The Global 200 : a representation Approach to Conserving the Earth’s Distinctive Ecoregions
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Relatively small rivers drain major portions of the Earth’s surface. In contrast to larger systems, such as the Amazon or Congo, the drainage basins of these flowing waters are much smaller. In many cases, these low order streams or rivers drain directly into coastal waters. Small Rivers encompass the full range of flow conditions and attendant habitats, from headwaters to alluvial lowlands. Afrotropicalpper Guinea Rivers and Streams [161] – Côte D’Ivoire, Guinea, Liberia, Sierra Leone
Geographic Location: West Africa Biodiversity Features: Wet conditions have existed more or less permanently over evolutionary time in the Upper Guinea ecoregion. The relative permanence of the aquatic landscape has allowed speciation through isolation and the persistence of relict species in this refuge zone. The Guinean mountain range (>1500 m elevation) and its many waterfalls and rapids have also limited the dispersal of aquatic species in the coastal basins into other West African basins. In particular, this ecoregion is distinguished by two endemic genera of crabs and dozens of endemic fish species. The many small river basins that drain into the Atlantic are also unique in their high fish richness by area. THESE RIVERS CONTAIN A DISTINCTIVE CONTINENTAL FAUNA INCLUDING MANY ENDEMIC FISH SPECIES. Selected Species: The ecoregion includes several fish species from a number of genera adapted to turbulent waters: Amphilius, Paramphilius, Chiloglanis, and Labeo. Individual fish species include Epiplatys njalaensis, E. olbrechtsi, and West African catfish (Chrysichthys maurus). The endemic Mount Nimba otter shrew (Micropotamogale lamottei), which inhabits montane streams on Mount Nimba, is endangered. The imperiled pygmy hippo (Choeropsis liberiensis) inhabits the forested watercourses of the lower coastal basins. A number of frogs are restricted to this ecoregion, such as Astylosternus occidentalis, Hyperolius occidentalis, Cardioglossa aureoli, and Bufo cristiglans. General Threats:Deforestation is heavy within certain areas of this ecoregion and much of the original forest cover has been removed to open land to agriculture. Mining of iron ore and diamonds in Liberia is causing the siltation of rivers and the loss of much riverine vegetation. Another threat to the biodiversity of the region is the political instability in Liberia and Sierra Leone has weakened the ability of these countries to manage their natural resources. .
adagascar Freshwater [162] – Madagascar Geographic Location: Island off southeast coast of Africa Biodiversity Features: The island has an elevated plateau from which short, swift rivers flow over a narrow strip of land as they descend to the Indian Ocean to the east. But to the west, long rivers flow down from the central plateaus across sedimentary beds into the Mozambique Channel. Due to climatic variability throughout the island, the rivers and streams are remarkably diverse, although they all experience seasonal flooding and high discharges. The freshwater fish of Madagascar demonstrate high levels of endemicity, particularly at higher taxonomic levels, with fourteen endemic genera and one endemic family (Bedotiidae). Several taxa also occupy “key” basal phylogenetic positions, important for understanding the evolution of fishes. Endemic aquatic mammals, reptiles, amphibians, gastropods, and crustaceans also inhabit these freshwater systems. Although poorly studied, aquatic insects are also thought to be highly endemic at the generic and species levels. One of the world’s most distinctive freshwater biotas with many regional and local endemics and unusual higher taxa Selected Species: The majority of the endemic freshwater fishes of Madagascar are from the herring (Clupeidae), sea catfish (Ariidae), bedotiid (Bedotiidae), sleeeper (Eleotridae), rivuline (Aplocheilidae), goby (Gobiidae) and cichlid (Cichlidae) families. A few of the endemic freshwater fishes of Madagascar are Chonophorus macrorhynchus, Teramulus kienerie, and Rheocles alaotrensis. The region contains a number of unusual aquatic plants, and is home to the endemic aquatic tenrec (Limnogale mergulus), one member of a family of insectivorous mammals restricted to Madagascar. Freshwater courses and their adjacent habitats also support the rare endemic turtle Eretmochelys madagascariensis, a large aquatic lizard (Scelotes astrolabi), and many endemic frogs. A rich community of endemic decapod crustaceans, including six species of parastacid crayfishes (Astacoides spp.), at least twenty speceis of atyid shrimps (Caridina spp.), three species of palaemonid shrimps (Machrobrachiumspp.), and nine species of patamonid crabs, inhabit the island’s rivers and streams. Madagascar also has a rich freshwater gastropod fauna, with 30 species, 12 endemics and one endemic genus (Melanatria). General Threats: The freshwater fishes of Madagascar are considered the island’s most endangered vertebrates. Habitat degradation due to deforestation and agriculture, overfishing, and introduced species are considered the main causes of species decline. Deforestation of upland forests has resulted in siltation, temperature increases, algal blooms and flow increases from runoff. Overfishing has played a major role in the decline of the island’s native cichlid fauna and possibly some of the larger Rheocles. In many rivers and streams, exotic fish species now dominate the fish fauna. Among the most problematic exotic species are water hyacinth (Eichhornia crassipes), floating fern, Salvinia natans; and fish including Xiphophorus helleri, Cyprinus carpio, Carassius auratus, Micropterus salmoides, Tilapia zillii, T. sparrmani, and Ophiocephalus striatus.
