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Wetlands

Salt Marshes and Brackish Marshes

Salt marsh, Nehalem Bay, Tillamook County

Salt marsh, Nehalem Bay, Tillamook County
(John A. Christy, Oregon Biodiversity Information Center)

Salt marshes and brackish marshes occur in the intertidal zone of coastal estuaries. They are dominated by salt-tolerant herbaceous plants and are usually intermixed with intertidal mudflats that are rich with invertebrates and seaweeds. Farther inland in an estuary, salinity becomes diluted by fresh water from rivers and streams, and a gradual transition to freshwater plants and animals occurs, and woody vegetation becomes more evident. The Cowardin Classification identifies the transition from Estuarine to Riverine and Palustrine systems at points where salinity drops to less than 0.5 parts per thousand (ppt). This transition zone is a moving target in upper estuaries, and is influenced by seasonal or episodic river flows and fluctuations in daily tidal cycles. With the anticipated rise in sea level associated with global climate change, many salt and brackish marshes may become permanently inundated, and their landward edges will advance into what are currently freshwater marshes, shrub swamps, and uplands. The estuarine-freshwater transition zone will also migrate upriver with rising sea level.

Salt Marsh Map

Salt Marsh Map


Habitat: Edges of estuaries, tidal rivers, and tidal streams
Water regime: Subtidal, tidal, regularly to irregularly flooded
Water chemistry: Saline to brackish

Ecoregion*: BM = Blue Mountains, BR = Northern Basin and Range, CB = Columbia Basin, CR = Coast Range, EC = East Cascades, KM = Klamath Mountains, WC = West Cascades, WV = Willamette Valley  
  Scientific & Common Name Global & State Rank Ecoregion*
wetland type image Argentina egedii - Symphyotrichum subspicatum Herbaceous Vegetation
Pacific silverweed - Douglas aster
G3S2 CR
wetland type image Bolboschoenus maritimus Salt Marsh [Provisional]
Seacoast bulrush (Eilers 1975: 225)
G3S2 CR
wetland type image Carex lyngbyei Salt Marsh
Lyngby sedge (NS)
G4S3 CR
wetland type image Carex lyngbyei - Potentilla anserina ssp. pacifica Salt Marsh
Lyngby sedge - Pacific silverweed (NS)
G4S2 CR
wetland type image Carex lyngbyei - (Distichlis spicata, Triglochin maritima) Salt Marsh
Lyngby sedge - (saltgrass, arrow grass) (NS)
G4S2 CR
wetland type image Carex obnupta - Potentilla anserina ssp. pacifica Brackish Marsh
Slough sedge - Pacific silverweed (Christy et al. 1998: 108; NS)
G4S4 CR
wetland type image Deschampsia cespitosa - Potentilla anserina ssp. pacifica Salt Marsh
Tufted hairgrass - Pacific silverweed (NS)
G3S2 CR
wetland type image Deschampsia caespitosa - Juncus balticus Brackish Marsh [Provisional]
Tufted hairgrass - Baltic rush (Taylor 1980: 71)
G4S2 CR
wetland type image Distichlis spicata - Potentilla anserina ssp. pacifica Salt Marsh [Provisional]
Saltgrass - Pacific silverweed (Christy et al. 1998: 124)
G3S2 CR
wetland type image Distichlis spicata - (Sarcocornia perennis) Salt Marsh
Saltgrass - (pickleweed) (NS)
G4S2 CR
wetland type image Juncus balticus - Carex obnupta Brackish Marsh [Provisional]
Baltic rush - slough sedge (Taylor 1980: 57; Kunze 1994: 22)
G4S4 CR
wetland type image Juncus falcatus - Trifolium wormskjoldii Wet Meadow
Sickle-leaved rush - springbank clover (NS)
G4S3 CR
wetland type image Lonicera involucrata / Potentilla anserina Brackish Shrub Swamp [Provisional]
Black twinberry / Pacific silverweed (Brophy 2007)
G3S2 CR
wetland type image Picea sitchensis / Lonicera involucrata - Malus fusca Wet Brackish Swamp Forest [Provisional]
Sitka spruce / black twinberry - western crabapple (Brophy et al. 2011)
G3S2 CR
wetland type image Potentilla anserina ssp. pacifica - Juncus balticus Salt Marsh
Pacific silverweed - Baltic rush (NS)
G3S2 CR
wetland type image Potentilla anserina ssp. pacifica - Symphyotrichum subspicatum Brackish Marsh
Pacific silverweed - Douglas aster (NS)
G3S2 CR
wetland type image Ruppia maritima Aquatic Vegetation
Beaked ditch-grass (NS)
G2S2 CR
wetland type image Salix hookeriana / Potentilla anserina ssp. pacifica - Carex obnupta Wet Shrubland [Provisional]
Hooker willow / Pacific silverweed - slough sedge (Christy et al. 1998: 76)
G4S4 CR
wetland type image Sarcocornia perennis - Distichlis spicata - Triglochin maritima (Jaumea carnosa) Salt Marsh
Pickleweed - saltgrass - arrow grass (fleshy jaumea) (NS)
G3S2 CR
wetland type image Schoenoplectus acutus Marsh
Hardstem bulrush (Christy 2004: 141; Crowe et al. 2004: 70; NS)
G5S5 CR
wetland type image Schoenoplectus maritimus Herbaceous Vegetation [Provisional]
Seacoast bulrush
G3S2 CR
wetland type image Schoenoplectus pungens (estuarine) Salt Marsh [Provisional]
Common three-square (Christy et al. 1998: 128, as S. americanus)
G3S2 CR
wetland type image Triglochin maritima - (Sarcocornia perennis) Salt Marsh
Arrow grass - (pickleweed) (NS)
G4S2 CR
wetland type image Zostera marina Pacific Aquatic Vegetation
Eelgrass (NVC)
G5S3 CR

Authored by John A. Christy, Wetlands Ecologist, (ORBIC) Oregon Biodiversity Information Center (2012 rev. 2017)

randomness