Coastal Subsistence, Maritime Trade, and the Colonization of Small Offshore Islands in Eastern African Prehistory

Recent archaeological research has firmly established eastern Africa's offshore islands as important localities for understanding the region's pre-Swahili maritime adaptations and early Indian Ocean trade connections. While the importance of the sea and small offshore islands to the development of urbanized and mercantile Swahili societies has long been recognized, the formative stages of island colonization—and in particular the processes by which migrating Iron Age groups essentially became “maritime”—are still relatively poorly understood. Here we present the results of recent archaeological fieldwork in the Mafia Archipelago, which aims to understand these early adaptations and situate them within a longer-term trajectory of island settlement and pre-Swahili cultural developments. We focus on the results of zooarchaeological, archaeobotanical, and material culture studies relating to early subsistence and trade on this island to explore the changing significance of marine resources to the local economy. We also discuss the implications of these maritime adaptations for the development of local and long-distance Indian Ocean trade networks

Coastal subsistence, maritime trade, and the colonization of small offshore islands in eastern African prehistory

Recent archaeological research has firmly established eastern Africa’s offshore islands as important localities for understanding the region’s pre-Swahili maritime adaptations and early Indian Ocean trade connections. While the importance of the sea and small offshore islands to the development of urbanized and mercantile Swahili societies has long been recognized, the formative stages of island colonization—and in particular the processes by which migrating Iron Age groups essentially became “maritime”—are still relatively poorly understood. Here we present the results of recent archaeological fieldwork in the Mafia Archipelago, which aims to understand these early adaptations and situate them within a longer-term trajectory of island settlement and pre-Swahili cultural developments. We focus on the results of zooarchaeological, archaeobotanical, and material culture studies relating to early subsistence and trade on this island to explore the changing significance of marine resources to the local economy. We also discuss the implications of these maritime adaptations for the development of local and long-distance Indian Ocean trade networks.The Sealinks Project is funded through a grant toNicole Boivin from the European Research Council (StarterGrant 206148) under the “Ideas” specific Programme of the 7th Framework Programme (FP7). Additional funding includes: postdoctoral fellowships from the British Academy (2010–2013) and the University of Queensland (2015–2017) to Alison Crowther; a Fondation Fyssen Postdoctoral Grant toEr´endira Quintana Morales; and a postdoctoral fellowship from the Government of the Balearic Islands (Conselleria d’Educaci´o) and the European Social Fund to Llorenc¸ Picornell-Gelabert. Fieldwork was carried out under COSTECH Research Permit no. 2012-303-ER-2011-85 and the Division of Antiquities (Ministry of Natural Resources and Tourism, Tanzania) excavation license no. EA.402/605/01 issued to Alison Crowther, and with the support and permission of theRegionalAdministrative Secretary (Dar es Salaam andCoast/Pwani), the District Administrative Secretary (Mafia), and the Village Executive Officer (Mtendaji wa Kijiji, Juani).http://www.tandfonline.com/loi/uica20hb2016Anthropology and Archaeolog

Coastal subsistence, maritime trade, and the colonization of small offshore islands in eastern African prehistory

Recent archaeological research has firmly established eastern Africa’s offshore islands as important localities for understanding the region’s pre-Swahili maritime adaptations and early Indian Ocean trade connections. While the importance of the sea and small offshore islands to the development of urbanized and mercantile Swahili societies has long been recognized, the formative stages of island colonization—and in particular the processes by which migrating Iron Age groups essentially became “maritime”—are still relatively poorly understood. Here we present the results of recent archaeological fieldwork in the Mafia Archipelago, which aims to understand these early adaptations and situate them within a longer-term trajectory of island settlement and pre-Swahili cultural developments. We focus on the results of zooarchaeological, archaeobotanical, and material culture studies relating to early subsistence and trade on this island to explore the changing significance of marine resources to the local economy. We also discuss the implications of these maritime adaptations for the development of local and long-distance Indian Ocean trade networks.The Sealinks Project is funded through a grant toNicole Boivin from the European Research Council (StarterGrant 206148) under the “Ideas” specific Programme of the 7th Framework Programme (FP7). Additional funding includes: postdoctoral fellowships from the British Academy (2010–2013) and the University of Queensland (2015–2017) to Alison Crowther; a Fondation Fyssen Postdoctoral Grant toEr´endira Quintana Morales; and a postdoctoral fellowship from the Government of the Balearic Islands (Conselleria d’Educaci´o) and the European Social Fund to Llorenc¸ Picornell-Gelabert. Fieldwork was carried out under COSTECH Research Permit no. 2012-303-ER-2011-85 and the Division of Antiquities (Ministry of Natural Resources and Tourism, Tanzania) excavation license no. EA.402/605/01 issued to Alison Crowther, and with the support and permission of theRegionalAdministrative Secretary (Dar es Salaam andCoast/Pwani), the District Administrative Secretary (Mafia), and the Village Executive Officer (Mtendaji wa Kijiji, Juani).http://www.tandfonline.com/loi/uica20hb2016Anthropology and Archaeolog

