Biomes are the composite of all species within a large scale ecological community. In the natural environment, these assemblies have typically co-evolved, so that they have a natural arrangement in terms of their positioning to compete for sunlight, water and nutrient resources; in some cases these associations are symbiotic, but in most cases they are simply optimal spatial arrangements to take advantage of all the resources available in a given habitat. For example, there is typically a vertical tiering, where plants of differing light requirements can occupy canopy, mid-level or forest floor niches; the same theory applies even in a grassland, where the canopy is simply the tallest of the grasses or herbs.
In the case of water competition, depth of rooting and tolerance to arid soils are chief determinants for spatial arrangement; as far as nutrient competition, plants will compete to determine the most robust competitor for a given edaphic niche. While the outcome geometry for the plant palette usually appears random, there is a complex network of ecological theory at work that determines the layout of the assembled community. The same concept applies to aquatic communities as to terrestrial systems, with some plants having immersed roots and others, either macrophytes or phytoplankton, floating or immersed at varying levels suitable for their sunlight needs.
The Iberian sclerophyllous and semi-deciduous forests support a complex and diverse flora with a notable number of endemic species. This vegetation is very valuable in terms...
Beringia lowland tundraLast Updated on 2014-03-06 14:57:34
The Beringia lowland tundra ecoregion is formed by three major disjunct areas along the Bering Sea coast of Alaska from the base of the Alaska Peninsula to Kotzebue Sound, as well as one smaller area on the east side of St. Lawrence Island and St. Matthew Island. The ecoregion is characterized by low, flat, or gently rolling terrain, wet soils, and resulting predominance of wet and mesic graminoid herbaceous vegetation. In better drained areas, especially in the somewhat more rolling portions of the section surrounding Bristol Bay, dwarf shrub communities occur interspersed with the wet herbaceous tundra, dominated by sedges, including Eriophorum angustoifolium and Carex spp. Dwarf shrub vegetation is usually dominated by ericaceous species, including crowberry (Empetrum nigrum). In some limited areas of favorable soil drainage and microclimate, stands of black and white spruce... More »
Montana valley and foothill grasslandsLast Updated on 2014-03-04 17:28:53The Montana valley and foothill grasslands ecoregion occupies high valleys and foothill regions in the central Rocky Mountains of Montana in the USA and Alberta, Canada. The ecoregion, part of the Nearctic realm, occupies the Rocky Mountain Front, the uppermost flatland reaches of the Missouri River drainage involving part of the Yellowstone River basin, and extends into the Clark Fork-Bitterroot drainage of the Columbia River system. The ecoregion also extends marginally into a small part of northern Wyoming. Having moderate vertebrate species richness, 321 different vertebrate taxa have been recorded in the Montana valley and foothill grasslands. The Montana valley and foothill grasslands is deemed an element of the Temperate Grasslands, Savannas, Shrublands Biome.
The Canadian component of this ecoregion is characterized by undulating to rolling topography, and surface deposits are... More »
Central tall grasslandsLast Updated on 2014-03-04 17:13:01The Central tall grasslands extend over southern Minnesota, most of Iowa, an element of eastern South Dakota, and present as a narrow finger through eastern Nebraska and northeastern Kansas in the USA. This ecoregion is within the Nearctic ecoregion category. The tallgrass prairie of the USA and Canada is divided into three ecoregions: the Central, Northern, and Flint Hills tall grasslands. Agricultural conversion and development of wind farms have brought considerable habitat destruction to this ecoregion.
The Central tall grasslands are the most mesichabitat characterized by moderate soil moisture of the grasslands of the central plains of North America. It can be distinguished from other grassland associations by the dominance of tallgrass species–a feature once relatively uniform across its range–and by the highest levels of precipitation (100 centimeters per... More »
Northern California coastal forestsLast Updated on 2014-03-04 16:26:53
The Northern California coastal forests ecoregion consists of two disjunctive geographic units in Northern California: (1) a smaller unit in the Santa Cruz and Montara Mountains and (2) the larger unit from Marin County, California to the Oregon border. These forests are classified as an element of the Temperate Coniferous Forests biome. There is moderate faunal diversity as exemplified by occurrence of 347 vertebrate taxa.
The Northern California coastal forests are largely defined by two features, the persistent moist environments provided by winter Pacific storms and coastal fog in the summer, and the distribution of the Coast Redwood (Sequoia sempervirens). Redwoods range from central California to the Oregon border, and are typically found within 65 kilometers of the coast. Redwood groves are patchily distributed among a variety of natural communities found within this... More »
EcoregionLast Updated on 2014-02-20 14:19:20An ecoregion is a relatively large unit of land or ocean that contains geographically distinct assemblage of natural communities with boundaries that approximate the original extent of natural communities prior to major land use change. Ecoregions:
share a large majority of their species and ecological dynamics;
share similar environmental conditions, and;
interact ecologically in ways that are critical for their long-term persistence.
The motivation for the ecoregion classification system is that scarce resources and dwindling time force conservationists to target their actions to stem the loss of biodiversity — a pragmatic approach, given the highly uneven distribution of species and threats. Unfortunately, the ability to focus strategically is hindered by the absence of a global biodiversity map with sufficient biogeographic resolution to accurately reflect the complex... More »
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