The impact of coastal erosion on the archaeology of the Cyrenaican coast of Eastern Libya

K Westley; Julia Nikolaus; Ahmed Emrage; Nic Flemming; Andrew Cooper

doi:10.1371/journal.pone.0283703

The impact of coastal erosion on the archaeology of the Cyrenaican coast of Eastern Libya

K Westley, Julia Nikolaus, Ahmed Emrage, Nic Flemming, Andrew Cooper

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18 Citations (Scopus)

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Abstract

Coastal erosion in Cyrenaica (Eastern Libya) represents a major problem for archaeology and heritage management. The area is rich in archaeological sites, often understudied or not fully documented, but also has extensive stretches of vulnerable eroding coastline. This study demonstrates the extent and impact of erosion via shoreline change assessment at two spatial scales. Firstly, wide area assessment using shorelines extracted from a time-series of medium-resolution Landsat imagery. Secondly, site-specific assessment using recent and historic Very High Resolution (VHR) satellite imagery. In both cases, extracted shorelines at different timesteps were compared using the Digital Shoreline Analysis System (DSAS) tool to quantify rates and magnitudes of shoreline movement. The results show extensive zones of erosion at and around the key ancient harbour sites of Apollonia, Ptolemais and Tocra. They also suggest increased rates of coastal retreat in recent years, which is likely linked to anthropogenic actions such as sand mining and urbanization. Forecasts based on present-day shoreline change rates, coupled with ground-level documentation of the vulnerable shorelines is used to identify archaeological features and structures which will likely be progressively damaged or destroyed over the next 20 years. The ability to actively protect archaeological sites is unclear, but there is a clear need for mitigation in the form of enhanced awareness of environmental problems (e.g. caused by sand mining) and more intensive survey/documentation of sites and areas which will be lost in the coming years.

Original language	English
Article number	e0283703
Pages (from-to)	1-38
Number of pages	38
Journal	PLoS ONE
Volume	18
Issue number	4
Early online date	12 Apr 2023
DOIs	https://doi.org/10.1371/journal.pone.0283703
Publication status	Published online - 12 Apr 2023

Bibliographical note

Funding information: This study is part of the Maritime Endangered Archaeology (MarEA) Project, funded by Arcadia - a charitable fund of Lisbet Rausing and Peter Baldwin (https://www.arcadiafund.org.uk/) (Award# 4067; authors KW, JN). VHR satellite image provision was supported by the European Space Agency (ESA) Third Party Missions Program (https://earth.esa.int/eogateway) (Proposal # 60657; authors KW, JN). Fieldwork was supported by the British Institute for Libyan and Northern African Studies (formerly Society for Libyan Studies: https://www.bilnas.org/) (authors JN, AE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Funding Information:
Funding:ThisstudyispartoftheMaritime EndangeredArchaeology(MarEA)Project,funded byArcadia-acharitablefundofLisbetRausing andPeterBaldwin(https://www.arcadiafund.org.

Funding Information:
This study is part of the Maritime Endangered Archaeology (MarEA) Project, funded by Arcadia - a charitable fund of Lisbet Rausing and Peter Baldwin (https://www.arcadiafund.org. uk/) (Award# 4067; authors KW, JN). VHR satellite image provision was supported by the European Space Agency (ESA) Third Party Missions Program (https://earth.esa.int/eogateway) (Proposal # 60657; authors KW, JN). Fieldwork was supported by the British Institute for Libyan and Northern African Studies (formerly Society for Libyan Studies: https://www.bilnas.org/) (authors JN, AE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We are indebted to our Libyan partners working on the Cyrenaica Coastal Survey and their tireless field documentation of endangered archaeological sites. Particular thanks to Saad Buyadem and Fouad El-Gumati for their field observations and photographs, and to Prof. Abdelkarem Elgazali for information on local coastal erosion.

Publisher Copyright:
© 2023 Westley et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding

Funding information: This study is part of the Maritime Endangered Archaeology (MarEA) Project, funded by Arcadia - a charitable fund of Lisbet Rausing and Peter Baldwin (https://www.arcadiafund.org.uk/) (Award# 4067; authors KW, JN). VHR satellite image provision was supported by the European Space Agency (ESA) Third Party Missions Program (https://earth.esa.int/eogateway) (Proposal # 60657; authors KW, JN). Fieldwork was supported by the British Institute for Libyan and Northern African Studies (formerly Society for Libyan Studies: https://www.bilnas.org/) (authors JN, AE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Funding Information: Funding:ThisstudyispartoftheMaritime EndangeredArchaeology(MarEA)Project,funded byArcadia-acharitablefundofLisbetRausing andPeterBaldwin(https://www.arcadiafund.org. Funding Information: This study is part of the Maritime Endangered Archaeology (MarEA) Project, funded by Arcadia - a charitable fund of Lisbet Rausing and Peter Baldwin (https://www.arcadiafund.org. uk/) (Award# 4067; authors KW, JN). VHR satellite image provision was supported by the European Space Agency (ESA) Third Party Missions Program (https://earth.esa.int/eogateway) (Proposal # 60657; authors KW, JN). Fieldwork was supported by the British Institute for Libyan and Northern African Studies (formerly Society for Libyan Studies: https://www.bilnas.org/) (authors JN, AE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We are indebted to our Libyan partners working on the Cyrenaica Coastal Survey and their tireless field documentation of endangered archaeological sites. Particular thanks to Saad Buyadem and Fouad El-Gumati for their field observations and photographs, and to Prof. Abdelkarem Elgazali for information on local coastal erosion. Publisher Copyright: © 2023 Westley et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Keywords

