Analysis of the late Holocene climate vis-a-vis vegetation dynamics along the southwest coast of India: Thrissur (Kerala)

Pollen analysis supplemented with diatom and phytolith from the surface and sub surface sediments from Kanjani, Thrissur district, Kerala was analyzed to reconstruct the vegetation and climate during a major part of the Holocene. Prior to 7270 cal BP, core mangroves of the intertidal zone viz., Rhizophora apiculata, Rhizophora mucronata, Avicennia spp., and Ceriops decandra grew in the vicinity of the site as indicated by the presence of their pollen grains, although the sediments are devoid of phytoliths and diatoms. Mangroves expanded during 7270–3530 cal BP. The presence of diatoms and phytoliths (pooid, chloridoid and panicoid) indicate continuation of a warm and humid climate, and the monsoon reached its peak at this time span. Subsequently, mangroves declined but phytoliths and diatom were well represented. This phase might be linked with the decrease of southwest monsoon influence in this region. Differential preservation of pollen, diatoms, and phytoliths in the same profile at different depths suggests that analyses of more proxies would be useful for better understanding of climate and environmental change.