Palaeogenomic analysis of black rat (Rattus rattus) reveals multiple European introductions associated with human economic history

The distribution of the black rat (Rattus rattus) has been heavily influenced by its association with humans. The dispersal history of this non-native commensal rodent across Europe, however, remains poorly understood, and different introductions may have occurred during the Roman and medieval periods. Here, in order to reconstruct the population history of European black rats, we first generate a de novo genome assembly of the black rat. We then sequence 67 ancient and three modern black rat mitogenomes, and 36 ancient and three modern nuclear genomes from archaeological sites spanning the 1st-17th centuries CE in Europe and North Africa. Analyses of our newly reported sequences, together with published mitochondrial DNA sequences, confirm that black rats were introduced into the Mediterranean and Europe from Southwest Asia. Genomic analyses of the ancient rats reveal a population turnover in temperate Europe between the 6th and 10th centuries CE, coincident with an archaeologically attested decline in the black rat population. The near disappearance and re-emergence of black rats in Europe may have been the result of the breakdown of the Roman Empire, the First Plague Pandemic, and/or post-Roman climatic cooling.Peer reviewe

Identifying species threatened with local extinction in tropical reef fisheries using historical reconstruction of species occurrence

Identifying the species that are at risk of local extinction in highly diverse ecosystems is a big challenge for conservation science. Assessments of species status are costly and difficult to implement in developing countries with diverse ecosystems due to a lack of species-specific surveys, species-specific data, and other resources. Numerous techniques are devised to determine the threat status of species based on the availability of data and budgetary limits. On this basis, we developed a framework that compared occurrence data of historically exploited reef species in Kenya from existing disparate data sources. Occurrence data from archaeological remains (750-1500CE) was compared with occurrence data of these species catch assessments, and underwater surveys (1991-2014CE). This comparison indicated that only 67 species were exploited over a 750 year period, 750-1500CE, whereas 185 species were landed between 1995 and 2014CE. The first step of our framework identified 23 reef species as threatened with local extinction. The second step of the framework further evaluated the possibility of local extinction with Bayesian extinction analyses using occurrence data from naturalists' species list with the existing occurrence data sources. The Bayesian extinction analysis reduced the number of reef species threatened with local extinction from 23 to 15. We compared our findings with three methods used for assessing extinction risk. Commonly used extinction risk methods varied in their ability to identify reef species that we identified as threatened with local extinction by our comparative and Bayesian method. For example, 12 of the 15 threatened species that we identified using our framework were listed as either least concern, unevaluated, or data deficient in the International Union for the Conservation of Nature red list. Piscivores and macro-invertivores were the only functional groups found to be locally extinct. Comparing occurrence data from disparate sources revealed a large number of historically exploited reef species that are possibly locally extinct. Our framework addressed biases such as uncertainty in priors, sightings and survey effort, when estimating the probability of local extinction. Our inexpensive method showed the value and potential for disparate data to fill knowledge gaps that exist in species extinction assessments

Iron Age agriculture, fishing and trade in the Mafia Archipelago, Tanzania: new evidence from Ukunju Cave

