Pollen‐based biome reconstructions for Colombia at 3000, 6000, 9000, 12 000, 15 000 and 18 000 ¹⁴C yr ago: Late Quaternary tropical vegetation dynamics

Abstract

Colombian biomes are reconstructed at 45 sites from the modern period extending to the Last Glacial Maximum (LGM). The basis for our reconstruction is pollen data assigned to plant functional types and biomes at six 3000‐yr intervals. A reconstruction of modern biomes is used to check the treatment of the modern pollen data set against a map of potential vegetation. This allows the biomes reconstructed at past periods to be assessed relative to the modern situation. This process also provides a check on the a priori assignment of pollen taxa to plant functional types and biomes. For the majority of the sites, the pollen data accurately reflect the potential vegetation, even though much of the original vegetation has been transformed by agricultural practices. At 18 000 14C yr BP, a generally cool and dry environment is reflected in biome, assignments of cold mixed forests, cool evergreen forests and cool grassland–shrub; the latter extending to lower altitudes than presently recorded. This signal is strongly recorded at 15 000 and 12 000 14C yr BP, the vegetation at these times also reflecting a relatively cool and dry environment. At 9000 14C yr BP there is a shift to biomes thought to result from slightly cooler environmental conditions. This trend is reversed by 6000 14C yr BP; most sites, within a range of different environmental settings, recording a shift to more xeric biome types. There is an expansion of steppe and cool mixed‐forest biomes, replacing tropical dry forest and cool grassland–shrub biomes, respectively. These changes in biome assignments from the modern situation can be interpreted as a biotic response to mid‐Holocene climatic aridity. At 3000 14C yr BP the shift is mainly to biomes characteristic of slightly more mesic environmental conditions.There are a number of sites that do not change biome assignment relative to the modern reconstruction, although the affinities that these sites have to a specific biome do change. These ‘anomalies’ are interpreted on a site‐by‐site basis. Spatially constant, but differential response of the vegetation to climatic shifts are related to changes in moisture sources and the importance of edaphic controls on the vegetation. The Late Quaternary reconstruction of large‐scale vegetation dynamics in Colombia allows an understanding of the environmental controls on these to be developed. In particular, shifts in the character of the main climatic systems that influence Colombian vegetation are described. Copyright © 2002 John Wiley & Sons, Ltd.

Milieu- en klimaatverandering: fossiel pollen als onuitputtelijke informatiebron

“…Als we voldoende locaties met informatie ter beschikking hebben, kunnen we vege- tatiekaarten reconstrueren voor elke periode die we wensen. 23,24 Voor eenzelfde periode kan een gekoppeld klimaat/vegetatiemodel een vegetatiekaart voorspellen. Door de 'gereconstrueerde' en de 'voorspelde' vegetatiekaart met elkaar te vergelijken, kunnen we uitspraken doen over de kwaliteit van het betreffende klimaatmodel.…”

“…Dit door NWO gefinancierde onderzoek is onze bijdrage aan het grote internationale BIOME-project. Het heeft voor Latijns Amerika tot grondleggende artikelen geleid 23,24,25,28 en een aantal andere publicaties. We hebben tweemaal geprobeerd hieraan een vervolg te geven, 29 maar helaas zijn nieuwe onderzoeksvoorstellen in de open competitie bij NWO gesneuveld omdat ze niet vernieuwend zouden zijn.…”

Caracterización De La Acumulación De Carbono en Pequeños Humedales Andinos en La Cuenca Alta Del Río Barbas (Quindío, Colombia)

“…Los humedales, los lagos, las lagunas y las lagunetas en Colombia, especialmente de las altas montañas han sido estudiados por su sensibilidad a las condiciones climáticas, convirtiendo sus suelos en registros de los cambios climáticos ocurridos en el Pleistoceno y Holoceno (Cardozo et al 2014, Marchant et al 2002, Kuhry 1988, Helmens & Kuhry 1986. Existe un importante análisis palinológico en diversas regiones del país que ha permitido establecer la sincronía del clima local con algunos cambios climáticos globales y también demostrar los incrementos recientes en temperatura asociados con actividades humanas.…”

“…Globalmente los humedales pequeños son considerados importantes a escalas locales para la regulación hídrica, la conservación de biodiversidad y la calidad del agua. En años recientes se han realizado varios estudios en humedales tropicales que buscan estimar la concentración de carbono con relación a la profundidad del suelo (gr C kg -1 de suelo), los depósitos de carbono de una profundidad determinada por unidad de área (kg C m -2 ) y las tasas de captura de carbono (kg C m , Marchant et al 2002, Kuhry 1988, Helmens & Kuhry 1986. Existe un importante análisis palinológico en diversas regiones del país que ha permitido establecer la sincronía del clima local con algunos cambios climáticos globales y también demostrar los incrementos recientes en temperatura asociados con actividades humanas.…”

Genetic analysis of paleo-colombians from Nemocón, Cundinamarca provides insights on the early peopling of northwestern South America

“…During Early Holocene (10 -8 Ka), the climate changed with a sudden rise in average annual temperature that increased evaporation, causing lakes and swampy areas to dry out. The biome reconstructions for the 9 -8 Ka reveal that there was a notable expansion of mesic biomes (Marchant, et al 2002; Van der Hammen 2011). Paleoecological / paleoenvironmental data predict that an initial wave of human occupation could have used coastal routes as primary adaptation areas.…”