Modern pollen spectra from tropical South India and Sri Lanka: altitudinal distribution


R. Bonnefille, CEREGE, B.P. 80, 13545 Aix-en- Provence Cedex 4, France. E-mail:


We analysed the pollen content of 106 surface soil samples from evergreen and deciduous tropical forests distributed between 6° and 13° of latitude north in South India and Sri Lanka. The samples were collected along altitudinal gradients, ranging from 50 to 2420 m, in five regions that experience different rainfall regimes. Original pollen data from tropical vegetation subjected to seasonal monsoon rains are presented along altitude/temperature gradients. This paper includes a summarized description of the vegetation types mapped in the area.

The pollen results are presented in the form of quantitative pollen diagrams and correspondence analyses. They show clear distinct pollen assemblages and markers for all types of vegetation in deciduous and evergreen vegetation. Forests are well identified by percentages of Arboreal Pollen greater than 50%, despite the fact that Dipterocarpaceae and Lauraceae are hardly recorded by pollen.

The pollen distinction between low, medium and high elevation evergreen forests matches that established by ecologists. The botanical limits, respectively, placed at 900 m and 1500 m limits, correspond to the 20 °C and 15 °C-values of mean temperature of the coldest month. They appear clearly identified in the modern pollen record. This justifies further use of pollen data in Biome modelling.