Alison Crowther

Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions

The exhibition of increasingly intensive and complex niche construction behaviors through time is a key feature of human evolution, culminating in the advanced capacity for ecosystem engineering exhibited by Homo sapiens. A crucial outcome of such behaviors has been the dramatic reshaping of the global biosphere, a transformation whose early origins are increasingly apparent from cumulative archaeological and paleoecological datasets. Such data suggest that, by the Late Pleistocene, humans had begun to engage in activities that have led to alterations in the distributions of a vast array of species across most, if not all, taxonomic groups. Changes to biodiversity have included extinctions, extirpations, and shifts in species composition, diversity, and community structure. We outline key examples of these changes, highlighting findings from the study of new datasets, like ancient DNA (aDNA), stable isotopes, and microfossils, as well as the application of new statistical and computational methods to datasets that have accumulated significantly in recent decades. We focus on four major phases that witnessed broad anthropogenic alterations to biodiversity—the Late Pleistocene global human expansion, the Neolithic spread of agriculture, the era of island colonization, and the emergence of early urbanized societies and commercial networks. Archaeological evidence documents millennia of anthropogenic transformations that have created novel ecosystems around the world. This record has implications for ecological and evolutionary research, conservation strategies, and the maintenance of ecosystem services, pointing to a significant need for broader cross-disciplinary engagement between archaeology and the biological and environmental sciences.

The oldest and longest enduring microlithic sequence in India: 35 000 years of modern human occupation and change at the Jwalapuram Locality 9 rockshelter

Abstract The Jwalapuram Locality 9 rockshelter in southern India dates back to 35 000 years ago and it is emerging as one of the key sites for documenting human activity and behaviour in South Asia. The excavated assemblage includes a proliferation of lithic artefacts, beads, worked bone and fragments of a human cranium. The industry is microlithic in character, establishing Jwalapuram 9 as one of the oldest and most important sites of its kind in South Asia.

Old World globalization and the Columbian exchange: comparison and contrast

Abstract A recent paper by Jones et al. (Food globalization in prehistory, World Archaeology, 2011, 43(4), 665–75) explores a prehistoric ‘Trans-Eurasian’ episode of food globalization characterized by the long-distance exchange of starch crops. Drawing upon a comparison to the Columbian Exchange, they emphasize the role of fast-growing crops in optimizing productivity, giving minimal consideration to other drivers. Here we re-evaluate the sequence and timing of the Trans-Eurasian exchange and give greater consideration to the social dimensions of plant translocation. We outline a model for thinking about plant translocations that highlights the way the conceptualization and use of introduced plants changes through time, with social factors frequently dominating in the early stages.

Exploring agriculture, interaction and trade on the eastern African littoral: preliminary results from Kenya

There is a growing interest in transoceanic connections between prehistoric communities occupying the Indian Ocean rim. Corroborative and well-sequenced archaeological data from eastern Africa have, however, been notably lacking. Recent excavations by the Sealinks Project in the coastal region of Kenya has sought to redress this imbalance by collecting base-line data on the local communities occupying this region between c. 1000 BC and AD 1000. Although our analyses are still preliminary, the quality of faunal and botanical material recovered demonstrates considerable potential for exploring local interactions and transitions between early hunter-forager and food-producing communities. A key finding in this regard was the identification of a suite of African crops (Sorghum, Pennisetum and Eleusine) at first millennium AD farming and hunter-forager sites, providing the first significant evidence for early agriculture on the Kenyan coast and the role of crops in forager-farmer trade. Other material data, notably the transfer of marine shell and glass beads inland, and the use of ceramics, indicate a tentative correspondence between the increased intensity of such local interactions in the latter half of the first millennium AD and the emergence of wider Indian Ocean connections.

The differential survival of native starch during cooking and implications for archaeological analyses: a review

Cooking makes foods more palatable and digestible, less toxic and suitable for longer-term storage. Starch granules usually undergo gelatinisation during cooking, resulting in the loss of native structure and morphology. Once fully gelatinised, starch is very difficult to recognise microscopically and to classify taxonomically, impeding identification of cooked starch in archaeological food residues. Gelatinisation involves a complex interplay between temperature, moisture content and the presence of solutes, lipids and proteins, as well as species-specific starch physicochemical properties. Understanding the influence of these factors, particularly moisture, on the degree and extent of starch conversion during heat treatment enables predictive models of native starch survival in archaeological samples based on cooking method and food type. The findings of this review indicate that differential native starch survival may significantly influence archaeobotanical reconstructions and interpretations of artefact function.