ulf of Guinea Rivers and Streams [163] – Angola, Cameroon, Democratic Republic of Congo, Equatorial Guinea, Gabon, Nigeria, Republic of Congo Geographic Location: Western Africa Biodiversity Features: The rivers in this ecoregion run through equatorial forest and savanna before emptying into the Gulf of Guinea. Some of the principal rivers are the Cross, Ogooué, Sanaga, Nyong, Ntem, and Kouilou Rivers. These rivers contain some of the highest endemism levels for any of Africa's riverine freshwater systems. At least ten endemic species of crabs in several endemic genera live in these waters. The ecoregion has the second highest fish species richness of river systems in Africa. Some of the highest richness and endemism LEVELS FOR freshwater biotas in Africa, high beta diversity Selected Species: Species include a variety of endemic killifish (Aphyosemion spp.), barbs (Barbus spp.), and cichlids (Cichlidae). Parts of this ecoregion reportedly support the highest densities of amphibian species in mainland Africa. The most distinctive of these, the goliath frog (Conraua goliath), is the world’s largest living frog, with adults reported to reach 3.25 kg in weight. These waters are also home to the giant African water shrew (Potomogale velox). General Threats:The planned construction of dams on many of these coastal rivers (e.g., the Ntem and Kouilou rivers) and continued deforestation in the area are the biggest threats to the aquatic habitats and species in the ecoregion. The aquarium trade and introduced species also threaten native fish populations.
ape Rivers and Streams [164] – South Africa Geographic Location: Southern Africa Biodiversity Features: This ecoregions rivers are influenced by the surrounding fynbos vegetation, which releases organic acids and stains the waters a dark hue. Streams within the region flow out of the Cape Fold mountains, and consequently contain high-gradient habitats. These waters support a highly distinctive fish, invertebrate, and plant biota, including a number of endemics. Many of these species may be relictual. HIGHLY DISTINCTIVE AQUATIC BIOTA, EXHIBITING HIGH LEVELS OF ENDEMSIM Selected Species: The Cape is home to two near-endemic fish genera, Austroglanis and Pseudobarbus, with two and six species in the ecoregion, respectively. Of biogeographic interest is the presence of Cape galaxias (Galaxius zebratus), the distribution of the Galaxiidae family in Australia, Africa, and South America gives clear evidence for continental drift. Streams and their associated wetlands and springs provide important habitat for a number of endangered or otherwise sensitive amphibian species. Among these are Rose’s toadlet (Capensibufo rosei), the endangered Hewitt’s ghost frog (Heleophryne hewitti), Cape caco (Cacosternum capense), the endangered Table Mountain ghost frog (H. rosei), and the micro frog (Microbatrachella capensis). General Threats: Introduced species, particularly North American gamefishes such as largemouth bass (Micropterus salmoides) and smallmouth bass (M. dolomieu), have heavily impacted indigenous species. Water is in great demand in this dry ecoregion, with both urban and agricultural uses competing with the needs of the unique aquatic fauna. The construction of dams and interbasin water transfers alter the natural flow regime and block species movements. As urban and agricultural areas in this ecoregion expand, pollution will continue to pose an additional threat. Australasia
ew Guinea Rivers and Streams [165] – Indonesia, Papua New Guinea Geographic Location: Southeast Asia Biodiversity Features: New Guinea’s central highlands divide the island into two faunal provinces, with the southern rivers containing the greater share of diversity. The freshwater organisms of New Guinea are mostly of marine origin, but they have evolved into numerous forms. Within the enormous southward-flowing Fly River alone there are over 100 fish species, representing 33 families. The Sepik River, also large, is less diverse but serves as a corridor for many marine and marine-derived taxa. This ecoregion also shares with Australia a diverse freshwater crab fauna of the family Parathelphusidae. Distinctive island freshwater fauna with high endemism and unusual adaptive radiations Selected Species: The diverse assemblage of spectacular forms found in New Guinea’s freshwaters include sharks, sawfish, and large saltwater crocodiles. Imperiled endemic fish species include Oktedi rainbowfish (Melanotaenia oktediensis) and glass blue-eye (Kiunga ballochi). Multiple freshwater turtle species are imperiled, including the Fly River turtle (Carettochelys insculpta), two snake-necked turtles (Chelodina parkeri, C. pritchardi), and two soft-shelled turtles (Pelochelys bibroni and P. cantorii). Barramundi (Lates calcarifer) and certain other aquatic species are of great economic importance as commercial food sources. General Threats: Deforestation as a result of commercial agriculture and industrial logging, which leads to increased erosion and altered hydrologic regimes, poses one of the most significant threats. Road building in association with logging has opened up new lands to shifting agriculture. Pollution from mining is a serious problem in this ecoregion, and pollution from industrial logging, agricultural processing, and urban sewage is nearly as important. Overfishing, both for subsistence use and the commercial trade, threatens native species. Exotics such as tilapia (Oreochromis mossambica) and water hyacinth (Eichhornia crassipes) place additional stresses on the island biota, and populations of exotics are apparently growing rapidly. The wildlife trade also threatens reptiles such as the saltwater crocodile (Crocodylus porosus), which is heavily hunted in the Sepik River region and elsewhere for its skins and live export.
