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Wetlands

Freshwater Tidal Wetlands

Tidal spruce swamp, Blind Slough, Clatsop County

Tidal spruce swamp, Blind Slough, Clatsop County
(John A. Christy, Oregon Biodiversity Information Center)

Freshwater tidal wetlands occur in the intertidal zone along coastal rivers, upstream from the Estuarine system where salinity ranges from 0.5 ppt to 0 ppt. They extend along the edges of rivers and their tributaries to the head of tidal influence, which can be up to 20 miles inland along the shorter coastal river to 143 miles inland along the Columbia River. The tidal cycle is similar to that on the coast, but timing is delayed and the amplitude of tidal surge attenuates further upstream to about 3 feet at Portland and 1 foot near Bonneville Dam. Freshwater tidal wetlands can be herbaceous, shrubby, or forested, and like salt marshes are hydrated by meandering tidal creeks. Plant species diversity in these wetlands is extremely rich, and many of thousands of acres have been diked, drained, and farmed.

Freshwater Tidal Wetlands

Freshwater Tidal Wetlands

Habitat: Edges of tidal rivers and streams
Water regime: Tidal, regularly to irregularly flooded
Water chemistry: Fresh

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 Athyrium filix-femina - Scirpus microcarpus Marsh [Provisional]
Lady fern (Christy 2004: 67)
G4S3 CR
wetland type image Bidens cernua Marsh [Provisional]
Nodding beggars-tick marsh (Murray 2000: 12; Christy 2004: 69)
G3S3 CR, WV
wetland type image Bidens frondosa Marsh [Provisional]
Leafy beggars-tick (Christy 2004: 70)
G4S4 CR, WV
wetland type image Carex lyngbyei Herbaceous Vegetation
Lyngby sedge freshwater marsh
G4S3 CR, WV
wetland type image Ceratophyllum demersum Western Aquatic Vegetation
Coontail (Christy 2004: 101; Crowe et al. 2004: 69; NS)
G5S5 CR, WV
wetland type image Eleocharis palustris Marsh
Creeping spikerush (Murray 2000: 17; Christy 2004: 113; Crowe et al. 2004: 66; Christy 2014: 33; NS)
G5S5 CR, WV
wetland type image Elodea canadensis Aquatic Vegetation
Short-awn foxtail (Christy 2016: 12)
G5S5 CR, WV
wetland type image Equisetum fluviatile Marsh
Water horsetail (NS)
G4S3 CR, WC
wetland type image Fontinalis (antipyretica, neomexicana) Nonvascular Aquatic Vegetation
Fountain moss (Christy 2004: 152; NS)
G5S5 CR, WV
wetland type image Lilaeopsis occidentalis Marsh [Provisional]
Lilaeopsis (Christy 2004: 128)
G3S3 CR, WV
wetland type image Persicaria amphibia Marsh [Provisional]
Water smartweed (Christy 2004: 135)
G5S3 WV
wetland type image Picea sitchensis / Cornus sericea / Lysichiton americanus Swamp Forest
Sitka spruce / creek dogwood / skunk cabbage (Christy 2004: 29; NS)
G2S1 CR
wetland type image Populus trichocarpa / Cornus sericea / Lysichiton americanus Riparian Forest
Black cottonwood / creek dogwood / skunk cabbage (Christy 2004: 32; NS)
G1S1 CR, WV
wetland type image Sagittaria latifolia Herbaceous Vegetation
Wapato (Christy 2004: 139; NS)
G3S2 CR, WV
wetland type image Salix hookeriana - (Malus fusca) / Carex obnupta - Lysichiton americanus Wet Shrubland
Hooker willow - (Oregon crabapple) / slough sedge - skunk cabbage (Christy 2004: 54; NS)
G3S3 CR
wetland type image Schoenoplectus acutus Marsh
Hardstem bulrush (Christy 2004: 141; Crowe et al. 2004: 70; NS)
G5S5 CR, WV
wetland type image Schoenoplectus pungens (estuarine) Salt Marsh [Provisional]
Common three-square (freshwater tidal) (Christy et al. 1998: 128, as S. americanus)
G3S2 CR, WV
wetland type image Schoenoplectus tabernaemontani Temperate Marsh
Softstem bulrush (Crowe et al. 2004: 70; NS)
G5S5 CR, WV
wetland type image Scirpus microcarpus Marsh
Small-fruited bulrush (Murray 2000: 25; Christy 2004: 142; Crowe et al. 2004: 134; Wells 2006: 133; NS)
G4S4 CR, WV
wetland type image Sparganium angustifolium Aquatic Vegetation
Narrowleaf bur-reed (Murray 2000: 26; Christy 2004: 144; Crowe et al. 2004: 58; Wells 2006: 156; NS)
G4S3 CR, WV
wetland type image Sparganium eurycarpum Aquatic Vegetation
Broadfruited bur-reed (Christy 2004: 145; Christy 2014: 47; NS)
G4S3 CR
wetland type image Typha (latifolia, angustifolia) Western Marsh
Cattail (broadleaf cattail, narrowleaf cattail) (Murray 2000: 29; Christy 2004: 149; Crowe et al. 2004: 56; Wells 2006: 157; NS)
G5S5 CR

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

randomness