Biomorphogenic Feedbacks and the Spatial Organization of a Dominant Grass Steer Dune Development

Dries Bonte,Ruben Van De Walle,Glenn Strypsteen,Pieter Rauwoens,Tomohiro Suzuki,Femke Batsleer,Toon Verwaest,Sam Provoost,Valérie Reijers,Sebastian Dan,Hans Matheve,Martijn L Vandegehuchte,Jasmijn Hillaert

doi:10.3389/fevo.2021.761336

Abstract

Nature-based solutions to mitigate the impact of future climate change depend on restoring biological diversity and natural processes. Coastal foredunes represent the most important natural flood barriers along coastlines worldwide, but their area has been squeezed dramatically because of a continuing urbanization of coastlines, especially in Europe. Dune development is steered by the development of vegetation in interaction with sand fluxes from the beach. Marram grass (Calamagrostis arenaria, formerlyAmmophila arenaria) is the main dune building species along most European coasts, but also in other continents where the species was introduced. Engineering of coastal dunes, for instance by building dunes in front of dikes, needs to be based on a solid understanding of the species’ interactions with the environment. Only quantitative approaches enable the further development of mechanistic models and coastal management strategies that encapsulate these biomorphogenic interactions. We here provide a quantitative review of the main biotic and physical interactions that affect marram grass performance, their interactions with sand fluxes and how they eventually shape dune development. Our review highlights that the species’ spatial organization is central to dune development. We further demonstrate this importance by means of remote sensing and a mechanistic model and provide an outlook for further research on the use of coastal dunes as a nature-based solution for coastal protection.

Highlights

As climate change induces sea level rise and possibly heavier storms, coastal protection is in a transition phase from hard structural engineering toward soft measures that can adapt dynamically to a changing environment (Borsje et al, 2011; IPCC, 2014, 2018; vousdoukas et al, 2018)
We subsequently review the quantitative evidence of feedbacks with sand dynamics and demonstrate by both a new model and remote sensing how marram grass spatial configuration affects dune development
A mechanistic understanding of the vegetation–sedimentation feedbacks that steer the natural development of coastal dunes is essential for conserving and restoring the function of coastal dunes as natural flood barriers

Summary

Introduction

As climate change induces sea level rise and possibly heavier storms, coastal protection is in a transition phase from hard structural engineering toward soft measures that can adapt dynamically to a changing environment (Borsje et al, 2011; IPCC, 2014, 2018; vousdoukas et al, 2018). Marram grass is such as an engineering species (Bakker, 1976; van Puijenbroek et al, 2017a,b) as its growth and performance depend on, and in turn influence, aeolian sand fluxes and dune development (Hesp, 2002; Zarnetske et al, 2015; Strypsteen et al, 2019).

Results

Conclusion