Salt marsh establishment in poorly consolidated muddy systems

Salt marsh establishment in poorly consolidated muddy systems: effects of surface drainage, elevation, and plant age

Cao, Haobing (East China Normal University; Universiteit Utrecht)
Zhu, Zhenchang (Guangdong University of Technology; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou))
van Belzen, Jim (Universiteit Utrecht)
Gourgue, Olivier (Universiteit Antwerpen)
van de Koppel, J. (Universiteit Utrecht)
Temmerman, O. Stijn (Universiteit Antwerpen)
Herman, P.M.J. (TU Delft Hydraulic Engineering)
Zhang, Liquan (East China Normal University)
Yuan, Lin (East China Normal University)
Bouma, Tjeerd J. (Universiteit Utrecht; Rijksuniversiteit Groningen; NIOZ Royal Netherlands Institute for Sea Research)

Hydraulic Engineering

2021

Conservation and restoration of salt marsh ecosystems are becoming increasingly important because of the many ecosystem services they provide. However, the processes controlling salt marsh establishment and persistence, especially on bare tidal flats in muddy areas, remain unclear. As muddy sediments typically experience a restriction of soil drainage, we expect that a surface drainage relief due to a heterogeneity topography, as might occur on the edge of tidal channels, can facilitate the establishment of salt marsh vegetation on muddy tidal flats. By means of a manipulative field experiment, using “Mega-Marsh Organ” mesocosms, we investigated the impact of surface drainage and elevation relative to mean sea level on (1) the survival of Spartina anglica seedlings from three different age classes: 1-yr, 3-month, and 1-week; and (2) the growth performance of mature S. anglica marsh tussocks. S. anglica seedling survival, especially in the establishment phase, was positively affected by better surface drainage, increases of seedling age, and higher elevation relative to mean sea level. That is, the survival rate of S. anglica seedlings at the end of 6th week increased from 0% (at surface water undrained, 1-week, 0 cm elevation) to 94.44% (at surface water drained, 1-yr, 90 cm elevation). In contrast, surface drainage did not affect the performance of large S. anglica marsh tussocks, as only increased elevation relative to mean sea level was shown to affect S. anglica tussock growth in terms of plant height, shoot numbers, and dry biomass. Based on our findings, we proposed a conceptual model to understand how surface drainage-driven feedbacks in a heterogeneous topography may be reinforced to induce salt marsh establishment in muddy systems. Further testing of present hypothesized model would be beneficial for insights into salt marsh establishment on tidal mudflats.

establishment
muddy sediment
plant age
relative elevation to mean sea level
salt marsh
surface drainage

http://resolver.tudelft.nl/uuid:cbf16540-8b2e-4d08-b8cb-3082a1427774

https://doi.org/10.1002/ecs2.3755

Ecosphere, 12 (9)

Institutional Repository

journal article

© 2021 Haobing Cao, Zhenchang Zhu, Jim van Belzen, Olivier Gourgue, J. van de Koppel, O. Stijn Temmerman, P.M.J. Herman, Liquan Zhang, Lin Yuan, Tjeerd J. Bouma