Wetland Classification Systems International Vegetation Classification System

Wetland classification systems

International Vegetation Classification System (Grossman et al. 1998; NatureServe 2004; Faber- Langendoen et al. 2008)

Table from Faber-Langendoen et al. (2012; 2016) and Cowardin et al. (1979) Wetland Definition Environmental Growth Mitsch & NWI Wetland Class category features forms Gosselink (2000) type Bog Bogs are shrubby or low- +/- ombrotrophic Stunted Peatland Palustrine Moss-Lichen (PML)*+/- statured treed, nutrient-poor pH <4.5 needle-leaved Palustrine Emergent (PEM) peatlands with distinctive >40 cm fibric/mesic tree, low Palustrine Scrub-Shrub (PSS) communities of ericaceous peat shrub, dwarf shrubs and hummock- shrub forming Sphagnum species, (ericaceous), sometimes with sedges, sphagnum adapted to high acid and oxygen-poor soil conditions. Trees between 5- 10 m typically 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.” Fen Fens are peatlands where Groundwater-fed Low shrub Peatland Palustrine Moss-Lichen (PML)+/- groundwater or stream pH >4.5 (often non- Palustrine Emergent (PEM) inflow maintains relatively (approximate ericaceous), Palustrine Scrub-Shrub (PSS) moderate to high mineral ranges include poor sedge (often content within the rooting fen 4.5-5.5, fine), grass, zone. Sites are characterized medium or reed, and by both ericaceous and non- intermediate fen brown moss, ericaceous shrubs, sedges, 5.5-6.5, rich fen with or grasses, reeds, and brown 6.5-7.5 and without mosses. Trees 5-10 m extremely rich fen > sphagnum. typically have <10% cover. 7.5). Less Ranges from poor fen to rich >40 cm fibric/mesic commonly, fen. Poor fens overlap with peat (including short trees. bogs and are sometimes marly peat) treated together as “acid peatland” separate from “alkaline peatland.” Freshwater A marsh-wet meadow is a Mineral soils or Grass, sedge Freshwater Palustrine Emergent (PEM) Marsh, shallowly flooded or well-humified peat, (often marsh Palustrine Scrub-Shrub (PSS) Wet saturated wetland dominated or rarely marl or coarse), forb, (emergent), Riverine Tidal Emergent (non- Meadow & by emergent grass-like, forb rocky substrates. low shrub, tall Tidal persistent) (R1EM2) or shrub vegetation. A Protracted shallow shrub freshwater Shrubland fluctuating water table is flooding (0.1 to 2.0 marsh, (non-tidal typical in marshes and wet m), prolonged soil Riparian and tidal) meadows, with early season profile saturation, ecosystems high water tables and some or freshwater or (wetland, flooding dropping through oligohaline tidal herb/shrub) the growing (or dry) season, inundation. 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. Trees > 5 m have <10% cover. Wetland Definition Environmental Growth Mitsch & NWI Wetland Class category features forms Gosselink (2000) type Salt Marsh Salt marshes are intertidal to Intertidal and Grass, sedge, Salt marsh, Estuarine Intertidal Emergent supratidal ecosystems that supratidal zones, forb, [Inland (E2EM) are flooded diurnally (or less), semi-diurnal to halophytic saline Estuarine Intertidal Scrub-Shrub sometimes with freshwater diurnal, flooding by (succulent) marsh] (E2SS) inputs, and have brackish or forb, communities dominated by saltwater [n.b. halophytic salt-tolerant emergent inland non-tidal shrub graminoids and succulents. saline wet Trees > 5 m have <10% cover meadows may also be placed here] Flooded & A swamp forest is a tree- Mineral soils or broad-leaved Freshwater Palustrine Forested (PFO) Swamp dominated mineral or peat well-humified peat. tree, needle- swamps, Estuarine Intertidal Forested Forest wetland, on sites with a Temporary to semi- leaved tree, Riparian (E2FO) (mainly freshwater) (non-tidal flowing/flooded or permanent flooding tall shrub, ecosystems fluctuating semi-permanent, (0.1 to 2 m deep), forb, (wetland, and tidal) near or at surface water or freshwater or graminoid, tree) table. A flooded forest occurs oligohaline tidal hydromorphic on sites where flooding varies inundation. herb (rarely) from temporary (<7 days) to semi-permanent (>180 days). Trees > 5 m have >10% cover Mangrove Mangroves occur in the inter- Intertidal and Mangrove, Mangrove Estuarine Intertidal Forested tidal and brackish backwater supratidal zones, halophytic (E2FO) of estuarine areas in tropical semi-diurnal to shrub, regions. Mangroves include diurnal, flooding by halophytic tree and shrub forms of brackish or (succulent) mangrove of all heights. saltwater forb, graminoids Aquatic Aquatic wetlands are shallow +/-Permanent deep Hydromorphic Freshwater Palustrine Aquatic Bed (PAB) Vegetation waters dominated by rooted, flooding (0.5 – 2 (aquatic) herb marsh Riverine Tidal Aquatic Bed (R1AB) (non-tidal submerged, and floating m), substrate can (aquatic) Lacustrine Aquatic Bed (L2AB) and tidal) aquatic plants. They are be muck, sand, associated with permanent marl or rocky still or slow-moving waters, substrates such as shallow potholes, ponds, rivers, and lakes. Aquatic plants may occur in mineral or in well-humified sedimentary peat. Emergent growth forms <10% cover, hydromorphic growth forms >1% cover.

