12-14 September, 2011, Lucknow - Earth Science India

National Conference on Science of Climate Change and Earth’s Sustainability: Issues and Challenges ‘A Scientist-People Partnership’
12-14 September, 2011, Lucknow
the region in between 11,000- 8500 yr BP. The grasses, other herbs (aquatic or
terrestrial) and ferns profoundly thriving suggesting high humidity and temperature
increase due to high SW monsoon activity. Subsequently, the area witnessed sudden
decline in vegetation concentration during 8500 to 7000 yr BP. The floristic
composition indicates the alteration of deciduous forest into tree savannah type of
vegetation almost certainly due to small spell of cooler and dryer climate which
corresponds to 8.2 ka short global cooling event. During 7000 to 5100 yr BP, the
alteration in palaeofloristic pattern from tree savannah type of vegetation to dry
deciduous forest has occurred due to warm and humid but probably not as humid as
Early Holocene. The moist tree taxa have certainly decreased although dry deciduous
taxa flourished suggesting less precipitation in the region as compared to early
Holocene.
Kusumelli Swamp trench profile (KDT) endowed the floristic composition which
reveals the grasses and other herbs with intermittent trees and shrubs constituted tree
savannah during 4000 to 3100 yr BP (KDT-1). The profound growth of grasses,
Chenopodiaceae /Amaranthaceae, Artemisia sp. while strewn record of other herbs and
hostile conditions for trees growth portrays cooler and dryer climatic conditions.
However, ameliorating trend of climate could be inferred towards the end of zone.
Subsequently, KDT-2 pollen zone show recurrence of both moist and dry deciduous
trees such as Tectona grandis, Shorea robusta, Lagerstoemia sp., Diospyros sp., Lannea
coromendalica, Buchnania lanza, Flacourtia sp., Mangifera indica, Azardirachta sp.,
Emblica officinalis, Meliacaea, Syzygium sp., Butea monosperma and Acacia. In
addition, increase of Terminalia sp, Madhuca indica and Holoptelea sp. have prompted
towards increase in total diversity of flora. The floristic composition envisages that tree
savannahs transformed into open mixed deciduous forest. The depletion in
Chenopodiaceae/Amaranthaceae growth accompanied by profound occurrence of
grasses exhibit amelioration of climate towards warmer and wetter conditions with
improved monsoon during 3100 to 1350 yr BP. Later on during 1350 to 377 yr BP
(KDT-3), the association of tree taxa suggests the recuperated growth of dry deciduous
trees with inter dispersed moist taxa and shrubs. The floristic composition shows
improving trends of vegetation enhancement towards edifice of dry deciduous forest.
The whole vegetational assemblage suggests a warm and humid climate coupled with
active inception of south west monsoon i.e. more or less similar to climatic condition
prevailing today.
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