Two Millennia of Plant Community Dynamics in North-Eastern Algeria: The Case of Nechaa Righia Peat, El Kala National Park

A sedimentary sequence of length about 420 cm was extracted from the alder-peatland of Nechaa Righia in north-eastern Algeria’s El Kala wetland complex, to clarify the relationship between past and present vegetation and understand climatic and ecological changes over the past two millennia in this key Mediterranean wetland. The pollen diagram, supported by A.M.S. radiocarbon dates, reveals a predominance of hygrophilous and aquatic taxa like Alnus , Cyperaceae and Juncaceae, indicating a wet environment. Regional vegetation includes mesophilic taxa such as Quercus , Erica arborea and Myrtus , suggesting a mixed landscape. Herbaceous taxa like Poaceae, Apiaceae and Fabaceae further illustrate the area’s variety of plants. Indicators of anthropogenic activity such as Olea , Vitis or Pistacia highlight human impact on the landscape. Around 1890 ± 40 BP, during the Medieval Warm Period, the region featured cork oak forests and mesophilic vegetation consistent with the warmer climate conditions noted in other Mediterranean studies. This vegetation persisted through the Little Ice Age, characterised by cooler conditions, and remains today. Significant human activity began around 1275 ± 50 BP when Yemenites introduced new agricultural practices, supplanting Roman civilisation. Their cultivation of cereals and Olea species significantly shaped the vegetation landscape. These findings align with similar climatic variations reported in the Northern Hemisphere and in the Mediterranean region.