Beach–dune sediment budgets and dune morphodynamics following coastal dune restoration, Wickaninnish Dunes, Canada

Ian B. Darke, Ian Walker, Patrick A. Hesp

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The results from three years of surveying and monitoring a dynamic foredune and dunefield restoration effort on Vancouver Island, Canada is presented. Complete removal of foredune vegetation occurred in three phases spaced a year apart in an effort to control invasive Ammophila spp. The collection of airborne LiDAR, orthophotographs, and bi-monthly topographic surveys provided a means to quantify and examine sediment budgets and geomorphic responses. Three survey swaths, corresponding with each phase of vegetation removal, were established to provide detailed topographic coverage over the impacted beach, foredune, and dunefield landscape units. The swath corresponding with the first phase of removal recorded a positive sediment budget of 1·3 m3 m−2 after three years. A control swath, with data collected for a year prior and two years following removal, exhibited a distinct pulse of sediment delivery into the dunefield unit with a maximum gain of 0·03 m3 m−2 pre-removal compared to 0·11 m3 m−2 post-removal. Vegetation analysis zones, associated with each of the three swaths, demonstrate a range of vegetation responses due to variation in the vegetation removal and subsequent re-invasion or removal methods employed. The first site to be cleared of vegetation, received ongoing invasive re-growth control, and three years following removal vegetation cover dropped from 57% in 2009 to 13% in 2012 (−44%). An adjacent site was cleared of vegetation two years later (only one year of recovery) but experienced rapid Ammophila re-invasion and percent cover changed from 61% in 2009 to 26% in 2012 (−35%). The data presented provides insights for improving the application of sediment budget monitoring in dynamic restorations and discusses the potential for detailed spatial–temporal survey data to improve our understanding of meso-scale landscape morphodynamics following foredune disturbance. Overall, the vegetation removal treatments reduced the extent of invasive grass and increased dunefield mobility and dynamic activity.

Original languageEnglish (US)
Pages (from-to)1370-1385
Number of pages16
JournalEarth Surface Processes and Landforms
Volume41
Issue number10
DOIs
StatePublished - Aug 1 2016
Externally publishedYes

Fingerprint

sediment budget
morphodynamics
restoration
dune
budget
Canada
invasion
monitoring
vegetation
coverage
removal
regrowth
surveying
vegetation cover
beach
grass
disturbance

Keywords

  • coastal dunes
  • invasive species
  • morphodynamics
  • restoration
  • sediment budgets

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Earth-Surface Processes
  • Earth and Planetary Sciences (miscellaneous)

Cite this

Beach–dune sediment budgets and dune morphodynamics following coastal dune restoration, Wickaninnish Dunes, Canada. / Darke, Ian B.; Walker, Ian; Hesp, Patrick A.

In: Earth Surface Processes and Landforms, Vol. 41, No. 10, 01.08.2016, p. 1370-1385.

Research output: Contribution to journalArticle

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