Late Quaternary Environmental History of the Horton Plains, Central Sri Lanka

Abstract

Pollen and mineral magnetic analyses performed on two peat sequences from the elevated area at 2300 m above sea level (a.s.l.)in the central part of Sri Lanka provide an almost continuous succession of data on the vegetation, climate and land-use history of the area since 18,000 BP. An amelioration of the arid Late Pleostoceme environment is indicated by the development of herbaceous and summer forest communities. Xerophytic woodlands predominated at the termination of the Pleistocene, about 13,000 BP. At the very end of the Pleistocene an incerase in precipitatin is indentified by the predominance f a montane rain forest (12,000 - 11,000 BP). The Holecene vegetation changes reflect two significant phases of expansion and diversification in the rain forest, in addition an arid climatic phase from 6000 to 5000 BP was observed, and a short wet phase around 600 BP.

The first indications of human impact in the pollen diagram, dated to approximately 14,000 BP, may be the result if severe deforestation, forest clearance and grazing. A pre-farming/pastrol culture existed from 14,000 to 10,000 BP, and changes in both human subsistence strategies and climate, and be recognized around 9000 BP, with the start of the first agricultural land-use (Hordeum sp.and Avena sp.). These activities continued until 6500 BP, whereas only limited agricultural activities and be identified during the period 6500 to 3000 BP. Thereafter, the area was abandoned until small-scale triticum cultivation started around 800 BP, lasting until 200 BP.