Phytolith assemblages of Shorea robusta Gaertn. (Sal) from West Bengal part of the Bengal Basin, India and their implications in palaeoclimate reconstructions

Abstract

ABSTRACT Phytolith assemblages of Shorea robusta Gaertn. (Dipterocarpaceae), an important constituent of tropical deciduous/semi-evergreen forests were studied from six different districts of West Bengal, the western margin of the Bengal Basin. Since S. robusta grows in the tropical mixed dry to wet deciduous and semi-evergreen forests and can tolerate a wide variability in temperature and precipitation regimes, we aim to understand if these climatic parameters drive any changes in phytolith production pattern of the plant. Eleven different phytolith morphotypes retrieved from 13 plant specimens collected along the temperature and precipitation gradients show considerable variations among the specimens. Phytolith assemblages thus retrieved have been subjected to detrended correspondence analysis (DCA), which has helped to understand indirectly the influence of climatic parameter(s) on the phytolith production pattern of S. robusta, if any. Further, canonical correspondence analysis (CCA) performed on the phytolith data reveals how temperature and precipitation influence the variations in phytolith assemblages of the plant. The data provide a basis to understand how phytolith spectra of non-grass plants capture signal of climatic variability of any region and could be used in regional palaeoclimate reconstructions if recovered in fossil sediments.