Drivers and Trajectories of Land Cover Change in East Africa
Total Page:16
File Type:pdf, Size:1020Kb
Earth-Science Reviews 178 (2018) 322–378 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Drivers and trajectories of land cover change in East Africa: Human and T environmental interactions from 6000 years ago to present ⁎ Rob Marchanta, , Suzi Richera,b, Oliver Bolesa, Claudia Capitania, Colin J. Courtney-Mustaphia,c, Paul Lanec,d, Mary E. Prendergaste, Daryl Stumpb, Gijs De Cortf,ae, Jed O. Kaplang,n, Leanne Phelpsh, Andrea Kayh, Dan Olagoi, Nik Petekc, Philip J. Plattsa,j, Paramita Punwongk, Mats Widgrenl, Stephanie Wynne-Jonesb,ai, Cruz Ferro-Vázquezb, Jacquiline Benardm, Nicole Boivinn, Alison Crowthern,o, Aida Cuní-Sancheza, Nicolas J. Deerep, Anneli Ekblomc, Jennifer Farmerq,r, Jemma Finchs, Dorian Fullert, Marie-José Gaillard-Lemdahlu, Lindsey Gillsonv, Esther Githumbia, Tabitha Kaborab, Rebecca Kariukia, Rahab Kinyanjuiw, Elizabeth Kyazikex, Carol Langb, Julius Lejjuy, Kathleen D. Morrisonz, Veronica Muiruriw, Cassian Mumbiaa, Rebecca Muthoniw, Alfred Muzukaab, Emmanuel Ndiemaac, Chantal Kabonyi Nzabandoraad, Isaya Onjalax, Annemiek Pas Schrijverl, Stephen Rucinaw, Anna Shoemakerc, Senna Thornton-Barnettb, Geert van der Plasae, Elizabeth E. Watsonaf, David Williamsonag, David Wrightah a York Institute for Tropical Ecosystems, Environment Department, University of York, York, YO10 5NG, United Kingdom b Department of Archaeology, University of York, The King's Manor, York, YO1 7EP, United Kingdom c Institutionen för arkeologi och antik historia, Uppsala Universitet, P.O. Box 256, 751 05, Uppsala, Sweden d School of Geography, Archaeology and Environmental Studies, University of Witwatersrand, South Africa e Department of Anthropology, Saint Louis University, Avenida del Valle 34, 28003 Madrid, Spain f Department of Earth Sciences, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium g ARVE Research SARL, Pully, Switzerland h Institute of Earth Surface Dynamics, University of Lausanne, 1015 Lausanne, Switzerland i Institute for Climate Change and Adaptation, University of Nairobi, Nairobi, Kenya j Department of Biology, University of York, York, YO10 5DD, United Kingdom k Faculty of Environment and Resource Studies, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand l Department of Human Geography, Stockholm University, SE 106 91, Stockholm, Sweden m Kenya Wildlife Service, Shimba Hills, Kenya n Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Strasse 10, D-07745 Jena, Germany o School of Social Science, University of Queensland, Brisbane, 4072, Australia p Durrell Institute of Conservation and Ecology (DICE), School of Anthropology and Conservation, Marlowe Building, University of Kent, Canterbury, CT2 7NR, UK q School of Biological Sciences, University of Aberdeen, Aberdeen, AB24 3FX, Scotland, United Kingdom r Carbon Foundation of East Africa, PO Box 70480, Lubowa Estate, Kampala, Uganda s Discipline of Geography, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Private Bag X01, Scottsville 3201, South Africa t Institute of Archaeology, University College London, 31-34 Gordon Square, London, WC1H 0PY, United Kingdom u Department of Biology and Environmental Science, Linnaeus University, PG Vejdes väg, 351 95, Växjö, Sweden v Plant Conservation Unit and Botany Department, University of Cape Town, Private Bag X3, Rondebosch, 7701, Cape Town, South Africa w Palynology and Palaeobotany Section, Department of Earth Sciences, National Museums of Kenya, P.O. Box 40658, 00100 Nairobi, Kenya x Department of History and Archaeology, Kyambogo University, Kampala, Uganda y Department of Biology, Mbarara University of Science and Technology, P.O. Box 1410, Mbarara, Uganda z Department of Anthropology, University of Pennsylvania, 3260 South Street, Philadelphia, PA 19104, USA aa Tanzania Wildlife Research Institute (TAWIRI), Arusha, Tanzania ab Department of Water Resources and Environmental Science and Engineering, Nelson Mandela African Institute of Science and Technology, Arusha, Tanzania ac Archaeology Section, National Museums of Kenya, P.O. Box 40658, 00100, Nairobi, Kenya ad L'Université Officielle de Bukavu, Bukavu, Congo ae Limnology Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat, 35 9000, Gent, Belgium af Department of Geography, University of Cambridge, Downing Place, Cambridge, CB2 3EN, United Kingdom ag Institut de recherche pour le développement (IRD), United Nations Avenue, Gigiri, P.O. Box 30677, 00100, Nairobi, Kenya ah Department of Archaeology and Art History, Seoul National University, 1 Gwanak-ro, Seoul 08826, South Korea ai Department of Anthropology and Archaeology, University of South Africa, PO Box 392, UNISA ⁎ Corresponding author