A project undertaken at The University of Adelaide, and supervised by Dr Alice Jones
Coastal vegetated ecosystems (seagrass, mangrove and saltmarsh) located at the boundary between land and sea provide valuable ecosystem services. They have undergone widespread degradation due to human impacts, including climate change and sea-level rise. Monitoring change in coastal ecosystems is difficult using traditional methods, which generate relatively short-term datasets (~100 years), leading to poor understanding of long-term dynamics.
Sediment cores are `muddy time capsules’, providing records of ecosystem change through time buried in sediment layers that are stored for millennia. We used environmental (e)DNA recovered from sediment cores to develop a new method for studying coastal ecosystem change over meaningful timescales (1000s of years).
Our project developed novel eDNA extraction methods that were combined with sediment dating to create an evidence base for reconstructing long-term coastal vegetation changes. We also generated a temperate coastal plant DNA reference database for 94 species, with corresponding vouchered specimens. Robust reference DNA sequence data are crucial for the interpretation of eDNA samples.
The results document shifts in plant community composition at high taxonomic resolution i.e., species, genus or family level in SA coastal systems and are proof-of-concept for our new eDNA method. They can be used to inform coastal conservation, restoration and management.