Colombia in the Quaternary: an overview of environmental and climatic change

We provide an overview of environmental and climatic change in Colombia during the Quaternary, the last ca. 2.58 Ma. This period is characterised by a suite of glacial–interglacial cycles which are remarkably well documented in Colombian sediments. The distribution of Colombia’s main ecosystems has changed repeatedly driven by orbital forcing at 21, 41, and 100 ky frequencies which were superimposed by millennial–scale (ca. 2.5 ky) climate oscillations. Fossil pollen records have detected biome dynamics through time but records vary in length: the shortest comes from the Chocó rainforest (extending back to ca. 7 ka) and dry inter–Andean forest (ca. 12 ka), followed by the savannas of the Llanos Orientales (ca. 20 ka), the Amazonian rainforests (ca. 40 ka), and lower montane forest (ca. 40 ka). The longest records are from the deep sedimentary basins Bogotá (Funza09, last 2.25 Ma) and Fúquene (last 284 ka), alternatingly located in the upper montane forest and páramo during interglacial and glacial conditions, respectively. Climate change caused shifting biome distributions: mainly latitudinally in the lowlands and elevationally in the mountains. Extrinsic drivers (e.g., mean annual precipitation, length of dry season, atmospheric pCO2, mean anual temperature, freezing days) of migration and changes in vegetation composition and intrinsic drivers (such as interspecies competition and legacy effects) are still insufficiently understood, and thus hamper meaningful projections of the effect of future environmental change on biomes. Multi–site Pleistocene and Holocene information has been spatially synthesised by developing the Latin American Pollen Database. Multi–site information has been analysed by the biomisation method to serve palaeodata–model comparisons and projections about the future of biomes in Colombia. A new method in which pollen–based palaeo–reconstructions are spatially analysed with digital elevation models improved our understanding of spatial and elevational shifts of ecotones, for example the upper forest line, in the northern Andes. In the supplementary information we highlight the strengths and weaknesses in current Quaternary palaeoecological research and provide suggestions for future research.