Pollen records related to vegetation and climate change from northern Chhattisgarh, central India during the late Quaternary

2017-02-02T13:49:22Z (GMT) by M.F. Quamar S.K. Bera
<p>Pollen records from a 1.8-m deep sediment profile from Lakadandh Swamp, Baikunthpur Forest Range of Koriya District, Chhattisgarh (C'garh, central India), show the late Quaternary vegetation and climate history. Lakadandh Swamp occurs in the core monsoon zone of India. The study revealed that between ∼12,785 and ∼9035 cal. yrs BP, tree savannah vegetation, – composed of Poaceae, Amaranthaceae, Tubuliflorae along with the tree taxa <i>Holoptelea</i> sp. and Sapotaceae; sparsely distributed <i>Acacia</i> sp., <i>Emblica officinalis, Lagerstroemia</i> sp., <i>Madhuca indica</i> and <i>Syzygium</i> sp., <i>thickets of Ricinus</i> and <i>Zizyphus</i> sp. – occurred in the region under a cool and dry climate probably indicative of reduced monsoon precipitation. The early part of this phase is comparable with the Younger Dryas (YD) cold event which occurred between ∼12,800 and ∼11,500 yrs BP. Between ∼9035 and ∼4535 cal. yrs BP, the expansion of existing taxa <i>Holoptelea</i> sp., Sapotaceae, <i>Madhuca indica</i>, <i>Ailanthus excelsa</i> and <i>Lagerstroemia</i> sp. as well as the appearance of <i>Acacia</i>, and <i>Shorea robusta</i>, Acanthaceae, <i>Rungia</i> sp., and <i>Ricinus</i> sp., shows the tree savannah vegetation was replaced by open mixed tropical deciduous forest under a regime of warm and moderately humid climate with increased monsoon precipitation. Since ∼4535 cal. yrs BP to Present, owing to the improvement of most of the forest constituents, particularly <i>Madhuca indica</i>, <i>Holoptelea</i> sp., Sapotaceae and <i>Lannea coromandelica</i>, and also with immigration of <i>Terminalia</i> sp., <i>Diospyros</i> sp., <i>Butea</i> sp. and <i>Maytenus</i> sp., mixed tropical deciduous forest has taken over the space covered by open mixed tropical deciduous forest under a warm and relatively more humid climate, with further increase in monsoon precipitation. The existing cereal-based agricultural practice increased during the latter two phases, which could be attributed to increased monsoon precipitation.</p>