Man-environment interaction and its impact since ca. 3600 years BP in West Bengal, India: A multiproxy approach

Abstract

Climatic variability during the Holocene and corresponding anthropogenic response have gained considerable attention in different parts of India, but surprisingly very little is known on climate-human interrelationship from eastern India especially from the Gangetic plains of West Bengal. As climate has played significant role behind the collapse of many of the ancient human civilizations hence, to explore the reason behind the abandonment of any archaeological site, understanding of the climate of the contemporaneous past is a prerequisite. Agricultural development, subsistence strategies and dynamic behavior of climate in the Lower Gangetic plains of West Bengal since ca. 3600 cal a BP (Chalcolithic period) and post-Chalcolithic period (ca. 2350-2120 cal a BP to recent) were explored using multiproxy approach including plant-animal macro remains, wood charcoals and pollen and non-pollen palynomorphs from an archaeological site at Pakhanna, district Bankura in West Bengal, India. Evidences from palynological and phytolith data suggest that a warm-moist tropical climate during ca. 3600 cal a BP supported the spread of a village farming community in this part of lower Gangetic plains of West Bengal who practiced double-cropping as evidenced by the recovery of cereals (rice) and pulses (black gram) from the cultural deposits of Chalcolithic and Early Historic periods. In addition, a plenty of animal remains (opercula of carp fishes, fragments of plastron of Indian Soft Shelled Turtle, Indian Flap Shelled Turtle, ramus of mandible with teeth of Indian Boar) from similar cultural deposits indicate their probable inclusion in dietary list. The climate started changing during the onset of Early Historic period ca. 2350 cal a BP as revealed by pollen and phytolith proxies and became warmer and drier than that in earlier phase which is continuing till recent. The observations of palynological and phytolith data were also corroborated by the results of correspondence analysis (CA) and canonical correspondence analysis (CCA) respectively. Recovery of rice and mustard from Early Historic deposits suggests their continued cultivation at a later phase. Rich assemblages of animal macro remains from the post-Chalcolithic deposits (ca. 2350-2120 cal a BP) indicate their use as food resources in later phase too. Considering the database obtained from all the proxies it can be concluded that a moist-tropical climatic condition was prevailing during Chalcolithic period (ca. 3600 cal a BP) and later gradually shifted to a slight drier condition in lower Gangetic West Bengal.