Ecological Systems (Comer et al. 2003)

NatureServe Explorer (http://explorer.natureserve.org/)

US Fish and Wildlife Service’s National Wetlands Inventory classification

See last column in above Table for International Vegetation Classification System for NWI Wetland Class which is based on Cowardin classification (Cowardin et al. 1979; FGDC 2013)

Southwest ReGap (http://swregap.nmsu.edu/HMdatabase/landc_database_report.pdf)

Hydrogeomorphic (HGM) classification system (Brinson 1993; NRCS 2008; Smith et al. 1995)

Table from Faber-Langendoen et al. (2016) and NRCS (2008) HGM Class Definition Riverine Riverine wetlands occur in floodplains and riparian corridors in association with stream channels. Dominant water sources are often overbank flow from the channel or subsurface hydraulic connections between the stream channel and wetlands. However, sources may be interflow and return flow from adjacent uplands, occasional overland flow from adjacent uplands, tributary inflow, and precipitation. At their headwater, RIVERINE wetlands often are replaced by SLOPE or DEPRESSIONAL wetlands where the channel morphology may disappear. They may intergrade with poorly drained flats or uplands. Perennial flow in the channel is not a requirement. Depressional Depressional wetlands occur in topographic depressions. Dominant water sources are precipitation, groundwater discharge, and both interflow and overland flow from adjacent uplands. The direction of flow is normally from the surrounding uplands toward the center of the depression. Elevation contours are closed, thus allowing the accumulation of surface water. Depressional wetlands may have any combination of inlets and outlets or lack them completely. Dominant hydrodynamics are vertical fluctuations, primarily seasonal. Depressional wetlands may lose water through intermittent or perennial drainage from an outlet, by evapotranspiration and, if they are not receiving groundwater discharge, may slowly contribute to groundwater. Peat deposits may develop in depressional wetlands. Prairie potholes are a common example of depressional wetlands. Slope Slope wetlands normally are found where there is a discharge of groundwater to the land surface. They normally occur on sloping land; elevation gradients may range from steep hillsides to slight slopes. Slope wetlands are usually incapable of depressional storage because they lack the necessary closed contours. Principal water sources are usually groundwater return flow and interflow from surrounding uplands, as well as precipitation. Hydrodynamics are dominated by downslope unidirectional water flow. Slope wetlands can occur in nearly flat landscapes if groundwater discharge is a dominant source to the wetland surface. Slope wetlands lose water primarily by saturation subsurface and surface flows and by evapotranspiration. SLOPE wetlands may develop channels, but the channels serve only to convey water away from the SLOPE wetland. Fens are a common example of slope wetlands. Mineral soil flats Mineral soils flats are most common on interfluves, extensive relic lake bottoms, or large historical floodplain terraces where the main source of water is precipitation. They receive no groundwater discharge, which distinguishes them from DEPRESSIONAL and SLOPE wetlands. Dominant hydrodynamics are vertical fluctuations. Mineral soil flats lose water by evapotranspiration, saturation overland flow, and seepage to underlying groundwater. They are distinguished from flat upland areas by their poor vertical drainage, often due to spodic