New York Natural Heritage Program
Community System Descriptions

System Description
Estuarine System
(subsystems)
The estuarine system consists of deepwater tidal habitats and adjacent tidal wetlands that are usually semi-enclosed but have open, partly obstructed, or sporadic access to open ocean or tidal fresh waters, and in which ocean water is at least occasionally diluted by freshwater runoff. The limits extend from the upstream limit of tidal influence seaward to an imaginary line closing the mouth of a river or bay. Salinity is usually less than 30.0 parts per thousand (ppt) ocean-derived salts, but can range from >40 ppt to 0.5-5 ppt.
Lacustrine System
(subsystems)
The lacustrine system consists of ponded waters situated in topographic depressions or dammed river channels, with persistent emergent vegetation sparse or lacking, but including any areas with abundant submerged or floating-leaved aquatic vegetation.
Marine System
(subsystems)
The marine system consists of open ocean overlying the continental shelf, the associated coastline that is exposed to wind and waves, and shallow coastal bays that are saline because they lack significant freshwater inflow. The limits extend from mean high water seaward, beyond the limits of rooted vascular vegetation. Salinity usually exceeds 30 parts per thousand (ppt) ocean-derived salts, with little or nor dilution except out side the mouths of estuaries where it can range as low as 18 ppt in New York.
Palustrine System
(subsystems)
The palustrine system consists of non-tidal, perennial wetlands characterized by emergent vegetation. The system includes wetlands permanently saturated by seepage, permanently flooded wetlands, and wetlands that are seasonally or intermittently flooded (these may be seasonally dry) if the vegetative cover is predominantly growing in water and soils are hydric (soil that formed under conditions of saturation, flooding or ponding). Wetland communities are distinguished by their plant composition, substrate, and flooding regime.

Peatlands, including bogs and fens, are a special type of wetland in which the substrate primarily consists of accumulated peat (partly decomposed plant material such as mosses, sedges, and shrubs) or marl (organically derived calcium carbonate deposits), with little or no mineral soil. In a natural landscape there are continuous gradients in soils from mineral soils to peat soils. The boundaries between different types of wetlands are not always discrete. Several different types of wetlands may occur together in a complex mosaic.
Riverine System
(subsystems)
The riverine system consists of linear aquatic communities of flowing, non-tidal waters with a discrete channel. Emergent vegetation is usually sparse or lacking, but may include areas with abundant submerged or floating-leaved aquatic vegetation.
Subterranean System
(subsystems)
The subterranean system consists of both aquatic and non-aquatic habitats beneath the earth's surface, including air-filled cavities with openings to the surface (caves), water-filled cavities and aquifers, and interstitial habitats in small crevices within an inorganic matrix. Different subterranean communities are distinguished by hydrology and substrate characteristics. There are apparently only few obligate cave species in New York, unlike the diversity found in caves of the Interior Lowlands of the Eastern U.S. and the caves of the Southwest U.S.
Terrestrial System
(subsystems)
The terrestrial system consists of upland habitats. These habitats have well-drained soils that are dry to moist, and vegetative cover that is never predominantly growing in water, even if the soil surface is occasionally or seasonally flooded or saturated. In other words, this is a broadly defined system that includes everything except aquatic, wetland, and subterranean communities.

Estuarine System (back to top)

Subsystem Description
Estuarine Cultural This subsystem includes communities that are either created and maintained by human activities, or are modified by human influence to such a degree that the physical conformation of the substrate, or the biological composition of the resident community is substantially different from the character of the substrate or community as it existed prior to human influence.
Estuarine Intertidal The estuarine intertidal subsystem consists of deepwater tidal habitats and adjacent tidal wetlands that are usually semi-enclosed but have open, partly obstructed, or sporadic access to open ocean or tidal fresh waters, and in which ocean water is at least occasionally diluted by freshwater runoff. The limits extend from the upstream limit of tidal influence seaward to an imaginary line closing the mouth of a river or bay. Salinity is usually less than 30.0 parts per thousand (ppt) ocean-derived salts.
Estuarine Subtidal This subsystem includes the area below the lowest tide; the substrate is permanently flooded with tidal water; it is continuously submerged.

Lacustrine System (back to top)

Subsystem Description
Lacustrine Cultural This subsystem includes communities that are either created and maintained by human activities, or are modified by human influence to such a degree that the trophic state, morphometry, water chemistry, or biological composition of the resident community are substantially different from the character of the lake community as it existed prior to human influence.
Natural Lakes And Ponds This subsystem includes the Great Lakes, and inland lakes and ponds in which the trophic state, morphometry, and water chemistry have not been substantially modified by human activities, or the native biota are dominant. The biota may include some introduced species (for example, non-native plants, stock, or accidentally introduced fishes), however the introduced species are not usually dominant in the lake or pond community as a whole.

Marine System (back to top)

Subsystem Description
Marine Cultural This subsystem includes communities that are either created and maintained by human activities, or modified by human influence to such a degree that the physical conformation of the substrate, or the biological composition of the resident community, is substantially different from the character of the substrate or community as it existed prior to human influence.
Marine Intertidal This subsystem includes the area between the highest tide level and the lowest tide level; the substrate is periodically exposed and flooded by two high tides and two low tides per tidal day.
Marine Subtidal This subsystem includes the area below the lowest tide that is permanently flooded with tidal water.

