LATE QUATERNARY VEGETATIONAL CHANGE IN THE CENTRAL PERUVIAN ANDES

New fossil pollen records from the central Peruvian Andes at elevation s above 4000 m including pollen-concentration data and additional radi ocarbon dates, provide information on late Quaternary vegetation chang e for the region. A pollen assemblage typical of superpuna plus low po llen concentrations, and % organics in the late glacial section of Lag una Tuctua indicate a cold/dry climate, but strong evidence for a late glacial climate reversal, i.e., the Younger Dryas, is not presently c onfirmed. An abrupt increase in Urticales pollen as Compositae and Pol ylepis-Acaena type pollen decline signals the beginning of the Holocen e. Subsequent increases in Urticales and Plantago rigida type pollen p oint to increased moisture as well as higher temperatures from about 1 1,000 to 7000 yr B.P. A possible correlation exists between the rapid expansion of puna and closed continuous forest and the rise in importa nce of camelids in the early Holocene. In the mid-Holocene Plantago ri gida cushion bogs and continuous montane forest elements decline, sugg esting a drier climate. Grasses and Cheno-Ams then increase, reaching maxima about 4000 yr B.P. Pastoralism and agriculture are thought to h ave developed at this time, according to ethnobotanical studies from t his area, and pollen evidence seems to support these findings. Between 3000 and 2000 yr B.P. pollen percentages of Poaceae, Plantago rigida type, and other local taxa decline as glacial activity was renewed in the higher mountains. Zea mays is present by 2000 yr B.P., and pollen of weeds and secondary successional plants associated with increasing agricultural disturbance are evident.