Guatemalan forest synthesis after Pleistocene aridity

Abstract

Sediments from 2 lakes in the Peten Department, Guatemala, provide palynologicl evidence from Central America of late Pleistocene aridity and subsequent synthesis of mesic forests. Late Glacial vegetation consisted of marsh, savanna and juniper scrub. An early Holocene temperate forest preceded a mesic tropical forest with Brosimum (ramon). Thus, primeval rain forests of Guatemala are no older than 10,000-11,000 yr and are considerably younger in the Peten due to Mayan disturbances. Among dated Neotropical sites, the Peten has the most mesic vegetation yet have supplanted xeric vegetation present during the Pleistocene. The arid late Glacial-humid early Holocene transition apparently was pantropical in the lowlands. The Peten was not a Pleistocene refugium for mesophytic taxa, as has been suggested. Genesis of extant rain forests in northern Central America and southern Mexico therefore remains unexplained.