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Subclass Detail Report: S44
Shrub & Herb Wetland Subclass

The U.S. National
Vegetation Classification
Shrub & Herb Wetland includes open bogs, fens, fresh and saltwater marshes, wet meadows and wet shrublands. The vegetation occurs from tropical to polar regions.
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Translated Name:Shrub & Herb Wetland Subclass
Colloquial Name:Shrub & Herb Wetland
Shrub & Herb Wetland includes open bogs, fens, fresh and saltwater marshes, wet meadows and wet shrublands. The vegetation occurs from tropical to polar regions.
Shrub & Herb Wetland is dominated by grasses and shrubs, with or without scattered trees (which may have up to 10% cover), sometimes with a wet moss layer (bogs and fens), halophytic growth forms (salt marsh), or a mix of emergent and hydromorphic growth forms, with seasonally to annually saturated or flooded soils, or standing water.
Vegetation Hierarchy
Name:Database Code:Classification Code:
Class 2 Shrub & Herb Vegetation C02 2
Subclass 2.C Shrub & Herb Wetland S44 2.C
Formation 2.C.3 Tropical Freshwater Marsh, Wet Meadow & Shrubland F030 2.C.3
Formation 2.C.2 Temperate to Polar Bog & Fen F016 2.C.2
Formation 2.C.4 Temperate to Polar Freshwater Marsh, Wet Meadow & Shrubland F013 2.C.4
Formation 2.C.5 Salt Marsh F035 2.C.5
Formation 2.C.1 Tropical Bog & Fen F002 2.C.1
These wetlands contain vegetation that is hydrophytic, but none-the-less, largely mesomorphic growth forms, not hydromorphic growth forms.

Related Type Name:

Short Citation:
  • Faber-Langendoen et al. 2015c
Range:This subclass is found widely throughout the world in lowland and montane wetland habitats, from the tropics to the poles.
US Forest Service Ecoregions
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This type is dominated by grasses and shrubs, with or without scattered trees (but tree cover typically <10%), sometimes with a strong moss (sphagnum or brown moss) component, or with hydromorphic growth forms. A summary of the range of variation for the various wetlands within the subclass is provided in Table 6.
Stands are found in a variety of wetland settings, including seasonally to annually saturated or flooded soils, or standing water. A summary of the range of variation for the various wetlands within the subclass is provided in Table 1.

Table 1. Major wetland types used to guide formation distinctions. Types and definitions are adapted from the National Wetlands Working Group (1997) and Mackenzie and Moran (2004), but need further review for tropical summaries.
Wetland Type Definition Environmental features Growth forms Mitsch & Gosselink (2000) type
Bog & Fen Bogs are shrubby, nutrient-poor peatlands with distinctive communities of ericaceous shrubs and hummock-forming Sphagnum species, sometimes with sedges, adapted to high acid and oxygen-poor soil conditions. Trees >2 m have <10% cover (rarely, raised bogs may contain some forested stands). Vegetation of bogs and poor fen often overlap and are sometimes treated together as "acid peatland." +/- ombrotrophic
pH <4.5
>40 cm fibric/mesic peat.
Stunted (<2 m tall) needle-leaved tree, stunted broad-leaved tree, low shrub, dwarf-shrub (ericaceous), sphagnum. Peatland
Fens are peatlands where groundwater inflow maintains relatively moderate to high mineral content within the rooting zone. Sites are characterized by non-ericaceous shrubs, sedges, grasses, reeds, and brown mosses (often with sphagnum). Ranges from poor fen to rich fen. Poor fens overlap with bogs and are sometimes treated as "acid peatland" separate from "alkaline peatland." Groundwater-fed
pH >4.5 (approximate ranges include poor fen 4.5-5.5, medium or intermediate fen 5.5-6.5, rich fen 6.5-7.5 and extremely rich fen >7.5).
>40 cm fibric/mesic peat.
Low shrub (often non-ericaceous, but evergreen), sedge (often fine), grass, reed, and brown moss, often with sphagnum. Peatland
Freshwater Marsh, Wet Meadow & Shrubland A marsh-wet meadow is a shallowly flooded or saturated wetland dominated by emergent grass-like vegetation. A fluctuating water table is typical in marshes and wet meadows, with early season high water tables and some flooding dropping through the growing (or dry) season, and exposure of the substrate or drying of the profile possible in late (or high of dry) season or drought years. Shrub wetlands (shrub carrs) occupy similar sites to wet meadows. Mineral soils or well-humified peat. Protracted shallow flooding (0.1 to 2.0 m) or prolonged soil profile saturation. Grass, sedge (often coarse), forb, low shrub, tall shrub. Freshwater marshes
Tidal freshwater marshes
Riparian ecosystem (wetland, herb/shrub)
Salt Marsh Saltwater marshes are intertidal to supratidal ecosystems that are flooded diurnally (or less), sometimes with freshwater inputs, and has communities dominated by salt-tolerant emergent graminoids and succulents. Intertidal and supratidal zones, semi-diurnal to diurnal, flooding by brackish or saltwater [n.b. inland non-tidal saline wet meadows may also be placed here]. Grass, sedge, forb, halophytic (succulent) forb, halophytic shrub. Tidal salt marshes
Wetlands Treated Elsewhere
Flooded & Swamp Forests (I.A.4, I.B.3, I.B.5) A swamp forest is a tree-dominated mineral or peat wetland, on sites with a flowing/flooded or fluctuating semipermanent, near- or at-surface water table. A flooded forest occurs on sites where flooding varies from temporary (<7 days) to semipermanent (>180 days). Mineral soils or well-humified peat, temporary to semipermanent flooding (0.1 to 2 m deep), rarely saline Broad-leaved tree, needle-leaved tree, tall shrub, forb, graminoid, hydromorphic herb (rarely), trees >10% cover. Freshwater swamps
Riparian ecosystems (wetland, tree)
Mangrove (I.A.5) Mangroves occur in the intertidal and brackish backwater of estuarine areas in tropical regions. Intertidal and supratidal zones, semi-diurnal to diurnal, flooding by brackish or saltwater. Mangrove, halophytic shrub, halophytic (succulent) forb, graminoids. Mangrove swamps
Aquatic Vegetation (5.A, 5.B) Aquatic wetlands are shallow waters dominated by rooted, submerged and floating aquatic plants. They are associated with permanent still or slow-moving waters, such as shallow potholes, ponds, rivers and lakes or in oceans. Aquatic plants may occur in mineral or in well-humified sedimentary peat. +/- Permanent deep flooding (0.5-2 m), or deep water lakes and oceans. Hydromorphic (aquatic) herb, emergents <10% cover.
No Data Available
D. Faber-Langendoen      Version Date: 17Oct2014