Palustrine System (back to top)

Subsystem Description
Forested Mineral Soil Wetlands This subsystem includes seasonally flooded forests, and permanently flooded or saturated swamps. These forests and swamps typically have at least 50% canopy cover of trees. For the purposes of this classification, a tree is a woody plant usually having one principal stem, a definite crown shape, and characteristically reaching a mature height of at least 16 ft (5 m).
Forested Peatlands Peatlands are a special type of wetland in which the substrate primarily consists of accumulated peat (partly decomposed plant material such as mosses, sedges, and shrubs) or marl (organically derived calcium carbonate deposits), with little or no mineral soil. Stable water levels or constant water seepage allow little aeration of the substrate in peatlands, slowing decomposition of plant litter, and resulting in peat or marl accumulation.

This subsystem includes peatlands with at least 50% canopy cover of trees. Substrates range from coarse woody or fibrous peat to fine-grained marl and organic muck.
Open Mineral Soil Wetlands This subsystem includes wetlands with less than 50% canopy cover of trees. For the purposes of this classification, a tree is a woody plant usually having one principal stem, a definite crown shape, and characteristically reaching a mature height of at least 16 ft (5 m). The dominant vegetation may include shrubs or herbs. Substrates range from mineral soils or bedrock to well-decomposed organic soils (muck). Fluctuating water levels allow enough aeration of the substrate to allow plant litter to decompose, so there is little or no accumulation of peat.
Open Peatlands Peatlands are a special type of wetland in which the substrate primarily consists of accumulated peat (partly decomposed plant material such as mosses, sedges, and shrubs) or marl (organically derived calcium carbonate deposits), with little or no mineral soil. Stable water levels or constant water seepage allow little aeration of the substrate in peatlands, slowing decomposition of plant litter, and resulting in peat or marl accumulation.

This subsystem includes peatlands with less than 50% canopy cover of trees. The dominant vegetation may include shrubs, herbs, or mosses. Substrates range from coarse fibrous or woody peat, to fine-grained marl and organic muck. Peat layer should be at least 20 cm deep.
Palustrine Cultural This subsystem includes communities that are either created and maintained by human activities, or are modified by human influence to such a degree that the physical conformation of the substrate, the hydrology, or the biological composition of the resident community is substantially different from the character of the substrate, hydrology, or community as it existed prior to human influence.

Riverine System (back to top)

Subsystem Description
Natural Streams This subsystem includes streams in which the stream flow, morphometry, and water chemistry have not been substantially modified by human activities, or the native biota are dominant. The biota may include some introduced species (for example, stocked or accidentally introduced fishes), however the introduced species are not usually dominant in the stream community as a whole.
Riverine Cultural This subsystem includes communities that are either created and maintained by human activities, or are modified by human influence to such a degree that stream flow, morphometry, water chemistry, or the biological composition of the resident community are substantially different from the character of the stream community as it existed prior to human influence. No biotic riverine cultural types have been noted. NYNHP is currently unaware of examples of streams without physical or chemical alterations that have become dominated by exotic biota such as water chestnut (Trapa natans) and Eurasian water milfoil (Myriophyllum spicatum).

Subterranean System (back to top)

Subsystem Description
Natural Caves This subsystem includes caves and cavities in which the structure and hydrology have not been substantially modified by human activities, and the native biota are dominant.
Subterranean Cultural This subsystem includes communities that are either created and maintained by human activities, or are modified by human influence to such a degree that the physical conformation of the substrate, or the biological composition of the resident community is substantially different from the character of the substrate or community as it existed prior to human influence.

Terrestrial System (back to top)

Subsystem Description
Barrens And Woodlands This subsystem includes upland communities that are structurally intermediate between forests and open canopy uplands. Several physiognomic types are included in this subsystem. Savannas are communities with a sparse canopy of trees (25 to 60% cover), and a groundlayer that is predominantly either grassy or shrubby (respectively, grass-savanna and shrub-savanna). Woodlands include communities with a canopy of stunted or dwarf trees (less than 16 ft or 4.9 m tall), and wooded communities occurring on shallow soils over bedrock with numerous rock outcrops. The term "barrens" is commonly applied to both savannas and woodlands (e.g. pine barrens).
Forested Uplands This subsystem includes upland communities with more than 60% canopy cover of trees; these communities occur on substrates with less than 50% rock outcrop or shallow soil over bedrock.
Open Uplands This subsystem includes upland communities with less than 25% canopy cover of trees; the dominant species in these communities are shrubs, herbs, or cryptogams (mosses, lichens, etc.). Three distinctive physiognomic types are included in this subsystem. Grasslands include communities that are dominated by grasses and sedges; they may include scattered shrubs (never more than 50% cover of shrubs), and scattered trees (usually less than one tree per acre, or 3 trees per hectare). Meadows include communities with forbs, grasses, sedges, and shrubs codominant; they may include scattered trees. Shrublands include communities that are dominated by shrubs (more than 50% cover of shrubs); they may include scattered trees.
Terrestrial Cultural This subsystem includes communities that are either created and maintained by human activities, or are modified by human influence to such a degree that the physical conformation of the substrate, or the biological composition of the resident community is substantially different from the character of the substrate or community as it existed prior to human influence.