Intensified mid-Holocene floods recorded by archeomalacological data and resilience of first farming groups of the Carpathian Basin

One of the most significant cultural transformations in European prehistory occurred in the middle of the 6th millennium BC in the heart of the Carpathian Basin. The northward expansion of Mediterranean farming groups (Starcevo-Koros-Cris cultural complex) halted and underwent a complete transformation giving rise to a new cultural group carrying an altered form of Neolithic traditions onward to Europe. This transformation is restricted to sites along a boundary found in the heart of the basin, north of which unfavorable ecological conditions hampered a long-term engagement in a Mediterranean type of agriculture. The majority of Early Neolithic Koros sites in eastern Hungary are confined to the alluvial plain of the Tisza River prone to natural biannual flooding. These wetland conditions were marginal for early farmers as it contained several elements that were hostile for herded animals and these groups were not adopted to cope with. Koros Culture pastoralists responded to these challenges posed by the new environment by complementing their diet with opportunistically exploited wild resources. This type of resilience of the first farmers seen in the alteration of traditional subsistence strategies was simply attributed to the static hostile conditions of the environment alone. Influence of dynamic changes in the hydrology has not been studied and documented so far. This paper presents a multiproxy archeomalacological approach to establish a mid-Holocene flood record in Southern Central Europe and assess the potential impacts of flood frequencies, climate change-induced higher floods on economic, societal development of the first farming groups from the heart of the Carpathian Basin. Based on our findings, intensified use of second-line subsistence resources marking resilience is coeval with intensified flooding during the second phase of cultural evolution preceding transformation. This marked transformation could have been traced regionally as well along the referred northern distribution line and is coeval with the initial phase of a minor climatic perturbation refered to as the IRD 5.b event. The southward expansion of cold waters in the North Atlantic yielded intensive cyclonic activity bringing more rain and cold weather to W Europe. In Hungary, higher continentality provided by the basin setting preserved warmer conditions. Nevertheless, increased rainfall onto the watershed of major rivers triggered heightened floods.