cover of Brazil in the last 21 ka: New insights into the Amazonian refugia and Pleistocenic arc hypotheses

Arruda

Schaefer

Fonseca

et al. 2017

Global Ecol Biogeogr

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“…Cleef, ; Hooghiemstra, ; Hooghiemstra & Van der Hammen, ; Van der Hammen, ; Van der Hammen & Cleef, ) because of the unique high elevation fossil pollen records that cover most of the Pleistocene (Bogotá‐A, Hooghiemstra, & Berrio, ; Bogotá‐Angel et al., ; Groot, Hooghiemstra, Berrio, & Giraldo, ; Groot et al., ; Torres, Hooghiemstra, Lourens, & Tzedakis, ). Under current conditions, the páramos form isolated archipelagos of ‘alpine (sky) islands’ (McCormack, Huang, & Knowles, ; Sklenář et al., ) but the rich collection of fossil pollen sequences throughout this region (Flantua et al., ) show that the páramos underwent substantial elevational shifts during the Pleistocene, resulting in extensive changes in surface area and connectivity (Flantua et al., ; Hooghiemstra & Van der Hammen, ; Sklenář et al., ; Van der Hammen, ). Thus, the topographical diversity and the robust catalogue of palaeoecological reconstructions make the Northern Andes a highly suitable model region to explore patterns of connectivity in mountain biomes in response to Pleistocene climate fluctuations.…”

Section: Introductionmentioning

confidence: 99%

The flickering connectivity system of the north Andean páramos

Flantua

O’Dea

Onstein

et al. 2019

Journal of Biogeography

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164

149

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Aim To quantify the effect of Pleistocene climate fluctuations on habitat connectivity across páramos in the Northern Andes. Location Northern Andes. Methods The unique páramos habitat underwent dynamic shifts in elevation in response to changing climate conditions during the Pleistocene. The lower boundary of the páramos is defined by the upper forest line, which is known to be highly responsive to temperature. Here, we reconstruct the extent and connectivity of páramos over the last 1 million years (Myr) by reconstructing the upper forest line from the long fossil pollen record of Funza09, Colombia, and applying it to spatial mapping on modern topographies across the Northern Andes for 752 time slices. Data provide an estimate of how often and for how long different elevations were occupied by páramos and estimate their connectivity to provide insights into the role of topography in biogeographical patterns of páramos. Results Our findings show that connectivity amongst páramos of the Northern Andes was highly dynamic, both within and across mountain ranges. Connectivity amongst páramos peaked during extreme glacial periods but intermediate cool stadials and mild interstadials dominated the climate system. These variable degrees of connectivity through time result in what we term the ‘flickering connectivity system’. We provide a visualization (video) to showcase this phenomenon. Patterns of connectivity in the Northern Andes contradict patterns observed in other mountain ranges of differing topographies. Main conclusions Pleistocene climate change was the driver of significant elevational and spatial shifts in páramos causing dynamic changes in habitat connectivity across and within all mountain ranges. Some generalities emerge, including the fact that connectivity was greatest during the most ephemeral of times. However, the timing, duration and degree of connectivity varied substantially among mountain ranges depending on their topographical configuration. The flickering connectivity system of the páramos uncovers the dynamic settings in which evolutionary radiations shaped the most diverse alpine biome on Earth.

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“…Toggweiler et al , ; Anderson et al , ; Moreno et al , ). A large number of records based on palynological studies have thus been produced in this region with a focus on questions regarding the behaviour of the SWW belt at different timescales (see Flantua et al , , and references therein). Western Patagonia is one of the regions of South America with the largest number of pollen records and these studies have sometimes led to different conclusions regarding the long‐term dynamics of the SWW belt (e.g.…”

Section: Introductionmentioning

confidence: 99%

A pollen–climate calibration from western Patagonia for palaeoclimatic reconstructions

Montade

Peyron

Favier

et al. 2019

J Quaternary Science

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Palaeoecological studies of sediment records from the western margins of southern South America have revealed vegetation dynamics to be under the influence of major regional climate drivers such as the Southern Westerly Winds, Southern Annular Mode and El Niño Southern Oscillation. Despite the substantial number of palynological records in this region, very few quantitative pollen‐based climate reconstructions using surface samples have been made. In this context, our objective was first to investigate the modern pollen–vegetation–climate relationships in the western Patagonian. The results show that the modern pollen dataset reflects the main vegetation types and that summer precipitation and winter temperature represent the main climate parameters controlling vegetation distribution. Secondly using this pollen–climate dataset we evaluate and compare the performance of two models (Weighted Averaging Partial Least Squares and Modern Analog Technique). We used these models to make climate reconstructions from two oceanic pollen records from western Patagonia. Compared with independent climate indicators, our pollen‐inferred climate reconstructions reveal the same overall trends, showing the potential of pollen–climate transfer functions applied to this region. This study provides much needed data for quantitative climate reconstructions in South America, but which also needs to be improved by enlarging the modern pollen dataset.

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Updated site compilation of the Latin American Pollen Database

Cited by 78 publications

References 121 publications

Vegetation cover of Brazil in the last 21 ka: New insights into the Amazonian refugia and Pleistocenic arc hypotheses

Vegetation cover of Brazil in the last 21 ka: New insights into the Amazonian refugia and Pleistocenic arc hypotheses

The flickering connectivity system of the north Andean páramos

A pollen–climate calibration from western Patagonia for palaeoclimatic reconstructions

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