Human Impact on the Vegetation of the Middle Atlas, Morocco, During the Last 5000 Years

Environmental Drivers of Holocene Forest Development in the Middle Atlas, Morocco

“…The coincidence of these changes and independent evidence for winter drying and lake level lowering at Lake Sidi Ali point to synergistic impacts of pastoral activities of the indigeneous Berber peoples of the Atlas and climate changes at the onset of the Late Holocene. Similar early signals were suggested for sites in the northern Middle Atlas (Afourgagh, Iffir) (Lamb et al, 1991), but predate the suggested 2,000 cal yr BP horizon of human impact reported for Ras el Ma, Tifounassine and sites in the Rif (Cheddadi et al, 2015). Important similarities with fire activity in SE Iberia (Gil-Romera et al, 2010) are noted, notably modest fire activity during the Early Holocene in a fuel-load limited system, low fire activity during a humid Mid Holocene associated with the installation of Cedrus at Lake Sidi Ali and a mesophytic tree maximum in SE Iberia, and dynamic fire activity during the Late Holocene in the context of drying and increased human activity.…”

“…Anthropogenic impact may be implicated in processes of matorralization and enhanced fire activity from 4,320 cal yr BP, but the timing coincides with lake level lowering and reduced winter rain during the Late Holocene and synergistic climate-human impacts may be implicated. The fifth phase (v) reflects opening and degradation of the forest cover from 1,300 cal yr BP, and probably marks a horizon of more intense human impact, evident across the southern Middle Atlas (Reille, 1976;Lamb et al, 1991;Tabel et al, 2016).…”

“…The studies also supported fundamental insights into palaeoclimatic linkages between Northwest Africa and the Atlantic region, linking lakelevel lowering in the Middle Atlas with North Atlantic cooling events . Alongside palaeoclimatic insights, key information emerged about the scale and nature of human impacts, through the complementary study of Holocene deposits at Taguelmam N'Harcha, Dayat Iffir, and Dayat Afoughagh (Lamb et al, 1991). The studies indicate a history of low intensity human impact on the Middle Atlas landscape during the last five millennia, intensification of impacts around 2,000 cal yr BP and a significant reduction of Cedrus populations at Taguelmam N'Harcha at 1,400 cal yr BP.…”

“…The second phase, marked by strong forest cover reduction and Cedrus decline in the first millennium AD, is evident at all sites in the southern Middle Atlas, including Lake Sidi Ali, Tigalmamine , Ait Ichou (Tabel et al, 2016), Taguelmam n'Harcha (Lamb et al, 1991), and Col du Zad (Reille, 1976). The timing at Sidi Ali (PAZ-5 boundary, 1,300 cal yr BP, or 650 AD) suggests a possible association with more intensive use of forest resources in the Middle Atlas following the Early Muslim conquest of Northwest Africa in the mid seventh century AD (Abun-Nasr, 1987).…”

“…The biological and bioclimatic diversity of the region, particularly as contained within the Atlas mountain ranges (Ozenda, 1975;Medail and Quezel, 1997), furthermore provides a valuable "test-bed" for understanding the wider response of FIGURE 1 | The study region and location of pollen records, showing: (a) the location of the Middle Atlas (MA), High Atlas (HA) and Rif mountain ranges in Morocco; (b) the western Middle Atlas and the location of the study site and other Holocene pollen studies cited in the text; and (c) length and chronological control of dated pollen records for the Middle Atlas. Key to sites: AFO-Dayat Afourgagh (Lamb et al, 1991); ALI-Lake Sidi Ali (1-Sidi Ali sub-basin, Lamb et al, 1999; 2-Sidi Ali deep lake, this study); CDZ-Col du Zad (Reille, 1976); HAC-Dayet Hachlaff (Nourelbait et al, 2016); HAR-Taguelmam N'Harcha (Lamb et al, 1991); ICH-Ait Ichou (Tabel et al, 2016); IFF-Dayat Iffir (Lamb et al, 1991); IFR-Dayat Ifrah (Rhoujjati et al, 2010;Reddad et al, 2013); RAS-Ras el Ma (Nourelbait et al, 2014); TIF-Tifounassine (Cheddadi et al, 2015); TIG-Tigalmamine (Lamb et al, 1989Lamb and van der Kaars, 1995;Cheddadi et al, 1998).…”