Coupled topographic and vegetation patterns in coastal dunes: Remote sensing observations and ecomorphodynamic implications. Issue 1 (12th January 2017) - Yousefi Lalimi, F.
Abstract: Vegetation plays a key role in stabilizing coastal dunes and barrier islands by mediating sand transport, deposition, and erosion. Dune topography, in turn, affects vegetation growth, by determining local environmental conditions. However, our understanding of vegetation and dune topography as coupled and spatially extensive dynamical systems is limited. Here we develop and use remote sensing analyses to quantitatively characterize coastal dune ecotopographic patterns by simultaneously identifying the spatial distribution of topographic elevation and vegetation biomass. Lidar‐derived leaf area index and hyperspectral‐derived normalized difference vegetation index patterns yield vegetation distributions at the whole‐system scale which are in agreement with each other and with field observations. Lidar‐derived concurrent quantifications of biomass and topography show that plants more favorably develop on the landward side of the foredune crest and that the foredune crestline marks the position of an ecotone, which is interpreted as the result of a sheltering effect sharply changing local environmental conditions. We conclude that the position of the foredune crestline is a chief ecomorphodynamic feature resulting from the two‐way interaction between vegetation and topography. Key Points: Lidar‐derived LAI provides a quantitative characterization of vegetation biomass and topography in coastal dunes Remote sensing can be used to quantify ecomorphodynamic patterns in dunes at the whole‐system scale Maximum vegetation productivity occurs on the landward side of the foredune crestline