ew Caledonia Rivers and Streams [166] – New Caledonia (France) Geographic Location: South Pacific Ocean Biodiversity Features: New Caledonia's exceptionally distinctive biota extends to its freshwater ecosystems. The freshwater biota contains endemic species of fish, crustaceans, snails, other invertebrates, and plants. Ten species of freshwater shrimp and a group of rare freshwater sponges with at least four species are found on the island. Over 70 species of freshwater fishes have successfully invaded these island waters and at least 50 species of hydrobiid snails have been described. globally distinctive island biota with unusual higher taxa Selected Species: Among the seventy-plus native fishes, five species of migratory eel occur in this ecoregion: Anguilla mozambica, A. marmorata, A. megastoma, A. obscure and A. reinhardtii. The freshwater snake-eel (Lamnostoma kampeni) is also an unusual inhabitant of these waters. New Caledonian habitats support a wide array of molluscs, including four genera of freshwater spring snails (Kanakyella, Pidaconomus, Caledoconcha, and Leiorhagium) that have recently been described. General Threats: Large areas of New Caledonia are mined for nickel, iron, copper, gold and other minerals. Threats also include agriculture, grazing, logging, bush fires and associated water pollution.
imberley Rivers and Streams [167] – Australia Geographic Location: Northwestern Australia Biodiversity Features: Characterized by a rugged landscape transected by number of perennial streams and marked by ephemeral freshwater swamps, this ecoregion exhibits a freshwater fauna with high levels of endemism. In particular, the fish fauna of nearly 50 species has about 25% endemism. Notable for their endemicity are several families of fish, including gudgeons (Eleotridae), grunters (Terapontidae), hardyheads (Atherinidae), and rainbowfish (Melanotaeniidae). REGIONAL CENTER OF DIVERSITY WITH HIGH LEVELS OF ENDEMISM AMONG FISHES AND OTHER TAXA Selected Species: Freshwater fish include several species of venomous eel-tail catfishes (Tandanus spp.), Kimberley grunter (Syncomistes kimberleyensis), Greenway’s grunter (Hannia greenwayi), and pygmy rainbowfish (Melanotaenia pygmaea). Endemic fish in the Eleotridae family include slender gudgeon (Hypseleotris ejuncida), Barnett River gudgeon (Hypseleotris kimberleyensis), and the only two members of the endemic genus Kimberleyeleotris, Mitchell gudgeon (K. hutchinsi) and Drysdale gudgeon (K. notata). In addition to a number of aquatic snakes, such as Liasis fuscus, freshwaters in this ecoregion also support populations of several aquatic lizards, including Mitchell’s and Mertens’ water monitors (Varanus mitchelli, V. mertinsi). Turtles found in this ecoregion include northern snake-necked turtle (Chelodina rugosa), northern snapping turtle (Elseya dentata), and Victoria short-necked turtle (Emydura victoriae). Both freshwater crocodile (Crocodylus johnstoni) and saltwater crocodile (Crocodylus porosus) occur here as well. General Threats: Overgrazing and resulting sedimentation are among the largest threats in this ecoregion. Mining is also an important land use, and tourism is becoming increasingly popular. There is only one large dam in the ecoregion. Potential problems are associated with the presence of a number of introduced species in this ecoregion’s rivers. Two important areas for freshwater biodiversity are found within the protected areas of Drysdale River National Park and Prince Regent Nature Reserve.