Small-scale excavations were recently undertaken at the site of Ukunju Cave in the Mafia Archipelago, Tanzania, to collect new bioarchaeological and material culture data relating to the site\u27s occupation and the nature of early subsistence and long-distance trade in the region. Our findings suggest that occupation of the cave began during the Middle Iron Age (MIA, seventh to tenth centuries AD), as indicated by the presence of local Early Tana Tradition (ETT)/Triangular Incised Ware (TIW) pottery in the lowest layers above bedrock, as well as small quantities of imported ceramics and glass beads also dating from the mid- to the late first millennium AD. Small assemblages of faunal and botanical remains, including introduced African crops (pearl millet, sorghum, baobab and possibly cowpea) were found in association with these finds, indicating that these MIA communities practised a mixed economy of fishing, domestic livestock keeping and agriculture. In addition, the presence of cotton suggests they may have also been producing fibres or textiles, most likely for local use, but possibly also for long distance trade. Although some quartz artefacts were recovered, we found no evidence of any pre-Iron Age LSA culture at the cave, contrary to previous claims about the site. Un travail pionnier visant à l\u27étude de l\u27occupation de la côte est-africaine avant l\u27Âge de Fer a relevé les indices d\u27une installation de groupes à l\u27Âge de Pierre tardif et au Néolithique sur plusieurs îles dont Zanzibar, Pemba et Mafia. Il a été proposé que ces occupations étaient associées à des marchandises de l\u27Océan Indien et des animaux domestiques et qu\u27elles dataient des derniers millénaires av. J.-C. Ces données ont fait l\u27objet de beaucoup de controverses et de débats, conduisant certains à remettre en cause la datation des sites, la qualité de la stratigraphie et l\u27identification des restes bio-archéologiques. Pour résoudre ces problèmes chronologiques, le projet Sealinks a récemment mené des fouilles à petite échelle dans la grotte de Ukunju, sur l\u27île de Juani, Mafia. Un ancien sondage a été ré-ouvert et les sédiments basaux fouillés jusqu\u27au sol stérile. Nos résultats suggèrent que l\u27occupation de la grotte commença au cours de l\u27Âge de Fer moyen (MIA), comme l\u27indique la présence de poterie de tradition Tana/Triangulaire Incisé (TT/TIW) dans les niveaux les plus bas, ainsi que de petites quantités de céramiques et de perles de verre importées datant de la deuxième moitié du premier millénaire ap. J.-C. Une petite quantité de plantes africaines introduites, y compris du mil, du sorgho, du baobab et peut-être du niébé, a été recueillie en association avec ces objets, ce qui indiquerait que ces communautés MIA cultivaient le mil et peut-être aussi des légumineuses. La présence de coton suggère qu\u27ils produisaient peut-être aussi des fibres ou des textiles, soit pour une utilisation locale ou pour le commerce sur de longues distances. Bien que certains lithiques en quartz aient été retrouvés, nous n\u27avons décelé aucune donnée indiquant une occupation de la grotte à l\u27Âge de Pierre tardif ou au Néolithique

Data from: Reconstructing Asian faunal introductions to eastern Africa from multi-proxy biomolecular and archaeological datasets

Human-mediated biological exchange has had global social and ecological impacts. In sub-Saharan Africa, several domestic and commensal animals were introduced from Asia in the pre-modern period; however, the timing and nature of these introductions remain contentious. One model supports introduction to the eastern African coast after the mid-first millennium CE, while another posits introduction dating back to 3000 BCE. These distinct scenarios have implications for understanding the emergence of long-distance maritime connectivity, and the ecological and economic impacts of introduced species. Resolution of this longstanding debate requires new efforts, given the lack of well-dated fauna from high-precision excavations, and ambiguous osteomorphological identifications. We analysed faunal remains from 22 eastern African sites spanning a wide geographic and chronological range, and applied biomolecular techniques to confirm identifications of two Asian taxa: domestic chicken (Gallus gallus) and black rat (Rattus rattus). Our approach included ancient DNA (aDNA) analysis aided by BLAST-based bioinformatics, Zooarchaeology by Mass Spectrometry (ZooMS) collagen fingerprinting, and direct AMS (accelerator mass spectrometry) radiocarbon dating. Our results support a late, mid-first millennium CE introduction of these species. We discuss the implications of our findings for models of biological exchange, and emphasize the applicability of our approach to tropical areas with poor bone preservation

Data from: Reconstructing Asian faunal introductions to eastern Africa from multi-proxy biomolecular and archaeological datasets

Human-mediated biological exchange has had global social and ecological impacts. In sub-Saharan Africa, several domestic and commensal animals were introduced from Asia in the pre-modern period; however, the timing and nature of these introductions remain contentious. One model supports introduction to the eastern African coast after the mid-first millennium CE, while another posits introduction dating back to 3000 BCE. These distinct scenarios have implications for understanding the emergence of long-distance maritime connectivity, and the ecological and economic impacts of introduced species. Resolution of this longstanding debate requires new efforts, given the lack of well-dated fauna from high-precision excavations, and ambiguous osteomorphological identifications. We analysed faunal remains from 22 eastern African sites spanning a wide geographic and chronological range, and applied biomolecular techniques to confirm identifications of two Asian taxa: domestic chicken (Gallus gallus) and black rat (Rattus rattus). Our approach included ancient DNA (aDNA) analysis aided by BLAST-based bioinformatics, Zooarchaeology by Mass Spectrometry (ZooMS) collagen fingerprinting, and direct AMS (accelerator mass spectrometry) radiocarbon dating. Our results support a late, mid-first millennium CE introduction of these species. We discuss the implications of our findings for models of biological exchange, and emphasize the applicability of our approach to tropical areas with poor bone preservation