horizons and hardpans, and low lateral drainage, usually due to low hydraulic gradients. Mineral soil flats that accumulate peat can eventually become the class ORGANIC SOIL FLATS. Pine flatwoods with hydric soils are a common example of MINERAL SOIL FLAT wetlands. Organic soil flats Organic soil flats, or extensive peatlands, differ from mineral soil flats, in part because their elevation and topography are controlled by vertical accretion of organic matter. They occur commonly on flat interfluves, but may also be located where depressions have become filled with peat to form a relatively large flat surface. Water source is dominated by precipitation, while water loss is by saturation overland flow and seepage to underlying groundwater. Raised bogs share many of these characteristics, but may be considered a separate class because of their convex upward form and distinct edaphic conditions for plants. Portions of the Everglades and northern Minnesota peatlands are common examples of organic soil flat wetlands. Estuarine fringe Estuarine Fringe wetlands occur along coasts and estuaries and are under the influence of sea level. They intergrade landward with Riverine wetlands where tidal currents diminish and riverflow becomes the dominant water source. Additional water sources may be groundwater discharge and precipitation. The interface between the estuarine fringe and Riverine classes is where bidirectional flows from tides dominate over unidirectional ones controlled by floodplain slope of Riverine wetlands. Because estuarine fringe wetlands frequently flood and water table elevations are controlled mainly by sea surface elevation, estuarine fringe wetlands seldom dry for significant periods. Estuarine fringe wetlands lose water by tidal exchange, by saturated overland flow to tidal creek channels, and by evapotranspiration. Organic matter normally accumulates in higher elevation marsh areas where flooding is less frequent and the wetlands are isolated from shoreline wave erosion by intervening areas of low marsh. Spartina alterniflora salt marshes are common examples of estuarine fringe wetlands. Lacustrine Lacustrine fringe wetlands are adjacent to lakes where the water elevation of the lake fringe maintains the water table in the wetland. In some cases, these wetlands consist of a floating mat attached to land. Additional sources of water are precipitation and groundwater discharge, the latter dominating where lacustrine fringe wetlands intergrade with uplands or SLOPE wetlands. Surface water flow is bidirectional, usually controlled by water-level fluctuations such as seiches in the adjoining lake. Lacustrine fringe wetlands are indistinguishable from depressional wetlands where the size of the lake becomes so small relative to fringe wetlands that the lake is incapable of stabilizing water tables. Lacustrine fringe wetlands lose water by flow returning to the lake after flooding, by saturation surface flow, and by evapotranspiration. Organic matter normally accumulates in areas sufficiently protected from shoreline wave erosion. Unimpounded marshes bordering the Great Lakes are a common example of lacustrine fringe wetlands.

Nevada Department of Wildlife classifications (WAPT 2012): Based on LANDFIRE with additional descriptions. a. Aspen woodland b. Intermountain riparian c. Mojave riparian d. Sierran riparian e. Spring / springbrook f. Marsh, riverine marsh g. Wet meadow h. Playa lake / ephemeral pool i. Playa with spring, marsh, or phreatophytes j. Mojave wash k. Terminal lake / delta / shore

