Classification of Wetlands and Deepwater Habitats of the United States

Appendix C


Glossary of Terms

acid
Term applied to water with a pH less than 5.5.
alkaline
Term applied to water with a pH greater than 7.4.
bar
An elongated landform generated by waves and currents, usually running parallel to the shore, composed predominantly of unconsolidated sand, gravel, stones, cobbles, or rubble and with water on two sides.
beach
A sloping landform on the shore of larger water bodies, generated by waves and currents and extending from the water to a distinct break in landform or substrate type (e.g., a foredune, cliff, or bank).
brackish
Marine and Estuarine waters with Mixohaline salinity. The term should not be applied to inland waters.
boulder
Rock fragments larger than 60.4 cm (24 inches) in diameter.
broad-leaved deciduous
Woody angiosperms (trees or shrubs) with relatively wide, flat leaves that are shed during the cold or dry season; e.g., black ash (Frazinus nigra).
broad-leaved evergreen
Woody angiosperms (trees or shrubs) with relatively wide, flat leaves that generally remain green and are usually persistent for a year or more; e.g., red mangrove (Rhizophora mangle).
calcareous
Formed of calcium carbonate or magnesium carbonate by biological deposition or inorganic precipitation in sufficient quantities to effervesce carbon dioxide visibly when treated with cold 0.1 normal hydrochloric acid. Calcareous sands are usually formed of a mixture of fragments of mollusk shell, echinoderm spines and skeletal material, coral, foraminifera, and algal platelets (e.g., Halimeda).
channel
"An open conduit either naturally or artificially created which periodically or continuously contains moving water, or which forms a connecting link between two bodies of standing water" (Langbein and Iseri 1960:5).
channel bank
The sloping land bordering a channel. The bank has steeper slope than the bottom of the channel and is usually steeper than the land surrounding the channel.
circumneutral
Term applied to water with a pH of 5.5 to 7.4.
codominant
Two or more species providing about equal areal cover which in combination control the environment.
cobbles
Rock fragments 7.6 cm (3 inches) to 25.4 cm (10 inches) in diameter.
deciduous stand
A plant community where deciduous trees or shrubs represent more than 50% of the total areal coverage of trees or shrubs.
dominant
The species controlling the environment.
dormant season
That portion of the year when frosts occur (see U.S. Department of Interior, National Atlas 1970:110-111 for generalized regional delineation).
emergent hydrophytes
Erect, rooted, herbaceous angiosperms that may be temporarily to permanently flooded at the base but do not tolerate prolonged inundation of the entire plant; e.g., bulrushes (Scirpus spp.), saltmarsh cordgrass.
emergent mosses
Mosses occurring in wetlands, but generally not covered by water.
eutrophic lake
Lake that has a high concentration of plant nutrients such as nitrogen and phosphorus.
evergreen stand
A plant community where evergreen trees or shrubs represent more than 50% of the total areal coverage of trees and shrubs. The canopy is never without foliage; however, individual trees or shrubs may shed their leaves (Mueller-Dombois and Ellenberg 1974).
extreme high water of spring tides
The highest tide occurring during a lunar month, usually near the new or full moon. This is equivalent to extreme higher high water of mixed semidiurnal tides.
extreme low water of spring tides
The lowest tide occurring during a lunar month, usually near the new or full moon. This is equivalent to extreme lower low water of mixed semidiurnal tides.
flat
A level landform composed of unconsolidated sediments -- usually mud or sand. Flats may be irregularly shaped or elongate and continuous with the shore, whereas bars are generally elongate, parallel to the shore, and separated from the shore by water.
floating plant
A non-anchored plant that floats freely in the water or on the surface; e.g., water hyacinth (Eichhornia crassipes) or common duckweed (Lemna minor).
floating-leaved plant
A rooted, herbaceous hydrophyte with some leaves floating on the water surface; e.g., white water lily (Nymphaea odorata), floating-leaved pondweed (Potamogeton natans). Plants such as yellow water lily (Nuphar luteum) which sometimes have leaves raised above the surface are considered floating-leaved plants or emergents, depending on their growth habit at a particular site.
floodplain
"a flat expanse of land bordering an old river. . . " (see Reid and Wood 1976:72, 84).
fresh
Term applied to water with salinity less than 0.5‰ dissolved salts.
gravel
A mixture composed primarily of rock fragments 2 mm (0.08 inch) to 7.6 cm (3 inches) in diameter. Usually contains much sand.
growing season
The frost-free period of the year (see U.S. Department of Interior, National Atlas 1970:110-111 for generalized regional delineation).
haline
Term used to indicate dominance of ocean salt.
herbaceous
With the characteristics of an herb; a plant with no persistent woody stem above ground.
histosols
Organic soils (see Appendix D).
hydric soil
Soil that is wet long enough to periodically produce anaerobic conditions, thereby influencing the growth of plants.
hydrophyte, hydrophytic
Any plant growing in water or on a substrate that is at least periodically deficient in oxygen as a result of excessive water content.
hyperhaline
Term to characterize waters with salinity greater than 40‰, due to ocean-derived salts.
hypersaline
Term to characterize waters with salinity greater than 40‰, due to land-derived salts.
macrophytic algae
Algal plants large enough either as individuals or communities to be readily visible without the aid of optical magnification.
mean high water
