Songo Mnara: a case study in Swahili induced intertidal aggradation.

The coastal landscape of Songo Mnara was explored during the 2009 season, as a case study for potential reconstruction of landscape through sampling of the surrounding mangrove. This approach combines Historical Ecology with field methods derived from geology and environmental sciences in order to derive a theoretical and archaeological framework for reconstructing socio-cultural transformations captured in coastal landscapes. The underlying premise is that socio-cultural transformations can necessitate changes in agricultural production strategies, resulting in varied signatures of erosion and therefore sediment delivered from agricultural plots to the coast. Mangrove trees trap eroded sediment along the coast and, over time, have the potential to accumulate a chronology of ecological impacts associated with socio-cultural transformations. The potential applicability and validity of this technique was explored at Songo Mnara. The region is attractive for such a study because it includes Kilwa Kisiwani, an urban settlement that was the largest and most impressive of the coast between the 14th and 15th centuries A.D., and has also hosted permanent hinterland populations since the mid-first millennium A.D. This paper presents the results of that case study. Despite regional specificity, the theoretical framework and archaeological fieldwork provided in this proposal are applicable to all tropical coastal regions lined by mangroveforests.