Holocene landscape development along the Portuguese Algarve coast – A high resolution palynological approach

Abstract

Along the Algarve coast, multi-proxy investigations of four estuaries detail the Holocene landscape evolution through high-resolution pollen and sediment analyses. This approach focuses on palynological results and enables the reconstruction of differentiated human impact around the studied archives between the Neolithic and modern times. During the Chalcolithic and Phoenician periods anthropogenic land use increases clearly and triggers erosional processes in the catchment. The increased agricultural area and the change in land use methods since the beginning of the second Islamic epoch form the actual landscape. According to the palynological results, since 8200 cal BP highly variable climatic conditions in terms of moisture availability have occurred during the entire Holocene. Arid periods occurred during the early Holocene prior to 8000 cal BP, around 7000 cal BP and between 6400 and 6200 cal BP. During the mid Holocene, two further dry periods with very different duration could be identified between 5000 and 3300 cal BP and between 2800 and 2500 cal BP. Finally, during the late Holocene between 1300 and 1050 cal BP and between 700 and 500 cal BP, further arid periods appeared. In conclusion, climatic and anthropogenic influences caused erosion in the catchments and in this way silting up of the estuaries along the Portuguese Algarve coast.