Vegetation and climatic variability in southeastern Madhya Pradesh, India since Mid-Holocene, based on pollen records

Pollen analysis of 1.75 m deep sediment core from Tula-Jalda (Amarkantak) in Anuppur district, Madhya Pradesh unravels that around 4500–3600 cal years BP, this region supported open mixed tropical deciduous forests comprising chiefly Madhuca indica followed by Terminalia, Mitragyna parvifolia, Haldina cordifolia, Emblica officinalis and Acacia, under a warm and relatively less humid climate. The retrieval of Cerealia and other cultural plants, viz. Artemisia, Cheno/Am and Caryophyllaceae signifies that the region was under cereal-based agricultural practice. The open mixed deciduous forests got enriched and dense around 3600–2761 cal years BP with the expansion of trees that already existed coupled with invasion of Symplocos, Diospyros, Lannea coromandelica and Radermachera with the inception of a warm and moderately humid climate in response to increased monsoon precipitation. Around 2761–2200 cal years BP, much expansion of the forests took place owing toinitiation of a warm and more humid climate, attributed to intensification of the southwest (SW) monsoon. The modern Sal (Shorea robusta) forests were established around 2200 cal years BP, as clearly deciphered by the steady presence of S. robusta along with close allies such as M. indica, Terminalia, H. cordifolia, E. officinalis, etc. This change in the vegetation scenario implies that a warm and relatively more humid climate prevailed with timely arrival of the more active SW monsoon.