Inland Wetlands

IUCN GET 2.0

Two main Biomes: TF1 Palustrine wetlands; F3 Artificial wetlands

Palustrine wetlands

biome consists of these Ecosystem Functional Groups (EFG): Tropical flooded forests and peat forests, Subtropical/temperate forested wetlands, Permanent marshes, Seasonal floodplain marshes, Episodic arid floodplains, Boreal, temperate and montane peat bogs, Boreal and temperate fens. At the interface of terrestrial and freshwater realms, the Palustrine wetlands biome includes vegetated floodplains, groundwater seeps, and mires with permanent or intermittent surface water. Although water and light are abundant at least periodically, saturation of the soil may result in oxygen deprivation below the ground. This suppresses microbial activity and, in many systems, production exceeds decomposition, resulting in peat accumulation. The water regime influences resource availability and productivity and thus regulates these ecosystems from the bottom-up. Interactions among catchment precipitation, local evapotranspiration, and substrate and surface morphology regulate run-on, runoff, infiltration, and percolation. This results in water regimes that vary from permanent shallow standing water or near-surface water tables to seasonally high water tables to episodic inundation with long inter-annual dry phases. As a consequence of their indirect relationships with climate, wetland biomes are traditionally classified as ‘azonal’. Spatial heterogeneity is a key feature of palustrine wetlands. At landscape scales, they function as resource sinks and refuges with substantially higher productivity than the surrounding matrix. Fine-scale spatial variation in the water regime often produces restricted hydrological niches and intricate mosaics of patch types with contrasting structure and biotic composition. Autotrophs dominate complex trophic webs. Amphibious macrophytes are the dominant autotrophs, although epibenthic algae are important in some systems. Amphibious plants have specialised traits enabling growth and survival in low-oxygen substrates and often engineer habitats for heterotrophs. Microbial decomposers and invertebrate detritivores are most abundant in surface soils. A range of microscopic and macroinvertebrates with sedentary adult phases (i.e. crustaceans) have obligate associations with Palustrine wetlands, which also provide important foraging and breeding sites for macroinvertebrate and vertebrate herbivores and predators that disperse more widely across the landscape, including waterbirds.

Artificial wetlands

biome consist of these Ecosystem Functional Groups (EFG): Large reservoirs, Constructed lacustrine wetlands, Rice paddies, Freshwater aquafarms, Canals, ditches and drains. The Artificial wetlands biome includes built structures that hold or transfer water for human use, treatment, or disposal, including large storage reservoirs, farm dams or ponds, recreational and ornamental wetlands, rice paddies, freshwater aquafarms, wastewater storages and treatment ponds, and canals, ditches and drains. These are globally distributed but are most often found in humid and subhumid tropical and temperate environments where rural and urban developments are predominant. Most of these ecosystems contain standing water with the exception of canals and drains. For most of these ecosystems, energy, water and nutrients come primarily from allochthonous sources, either incidentally from runoff (e.g. farm dams, ditches and storm water canals) or groundwater, or deterministically by management (e.g. rice paddies, aquafarms, and wastewater ponds), but autochthonous energy sources (in situ algae and macrophytes) can be important in some artificial waterbodies. Water chemistry varies with human use, with some wastewater ponds accumulating toxins or eutrophic levels of nutrients, while large reservoirs with undisturbed catchments may be oligotrophic. Artificial wetlands are generally less temporally variable, more spatially homogeneous, and often support less biological diversity and trophic complexity of their natural analogues. Nonetheless, in some highly transformed landscapes, they may provide anthropogenic refuges and critical habitat for complementary suites of native biota to that remaining in depleted wetlands, including some biota that no longer occur in natural or semi-natural ecosystems, as well as a range of opportunistic colonists. Trophic webs vary with the connectivity and depth of the water body, temperature and substrate. The simplest artificial wetlands support only microbial biota, while the most diverse can include submerged or emergent plant communities, which promote complex habitats for invertebrates, fish, waterbirds, amphibians, reptiles and, sometimes, amphibious mammals.

ESVD

Inland wetlands include: Swamps, marshes; Peatland, Non-forested; Peatland, Forested; Peatland, Tropical; Peatland, Boreal; Wetlands, Forested (on alluvial soils); Wetlands, Groundwater-dependent; Floodplains; Other (inland wetlands)

FEMA ESV

Inland Wetlands: Areas dominated (20 percent or more) by perennial herbaceous vegetation, vegetation that grows and forms a continuous cover on or at the surface of the water, shrubland vegetation, or forest; AND the soil or substrate is at least periodically saturated with or covered with water; AND these waters are tidally influenced and have a salinity less than 0.5 parts per thousand.

This definition is based on the Coastal Change Analysis Program (C-CAP) Regional Land Cover Classification Scheme definitions for Palustrine wetlands and aquatic beds.

Other

USGS does have a Wetlands category while ESRI and Dynamic World use Water and Flooded Vegetation.

USGS (NLCD) Wetlands:

Woody Wetlands - areas where forest or shrubland vegetation accounts for greater than 20% of vegetative cover and the soil or substrate is periodically saturated with or covered with water.

Emergent Herbaceous Wetlands - Areas where perennial herbaceous vegetation accounts for greater than 80% of vegetative cover and the soil or substrate is periodically saturated with or covered with water.