A 2000-year reconstruction of forest disturbance from southern Pacific Costa Rica

We reconstruct prehistoric and historic human forest disturbance and vegetation change in southern Pacific Costa Rica, in the vicinity of the Las Cruces Biological Station and the La Amistad International Park and Biosphere Reserve. Pollen and charcoal in sediments from Laguna Santa Elena reveal a nearly continuous record of human alteration of these tropical forests over the past two millennia. The basal portion of the core shows nearly intact premontane forests approximately 1800 cal. year B.P., although there is evidence of human presence on the landscape in the form of maize pollen and charcoal. Clearing for agriculture resulted in the dominance of disturbance taxa in the watershed beginning at least 1400 cal. year B.P. The pollen record reveals a possible, brief hiatus in human occupation of the watershed at approximately 540 cal. year B.P., although secondary succession began to occur in the Laguna Santa Elena watershed prior to that time, beginning about 700 cal. year B.P. Three eruptions of nearby Volcan Baru which we date to approximately 610, 1080, and 1440 cal. year B.P., apparently had little direct effect on the prehistoric populations in the immediate vicinity of the lake. Historic and modern land clearance has perpetuated a modem vegetation assemblage of disturbance and successional taxa, (c) 2005 Elsevier B.V. All rights reserved.