Impact of farming on African landscapes (original) (raw)
Early human impacts and ecosystem reorganization in southern-central Africa
2021
Early modern humans fundamentally altered ecology and landscapes in southern-central Africa using fire. Modern Homo sapiens engage in substantial ecosystem modification, but it is difficult to detect the origins or early consequences of these behaviors. Archaeological, geochronological, geomorphological, and paleoenvironmental data from northern Malawi document a changing relationship between forager presence, ecosystem organization, and alluvial fan formation in the Late Pleistocene. Dense concentrations of Middle Stone Age artifacts and alluvial fan systems formed after ca. 92 thousand years ago, within a paleoecological context with no analog in the preceding half-million-year record. Archaeological data and principal coordinates analysis indicate that early anthropogenic fire relaxed seasonal constraints on ignitions, influencing vegetation composition and erosion. This operated in tandem with climate-driven changes in precipitation to culminate in an ecological transition to an...
Earth-Science Reviews, 2018
East African landscapes today are the result of the cumulative effects of climate and land-use change over millennial timescales. In this review, we compile archaeological and palaeoenvironmental data from East Africa to document land-cover change, and environmental, subsistence and land-use transitions, over the past 6000 years. Throughout East Africa there have been a series of relatively rapid and high-magnitude environ- mental shifts characterised by changing hydrological budgets during the mid- to late Holocene. For example, pronounced environmental shifts that manifested as a marked change in the rainfall amount or seasonality and subsequent hydrological budget throughout East Africa occurred around 4000, 800 and 300 radiocarbon years before present (yr BP). The past 6000 years have also seen numerous shifts in human interactions with East African ecologies. From the mid-Holocene, land use has both diversified and increased exponentially, this has been associated with the arrival of new subsistence systems, crops, migrants and technologies, all giving rise to a 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.
NEW STUDIES ON FORMER AND RECENT LANDSCAPE CHANGES IN AFRICA
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Journal of Archaeological Science, 1984
The Mfolozi and Hluhluwe Valleys of southeastern Africa are representative of a sub-tropical biome and have archaeological evidence for farming settlement spanning more than 1500 years. By collecting information on soils and plant communities within the same sample frame as archaeological data, the relative importance of environmental and anthropomorphic influences can be assessed. It is argued that, although climate and soils have determined the overall distribution of plant communities, human land use has had a considerable effect on the composition of both woodland and grassland. The nature of this interaction between man and environment provides inferential data on prehistoric economies and also aids the formulation of conservation policies in protected areas.
Journal of World Prehistory, 2019
Many societal and environmental changes occurred from the 2nd millennium BC to 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, historic, 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 in turn 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 on human-environment interactions in the past, and highlight major spatial and temporal gaps in data that may guide future field studies.
Pastoralism, Biodiversity, and the Shaping of Savanna Landscapes in East Africa
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Archaeology of African Agro-systems: A Macro-Evolutionary Perspective
The neolithization processes-the shift from hunting-gathering to food production-was kicked off at the end of the Late Glacial Maximum and amplified at different pace in different places during the Holocene. The virtual simultaneity of these transformations in different parts of the world begs for explanation. The Early Holocene Global warming triggered profound environmental changes that offered new resources cohorts and subsistence opportunities to post-Pleistocene huntersgatherers. Plants and animals' domestication resulting from the long-term exploitation and manipulation of selected range of species took place in different parts of the world. Different hypotheses have been formulated to understand the forces driving this shift and the mechanisms sustaining these processes. The prime-movers in these reviewed models include climate change, population growth, the dynamic of exchange, feasting, or religions. This paper focuses on the genesis of African agro-systems in a macro-evolutionary perspective. Plant domestication and the ensuing agricultural system derived from the operation of coevolutionary process involving nature, biological entities, and human agency in constant directional feedback loops. The derived African agro-systems, their genesis, diversity, chronology, and long-term evolution are outlined and discussed. The domestication of Pearl-millet (Pennisetum glaucum) as well as its expansion in the continent are featured in a case-study showcasing the core Extended Evolutionary Synthesis (EES) assumptions that are: directionality, causality, targets of selection, mode of inheritance, and pace of evolution operating at micro as well as macro levels.
Archaeobotanical evidence for the emergence of pastoralism and farming in southern Africa
Acta Palaeobotanica, 2022
Several models which remain equivocal and controversial cite migration and/or diffusion for the emergence and spread of pastoralism and farming in southern Africa during the first millennium AD. A synthesis of archaeobotanical proxies (e.g., palynology, phytoliths, anthracology) consistent with existing archaeobotanical and archaeological data leads to new insights into anthropogenic impacts in palaeorecords. Harnessing such archaeobotanical evidence is viable for tracing the spread of pastoralism and farming in the first millennium AD because the impact of anthropogenic practices is likely to result in distinct patterns of vegetation change. We assess this impact through the synthesis of published archaeobotanical evidence of pastoralism and farming, as well as vegetation changes in southern Africa during the first millennium AD. It has been argued that the decline of forests during the first millennium AD in southern Africa predominantly relates to climate change. This argument of...
Fauna, Fire, and Farming: Landscape Formation over the Past 200 years in Pastoral East Pokot, Kenya
Human Ecology, 2017
Fire was a key element of grass savanna formation all over eastern Africa. In the northern Baringo plains, Pokot pastoralists prospered in the nineteenth century, coexisting with huge herds of wildlife. During the twentieth century, the savanna ecosystem changed from a grass-dominated to bush-dominated as a result of growing numbers of livestock and people, which brought not only elephant hunts but also intensive grazing and changing fire regimes. Subsequently, herders diversified their livelihoods, and these land-use changes in the East Pokot highlands led to the spread of the endemic plant Dodonaea viscosa (Sapindaceae) beyond its original habitat. Ingolds' concept of taskscape is applied here to illustrate a temporal, consecutive perspective of landscape transitions against the background of disappearing landscape agents (in this case large herbivores and fire).