Ancient crops provide first archaeological signature of the westward Austronesian expansion

Significance The prehistoric settlement of Madagascar by people from distant Southeast Asia has long captured both scholarly and public imagination, but on the ground evidence for this colonization has eluded archaeologists for decades. Our study provides the first, to our knowledge, archaeological evidence for an early Southeast Asian presence in Madagascar and reveals that this settlement extended to the Comoros. Our findings point to a complex Malagasy settlement history and open new research avenues for linguists, geneticists, and archaeologists to further study the timing and process of this population movement. They also provide insight into early processes of Indian Ocean biological exchange and in particular, Madagascar’s floral introductions, which account for one-tenth of its current vascular plant species diversity. The Austronesian settlement of the remote island of Madagascar remains one of the great puzzles of Indo-Pacific prehistory. Although linguistic, ethnographic, and genetic evidence points clearly to a colonization of Madagascar by Austronesian language-speaking people from Island Southeast Asia, decades of archaeological research have failed to locate evidence for a Southeast Asian signature in the island’s early material record. Here, we present new archaeobotanical data that show that Southeast Asian settlers brought Asian crops with them when they settled in Africa. These crops provide the first, to our knowledge, reliable archaeological window into the Southeast Asian colonization of Madagascar. They additionally suggest that initial Southeast Asian settlement in Africa was not limited to Madagascar, but also extended to the Comoros. Archaeobotanical data may support a model of indirect Austronesian colonization of Madagascar from the Comoros and/or elsewhere in eastern Africa.

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 sites 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.

Continental Island Formation and the Archaeology of Defaunation on Zanzibar, Eastern Africa.

With rising sea levels at the end of the Pleistocene, land-bridge or continental islands were formed around the world. Many of these islands have been extensively studied from a biogeographical perspective, particularly in terms of impacts of island creation on terrestrial vertebrates. However, a majority of studies rely on contemporary faunal distributions rather than fossil data. Here, we present archaeological findings from the island of Zanzibar (also known as Unguja) off the eastern African coast, to provide a temporal perspective on island biogeography. The site of Kuumbi Cave, excavated by multiple teams since 2005, has revealed the longest cultural and faunal record for any eastern African island. This record extends to the Late Pleistocene, when Zanzibar was part of the mainland, and attests to the extirpation of large mainland mammals in the millennia after the island became separated. We draw on modeling and sedimentary data to examine the process by which Zanzibar was most recently separated from the mainland, providing the first systematic insights into the nature and chronology of this process. We subsequently investigate the cultural and faunal record from Kuumbi Cave, which provides at least five key temporal windows into human activities and faunal presence: two at the end of the Last Glacial Maximum (LGM), one during the period of post-LGM rapid sea level rise and island formation, and two in the late Holocene (Middle Iron Age and Late Iron Age). This record demonstrates the presence of large mammals during the period of island formation, and their severe reduction or disappearance in the Kuumbi Cave sequence by the late Holocene. While various limitations, including discontinuity in the sequence, problematize attempts to clearly attribute defaunation to anthropogenic or island biogeographic processes, Kuumbi Cave offers an unprecedented opportunity to examine post-Pleistocene island formation and its long-term consequences for human and animal communities.

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

ABSTRACT Recent archaeological research has firmly established eastern Africas offshore islands as important localities for understanding the regions 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.

Zanzibar and Indian Ocean trade in the first millennium CE: the glass bead evidence

Recent archaeological excavations at the seventh- to tenth-century CE sites of Unguja Ukuu and Fukuchani on Zanzibar Island have produced large numbers of glass beads that shed new light on the island’s early interactions with the wider Indian Ocean world. A selected sample of the beads recovered was analyzed by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to determine the origins of the glass used to make the beads and potential trade relationships are considered. The data show that two major glass types can be identified: mineral-soda glass, m-Na-Al, produced in Sri Lanka (and possibly South India) and plant ash soda glass. The latter comprises three subtypes: two with low alumina concentrations and different quantities of lime (here designated v-Na-Ca subtypes A and B) and one with high alumina (designated v-Na-Al). The v-Na-Ca subtype A beads are chemically similar to Sasanian type 1 glass as well as Zhizo beads found in southern Africa, while v-Na-Ca subtype B compares reasonably well with glasses from Syria and the Levant. While the mineral-soda beads were made in South Asia, it appears likely that at least some of the plant ash beads were made in South or Southeast Asia from imported raw and/or scrap Middle Eastern glass. In contrast, during this period, all beads imported into southern Africa were made of Middle Eastern glass from east of the Euphrates (v-Na-Ca subtype A) and appear to have arrived on ships from Oman and the Persian Gulf. These data suggest that the two sections of the African coast were engaged in different Indian Ocean trade circuits.