Climate change and vegetation succession in Lalitpur area, Uttar Pradesh (India) during late holocene

The palynological study was carried out in three sediment cores one each from centripetal perennial lakes in Talbehat (depth 1.0 m; 25 degrees 0' 10 '' N and 78 degrees 26' 20 '' E), Madaura (depth 0.8 m; 24 degrees 22' 35 '' N and 78 degrees 48' 9 '' E) and Dhaura (depth 1.2 m; 24 degrees 17' 40 '' N and 78 degrees 51' 8 '' E) flanked at three corners of the Lalitpur district, Uttar Pradesh, in order to understand the climate and vegetation pattern during late holocene. Three pollen zones could be identified indicating the succession of vegetation from Moist Deciduous Forest (similar to 4000 yrs BP) to Mixed Deciduous Forest (similar to 2000 yrs BP) and finally to Dry Deciduous Forest since similar to 1400 yrs. BP. Dominance of Shorea, Hopea in the beginning of late holocene along with other moisture loving tree taxa and their decline since similar to 1400 yrs BP indicate an increase in aridity/weakened monsoon. However, the diversification of vegetation since the last millenium in the study area is unlike the reduction in tree taxa recorded during the same period from the fertile Gangetic plain. This difference is attributed to (1) gradual nutrient enrichment and accumulation of in-situ undisturbed soil cover in time, retaining more soil moisture during monsoons, and (2) slow pace of agricultural development due to rugged, undulating terrain resulting into lower anthropogenic pressure compared to the Gangetic plain.