at: York Institute for Tropical Ecosystems, Environment Department, University of York, York YO10 5NG, United Kingdom. E-mail address: [email protected] (R. Marchant). https://doi.org/10.1016/j.earscirev.2017.12.010 Received 1 August 2017; Received in revised form 6 December 2017; Accepted 14 December 2017 Available online 06 January 2018 0012-8252/ © 2018 Elsevier B.V. All rights reserved. R. Marchant et al. Earth-Science Reviews 178 (2018) 322–378 ARTICLE INFO ABSTRACT Keywords: East African landscapes today are the result of the cumulative effects of climate and land-use change over Archaeology millennial timescales. In this review, we compile archaeological and palaeoenvironmental data from East Africa Iron technology to document land-cover change, and environmental, subsistence and land-use transitions, over the past Pottery 6000 years. Throughout East Africa there have been a series of relatively rapid and high-magnitude environ- Pastoralism mental shifts characterised by changing hydrological budgets during the mid- to late Holocene. For example, Agriculture pronounced environmental shifts that manifested as a marked change in the rainfall amount or seasonality and Livelihoods Palaeoenvironments subsequent hydrological budget throughout East Africa occurred around 4000, 800 and 300 radiocarbon years Savannah before present (yr BP). The past 6000 years have also seen numerous shifts in human interactions with East LandCover6k African ecologies. From the mid-Holocene, land use has both diversified and increased exponentially, this has Sustainable Development Goals been associated with the arrival of new subsistence systems, crops, migrants and technologies, all giving rise to a Land use sequence of significant phases of land-cover change. The first large-scale human influences began to occur around 4000 yr BP, associated with the introduction of domesticated livestock and the expansion of pastoral communities. The first widespread and intensive forest clearances were associated with the arrival of iron-using early farming communities around 2500 yr BP, particularly in productive and easily-cleared mid-altitudinal areas. Extensive and pervasive land-cover change has been associated with population growth, immigration and movement of people. The expansion of trading routes between the interior and the coast, starting around 1300 years ago and intensifying in the eighteenth and nineteenth centuries CE, was one such process. These caravan routes possibly acted as conduits for spreading New World crops such as maize (Zea mays), tobacco (Nicotiana spp.) and tomatoes (Solanum lycopersicum), although the processes and timings of their introductions remains poorly documented. The introduction of southeast Asian domesticates, especially banana (Musa spp.), rice (Oryza spp.), taro (Colocasia esculenta), and chicken (Gallus gallus), via transoceanic biological transfers around and across the Indian Ocean, from at least around 1300 yr BP, and potentially significantly earlier, also had profound social and ecological consequences across parts of the region. Through an interdisciplinary synthesis of information and metadatasets, we explore the different drivers and directions of changes in land-cover, and the associated environmental histories and interactions with various cultures, technologies, and subsistence strategies through time and across space in East Africa. This review suggests topics for targeted future research that focus on areas and/or time periods where our understanding of the interactions between people, the environment and land-cover change are most contentious and/or poorly resolved. The review also offers a perspective on how knowledge of regional land-use change can be used to inform and provide perspectives on contemporary issues such as climate and ecosystem change models, con- servation strategies, and the achievement of nature-based solutions for development purposes. 1. Introduction enmeshed nature of both the natural and cultural drivers of the tem- poral and spatial character of land-cover change. When palaeoecology There is little doubt that physical, biological and climatological is combined with archaeological data there is the potential to begin to systems have influenced the timing and trajectory of the development empirically explore these past interactions by providing linked and of human societies (Marchant and Lane, 2014). For example, the early extended time series that document various components of the living to mid-Holocene was a time of profound cultural transition: settled environment (Gillson and Marchant, 2014). Palaeoecological records agrarian societies emerged and were established across much of the provide perspectives on the long-term