Land use, settlement, and plant diversity in Iron Age Northwest France

Abstract

Various studies using pollen stratigraphies have demonstrated significant correlations between Holocene plant diversity, climate, and human activities. Studies that have analyzed longer Holocene timescales tend to discuss cultural data very superficially. This is remarkable because detailed insights into past human activities may be key to gain an understanding of the observed trends in biodiversity. This study aims to reconstruct and explain spatio-temporal trends in past plant diversity (alpha, temporal, and spatial beta diversity) by integrating data on vegetation dynamics, human subsistence economy, and land-use patterns. The landscape of Northwest France during the greater part of the Iron Age and the start of the Roman period (600 BC–AD 100) is selected as a case study. In total, 30 high-quality pollen-stratigraphical sequences allow for the reconstruction of the main long-term trends in plant diversity and more generally of the changing fabric of the landscape. Additionally, increasingly detailed images of the Iron Age rural landscape are available because of a steep increase in archaeological data (aerial photography, surveys, and excavations). These different types of data are integrated and used as input for a wider discussion on the relation between human activities and plant diversity. In general, the taxonomic richness increases steadily during the period under study. Some spatio-temporal differences are observed. The increasing richness values correspond with the growing impact of human activities on the landscape. Archaeologically documented land-use changes on smaller timescales are less clearly reflected in the richness values and vegetation dynamics, which might result from the (large-scale) research design.

Sedimentological and palynological records since 10 ka BP along a proximal-distal gradient on the Armorican shelf (NW France)

“…10c). This palynological trend confirms the major human-induced landscape transformation that occurred under enhanced agro-pastoral activities discussed with archeological (Pailler and Nicolas, 2019) and continental palynological (Marguerie, 1990(Marguerie, , 1992(Marguerie, , 1993Gaudin, 2004;van Beek et al, 2018) data. In Guidel, a second major shift in terms of human impact, highlighted by the sharp drop of arboreal taxa and the related increase of Poaceae percentages (Fig.…”

“…These API increases are also observed in core MD08-3204 CQ, except for the 6.4-5.1 ka BP interval that corresponds to a Mid-Holocene period when we argue for a less continental influence and therefore a lower API transmission to the platform (subsection 5.3.2.). General intensification of anthropogenic activities during these three intervals was not recorded in previous continental studies (Visset et al, 1995(Visset et al, , 1996Gaudin, 2004;Visset and Bernard, 2006;van Beek et al, 2018). Regarding core CBT-CS11, the API signal seems to show an opposite behavior, although the anthropogenic history of the Loire watersheds is not opposite to that of the South Brittany ones.…”

Climate and human induced 2000-year vegetation diversity change in Yunnan, southwestern China

“…On the other hand, positive correlation between vegetation diversity (i.e. richness) and human activities were revealed as well (Paillet et al, 2010; van Beek et al, 2018), under the condition of so-called intermediate disturbance (Wilkinson, 1999). The record from Beihai Wetland revealed that the driving forces of regional vegetation diversity shifted from natural factors to human induced impacts.…”