Recent climatic and anthropogenic impacts on endemic species in southwestern Morocco

• Published in: Quaternary Science Reviews
• Main Authors: Zhao, Xueqin, Dupont, Lydie, Cheddadi, Rachid, Kölling, Martin, Reddad, Hanane, Groeneveld, Jeroen, Ain-Lhout, Fatima Zohra, Bouimetarhan, Ilham
• Other Authors: Center for Marine Environmental Sciences Bremen (MARUM), Universität Bremen, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS), Université Sultan Moulay Slimane (USMS ), Université Ibn Zohr Agadir, This work was funded by the German Federal Ministry of Education and Research (BMBF),Germany with grant number (PMARS2015-100) through the PMARS initiative “Programme Marocco-Allemand de la Recherche Scientifique (PMARS III)” granted to Dr. Ilham Bouimetarhan.
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDE.ES]Environmental Sciences/Environment and Society; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.science/hal-02354638; https://doi.org/10.1016/j.quascirev.2019.105889

International audience Morocco is an area subject to recurrent severe droughts, desertification and an increasing land degradation. It is within a Mediterranean hotspot of biodiversity as it harbors many threatened endemic species such as the argan tree (Argania spinosa). In this context, past climate records are needed to analyze the impact of climate variability on the occurrence and future persistence of these endemic species. In order to evaluate the impact of past climate changes on the endemic Argan tree in southern Morocco, we reconstructed its modern range using an extensive pollen dataset. The modern pollen distribution off southwestern Morocco was then utilized to interpret the high-resolution pollen record with complementary micro-charcoal and XRF element records from a marine sediment core GeoB8601-3 off Cape Ghir in southwestern Morocco covering the last three millennia. This multi-proxy study has shown clear evidence of wetter conditions resulting in higher fluvial input which could be correlated with a negative mode of the North Atlantic Oscillation (NAO), in contrast to the published pollen and XRF element records from another nearby core that showed limited effect of climate changes. On the other hand, clear opposite trend between the pollen occurrences of Argania spinosa and the fire frequency was observed throughout our fossil record. The increase of Argania spinosa pollen occurrences, along with herbaceous taxa, and lower fire frequency might suggest an increase in human impact on the landscape leading to a sparse vegetation cover and subsequently increased erosion. The reconstructed pollen-based vegetation, micro-charcoal-based fire activities and geochemical changes in our marine record suggest interplay of climate and anthropogenic effects on the landscape.