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:
Arizona Mountains forestsLast Updated on 2013-12-10 10:46:49
The Arizona Mountain Forests extend from the Kaibab Plateau in northern Arizona to south of the Mogollon Plateau into portions of southwestern Mexico and eastern Arizona. This ecoregion is an element of the Temperate Coniferous Forests biome. The species richness in this ecoregion is moderate, with vertebrate taxa numbering 375 species. The topography consists chiefly of steep foothills and mountains, but includes some deeply dissected high plateaus. Elevations range from 1370 to 3000 meters (m) with some peaks as high as 3840 m. Soil types have not been well defined; however, most soils are entisols, with alfisols and inceptisols in upland areas. Stony terrain and rock outcrops occupy large areas on the mountains and foothills.
Vegetation zones in this ecoregion resemble the Rocky Mountain Life Zones but at higher elevations. Although forests in this ecoregion are too far south to... More »
Chihuahuan DesertLast Updated on 2013-12-06 23:07:07The Chihuahuan Desert encompasses one of the most biologically diverse arid regions on Earth. This ecoregion extends from within the United States south into Mexico. This desert is unique, as it has been sheltered from the influence of other arid regions such as the Sonoran Desert by the large mountain ranges of the Sierra Madres. This isolation has allowed the evolution of many endemic species; most notable is the high number of endemic plants; in fact, there are a total of 653 vertebrate taxa recorded in the Chihuahuan Desert. Moreover, this ecoregion also sustains some of the last extant populations of Mexican Prairie Dog, wild American Bison and Pronghorn Antelope.
Severe conservation pressures are on the Chihuahuan Desert. On the Mexico side, there are destructive activities from illegal poaching, habitat destruction from illegal drug trafficking and large scale movements of... More »
Sonoran DesertLast Updated on 2013-12-06 15:53:38The Sonoran Desert covers approximately 200,000 square miles (520,000 square kilometers), including about 100,000 square miles of land, and often defined to also cover around 100,000 square miles of sea; moreover, the Sonoran comprises much of the state of Sonora, Mexico, most of the southern half of the USA states of Arizona, southeastern California, most of the Baja California peninsula, and the numerous islands of the Gulf of California. Its southern third straddles 30° north latitude and is a horse latitudeA horse latitude is a subtropical latitude between 30 and 35 degrees both north and south. desert; the rest is rainshadow desert. It is lush in comparison to most other deserts. There is a moderate diversity of faunal organisms present, with 550 distinct vertebrate species having been recorded here.
The Sonoran Desert can be divided into seven subdivisions based on... More »
Costa Rican seasonal moist forestsLast Updated on 2013-12-05 17:53:35The Costa Rican seasonal moist forests ecoregion is quite different from the surrounding dry and moist forest habitat types. Deciduous trees that shed leaves during the distinct dry season make up the dominant vegetation in these forests. The ecoregion fauna have a moderate species richness, with the number of vertebrates occurring here amounting to 698 taxa; however, faunal endemism is rather low. The flora are more adapted and capable of surviving in such a seasonally based ecoregion. Animals also are adapted to this fluctuation between wet and dry climate changes, and the subsequent changes in the plantlife.
The natural environment of this ecoregion has been substantially destroyed, chiefly by deforestation by the Costa Rican and Nicaraguan people, to clear land for grazing of livestock and other agricultural uses. Disruption to the Nicaragua portion of the ecoregion has also... More »
Sierra de la Laguna dry forestsLast Updated on 2013-12-03 15:31:09
Located at the southern end of the Baja California Peninsula in Mexico, the Sierra de la Laguna dry forests ecoregion was once an isolated island, containing a large number of endemic species. After sufficient mountain uplift and the joining the Baja Peninsula mainland, this ecoregion underwent significant speciation, and is thus today high in species diversity; this portion of the peninsula contains the majority of the species found in the southern part of the Baja Peninsula. The Sierra de la Laguna dry forest is a subtropical dry forest classified within the Tropical and Subtropical Broadleaf Forests biome; the ecoregion is threatened by overgrazing from domestic cattle and the hunting by humans. Designated as a Protected Natural Area (PNA), this important ecoregion is at risk from habitat fragmentation.
This ecoregion is contained in a larger geographic unit known as the Cape... More »
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