Lost Landscapes of Plymouth: Historical Land Reclamation and Coastal Urbanisation Continue to Shape Britain's Ocean City

Coastal cities worldwide face increasing vulnerability to erosion, storm damage, flooding and sea level rise. Many are partially situated on reclaimed land, and the transformation of coastal and estuarine habitats into hard infrastructure has led to significant losses of vital wetlands and intertidal habitats, impacting biodiversity and ecosystem service provision. Shifting Baseline Syndrome-the lack of awareness of the historical existence and extent due to changes in human perception-complicates conservation efforts. Using Plymouth, UK, as a case study, we used a combination of historical maps, satellite imagery and published works to characterise and quantify historical transformations of the coastline. We estimated that approximately 800 hectares of land have been reclaimed in Plymouth Sound and its estuaries since the medieval period (~1200 years CE). Land reclamation occurred for various purposes, including agriculture, milling, urban expansion, infrastructure development and industrialisation. A survey of Plymouth residents revealed limited understanding of local land reclamation history, with the majority unaware of the extent and impact of past transformations. Longer-term residents showed greater awareness, highlighting evidence of Shifting Baseline Syndrome. Additionally, we assessed the multifunctional potential of coastal structures along the Plymouth Hoe foreshore, revealing their historical significance and ecological value. Many structures supported diverse marine life, serving as valuable habitat while simultaneously supporting human activities (e.g. swimming, access and fishing). Understanding the cultural and natural heritage value and historical context of coastal structures can inform conservation and management efforts in urban coastal areas. Greater public awareness of past transformations and their ecological consequences is essential for informed decision-making and sustainable coastal management globally.