El Bosque perdido: A cultural-ecological history of Holocene environmental change in western El Salvador

El Salvador is a land of human and environmental extremes. As of 1999 there were 297 people for each square kilometer of land, the highest population density in the mainland Americas. Ninety-four percent of the country's land surface today is taken up by horticulture, pasture and urbanized landscapes; six percent is forested. The largely interwoven phenomena of high population density and deforestation go back well into the Precolumbian period. Although the rich agricultural soils of El Salvador have been intensively farmed for millennia, little is currently known about how and when prehistoric agricultural practices began to impact the environment; and virtually nothing is known about the regional climatic regime under which the intensive agricultural system developed.; The purpose of this study was to reconstruct the Holocene environmental history of western El Salvador as it related to the human inhabitants of the region. Paleoecological records from three lakes in the Rio Paz drainage basin were analyzed to record changes in vegetation, rates of erosion, and fire. These environmental changes are attributed to three factors: climate change, extreme geophysical events (volcanism) and human agency.; The pollen evidence indicates warm, wet conditions during the Middle Holocene (ca. 8000–5500 cal yr B.P.); a gradual cooling and drying from ca. 5500 until 3500 cal yr. B.P.; and more variable climate after ca. 3500 cal yr B.P. The three paleoecological records reported here also provide evidence for the emergence of humans as significant ecological factors beginning around 4000 cal yr B.P.; The late Holocene sequence of progressively increasing human impacts is interrupted by two dramatic population declines: the first caused by the ca. 1520 cal yr B.P. Tierra Blanca Joven (TBJ) eruption of the Ilopango volcano, and the second resulting from the early 16th century introduction of Old World epidemic diseases. The decreased human pressure on forest resources following the second depopulation led to widespread forest recovery during the 17th and 18th centuries. Resumed forest clearance since the 19th century is attributed to grazing, fuelwood harvesting, and commercial and subsistence agriculture.