  • Faber-Langendoen, D., T. Keeler-Wolf, D. Meidinger, C. Josse, A. Weakley, D. Tart, G. Navarro, B. Hoagland, S. Ponomarenko, J.-P. Saucier, G. Fults, and E. Helmer. 2015c. Classification and description of world formation types. General Technical Report RMRS-GTR-000. USDA Forest Service, Rocky Mountain Research Station, Fort Collins, CO.

USNVC Credits: Detailed Description of the National Vegetation Classification Types

Date Accessed:

To cite a description:
Author(s). publicationYear. Description Title [last revised revisionDate]. United States National Vegetation Classification. Federal Geographic Data Committee, Washington, D.C.

About spatial standards:
The United States Federal Geographic Data Committee (hereafter called the FGDC) is tasked to develop geospatial data standards that will enable sharing of spatial data among producers and users and support the growing National Spatial Data Infrastructure (NSDI), acting under the Office of Management Budget (OMB) Circular A-16 (OMB 1990, 2000) and Executive Order #12906 (Clinton 1994) as amended by Executive Order #13286 (Bush 2003). FGDC subcommittees and working groups, in consultation and cooperation with state, local, tribal, private, academic, and international communities, develop standards for the content, quality, and transferability of geospatial data. FGDC standards are developed through a structured process, integrated with one another to the extent possible, supportable by the current vendor community (but are independent of specific technologies), and publicly available.

About this document
This document contains type descriptions at the Subclass level of the U.S. National Vegetation Classification. These descriptions were primarily written by NatureServe ecologists in collaboration with Federal Geographic Data Committee Vegetation Subcommittee and a wide variety of state, federal and private partners as a part of the implementation of the National Vegetation Classification. Formation descriptions were written by the Hierarchy Revisions Working Group. The descriptions are based on consultation with natural resource professionals, published literature, and other vegetation classification systems. The Ecological Society of America's Panel on Vegetation Classification is responsible for managing the review and formal adoption of these types into the National Vegetation Classification. Partners involved in the implementation of the USNVC include:

U.S. Government
  • Department of Agriculture (USDA)
  • Department of Commerce (DOC)
  • Department of Defense (DOD)
  • Department of the Interior (USDI)
  • Forest Service (FS) - Chair
  • National Agriculture Statistical Service (NASS)
  • Natural Resources Conservation Service (NRCS)
  • National Oceanic and Atmospheric Administration (NOAA)
  • National Marine Fisheries Service (NMFS)
  • U.S. Army Corps of Engineers (USACE)
  • U.S. Navy (NAVY)
  • Bureau of Land Management (BLM)
  • Fish and Wildlife Service (FWS)
  • National Park Service (NPS)
  • U.S. Geological Survey (USGS)
  • Environmental Protection Agency (EPA)
  • National Aeronautics and Space Administration (NASA)
Non U.S. Government
  • NatureServe (NS)
  • Ecological Society of America (ESA)

Given the dynamic nature of the standard, it is possible a type description is incomplete or in revision at the time of download; therefore, users of the data should track the date of access and read the revisions section of the website to understand the current status of the classification. While USNVC data have undergone substantial review prior to posting, it is possible that some errors or inaccuracies have remained undetected.

For information on the process used to develop these descriptions see:

Faber-Langendoen, D., T. Keeler-Wolf, D. Meidinger, D. Tart, B. Hoagland, C. Josse, G. Navarro, S. Ponomarenko, J.-P. Saucier, A. Weakley, P. Comer. 2014. EcoVeg: A new approach to vegetation description and classification. Ecological Monographs 84:533-561 (erratum 85:473).

Franklin, S., D. Faber-Langendoen, M. Jennings, T. Keeler-Wolf, O. Loucks, A. McKerrow, R.K. Peet, and D. Roberts. 2012. Building the United States National Vegetation Classification. Annali di Botanica 2: 1-9.

Jennings, M. D., D. Faber-Langendoen, O. L. Louckes, R. K. Peet, and D. Roberts. 2009. Standards for associations and alliances of the U.S. National Vegetation Classification. Ecological Monographs 79(2):173-199.

FGDC [Federal Geographic Data Committee]. 2008. Vegetation Classification Standard, FGDC-STD-005, Version 2. Washington, DC., USA. []

For additional information contact:

  • Implementation of the U.S. National Vegetation Classification Standard - Alexa McKerrow (
  • NatureServe's Development of NVC Type Descriptions - Don Faber-Langendoen (don_faber-
  • Ecological Society of America's Review of the Type Descriptions
  • Federal Geographic Data Committee - Vegetation Subcommittee's Activities - Marianne Burke (