The Archaeology of Social Transformation in Rural Zanzibar, Tanzania, from the Eleventh Through Nineteenth Centuries CE

Open-Access Archaeological Predictive Modeling Using Zonal Statistics: A Case Study from Zanzibar, Tanzania

“…Having considered the environmental factors that structure Models A and B, the next section ground truths the models by comparing them to the locations of major precolonial sites of the late first and early second millennium on Zanzibar (Fitton 2018;Horton and Clark 1985), and to a dataset of sites recovered during a systematic survey across multiple environmental zones in northern Zanzibar in 2019 (Alders 2023). These latter surveys identified and recorded 44 new archaeological sites, with 31 found in the course of a systematic random stratified sample in a region of 32 km 2 .…”

“…Workflows for historical map digitization, zonal statistical analyses, and raster calculation are modeled in QGIS 3.28, a free and open-source GIS. The archaeological predictive model was ground-truthed using a random stratified survey across an environmentally and sociopolitically diverse zone in rural northern Zanzibar (Alders 2023), and also compared to major known precolonial sites on the island (Horton and Clark 1985;Fitton 2018).…”

“…Tables 18 and 19 show zonal statistics for the sites recorded during field surveys (see Alders 2022;2023) in relation to the two predictive models. The tables are stratified by site type, considering artifact scatters in fields in the top rows and permanent, village-sized sites in the bottom rows.…”

“…This study builds on this recent research, contributing to an understanding of the environmental affordances that structured long-term settlement and social change. Modeling human-environment relationships may enable future archaeological prospection on the island where settlement patterns are poorly understood, especially with regard to sites that do not possess standing stone architecture (Alders 2023;Fitton 2018;Horton and Clark 1985). In doing so, this research contributes to a long-standing orientation toward uncovering "hidden majorities" (Fleisher and LaViolette 1999) of Swahili non-elites, who created complex and independent rural societies beyond the boundaries of monumental stone-built towns (Kusimba et al 2013;LaViolette and Fleisher 2018;.…”

“…Zanzibar is an island region in Tanzania that was centrally important to the sociopolitical development of the Swahili Coast and the western Indian Ocean social system over the last two millennia (Crowther et al 2016;Fitton 2018). The island of Zanzibar is environmentally diverse, with two major ecological zones: an agriculturally fertile northwestern region with deep soils and above-ground streams, and a rocky, agriculturally marginal karstic limestone landscape in the south and east, where water does not persist above ground (Alders 2023). Archaeologists have increasingly investigated ecological relationships between Swahili people and their landscapes on Zanzibar Fitton et al 2023;Kotarba-Morley et al 2022;Prendergast et al 2017;Quintana Morales et al 2022).…”