Biogeography is the study of the distribution of biological organisms. The scale of analysis ranges from very small micro-topography regimes to continental dimensions. Fundamental concepts in this field of study are the nature of barrier formation and response of species to their patterns of travel and migration; in particular, the presence of rivers, mountain ranges, deserts and other natural boundaries are examples of large scale barriers. Besides such major landform barriers there are soil, topographic and meteorological factors that influence the distribution of each species. In the case of smaller scale regimes that are applicable for some bacteria or limited range plant species, there are often very restricted niches; for example, certain bacteriaextremophiles may be limited to such localized features as small geyser pools, and some rare plants may have a single extant colony defined specialized soils such as serpentine and narrow climatic zone. Inherent in the concept of biogeography are the processes of speciation, extinction, dispersal and migration.
Chile has eight ecoregions that occur entirely or partly within its borders on the mainland and three ecorgions offshore:
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 »
Western short grasslandsLast Updated on 2014-03-04 17:53:40The Western short grasslands is the second largest grassland ecoregion of North America, covering slightly more than 435,000 square kilometers.
This unit ranges over portions of western Nebraska and southeastern Wyoming, across much of eastern Colorado, southwestern Kansas, west Texas, the Oklahoma panhandle and into eastern New Mexico. The Western short grasslands are bisected by the upper reaches of the Arkansas River and upper reaches of the Red River.
This grassland ecoregion is distinguished from other grassland units by low rainfall, relatively long growing seasons, and warm temperatures. From a structural standpoint, the short stature of the dominant sod-forming grasses, Needle Grama (Bouteloua aristidoides) and Buffalo Grass (Buchloe dactyloides), separate the Western short grasslands ecoregion from other units.
Küchler classified this ecoregion as grama-buffalo grass... 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 »
Southland temperate forestsLast Updated on 2014-02-20 13:10:50The Southland temperate forests ecoregion covers the southeastern tip of New Zealand's South Island; however, much of the Southland region is modified and large areas are intensively farmed. Nevertheless, there are still significant coastal wetlands and upland areas of beech forest and tussock grasslands. The Eyre Mountains support distinctive local endemic plant species and the Catlins National Park contains an outstanding range of habitats, ranging from coastal habitat to alpine bogs.
The region entered a biodiversity downturn with advent of the Maori peoples, who significantly deforested this ecoregion; moreover, the destruction expanded with advent of Europeans and introduction of lanrge scale domesticated livestock grazing. A number of protected areas are found in the region, but lowland and grassland communities are underrepresented in conservation reserves; moreover,... More »
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