The average height of the high water over 19 years.
mean higher high tide
The average height of the higher of two unequal daily high tides over 19 years.
mean low water
The average height of the low water over 19 years.
mean lower low water
The average height of the lower of two unequal daily low tides over 19 years.
mean tide level
A plane midway between mean high water and mean low water.
mesohaline
Term to characterize waters with salinity of 5 to 18‰, due to ocean-derived salts.
mesophyte, mesophytic
Any plant growing where moisture and aeration conditions lie between extremes. (Plants typically found in habitats with average moisture conditions, not usuall dry or wet.)
mesosaline
Term to characterize waters with salinity of 5 to 18‰, due to land-derived salts.
mineral soil
Soil composed of predominantly mineral rather than organic materials.
mixohaline
Term to characterize water with salinity of 0.5 to 30‰, due to ocean salts. The term is roughly equivalent to the term brackish.
mixosaline
Term to characterize waters with salinity of 0.5 to 30‰, due to land-derived salts.
mud
Wet soft earth composed predominantly of clay and silt--fine mineral sediments less than 0.074 mm in diameter (Black 1968; Liu 1970).
needle-leaved deciduous
Woody gymnosperms (trees or shrubs) with needle-shaped or scale-like leaves that are shed during the cold or dry season; e.g., bald cypress (Tazodium distichum).
needle-leaved evergreen
Woody gymnosperms with green, needle-shaped, or scale-like leaves that are retained by plants throughout the year; e.g., black spruce (Picea mariana).
nonpersistent emergents
Emergent hydrophytes whose leaves and stems break down at the end of the growing season so that most above-ground portions of the plants are easily transported by currents, waves, or ice. The breakdown may result from normal decay or the physical force of strong waves or ice. At certain seasons of the year there are no visible traces of the plants above the surface of the water; e.g., wild rice (Zizania aquatica), arrow arum (Peltandra virginica).
obligate hydrophytes
Species that are found only in wetlands -- e.g., cattail (Typha latifolia) as opposed to ubiquitous species that grow either in wetland or on upland -- e.g., red maple (Acer rubrum).
oligohaline
Term to characterize water with salinity of 0.5 to 5.0‰ due to ocean-derived salts.
oligosaline
Term to characterize water with salinity of 0.5 to 5.0‰ due to land-derived salts.
organic soil
Soil composed of predominantly organic rather than mineral material. Equivalent to Histosol.
persistent emergent
Emergent hydrophytes that normally remain standing at least until the beginning of the next growing season; e.g., cattails (Typha spp.) or bulrushes (Scirpus spp.).
photic zone
The upper water layer down to the depth of effective light penetration where photosynthesis balances respiration. This level (the compensation level) usually occurs at the depth of 1% light penetration and forms the lower boundary of the zone of net metabolic production.
pioneer plants
Herbaceous annual and seedling perennial plants that colonize bare areas as a first stage in secondary succession.
polyhaline
Term to characterize water with salinity of 18 to 30‰, due to ocean salts.
polysaline
Term to characterize water with salinity of 18 to 30‰, due to land-derived salts.
saline
General term for waters containing various dissolved salts. We restrict the term to inland waters where the ratios of the salts often vary; the term haline is applied to coastal waters where the salts are roughly in the same proportion as found in undiluted sea water.
salinity
The total amount of solid material in grams contained in 1 kg of water when all the carbonate has been converted to oxide, the bromine and iodine replaced by chlorine, and all the organic matter completely oxidized.
sand
Composed predominantly of coarse-grained mineral sediments with diameters larger than 0.074 mm (Black 1968) and smaller than 2 mm (Liu 1970; Weber 1973).
shrub
A woody plant which at maturity is usually less than 6 m (20 feet) tall and generally exhibits several erect, spreading, or prostrate stems and has a bushy appearance; e.g., speckled alder (Alnus rugosa) or buttonbush (Cephalanthus occidentalis).
sound
A body of water that is usually broad, elongate, and parallel to the shore between the mainland and one or more islands.
spring tide
The highest high and lowest low tides during the lunar month.
stone
Rock fragments larger than 25.4 cm (10 inches) but less than 60.4 cm (24 inches).
submergent plant
A vascular or nonvascular hydrophyte, either rooted or nonrooted, which lies entirely beneath the water surface, except for flowering parts in some species; e.g., wild celery (Vallisneria americana) or the stoneworts (Chara spp.).
terrigenous
Derived from or originating on the land (usually referring to sediments) as opposed to material or sediments produced in the ocean (marine) or as a result of biologic activity (biogenous).
tree
A woody plant which at maturity is usually 6 m (20 feet) or more in height and generally has a single trunk, unbranched for 1 m or more above the ground, and a more or less definite crown; e.g., red maple (Acer rubrum), northern white cedar (Thuja occidentalis).
water table
The upper surface of a zone of saturation. No water table exists where that surface is formed by an impermeable body (Langbein and Iseri 1960:21).
woody plant
A seed plant (gymnosperm or angiosperm) that develops persistent, hard, fibrous tissues, basically xylem; e.g., trees and shrubs.
xerophyte, xerophytic
Any plant growing in a habitat in which an appreciable portion of the rooting medium dries to the wilting coefficient at frequent intervals. (Plants typically found in very dry habitats.)

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