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:
Species range limitsLast Updated on 2014-11-09 18:49:44Species range limits (SRLs) are defined as the spatial boundaries beyond which no living individuals of a given species occur. Populations occurring near or at SRLs are often referred to as “marginal,” “peripheral,” “edge,” or “border” populations. SRLs may represent areas beyond which individuals cannot physiologically tolerate ecological conditions or areas where they have not yet dispersed. SRLs may be stable (i.e., at equilibrium) or may represent areas where range expansion through migration or population growth is in the process of occurring. SRLs are significant to ecology, evolution, and conservation for several reasons. They provide opportunities to understand the conditions under which populations expand or contract, and the conditions under which populations may evolve new forms. Additionally, SRLs... More »
Sundarbans, BangladeshLast Updated on 2014-10-19 18:16:11The Sundarbans (21°30'- 22°30'N, 89°12'-90°18'E) are a World Heritage Site which consists of three wildlife sanctuaries (Sundarbans West, East and South) lying on disjunct deltaic islands in the Sundarbans Forest Division of Khulna District, close to the border with India and immediately west of the principal outflow of the Ganges, Brahmaputra and Meghna rivers. The Sundarbans belong to Bengalian Rainforest biogeographical province.
1977: All three wildlife sanctuaries established under the Bangladesh Wildlife (Preservation) (Amendment) Act, 1974,
1878: The three sanctuaries gazetted as forest reserves.
1996: The total area of wildlife sanctuaries extended; the entire Sundarbans is reserved forest, established under the Indian Forest Act, 1878.
1997: The Sundarbans inscribed on the World Heritage List.
The total area of the Bangladesh... More »
Ecoregions of BangladeshLast Updated on 2014-10-19 17:45:45Bangladesh has five ecoregions:
Sundarbans freshwater swamp forests
Lower Gangetic Plains moist deciduous forests
Mizoram-Manipur-Kachin rain forests
Myanmar coastal rain forests
The ecoregion lies in the vast delta formed by the confluence of the Ganges, Brahmaputra, and Meghna rivers. The maze of mangrove channels extends across southern Bangladesh and India's West Bengal State.The Sundarbans Mangroves ecoregion is the world's largest mangrove ecosystem.
Named after the dominant mangrove species Heritiera fomes, locally known as sundri, this is the only mangrove ecoregion that harbors the Indo-Pacific region's largest predator, the tiger (Panthera tigris).
Unlike in other habitats, here tigers live and swim among the mangrove islands, where they hunt scarce prey such as chital deer (Cervus axis), barking deer (Muntiacus muntjak), wild... More »
Mangrove ecologyLast Updated on 2014-10-19 17:31:46
Mangrove ecology is the study of biotic interactions within mangrove swamp ecosystems. These habitats are significant not only for the biodiversity they represent, but also for the protection of coastal erosion, and for the provision of protected nursery areas for marine fauna.
Mangroves worldwide cover an approximate area of 240 000 square kilometers of sheltered coastlines in the tropics and subtropics.
Mangroves stabilize coastal intertidal soils pereventing coastal erosion
Four of the most common ecotypes include fringe, riverine, basin, and scrub forests.
Mangroves are restricted to the intertidal zone.
Mangroves in general have a great capacity to recover from major natural disturbances.
Mangroves maintain water quality by trapping sediments and taking up excess... More »
Big Bend National Park, United StatesLast Updated on 2014-10-19 16:55:59Big Bend National Park is one of the two National Parks located in the state of Texas, in the USA. Big Bend National Park is located in the Big Bend region along the border of Texas and Mexico where the Rio Grande bends toward the Gulf of Mexico.
Because the park contains a variety of habitat types including mountains, deserts, and riparian habitats, the park is home to a diverse flora and fauna. Visitors arrive at Big Bend National Park to hike, camp, watch wildlife, and experience the river by rafting or canoeing.
Big Bend National Park is located in the big bend of the Rio Grande along more than 161 kilomters (100 miles) of the Texas-Chihuahua-Coahuila border southeast of El Paso, Texas in Brewster County, Texas. It includes a large portion of the Chihuahuan Desert as well as the Chisos Mountains on the Texas side of the Rio Grande’s expansive steep canyons.
In 1933,... More »
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