, Volume 19, Issue 1, pp 13–27

Response of marine deltaic surfaces to major earthquake uplifts in southcentral Alaska

  • Keith Boggs
  • Michael Shephard

DOI: 10.1007/BF03161729

Cite this article as:
Boggs, K. & Shephard, M. Wetlands (1999) 19: 13. doi:10.1007/BF03161729


Major earthquake uplifts in south-central Alaska of marine deltaic surfaces to an inter-tidal or supra-tidal status cause drastic shifts in processes and vegetation. To assess long-term ecosystem changes as a deltaic landscape converted from a tidal marsh to a supra-tidal wetland, we studied a four-stage chronosequence of deltaic surfaces (30-yr-old inter-tidal surface, 352-yr-old inter-tidal surface, 30-yr-old supra-tidal surface, and 280-yr-old supra-tidal surface). Plots were used to gather landform, soils, and vegetation information, and landform schematics and aerial photo interpretation were used to determine their spatial distribution. Succession progressed on inter-tidal surfaces from pioneer species (principallyCarex lyngbyaei) on newly uplifted mud flats, to a mature tidal marsh with channels, levees, and basins dominated byCarex lyngbyaei with thick root mats. Uplift of the mature tidal surface to a supra-tidal status allowed freshwater tolerant species (Equisetum fluviatile, Sphagnum spp.) to invade the basins, and trees and shrubs displaced herbaceous vegetation on levees. On the oldest supra-tidal surface, basins developed peatlands (Andromeda polifolia, Sphagnum spp.), and pH decreased. Levees supported trees or shrubs on mineral or peat soils. Vegetation zonation within a basin-levee complex was evident and repeated, with some variation, across the surfaces. At the landscape scale moving inland, gradients in vegetation occurred on all surface ages.

Key Words

AlaskaCarex lyngbyaeideltaearthquakelandformlandscape evolutionpeatlandsoilsSphagnumsuccessiontidal marshvegetation pattern

Copyright information

© Society of Wetland Scientists 1999

Authors and Affiliations

  • Keith Boggs
    • 1
  • Michael Shephard
    • 2
  1. 1.Alaska Natural Heritage ProgramUniversity of Alaska AnchorageAnchorageUSA
  2. 2.U.S. Forest ServiceTongass National ForestSitkaUSA