TY - JOUR

T1 - Species-specific and seasonal differences in the resistance of salt-marsh vegetation to wave impact

AU - Reents, Svenja

AU - Möller, Iris

AU - Evans, Ben R.

AU - Schoutens, Ken

AU - Jensen, Kai

AU - Paul, Maike

AU - Bouma, Tjeerd J.

AU - Temmerman, Stijn

AU - Lustig, Jennifer

AU - Kudella, Matthias

AU - Nolte, Stefanie

N1 - Funding Information: The work described in this publication was supported by the European Community’s Horizon 2020 Research and Innovation Programme through the grant to HYDRALAB-PLUS (contract no. 654110). SR was funded by the German Research Foundation (DFG, Deutsche Forschungsgemeinschaft, project no. 401564364) and KS by the Research Foundation Flanders, Belgium (FWO, PhD fellowship for fundamental research, 1116319 N). Additional support was provided by the RESIST-UK project (UKRI Natural Environment Research Council grant no. NE/R01082X/1). We acknowledge support by the Open Access Publication Funds of Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung. Acknowledgments: We would like to thank the team from the Forschungszentrum Küste (FZK) as well as Meline Brendel, Helen Brooks, Haobing Cao, Elizabeth Christie, Rachael Dennis, Anke van Eggermond, Grazia Doronzo and Lennart van IJzerloo.

PY - 2022/12/14

Y1 - 2022/12/14

N2 - The coastal protection function provided by the vegetation of tidal wetlands (e.g. salt marshes) will play an important role in defending coastlines against storm surges in the future and depend on how these systems respond to such forcing. Extreme wave events may induce vegetation failure and thereby risking loss of functionality in coastal protection. However, crucial knowledge on how hydrodynamic forces affect salt-marsh vegetation and whether plant properties might influence plant resistance is missing. In a true-to-scale flume experiment, we exposed two salt-marsh species to extreme hydrodynamic conditions and quantified wave-induced changes in plant frontal area, which was used to estimate plant damage. Moreover, half of the plants were artificially weakened to induce senescence, thus allowing us to examine potential seasonal effects on plant resistance. Morphological, biomechanical as well as biochemical plant properties were assessed to better explain potential differences in wave-induced plant damage. Our results indicate that the plants were more robust than expected, with pioneer species Spartina anglica showing a higher resistance than the high-marsh species Elymus athericus. Furthermore, wave-induced plant damage mostly occurred in the upper part of the vegetation canopy and thus higher canopies (i.e. Elymus athericus) were more vulnerable to damage. Besides a taller canopy, Elymus athericus had weaker stems than Spartina anglica, suggesting that biomechanical properties (flexural stiffness) also played a role in defining plant resistance. Under the highest wave conditions, we also found seasonal differences in the vulnerability to plant damage but only for Elymus athericus. Although we found higher concentrations of a strengthening compound (biogenic silica) in the plant material of the weakened plants, the flexibility of the plant material was not affected indicating that the treatment might not has been applied long enough. Nevertheless, this study yields important implications since we demonstrate a high robustness of the salt-marsh vegetation as well as species-specific and seasonal differences in the vulnerability to plant damage.

AB - The coastal protection function provided by the vegetation of tidal wetlands (e.g. salt marshes) will play an important role in defending coastlines against storm surges in the future and depend on how these systems respond to such forcing. Extreme wave events may induce vegetation failure and thereby risking loss of functionality in coastal protection. However, crucial knowledge on how hydrodynamic forces affect salt-marsh vegetation and whether plant properties might influence plant resistance is missing. In a true-to-scale flume experiment, we exposed two salt-marsh species to extreme hydrodynamic conditions and quantified wave-induced changes in plant frontal area, which was used to estimate plant damage. Moreover, half of the plants were artificially weakened to induce senescence, thus allowing us to examine potential seasonal effects on plant resistance. Morphological, biomechanical as well as biochemical plant properties were assessed to better explain potential differences in wave-induced plant damage. Our results indicate that the plants were more robust than expected, with pioneer species Spartina anglica showing a higher resistance than the high-marsh species Elymus athericus. Furthermore, wave-induced plant damage mostly occurred in the upper part of the vegetation canopy and thus higher canopies (i.e. Elymus athericus) were more vulnerable to damage. Besides a taller canopy, Elymus athericus had weaker stems than Spartina anglica, suggesting that biomechanical properties (flexural stiffness) also played a role in defining plant resistance. Under the highest wave conditions, we also found seasonal differences in the vulnerability to plant damage but only for Elymus athericus. Although we found higher concentrations of a strengthening compound (biogenic silica) in the plant material of the weakened plants, the flexibility of the plant material was not affected indicating that the treatment might not has been applied long enough. Nevertheless, this study yields important implications since we demonstrate a high robustness of the salt-marsh vegetation as well as species-specific and seasonal differences in the vulnerability to plant damage.

KW - flume experiment

KW - plant properties

KW - salt marshes

KW - seasonality

KW - wave-induced damage

UR - http://www.scopus.com/inward/record.url?scp=85145102561&partnerID=8YFLogxK

U2 - 10.3389/fmars.2022.898080

DO - 10.3389/fmars.2022.898080

M3 - Article

AN - SCOPUS:85145102561

VL - 9

JO - Frontiers in Marine Science

JF - Frontiers in Marine Science

SN - 2296-7745

M1 - 898080

ER -