Tracing 8,000 years of climate change and human influence in the Middle Atlas, Morocco: A palynological study from Lake Iffer

Abstract

This study reconstructs Middle to Late Holocene environmental changes and human impacts in the Moroccan Middle Atlas, using palynological data from Lake (Dayet) Iffer. The sedimentary sequence spans the last 8000 calendar years before present (cal yr BP), revealing a dynamic interaction between natural and anthropogenic factors shaping the vegetation in the region. Tree taxa, primarily Pinus, Pistacia, and Quercus (ilex-type and faginea-type), dominated the landscape until ca. 5500 cal yr BP. The onset of the expansion of drought-tolerant species and herbaceous plants aligns with increasing human activities, as inferred from a significant rise in Olea europaea pollen and forest degradation after ca. 3500 cal yr BP. This period recorded the retreat of pine forests and the emergence of Cistus species, reflecting intensified anthropogenic pressures and changing land use. The study also identifies a major shift around 2500 cal yr BP, characterized by extensive deforestation, soil erosion, and the decline of Cedrus atlantica, likely due to combined effects of aridification and sustained human exploitation.