outhwest Australia Rivers and Streams [168] – Australia Geographic Location: Southwestern Australia Biodiversity Features: Comprised of short coastal rivers, this region exhibits lower species richness than that of eastern Australia, but high levels of endemism due to long periods of isolation. Nine of fourteen fish species are endemic, as are twelve of nineteen fairy shrimp (Anostraca) species. The ephemeral pools and marshes that form among granitic outcrops also support unusual species adapted to unpredictable water availability, such as plants of the Lycopsida group, and chrironomid midges. CENTER OF ENDEMISM; ALSO HARBORS SEVERAL PRIMITIVE HIGHER TAXA AND SEVERAL SPECIES WITH HIGHLY UNUSUAL FRESHWATER LIFE HISTORIES. Selected Species: Among this ecoregion’s distinctive species is the salamanderfish (Lepidogalaxias salamandroides), the only species in the family Lepidogalaxiidae. The salamanderfish may be related to galaxiids, of which there are three endemic species in this ecoregion as well: western minnow (Galaxia occidentalis), black-stripe minnow (Galaxiella nigrostriata), and western mud minnow (G. munda). Other endemics are freshwater cobbler (Tandanus bostocki), nightfish (Bostockia porosa), western pygmy perch (Edelia vittata), long-headed goby (Afurcagobius suppositus), and King River perchlet (Nannatherina balstoni). In addition, the anadromous and monotypic pouched lamprey (Geotria australis) inhabits this ecoregion. General Threats: A number of introduced species, including rainbow trout (Onchorhynchus mykiss) and brown trout (Salmo trutta), have proliferated in streams and rivers of the region. With the exception of one endemic species, all of the exotic species far outsize the native freshwater fauna found here. Habitat loss, particulary of important ephemeral pools; alteration of the natural flow regime; and negative impacts from agricultural practices, including loss of riparian buffers, all pose threats to the native biota. In addition, loss of natural vegetation in many areas has led to increased salinization of land and adjacent streams.
astern Australia Rivers and Streams [169] – Australia Geographic Location: Eastern Australia Biodiversity Features: Both species richness and endemism are high in eastern Australia’s streams, in contrast to streams in western regions. Southeast Australia has a particularly species-rich and endemic crayfish (family Parastacidae) fauna, and the ecoregion’s freshwater fish fauna is distinguished by its high endemicity as well. Rivers, lakes, and springs of this ecoregion contain numerous relict species, including many species of dragonflies (Odonata), mayflies (Ephemeroptera), and mountain shrimp (Syncarida), the latter restricted to Tasmania. Tasmania is also home to 15 species of galaxiid fishes in three genera. the most distinctive freshwater biotas in australia ARE FOUND IN THE AQUATIC HABITATS OF THIS ECOREGiON, INCLUDING many local endemic species AND RELICT TAXA. MANY SPECIES OF ANCIENT GONDWANAN ORIGIN, INCLUDING THE LUNGFISH Selected Species: The most famous resident of eastern Australia’s freshwater systems is the platypus (Ornithorhynchus anatinus). The ecoregion includes an unusual group of gastric-brooding frogs in the genus Rheobatrachus. A large number of freshwater snails in the family Hydrobiidae have very localized distributions within portions of the ecoregion. Characteristic fish species include one of the world’s largest freshwater fish (reaching lengths greater than 1.5 m), Murray cod (Maccullochella peelii), and lungfish (Neoceratodus fosteri), which is the only living representative of the Ceratodontidae family. Among the many endemic fishes are Murray jollytail (Galaxias rostratus), the primitive spotted bonytongue (Scleropages leichardti), and the migratory Australian grayling (Prototroctes maraena), which may be the only extant member of its genus and is considered vulnerable. Tasmania has a highly endemic fish fauna of its own, including Shannon paragalaxias (Paragalaxias dissimilis) and Tasmanian whitebait (Lovettia sealii). Distinctive endemic crayfish include the massive Tasmanian Astacopis gouldi, and the diminutive Tenuibranchiurus glypticus. General Threats: Threats to freshwater biodiversity are numerous. Rivers and streams have been highly modified by the construction of weirs and dams, channelization, and the removal of riparian vegetation. Agricultural, urban, and industrial pollution are growing problems in some areas. Introduced species, including fish and aquatic plants, threaten natives; these exotics include species translocated from other Australian regions. Aquaculture threatens to further the spread of nonnative species, as well as to release wastewater to freshwater ecosystems. Forest clearing for agriculture and timber production, and subsequent increases in sedimentation, may be one of the most serious problems. Directory: downloads downloads -> Northern England’s set-jetting locations downloads -> Dynatest 3031 lwd light Weight Deflectometer downloads -> Forth coming competitive exams downloads -> Brush High School Morning Announcements Friday, September 05, 2014 all school downloads -> Year 9 The Arts — Music downloads -> Years 7 and 8 standard elaborations — Australian Curriculum: Music draft downloads -> Chris Young sets 2016 “I’m Comin’ Over” Tour headlining dates downloads -> Slavery and Abolition: the Plymouth Connection Introduction downloads -> Summer Assignment Download 2.75 Mb. Share with your friends:
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