Coastal areas are dynamic and susceptible zones to natural and anthropogenic disturbances, fulfilling valuable ecosystem functions. Vegetation has been observed as an indirect contributor to coastline protection by assisting in the accumulation of sediment in these systems. In this study carried out along Catalan and Andalusian coast, we evaluated the mechanism by which vegetation retains sediment in coastal ecosystems, both emerged and submerged (dunes, salt marshes and seagrass meadows). This process is influenced by the presence or absence of vegetation and other ecological variables (patch area, species richness or dominance). Specifically, we carried out transects with a RTK GNSS receiver to accurately measure ground elevation inside and outside vegetation patches. We also collected aerial imagery using UAVs to expand the spatial scale. Our results show that the presence of vegetation facilitates sediment retention in all ecosystems. Greater species diversity and larger patch areas increased sediment retention capacity. In dune ecosystems, Ammophila arenaria was significantly better at retaining sediment than any of the other species surveyed, while in salt marshes and seagrass meadows we did not find significant differences between species.  Our study sheds light to how vegetation presence, patch size, patch plant diversity and plant traits influence sediment retention capacity across habitat types and scales. This is not only important to face event-scale shoreline changes (e.i. individual storms), but also broader impacts related to climate change.

Primary Presenter: Lucía Rodríguez-Arias, CEAB - CSIC (lucia.rodriguez@ceab.csic.es)

Authors:

Lucía Rodríguez-Arias, CEAB-CSIC  (lucia.rodriguez@ceab.csic.es)

Jordi Pagès, CEAB-CSIC  (jpages@ceab.csic.es)

Fernando García-González, CEAB-CSIC  (f.garcia@ceab.csic.es)

Teresa Alcoverro, CEAB-CSIC  (teresa@ceab.csic.es)