The Colombian Amazon has an area of 450,485 km2 and includes the departments of Meta, Caquetá, Cauca, Nariño, Putumayo, Guaviare, Amazonas, Vaupes, Vichada, and Guainía . As a result of a number of geological processes, this is a region of confluence for the Andes, the sedimentary plain and the Guiana Shield. The following are its main features:
Geology: The Colombian Amazon is incorporated in its greatest extent by sandy and clay sediments originating from the Paleozoic period. The sandy composition has restricted the growth of heterogeneous high forests and in contrast, the clay content has given rise to salt licks and is associated with the development of high and heterogeneous forests. Additionally, this region in Colombia is composed of metamorphic rocks of Precambrian origin.
Soils: In general, the soils of the Colombian Amazon are considered poor because of its low concentration of minerals. Therefore, its main source of nutrients is associated with leaf litter and other decaying plant material. Soils formed from river sediments of Andean origin (Amazonas, Caquetá and Putumayo) present a wealth of nutrients that promotes the implementation of agricultural activities; however, these are poorly drained and are subject to prolonged flooding.
Climate: The Colombian Amazon has a characteristic climate of the equatorial region, with incident solar radiation throughout the year and convergence of the trade winds of the northern and southern hemisphere. Its average temperature is between 22 and 24 ° C, and exhibits extreme values between 10° C in Andean areas and 28° C in plains areas. The precipitation regime in this region is unimodal, with the lowest rainfall during December and January, and the highest in May and June.
Limnology: The Colombian Amazon extends into parts of the Orinoco and Amazon Basins, the latter being the main reservoir of fresh water on the planet and the largest tributary to the oceans. The main rivers in Colombia are Vichada, Guaviare, Vaupes, Caquetá, Putumayo and Amazonas.
Additionally, this region contains rivers of white, black, clear and mixed waters. White water rivers originate in the Andes and are characterized by high concentrations of nutrients that promote the development of fish fauna and the renewal of fertile riparian areas; black water rivers begin in the large central area and have low productivity; the clear rivers emerge from the summits of the southern and northern peripheral Amazonia, and have low nutrient richness; finally, mixed-water rivers are the result of the mixture of white water with other water types and create conditions that promote primary productivity.
Ruiz S. L., Sánchez E., Tabares E., Prieto A., Arias J. C, Gómez R., Castellanos D., García P., Rodríguez
L. (eds). 2007. Diversidad biológica y cultural del sur de la Amazonia colombiana – Diagnóstico. Corpoamazonia, Instituto Humboldt, Instituto Sinchi, UAESPNN, Bogotá D. C. – Colombia. 636 p.
Jaramillo D., Rojas A., Ortíz N. 2011. Retos para un desarrollo sostenible: Transformaciones en la Amazonia colombiana. Fundación Alisos. Bogotá D.C. – Colombia. 126 p.