Landscape versus climate changes at Lake Volvi (Macedonia, Greece) during the Holocene

The present PhD thesis concerns the application of paleopalynology for the study of the human- environment relationship. The research focuses on the reconstruction of the Late-Holocene vegetation dynamics and the interactions between environment and human societies with a strict focus on Macedonian region (Greece) and on a large scale considering the whole Europe. In this thesis, palynological data are used in multidisciplinary studies to understand the evolution of the vegetation, the climate changes and the interaction with past societies, providing high-resolution sequences. The project is linked to a larger research lead by the “Palaeo-Science and History” Independent Max Planck Research Group whose purpose is to develop an interdisciplinary method, involving scientific and humanistic disciplines, to better investigate human history and its relation to environmental changes. Due to the biodiversity richness, Macedonia region is considered one of major hot spots of the Mediterranean basin. Inhabited since the Palaeolithic, it was the cradle of some of the most important societies in human history. Palynological analysis of two sediments cores from the Central Macedonia have been provided: Volvi Lake is the second largest natural lake in Greece and is located on a strategic position for ancient trades; Paliouras lagoon is a coastal site located near the city of Thessaloniki, capital of the ancient Macedonia. The two sites show some analogies in the evolution of the landscape under climatic changes and human pressure but also differences in the environmental composition. Lake Volvi pollen sequence covers the last 2400 years describing an environment characterised by a balance mix of mediterranean taxa, thermophilous and mesophilous forest. Human impact is attested by the presence of cereals pollen and cultivated trees dated since the Hellenistic age (ca. 2300 cal. yr BP). Agriculture is accompanied by animal husbandry as highlighted by the expansion of weed and ruderal taxa and coprophilous fungus. The cultivation of cereals and edible plants increased during the Roman occupation of the region (ca. 1900- 1800 cal. yr BP). Both cultivation and pastoral activities characterised the last centuries with the introduction of the cultivation of the olive tree and chestnut with the Ottomans. The Paliouras lagoon sequence describes the environmental changes of the last 4000 years. Arboreal vegetation is mainly composed by pine and deciduous-semideciduous and evergreen oaks, with a strong reduction in the last millennia. The great expansion of pine between 4000 and 2300 yr cal. BP is probably related to wind transportation from the nearby pine stands along the coast. Signs of human impact are recorded during the colonisation of the Halkidiki peninsula by southern Greek populations (ca. 3000 cal. yr BP). A more intensive land management marks the rise of the Roman empire. In the upper part of the sequence, high percentages of Cichorieae, that colonise arable fields as well as coastal environment, can be ascribed to a combination of human activity and environmental factors. The pollen data of the two Greek sequences have been included in a side project of the PhD research. A big database with a collection of 261 pollen sequences selected among hundreds of pollen records has been built to evaluate the impacts of the Black Death on the demography and consequently on the landscape in different regions of Europe. A new specifical statistical approach called Big-Data Paleoecology (BDP) has been developed based on high-resolution pollen data in order to link big historical events to land-use changes demonstrating strong differences in mortality among the considered regions. Different aspects of the pollen potential have been explored. The palynological records provided a high temporal resolution reconstruction of the Late-Holocene environmental development in Macedonia and allowed consideration on the roles that ecological dynamics, climate changes and human influence have played in determining the vegetational composition of the region. Moreover, pollen data have been successfully applied to shed light on the demographic variabilities and extent of mortality caused by the spread of the Black Death in Europe. This thesis contributed to highlight the natural and anthropic environmental transformations and the development of the societies’ strategies and resilience in a changing human-environment.