Measuring biodiversity and the loss of indigenous landscapes in coastal Louisiana using airborne imagery and satellite data

ABSTRACT

The Adams Bay site is a Native American monumental centre located in the Mississippi River Delta (MRD), a dynamic, geomorphic environment comprised of marshes, bayous, and rivers. The site itself was constructed approximately 600 to 800 years ago by Indigenous communities who are the ancestors of modern-day coastal communities. Earthen mounds at Adams Bay have disappeared over the past 70 years, and the last remaining mound at the site has almost completely eroded away over the past 10 years. This is an environment that is rapidly subsiding, eroding, and becoming inundated due to sea-level rise, and within this environment are hundreds of earthen and shell mounds. This study uses Sentinel-2 and National Agriculture Imagery Program data to document decadal changes to the landscape at Adams Bay and posits that mound-building had net positive impacts on biodiversity and vegetation in this marshy, deltaic environment. Sites like Adams Bay provide remarkable ecosystem services, enhancing the resilience of coastal ecosystems, and they must be studied and/or preserved before being lost to climatic and environmental forces. Finally, these sites are still incredibly significant to modern Indigenous communities who live in the coastal zone today, and additional resources need to be dedicated towards their conservation.

KEYWORDS:

• Anthropogenic landscapes
• biodiversity
• monumentality

Acknowledgements

National Geographic supported the fieldwork and made it possible to document the site as it was disappearing. Brian Ostahowski and Ted Marks were integral to fieldwork, teaching, and other publications on this site. Louisiana Division of Archaeology staff assisted with background research and facilitated access to online datasets. NOVAC and their staff assisted in teaching local students about the importance of Louisiana’s cultural heritage and brought their students to Adams Bay. Thanks to Tom Leppard, Elizabeth Chamberlain, and Haley Mehta for providing feedback during the writing stage.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

National Agriculture Imagery Program (NAIP) photographs are available through USGS Earth Explorer and the EO Browser by Sentinel Hub. Analyses conducted herein are stored at https://osf.io/kezt6/ using the Open Science Framework. Additional data will be made available on request.

Additional information

Funding

This work was supported by the National Geographic Society, NSF Award RISE 2052930.

Notes on contributors

Jayur Madhusudan Mehta

Jayur Madhusudan Mehta is an Assistant Professor in Anthropology at Florida State University, specializing in the study of North American Native Americans, human-environment relationships, and the consequences of French and Spanish colonization in the Gulf South. Dr. Mehta earned his PhD in Anthropology from Tulane University (2015) and his MA (2007) from the University of Alabama. He received his BA from the University of North Carolina (2004). Dr. Mehta is lead investigator for Resilience in the Ancient Gulf South (RAGS), an interdisciplinary investigation into delta formation, hunter-gather settlement dynamics, and monumentality in the Mississippi River Delta region south of New Orleans. Dr. Mehta is a National Geographic research fellow and he has published research in the fields of environmental archaeology, ethnohistory, and indigenous religious and ritual practices. His research on the Gulf Coast works to preserve the health, resilience, and lifeways of coastal communities threatened by sea-level rise and climate change.