Alternative site for the Global ecosystem typology with additional information for ecosystem profiles and indicative maps.
This site is maintained by jrfep
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 ground. This suppresses microbial activity and, in many systems, production exceeds decomposition resulting in accumulation of peat. The water regime profoundly influences resource availability and productivity, and thus regulates these ecosystems from the bottom-up. It is a product of interactions among catchment precipitation, local evapotranspiration, surface morphology which regulates run-on and run-off, and infiltration and percolation, dependent on substrate and surface morphology. 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 interannual dry phases. As a consequence of their conditional relationships with climate, wetland biomes are traditionally classified as azonal biomes. 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 the 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 the habitats of heterotrophs. Microbial decomposers and invertebrate detritivores are most abundant in surface soils. A range of microscopic and macroinvertebrates with sedentary adult phases (e.g. 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, notably waterbirds.