PRE-COLUMBIAN AGRICULTURE AND FOREST DISTURBANCE IN COSTA-RICA - PALEOECOLOGICAL EVIDENCE FROM 2 LOWLAND RAIN-FOREST LAKES

Lake-sediment cores from Laguna Bonilla and Laguna Bonillita provide s ome of the first evidence of prehistoric human impacts on lowland rain forests in Costa Rica. The longer Bonillita sediment record documents permanent settlement of the lake shores by 2560 BP, about 600 years ea rlier than previously inferred from the archaeological record. Zea pol len and charcoal fragments in cores from both lakes indicate a subsist ence strategy that included maize cultivation and some use of fire. A dramatic decline in Myrsine pollen percentages about 1300 BP su pests local eradication of this woody plant, likely as a result of land clea rance and/or the use of Myrsine for construction.