TY - JOUR
T1 - Quantifying critical conditions for seaward expansion of tidal marshes
T2 - A transplantation experiment
AU - Silinski, Alexandra
AU - van Belzen, Jim
AU - Fransen, Erik
AU - Bouma, Tjeerd J.
AU - Troch, Peter
AU - Meire, Patrick
AU - Temmerman, Stijn
N1 - Funding Information:
This project was financed by the Research Foundation Flanders (FWO grant to A. Silinski, grant number 11E0914N ), the FWO scientific research community (WOG) on “The functioning of river ecosystems through plant-flow-soil interactions” (grant-number WO.027.11N ), the Antwerp Port Authority and UA-BOF (COF AUHA). Work by J. van Belzen and T.J. Bouma was supported by STW-NWO grant 07324 and the EU-funded THESEUS (“Innovative Technologies for Safer European Coasts in a Changing Climate”) project, IP7. 2009-1, contract 244104. We would like to thank Bas Koutstaal from NIOZ for his help with growing the plants for our experiment; Tom Versluys from UGent for his support with the wave meters and the LabView script for analysing the raw data; Zeeuwse Landschappen and Natuurpunt for authorizing the access to the marshes; GEBERIT for providing the PE poles for the SEB installations; Christian Schwarz and Willem-Jan Emsens from ECOBE (UA) for their good advice and valuable input for the interpretation of the results; two anonymous reviewers for their comments that helped improve the manuscript considerably; and finally the many field helpers for their unfailing support during the long monitoring campaigns.
Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2016/2/5
Y1 - 2016/2/5
N2 - The alternative stable states theory is increasingly applied to tidal marsh shorelines, where the two opposing stable states - a dense vegetated state on the one hand and a bare tidal flat on the other hand - can coexist in time but differ in space. The shift from the bare to vegetated state by the establishment of individual plants (seedlings, rhizome-grown shoots) on the bare tidal flat is known to be triggered by the occurrence of windows of opportunity. These are periods when species- and life stage-dependent thresholds, such as sediment dynamics or wave impact, are not exceeded. One controlling environmental parameter in intertidal wetlands is elevation as many important stressors for plants - such as hydroperiod, sediment dynamics and wave properties (wave period and wave height) - are typically correlated to it. Disentangling the respective impact of these correlated stressors remains challenging. In this paper, we present the results of a transplantation experiment where the establishment of three different life stages (seedlings, rhizome-grown shoots and patches) of the brackish pioneer Scirpus maritimus was tested over an elevation gradient at two locations of contrasting wave exposure. This gradient reached from the bare tidal flat into the marsh and covered an elevation range at which continuous S. maritimus-dominated pioneer marsh is known to occur. We found that erosion stress influences seedling survival on tidal flats while drought stress seems to limit long-term establishment of individual shoots and seedlings in the marsh. Furthermore, survival of transplants was more successful on the tidal flat of the sheltered site compared to the tidal flat of the exposed site whereas survival time within the marsh did not differ between sites. This highlights the attenuation of waves and currents in exposed marshes. However, no long-term establishment occurred on the tidal flat, emphasizing the importance of clonal integration for tidal flat colonization.
AB - The alternative stable states theory is increasingly applied to tidal marsh shorelines, where the two opposing stable states - a dense vegetated state on the one hand and a bare tidal flat on the other hand - can coexist in time but differ in space. The shift from the bare to vegetated state by the establishment of individual plants (seedlings, rhizome-grown shoots) on the bare tidal flat is known to be triggered by the occurrence of windows of opportunity. These are periods when species- and life stage-dependent thresholds, such as sediment dynamics or wave impact, are not exceeded. One controlling environmental parameter in intertidal wetlands is elevation as many important stressors for plants - such as hydroperiod, sediment dynamics and wave properties (wave period and wave height) - are typically correlated to it. Disentangling the respective impact of these correlated stressors remains challenging. In this paper, we present the results of a transplantation experiment where the establishment of three different life stages (seedlings, rhizome-grown shoots and patches) of the brackish pioneer Scirpus maritimus was tested over an elevation gradient at two locations of contrasting wave exposure. This gradient reached from the bare tidal flat into the marsh and covered an elevation range at which continuous S. maritimus-dominated pioneer marsh is known to occur. We found that erosion stress influences seedling survival on tidal flats while drought stress seems to limit long-term establishment of individual shoots and seedlings in the marsh. Furthermore, survival of transplants was more successful on the tidal flat of the sheltered site compared to the tidal flat of the exposed site whereas survival time within the marsh did not differ between sites. This highlights the attenuation of waves and currents in exposed marshes. However, no long-term establishment occurred on the tidal flat, emphasizing the importance of clonal integration for tidal flat colonization.
KW - Clonal integration
KW - Colonization
KW - Scirpus maritimus
KW - Thresholds
KW - Windows of opportunity
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U2 - 10.1016/j.ecss.2015.12.012
DO - 10.1016/j.ecss.2015.12.012
M3 - Article
AN - SCOPUS:84951804522
VL - 169
SP - 227
EP - 237
JO - Estuarine, Coastal and Shelf Science
JF - Estuarine, Coastal and Shelf Science
SN - 0272-7714
ER -