Shores
Image processing
Archaeology
Beaches
Linear regression analysis
Sediment
Erosion
Urbanization
Libya
Sand

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1371/journal.pone.0283703Licence: CC BY

journal.pone.0283703Final published version, 10.7 MBLicence: CC BY

Cite this

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title = "The impact of coastal erosion on the archaeology of the Cyrenaican coast of Eastern Libya",

abstract = "Coastal erosion in Cyrenaica (Eastern Libya) represents a major problem for archaeology and heritage management. The area is rich in archaeological sites, often understudied or not fully documented, but also has extensive stretches of vulnerable eroding coastline. This study demonstrates the extent and impact of erosion via shoreline change assessment at two spatial scales. Firstly, wide area assessment using shorelines extracted from a time-series of medium-resolution Landsat imagery. Secondly, site-specific assessment using recent and historic Very High Resolution (VHR) satellite imagery. In both cases, extracted shorelines at different timesteps were compared using the Digital Shoreline Analysis System (DSAS) tool to quantify rates and magnitudes of shoreline movement. The results show extensive zones of erosion at and around the key ancient harbour sites of Apollonia, Ptolemais and Tocra. They also suggest increased rates of coastal retreat in recent years, which is likely linked to anthropogenic actions such as sand mining and urbanization. Forecasts based on present-day shoreline change rates, coupled with ground-level documentation of the vulnerable shorelines is used to identify archaeological features and structures which will likely be progressively damaged or destroyed over the next 20 years. The ability to actively protect archaeological sites is unclear, but there is a clear need for mitigation in the form of enhanced awareness of environmental problems (e.g. caused by sand mining) and more intensive survey/documentation of sites and areas which will be lost in the coming years.",

keywords = "Shores, Image processing, Archaeology, Beaches, Linear regression analysis, Sediment, Erosion, Urbanization, Libya, Sand",

author = "K Westley and Julia Nikolaus and Ahmed Emrage and Nic Flemming and Andrew Cooper",

note = "Funding information: This study is part of the Maritime Endangered Archaeology (MarEA) Project, funded by Arcadia - a charitable fund of Lisbet Rausing and Peter Baldwin (https://www.arcadiafund.org.uk/) (Award\# 4067; authors KW, JN). VHR satellite image provision was supported by the European Space Agency (ESA) Third Party Missions Program (https://earth.esa.int/eogateway) (Proposal \# 60657; authors KW, JN). Fieldwork was supported by the British Institute for Libyan and Northern African Studies (formerly Society for Libyan Studies: https://www.bilnas.org/) (authors JN, AE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Funding Information: Funding:ThisstudyispartoftheMaritime EndangeredArchaeology(MarEA)Project,funded byArcadia-acharitablefundofLisbetRausing andPeterBaldwin(https://www.arcadiafund.org. Funding Information: This study is part of the Maritime Endangered Archaeology (MarEA) Project, funded by Arcadia - a charitable fund of Lisbet Rausing and Peter Baldwin (https://www.arcadiafund.org. uk/) (Award\# 4067; authors KW, JN). VHR satellite image provision was supported by the European Space Agency (ESA) Third Party Missions Program (https://earth.esa.int/eogateway) (Proposal \# 60657; authors KW, JN). Fieldwork was supported by the British Institute for Libyan and Northern African Studies (formerly Society for Libyan Studies: https://www.bilnas.org/) (authors JN, AE). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We are indebted to our Libyan partners working on the Cyrenaica Coastal Survey and their tireless field documentation of endangered archaeological sites. Particular thanks to Saad Buyadem and Fouad El-Gumati for their field observations and photographs, and to Prof. Abdelkarem Elgazali for information on local coastal erosion. Publisher Copyright: {\textcopyright} 2023 Westley et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.",

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KW - Linear regression analysis

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The impact of coastal erosion on the archaeology of the Cyrenaican coast of Eastern Libya

Abstract

Bibliographical note

Funding

Keywords

UN SDGs

Access to Document

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