References: Brinson MM. 1993. A Hydrogeomorphic Classification for Wetlands. Wetlands Research Program Technical Report WRP-DE-4. Vicksburg: US Army Corps of Engineers, Waterways Experiment Station. Available at https://wetlands.el.erdc.dren.mil/pdfs/wrpde4.pdf#view=fit&pagemode=none. Comer P, Faber-Langendoen D, Evans R, Gawler S, Josse C, Kittel G, Menard S, Pyne M, Reid M, Schulz K, Snow K, Teague J. 2003. Ecological Systems of the United States: A Working Classification of U.S. Terrestrial Systems. NatureServe, Arlington, VA. Available at http://www.natureserve.org/library/usEcologicalsystems.pdf. Cowardin LM, Carter V, Golet FC, LaRoe ET. 1979. Classification of the wetlands and deepwater habitats of the United States. Washington (DC): U.S. Fish and Wildlife Service. Available as .pdf at https://www.fws.gov/wetlands/documents/Classification-of-Wetlands-and-Deepwater- Habitats-of-the-United-States.pdf and as html at https://www.fws.gov/wetlands/documents/classwet/index.html Faber-Langendoen D, Kudray G, Nordman C, Sneddon L, Vance L, Byers E, Rocchio J, Gawler S, Kittel G, Menard S, Comer P, Muldavin E, Schafale M, Foti T, Josse C, Christy J. 2008. Ecological Performance Standards for Wetland Mitigation: An Approach Based on Ecological Integrity Assessments. NatureServe, Arlington, VA. Faber-Langendoen D, Keeler-Wolf T, Meidinger D, Josse C, Weakley A, Tart D, Navarro G, Hoagland B, Ponomarenko S, Saucier J-P, Fults G, Helmer E. 2012. Classification and Description of World Formation Types. Part 1. Introduction. Federal Geographic Data Committee, FGDC Secretariat, US Geological Survey, Reston, VA and NatureServe, Arlington, VA. Available at https://www.fs.fed.us/global/iitf/pubs/other_iitf_2012_Faberp1.pdf. Faber-Langendoen D, Nichols B, Walz KS, Rocchio J, Lemly J, Gilligan L. 2016. NatureServe Ecological Integrity Assessment: Protocols for Rapid Field Assessment of Wetlands, v2. Arlington: NatureServe. [FGDC] Federal Geographic Data Committee. 2013. Classification of wetalnds and deepwater habitats of the United States. FGDC-STD-004-2013. Second Edition. Wetlands Subcommittee, Federal Geographic Data Committee and U.S. Fish and Wildlife Service, Washington, D.C. Available at https://www.fws.gov/wetlands/documents/Classification-of-Wetlands-and-Deepwater- Habitats-of-the-United-States-2013.pdf. Grossman DH et al. 1998 International Classification of Ecological Communities: Terrestrial Vegetation of the United States. Volume I: The National Vegetation Classification Standard. Arlington: The Nature Conservancy. Mitsch WJ, Gosselink JG. 2000. Wetlands, 3rd edition. J. Wiley & Sons, Inc. 920 pp. NatureServe. 2004 International Ecological Classification Standard: Terrestrial Ecological Classifications. NatureServe Central Databases. Arlington, Virginia. [NRCS] Natural Resources Conservation Service. 2008. Hydrogeomorphic Wetland Classification System: An Overview and Modification to Better Meet the Needs of the Natural Resources Conservation Service. USDA Technical Note NO. 190-8-76. Available at https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_010784.pdf. Smith RD, Ammann A, Bartoldus C, Brinson MM. 1995. An Approach for Assessing Wetland Functions Using Hydrogeomorphic Classification, Reference Wetlands, and Functional Indices. Wetlands Research Program Technical Report WRP-DE-9. Vicksburg: US Army Corps of Engineers, Waterways Experiment Station. Available at https://wetlands.el.erdc.dren.mil/pdfs/wrpde9.pdf#view=fit&pagemode=none [WAPT] Wildlife Action Plan Team. 2012. Nevada Wildlife Action Plan. Nevada Department of Wildlife, Reno, NV. Available at http://www.ndow.org/Nevada_Wildlife/Conservation/Nevada_Wildlife_Action_Plan/.