This research project is intended to determine the recent environmental evolution of the salt marshes in the eastern Cantabrian coast as a consequence of: a) their formation 3 ka ago when Holocene sea level became stable; b) their human occupation for agricultural purposes during the 18th and 19th centuries; c) their abandonment and natural regeneration during the 20th century; and d) their response to the sea-level oscillations during the last decades as a consequence of the possible ongoing climate change. Moreover, this work aims to reconstruct sea-level changes in this coastal area over the past 500 years.