Study of Animal Extinctions Helps Scientist Better Understand How Island of Zanzibar Was Formed; Findings May Aid Efforts to Preserve Island Biodiversity

Researchers at the University of York (UK) have been part of the first comprehensive study of how the island of Zanzibar was formed, charting the extinction of various animals from the region. In a collaborative project between environmental scientists and archaeologists, a team charted the history of sea level change by examining mangrove sediments, and conducting analysis on animal remains found in Kuumbi Cave, an important archeological site. Focusing on evidence from three distinct time periods - the end of the last Ice Age, the stage when Zanzibar became an island 11,000 years ago, and the time of being an island - researchers found that numerous large mammals had disappeared by the later stage. The work was published online on February 22, 2016 in the open-access journal PLOS ONE. The article is titled “Continental Island Formation and the Archaeology of Defaunation on Zanzibar, Eastern Africa." Analyzing over 6,000 bone specimens, it was found that large fauna such as zebra, buffalo, waterbuck, and gazelle were present in the time of island formation. However, after sea levels had risen and the island had been inhabited by coastal cultures, those animals disappeared. Other small fauna, such as porcupines and hares, were also no longer present. Analysis of sea level changes, combined with archeological data on the history of the island's fauna through excavation, has never been done before in charting Zanzibar's history. This unique interdisciplinary approach provides a new, accurate account of the island's prehistory and defaunation. Dr. Robert Marchant, Reader in the University's Environment Department, said: "An understanding of the long-term history of faunal change allows us to identify patterns in the interplay of natural and anthropogenic factors that have shaped Zanzibar's ecosystems today.
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