A millennium of anthropic and climate dynamics in the Lake Izabal Basin, eastern lowland Guatemala

Abstract

Modern precipitation gradients across the Maya region in Central America result in a diverse vegetational mosaic that varies from scrub forest to rainforest. In this region, evidence of past changes in the distribution of vegetation indicates two main patterns: i) a Holocene long-term trend towards a more seasonal forest, and ii) sharp changes in vegetation cover resulting from human occupation. The history of vegetation in moister areas of the Maya region, however, has been mostly extrapolated from studies carried out in the Yucatan Peninsula. We reconstructed the paleoenvironmental and paleoecological dynamics of the last ∼1300 years in the Lake Izabal Basin, one of the wettest areas within the Maya region. Palynological and geochemical evidences indicate that from ∼650–1150 CE, vegetation assemblages were dominated by disturbance taxa, under relatively low erosion in the catchment area. This pattern probably resulted from anthropogenic activities during the Terminal Classic Period (800–950 CE) combined with the dry and more seasonal conditions of the Medieval Climate Anomaly. The record from 1150 to 1400 CE points to an increase in moisture availability with a change towards a forested landscape. From 1400 to 1950 CE, geochemical data indicate lower precipitation, while the vegetation appears less fragmented and a mature forest developed. Such pattern probably emerged from lower evapotranspiration associated with the Little Ice Age (1350–1850 CE) favoring vegetation recovery. During the last 1300 years, vegetation change in the Lake Izabal Basin parallels that of the Yucatan Peninsula, with anthropogenic influences and moisture availability exerting first- and second-order controls on vegetation turnover, respectively.