Diversification, Intensification and Specialization: Changing Land Use in Western Africa from 1800 BC to AD 1500

Andrea U Kay,Eric Huysecom,Katharina Neumann,Stefano Biagetti,Veerle Linseele,Dorian Q Fuller,Barbara Eichhorn,Marco Madella,Julie Morin-Rivat,Jed O Kaplan,Laurent Lespez,Ulrich Salzmann,Louis Champion,Alexa Höhn,Sylvain Ozainne

doi:10.1007/s10963-019-09131-2

Abstract

Many societal and environmental changes occurred between the 2nd millennium BC and the middle of the 2nd millennium AD in western Africa. Key amongst these were changes in land use due to the spread and development of agricultural strategies, which may have had widespread consequences for the climate, hydrology, biodiversity, and ecosystem services of the region. Quantification of these land-use influences and potential feedbacks between human and natural systems is controversial, however, in part because the archaeological and historical record is highly fragmented in time and space. To improve our understanding of how humans contributed to the development of African landscapes, we developed an atlas of land-use practices in western Africa for nine time-windows over the period 1800 BC–AD 1500. The maps are based on a broad synthesis of archaeological, archaeobotanical, archaeozoological, historical, linguistic, genetic, and ethnographic data, and present land use in 12 basic categories. The main differences between categories is the relative reliance on, and variety of, domesticated plant and animal species utilized, and the energy invested in cultivating or keeping them. The maps highlight the irregular and frequently non-linear trajectory of land-use change in the prehistory of western Africa. Representing an original attempt to produce rigorous spatial synthesis from diverse sources, the atlas will be useful for a range of studies of human–environment interactions in the past, and highlight major spatial and temporal gaps in data that may guide future field studies.

Highlights

In sub-Saharan Africa over the last four millennia, the types of societal shifts that either occurred in response to environmental change or that acted as drivers of that change include the shift to food production, the development of iron metallurgy, population growth, and the emergence of centralized states and empires
The results of this study are both a revision of the livelihood categories previously described by Kay and Kaplan (2015), and an atlas of land-use maps showing the distribution of those categories within the geographic bounds of West and western Central Africa for nine time-windows covering the period 1800 BC–AD 1500
This revision and mapping have been restricted to the smaller case-study area of western and parts of central sub-Saharan Africa, but future work will expand the coverage to include the rest of sub-Saharan Africa

Summary

Introduction

In sub-Saharan Africa over the last four millennia, the types of societal shifts that either occurred in response to environmental change or that acted as drivers of that change include the shift to food production, the development of iron metallurgy, population growth, and the emergence of centralized states and empires. Deforestation and species extinction are the most commonly cited examples of human influence on the environment in sub-Saharan Africa (e.g. Fairhead and Leach 1995, 1996; Norris et al 2010), and at least one study has shown that present-day patterns of tree cover are more strongly controlled by human land use than by climate (Aleman, Blarquez and Staver 2016). The implications of human land use are not necessarily negative and there are several examples of sustainable agricultural practices or other forms of beneficial land management that might preserve or increase biodiversity (e.g. Backes 2001; Butzer 1996; Denevan 1995; Fairhead and Leach 1996; Heckenberger, Christian Russell, Toney and Schmidt 2007; Niemeijer 1996), or even mitigate climate change (Solomon et al 2016)

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