Elevated micro-topography boosts growth rates in Salicornia procumbens by amplifying a tidally driven oxygen pump: implications for natural recruitment and restoration

Gregory S Fivash; Jim van Belzen; Ralph J M Temmink; Karin Didderen; Wouter Lengkeek; Tjisse van der Heide; Tjeerd J Bouma

doi:10.1093/aob/mcz137

Elevated micro-topography boosts growth rates in Salicornia procumbens by amplifying a tidally driven oxygen pump: implications for natural recruitment and restoration

Ann Bot. 2020 Feb 3;125(2):353-364. doi: 10.1093/aob/mcz137.

Authors

Gregory S Fivash¹, Jim van Belzen¹, Ralph J M Temmink², Karin Didderen³, Wouter Lengkeek³, Tjisse van der Heide^{4

5}, Tjeerd J Bouma^{1

6

7}

Affiliations

¹ Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research and Utrecht University, Yerseke, the Netherlands.
² Aquatic Ecology and Environmental Biology, Institute for Water and Wetland Research, Radboud University, Nijmegen, the Netherlands.
³ Bureau Waardenburg, Culemborg, the Netherlands.
⁴ Department of Coastal Systems, Royal Netherlands Institute for Sea Research and Utrecht University, Den Burg, the Netherlands.
⁵ Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands.
⁶ Delta Academy Applied Research Centre, HZ University of Applied Sciences, Vlissingen, the Netherlands.
⁷ Faculty of Geosciences, Department of Physical Geography, Utrecht University, TC Utrecht, the Netherlands.

Abstract

Background and aims: The growth rate of pioneer species is known to be a critical component determining recruitment success of marsh seedlings on tidal flats. By accelerating growth, recruits can reach a larger size at an earlier date, which reduces the length of the disturbance-free window required for successful establishment. Therefore, the pursuit of natural mechanisms that accelerate growth rates at a local scale may lead to a better understanding of the circumstances under which new establishment occurs, and may suggest new insights with which to perform restoration. This study explores how and why changes in local sediment elevation modify the growth rate of recruiting salt marsh pioneers.

Methods: A mesocosm experiment was designed in which the annual salt marsh pioneer Salicornia procumbens was grown over a series of raised, flat and lowered sediment surfaces, under a variety of tidal inundation regimes and in vertically draining or un-draining sediment. Additional physical tests quantified the effects of these treatments on sediment water-logging and oxygen dynamics, including the use of a planar optode experiment.

Key results: In this study, the elevation of sediment micro-topography by 2 cm was the overwhelming driver of plant growth rates. Seedlings grew on average 25 % faster on raised surfaces, which represented a significant increase when compared to other groups. Changes in growth aligned well with the amplifying effect of raised sediment beds on a tidally episodic oxygenation process wherein sediment pore spaces were refreshed by oxygen-rich water at the onset of high tide.

Conclusions: Overall, the present study suggests this tidally driven oxygen pump as an explanation for commonly observed natural patterns in salt marsh recruitment near drainage channels and atop raised sediment mounds and reveals a promising way forward to promote the establishment of pioneers in the field.

Keywords: Salicornia procumbens; Micro-topography; drainage; establishment; oxygen penetration; restoration; salt marshes.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Chenopodiaceae*
Oxygen*
Water
Wetlands

Substances

Water
Oxygen