Biogeography

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 bacteria extremophiles 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.   

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Recently Updated
Namibian savanna woodlands Last Updated on 2015-07-25 20:49:25 WWF Terrestrial Ecoregions Collection The Namibian savanna woodlands ecoregion covers the Great Escarpment that delimits the interior of southern Africa from both the Kaokoveld Desert and Namib Desert. This broken and deeply dissected escarpment is an area of high endemism for plants, invertebrates, amphibians, reptiles, mammals and birds. The northern area of the ecoregion, the Kaoko escarpment, is an endemism "hotspot" (an area of extremely high species richness and endemism). The Namibian savanna woodlands comprise a land area of approximately 87,100 square miles. This northern area is poorly protected and is under threat from poaching, off-road driving, and to a lesser extent from farming, and resultant habitat fragmentation;  much of this destabilisation in the Angolan portion of the ecoregion stems from the Cuban mercenaries... More »
Kalahari xeric savanna Last Updated on 2015-07-10 18:01:28 WWF Terrestrial Ecoregions Collection The Kalahari xeric savanna is an ecoregion in southern Africa characterized by a harsh climate, where temperatures may vary by 44°C from night to day, and rainfall is infrequent. Rain appears only during the austral summer on the reddish-brown Kalahari sands , pelting the savanna with violent, localized storms. Although this area is semi-arid, there is an impressive diversity of migratory birds and large mammals, both herbivorous and carnivorous; in fact, 550 different vertebrates have been observed in the Kalahari xeric savanna.  This ecoregion is classified within the Deserts and Xeric Shrublands biome. A considerable fraction (approximately 18 percent) of the Kalahari xeric savanna is protected. Where lands are not protected, overgrazing has often severely degraded habitat. Fences are a significant... More »
Highveld grasslands Last Updated on 2015-07-07 21:46:02 WWF Terrestrial Ecoregions Collection Highveld grasslands ecoregion covers a large portion of west-central South Africa. Grasslands all over the world have experienced dramatic habitat destruction as a result of anthropogenic changes. The Highveld grasslands are no exception, with agriculture severely fragmenting this once-expansive region. This ecoregion now provides the last remaining stronghold of a number of grassland species that have suffered major reductions in abundance in the grassland biome, and which are consequently threatened with extinction (e.g. the Blue Crane (Anthropoides paradisea). There is a relatively biodiverse vertebrate fauna, with 608 taxa recorded. This ecoregion is part of the Montane Grasslands and Shrublands biome, within the Afrotropics Realm. The ecoregion draws its name from the high interior plateau known as... More »
Habitat fragmentation Last Updated on 2015-07-04 14:10:43 Habitat fragmentation involves alteration of habitat resulting in spatial separation of habitat units from a previous state of greater continuity. Figure 1. Aerial photograph of dry forest scrub in southern Zambia, fragmented by agricultural land conversion. 2008. Source: C.Michael Hogan This phenomenon occurs naturally on a geologic time-scale or in unusual and catastrophic events: however, since the Holocene era, humans have produced dramatic and swift transformation of landscapes throughout the world, resulting in a level of habitat fragmentation that has induced worldwide reduction in biodiversity and interuption of  sustainable yields of natural resources. Humans produce habitat fragmentation chiefly from agricultural land conversion, urbanization, pollution, deforestation and introduction of alien species; ironically, both human caused... More »
Madagascar spiny thickets Last Updated on 2015-06-25 20:16:56 WWF Terrestrial Ecoregions Collection The Madagascar spiny thickets or spiny desert of southern Madagascar, also referred to as deciduous thicket, is a globally distinctive ecoregion. This ecoregion is part of the Deserts and Xeric Shrublands biome, within the Afrotropics Realm. While the island of Madagascar is notable for exceptional levels of endemic plants and animals, the spiny thicket is particularly distinctive with 95 percent of the plant species endemic to the ecoregion. Members of the endemic Didiereaceae family present dominate the thicket, which have similar xeric adaptations to New World cacti, such as small leaves and spines, but with the Madagascar spiny thickets displaying more woody rather than succulent characteristics. There are a total of 288 recorded vertebrate taxa in the Madagascar spiny thickets, including several endemic... More »