High-Resolution Multiproxy Record of Environmental Changes and Anthropogenic Activities at Unguja Ukuu, Zanzibar, Tanzania during the Last 5000 Years

TY - JOUR

T1 - High-Resolution Multiproxy Record of Environmental Changes and Anthropogenic Activities at Unguja Ukuu, Zanzibar, Tanzania during the Last 5000 Years

AU - Englong, Apichaya

AU - Punwong, Paramita

AU - Marchant, Rob

AU - Seelanan, Tosak

AU - Wynne-Jones, Stephanie

AU - Chirawatkul, Prae

N1 - Funding Information: Appreciation is expressed to Rebecca Newman for her support and assistance throughout this fieldwork. We would like to express our gratitude to Asst. Akkaneewut Jirapinyakul for helpful suggestions. Special thanks to Luke Andrews for laboratory help. We would like to thank the Department of Botany Chulalongkorn University, the Faculty of Environment and Resource Studies, Mahidol University and the Department of Environment and Geography, University of York for support in the laboratory and other areas. The authors would like to acknowledge the Synchrotron Light Research Institute (Public Organization), SLRI, for provision of beamtime and assistance from the staff of BL1.1W. This research was supported by Science Achievement Scholarship of Thailand (SAST) from Ministry of Higher Education, Science, Research and Innovation and the CU Graduate School Thesis Grant (GCUGR1225642035D) from the Graduate School, Chulalongkorn University. Publisher Copyright: © 2023 by the authors.

PY - 2023/3/13

Y1 - 2023/3/13

N2 - A high-resolution multiproxy sedimentary record comprising pollen, charcoal, trace element, stratigraphy and particle size data is used to reveal environmental changes from the mangrove ecosystem at Unguja Ukuu, Zanzibar, Tanzania, over the last 5000 years. Historical human–environment interactions over the last millennia are explored by a comparison of the stratigraphic and archaeological data. The area was characterised by a mixture of mangrove forest and beaches, indicating a low level of tidal inundation to at least 3300 BCE. From 2750 BCE, mangrove forest expanded as the area experienced sea-level rise. Further sea-level rise is recorded between 600 and 1100 CE, indicated by the pollen record, particle size analysis and the presence of shell fragments. After 1100 CE, mangrove forest decreased with back mangrove species increasing, indicating a falling sea level. Cocos nucifera decreased after 1900 CE, which reflects a recent sea-level rise and possibly a phase of exploitation. Cereal pollen shows a high presence at around 1500 CE, which coincided with the arrival of the Portuguese on Zanzibar and the transition to Omani colonisation. The sedimentation rate in the core top indicates that mangroves in Unguja Ukuu cannot keep pace with the current rate of sea-level rise.

AB - A high-resolution multiproxy sedimentary record comprising pollen, charcoal, trace element, stratigraphy and particle size data is used to reveal environmental changes from the mangrove ecosystem at Unguja Ukuu, Zanzibar, Tanzania, over the last 5000 years. Historical human–environment interactions over the last millennia are explored by a comparison of the stratigraphic and archaeological data. The area was characterised by a mixture of mangrove forest and beaches, indicating a low level of tidal inundation to at least 3300 BCE. From 2750 BCE, mangrove forest expanded as the area experienced sea-level rise. Further sea-level rise is recorded between 600 and 1100 CE, indicated by the pollen record, particle size analysis and the presence of shell fragments. After 1100 CE, mangrove forest decreased with back mangrove species increasing, indicating a falling sea level. Cocos nucifera decreased after 1900 CE, which reflects a recent sea-level rise and possibly a phase of exploitation. Cereal pollen shows a high presence at around 1500 CE, which coincided with the arrival of the Portuguese on Zanzibar and the transition to Omani colonisation. The sedimentation rate in the core top indicates that mangroves in Unguja Ukuu cannot keep pace with the current rate of sea-level rise.

KW - archaeobotany

KW - palaeoecology

KW - pollen analysis

KW - sea-level change

UR - http://www.scopus.com/inward/record.url?scp=85150977705&partnerID=8YFLogxK

U2 - 10.3390/quat6010021

DO - 10.3390/quat6010021

M3 - Article

AN - SCOPUS:85150977705

SN - 2571-550X

VL - 6

JO - Quaternary

JF - Quaternary

IS - 1

M1 - 21

ER -