In order to quantify the Indian summer monsoon (ISM) variability for a monsoon dominated agrarian based Indian socio-economy, we used combined high resolution δ13C, total organic carbon (TOC), sediment texture and environmental magnetic data of the samples from a ~3 m deep glacial outwash sedimentary profile from the Sikkim Himalaya. Our decadal to centennial scale records identified five positive and three negative excursions of the ISM since last ~13 ka. The most prominent abrupt negative ISM shift was observed during the termination of the Younger Dryas (YD) between ~11.7 and 11.4 ka. While, ISM was stable between ~11 and 6 ka, and declined prominently between 6 and 3 ka. Surprisingly, during both the Medieval Warm Period (MWP) and Little Ice age (LIA) spans, ISM was strong in this part of the Himalaya. These regional changes in ISM were coupled to southward shifting in mean position of the Intertropical Convergence Zone (ITCZ) and variations in East Asian monsoon (EAM). Our rainfall reconstructions are broadly in agreement with local, regional reconstructions and PMIP3, CSIRO-MK3L model simulations.

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The present communication reviews the pattern of modern pollen-rain studies carried out in southwestern Madhya Pradesh, India. The study largely revealed that Tectona grandis (teak), despite being an enormous pollen producer (7500 average number of absolute pollen/flower) and the dominant forest constituent (80 to 95% of the total forest constituents), is recorded mostly in low frequencies, attributable to its low pollen dispersal efficiency as well as poor pollen preservation in the sediments. However, Madhuca indica (Mahua) and other dominant members of Sapotaceae (cf. Manilkara hexandra and Mimusops elangi) have always shown their typical behaviour in the pollen spectra and are represented in high frequencies, which are assigned to their local abundance around the provenance of the samples, coupled with high dispersal efficiency as well as good pollen preservation in the sediments. Meanwhile, the other usual and characteristic associates of teak (Tectona grandis) in the tropical deciduous forests, despite being the common elements of the forests, are under-represented, sporadically represented or not represented at all, which could be ascribed to their low pollen productivity owing to entomogamy. Various factors that affect the deposition pattern of the diverse constituents of the tropical deciduous forests dominated by teak (Tectona grandis) have been discussed and suggestions are also given while interpreting the pollen sequences generated from the sedimentary beds in terms of past vegetation and climate in a chronological order in the region during the Late Quaternary Period.

The present paper analyses the pollen deposition pattern in a swampy area of tropical mixed deciduous forest at the Baikunthpur Forest Range in the Koriya District of Chhattisgarh, India, based on the palynological investigation of surface samples. The palynological assemblages revealed the dominance of non-arboreal pollen taxa (NAPs: herbs) over the arboreal pollen taxa (APs: trees and shrubs). Among the arboreal taxa, trees constitute on average 41.92% of the pollen in the total pollen rain, whereas the average contribution of shrubs is only 2.19%. Among the herbaceous taxa, Poaceae (grasses) has a relatively high frequency (average 38.20%). The NAPs, on the whole, constitute on average 53.51% of the pollen in the total pollen rain. Cerealia, Chenopodiaceae/Amaranthaceae, Caryophyllaceae, Brassicaceae, Artemisia and Alternanthera reflect the agrarian activities in the study area. Cyperaceae and other marshy taxa represent boggy places around the sampling site and Typha, Lemna, Potamogeton and Nymphoides the aquatic vegetation. Pinus, Cedrus, Picea and Alnus occur in low frequencies and are exclusively wind transported from the Himalayas. Trilete fern spores and lycopods are indicative of humid climatic condition.

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