Southwestern Sri Lanka rivers and streams is a

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

. The ecoregion is listed in

Global 200 The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature ( WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or w ...

, a list of ecoregions compiled by the

World Wide Fund for Nature The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the Wor ...

for conservation priorities. The extensive network of rivers and streams of Sri Lanka drains a total of 103 distinct natural river basins. Several waterfall habitats have been formed as a result of rivers and streams flowing through high and mid elevation areas. The ecoregion spreads over 15,500 km² in the wet zone of the southwestern part of Sri Lanka. More than a quarter of the

freshwater fish Freshwater fish are those that spend some or all of their lives in fresh water, such as rivers and lakes, with a salinity of less than 1.05%. These environments differ from marine conditions in many ways, especially the difference in levels of s ...

es that have been discovered in Southwestern Sri Lanka rivers and streams are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

. Nine endemic genera of freshwater fishes of Western Ghats and

hotspot

Malpulutta The ornate paradisefish (''Malpulutta kretseri'') or spotted gourami, is a species of gourami Endemism, endemic to Sri Lanka. It is the only recognized species in its genus. It inhabits shallow, slow-flowing streams in forested areas shaded with ...

are found only in Sri Lanka. Studies suggest that the number of species still to be discovered is quite high. Until recently wetlands in

were used for drainage, construction sites and land fills.

Biodiversity

Diverse types of plants, fish and

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

s are supported by rivers and streams that flow through this region, sourced in the central highlands.

harbors 90 species of

and 21 species of

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s. Twenty six species of fish are confined to this ecoregion. As unraveling of new species is continuing, the number of endemics is expected to rise greatly. Most of these fishes are small and specialized to their rivers and streams. Some of the fish species inhabiting this ecoregion include Two Spot Barb,

Black ruby barb The black ruby barb (''Pethia nigrofasciata'', formerly ''Puntius nigrofasciatus'') or purplehead barb is a tropical cyprinid fish endemic to Sri Lanka, where it occurs in forested streams from the Kelani basin to the Nilwala basin. They are fo ...

, Cherry barb and Black-lined Barb. More rare species in this ecoregion include Spotted Loach,

Ornate paradisefish The ornate paradisefish (''Malpulutta kretseri'') or spotted gourami, is a species of gourami endemic to Sri Lanka. It is the only recognized species in its genus. It inhabits shallow, slow-flowing streams in forested areas shaded with plentiful ...

, Rasbora wilpita, Puntius martenstyni and Pearly rasbora. Many of the fishes of this ecoregion have commercial value and are harvested in

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

and traded for

aquarium An aquarium (plural: ''aquariums'' or ''aquaria'') is a vivarium of any size having at least one transparent side in which aquatic plants or animals are kept and displayed. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, aq ...

s. Apart from fishes, this ecoregion is also rich with

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...

turtle Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

s and

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

Human impact

Forests in this ecoregion are cleared for

tea Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of '' Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of southwestern China and northe ...

and

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

plantations.

Poaching Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set a ...

and the extraction of timber are problems even in protected areas, resulting in

habitat fragmentation Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...

and edge effects. Farmers have changed some of the slow moving waterways into rice fields.

and Cherry barb populations are being reduced due to the ornamental fish trade. Competition with introduced alien fish and plants poses a threat to native species. Using agrochemicals unrestrictedly poses a different threat to the ecosystem and to species groups such as amphibians.

Rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coasta ...

Clown knifefish The clown featherback, clown knifefish, or spotted knifefish, ''Chitala ornata'', is a nocturnal tropical fish with a long, knife-like body. This knifefish is native to freshwater habitats in Cambodia, Laos, Thailand, and Vietnam, but it has al ...

Walking catfish The walking catfish (''Clarias batrachus'') is a species of freshwater airbreathing catfish native to Southeast Asia. It is named for its ability to "walk" and wiggle across dry land, to find food or suitable environments. While it does not trul ...

and

Red-eared slider The red-eared slider or red-eared terrapin (''Trachemys scripta elegans'') is a subspecies of the pond slider (''Trachemys scripta''), a semiaquatic turtle belonging to the family Emydidae. It is the most popular pet turtle in the United States, ...

are some of the invasive species causing direct exploitation or destruction. There is some protection in place for central highland water courses in the

Peak Wilderness Sanctuary Peak Wilderness sanctuary is a natural reserve in Sri Lanka. It is the third largest (by area) of the 50 sanctuaries in the country. "Sri Pada" Peak Wilderness sanctuary is a tropical rain forest that spreads over a land of 224 square kilometers ...

and

Horton Plains National Park Horton Plains National Park ( si, හෝර්ටන් තැන්න ජාතික උද්‍යානය, Hortan Thanna Jathika Udyanaya) is a national park in the central highlands of Sri Lanka that was designated in 1988. It is locate ...

References

External links

Wildworld ecoregion profile
{{DEFAULTSORT:Southwestern Sri Lanka rivers And streams Water in Sri Lanka ecoregions of Sri Lanka Biota of Sri Lanka Freshwater ecoregions

Biodiversity

Human impact

See also

References

External links