Impacts of salt marsh plants on tidal channel initiation and inheritance

C. Schwarz*, Q. H. Ye, D. Van Der Wal, L. Q. Zhang, T.J. Bouma, T. Ysebaert, P. M.J. Herman

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

28 Citations (Scopus)

Abstract

At the transition between mudflat and salt marsh, vegetation is traditionally regarded as a sustaining factor for previously incised mudflat channels, able to conserve the channel network via bank stabilization following plant colonization (i.e., vegetation-stabilized channel inheritance). This is in contrast to recent studies revealing vegetation as the main driver of tidal channel emergence through vegetation-induced channel erosion. We present a coupled hydrodynamic morphodynamic plant growth model to simulate plant expansion and channel formation by our model species (Spartina alterniflora) during a mudflat-salt marsh transition with various initial bathymetries (flat, shoal dense, shoal sparse, and deep dense channels). This simulated landscape development is then compared to remote sensing images of the Yangtze estuary, China, and the Scheldt estuary in Netherlands. Our results propose the existence of a threshold in preexisting mudflat channel depth, which favors either vegetation-stabilized channel inheritance or vegetation-induced channel erosion processes. The increase in depth of preexisting mudflat channels favors flow routing through them, consequently leaving less flow and momentum remaining for vegetation-induced channel erosion processes. This threshold channel depth will be influenced by field specific parameters such as hydrodynamics (tidal range and flow), sediment characteristics, and plant species. Hence, our study shows that the balance between vegetation-stabilized channel inheritance and vegetation-induced channel erosion depends on ecosystem properties. Key Points Plant, flow and sediment interaction in response to various initial bathymetry Plant-flow interactions drive landscape development at initial flat bathymetry Initial bathymetry is able to influence the magnitude of plant-flow interactions

Original languageEnglish
Pages (from-to)385-400
Number of pages16
JournalJournal of Geophysical Research: Earth Surface
Volume119
Issue number2
DOIs
Publication statusPublished - 1 Jan 2014

Keywords

  • biogeomorphology
  • ecosystem engineering
  • salt marsh
  • Spartina
  • tidal creek
  • ITC-ISI-JOURNAL-ARTICLE

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