The Global 200 : a representation Approach to Conserving the Earth’s Distinctive Ecoregions
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Large River DeltasRepresenting the zone where rivers flatten out, Large River Deltas are low gradient systems whose waters are affected by oceanic tides. Salinity is a major factor in these systems, as is the slow moving nature of the water. Deltas are characterized by broad expanses of water and semi-permanent islands formed by the deposition of sediment carried downstream. These areas are highly productive, supporting abundant fish, invertebrate, and waterbird populations. Afrotropical
Niger River Delta [155] - NigeriaGeographic Location: Western Africa Biodiversity Features: Where Africa’s third largest river, the Niger, flows into the Gulf of Guinea, a delta over 50,000 km2 in extent is formed. The Niger’s relatively nutrient-rich, silt-laden whitewaters converge with the black and clear waters carried by other tributaries, creating an ecosystem that supports nearly 200 fish species. The Niger Delta is considered a biogeographical crossroads between the Nilo-Sudan and Guinea-Congo ichthyofaunal areas. ONE OF THE LARGEST DELTAS IN THE WORLD, THIS ECOREGION IS A BIOGEOGRAPHICAL CROSSROADS FOR AFRICAN ICHTHYOFAUNA Selected Species: Several endemic or near-endemic fish families inhabit this ecoregion, including Denticipidae and Phractolaemidae. The delta provides habitat for hippopotamus (Hippopotamus amphibius), the vulnerable pygmy hippo (Choeropsis liberiensis), and West African manatee (Trichechus senegalensis). General Threats: The delta system is highly threatened by oil pollution. Other threats include population growth and attendant coastal urbanization, oil and gas exploration and exploitation, industrialization, domestic and industrial waste discharges, the menace of introduced water hyacinth (Eichhornia crassipes), coastal erosion, and problems associated with aquaculture. Indo-MalayanIndus River Delta [156] – Pakistan, IndiaGeographic Location: Western portion of the Indian Subcontinent Biodiversity Features: Originating at Lake Ngangla Ringco high on the Tibetan Plateau, the Indus flows more than 3,000 kilometers to the Arabian Sea. Its waters are home to one of the few species of freshwater dolphin worldwide, the Indus River dolphin (Platanista minor) and numerous species of distinctive fishes, many of which live in or migrate through the waters of the Indus River Delta. Important food species like large freshwater shrimp (Macrobrachium spp.) are part of the abundant aquatic life of the delta. PRODUCTIVE LARGE RIVER DELTA HOME TO ABUNDANT POPULATIONS OF MIGRATORY SPECIES Selected Species: In addition to Indus River dolphin, the river is home to a number of endemic fishes, including Indus baril (Barilius modestus), Indus garua (Clupisoma naziri) and rita catfish (Rita rita). Several snakehead fishes also live here, including giant snakehead (Channa marulius). Several fish species, such as hilsa shad (Tenualosa ilisha), return from the Arabian Sea to spawn in freshwater. General Threats: Dams on the river reduce flows in lower portions of the system and limit the transport of fertile sediments downstream into the delta. They also pose a serious threat to the survival of the Indus River dolphin, as the remaining dolphins become isolated into smaller groups. Water extraction for irrigation, runoff of chemicals into the rivers, and introduced species also threaten the freshwater species of the delta. Palearctic V olga River Delta [157] – Kazakhstan, Russia Geographic Location: Western Asia Biodiversity Features: The rich delta of the Volga River is one of the world's largest and most important temperate deltas. Flows into the delta separate into over 500 channels, arms and rivulets and spread out onto the adjacent floodplain, forming shallow lakes. The delta supports 124 species of fish from 17 families, many of which are large river, anadromous species. It is considered one of the world’s most productive areas for fish. The ecoregion also supports millions of birds, including swans, ducks, herons, terns, and ibis. one oF eastern eurasia’s largest and most productive river deltas General Threats: The natural flow regime of the river and its sediment load has been altered by dams upstream of the delta and by water withdrawals. Changes in the hydrology have negatively affected the productivity of the delta and its fauna. Planned impoundments and water diversions further threaten the health of populations dependent upon the delta ecosystem. Wastewater from industrial, agricultural, and domestic sources is severe in the Volga river. Cyanobacterial blooms and deoxygentation have increased in recent years. Selected Species: Sturgeon species found in the delta are the Russian (Acipenser gueldenstaedti), beluga (Huso huso), sterlet (A. ruthenus), and stellate (A. stellatus) sturgeons. Other migratory species include whitefish (Salmonidae) and herrings (Clupeidae). Rare fish species found here include white-eyed bream (Abramis sapa) and the endemic Volga lamprey (Caspiomyzon wagneri). The delta contains unusual bird species like Dalmatian pelican (Pelecanus crispus), great white egret (Egretta alba), and penduline tit (Remiz penduculinus).
esopotamian Delta and Marshes [158] – Iran, Iraq, Kuwait Geographic Location: Middle East
Biodiversity Features: At the northern end of the Persain Gulf is the vast deltaic plain of the Euphrates, Tigris and Karun rivers. This complex of shallow freshwater lakes, swamps, marshes, and seasonally inundated plains between the Tigris and Euphrates rivers is among the most important wintering areas for migratory birds in Eurasia. Of the 278 species of birds that have been recorded in the lower Mesopotamia, 134 species are dependent to some extent on the wetland habitats. Cyprinids dominate the rich fish fauna of this ecoregion. large river delta in southwestern asia with globally outstanding marshlands Selected Species: These marshes support almost the entire world population of two bird species, Basra reed warbler (Acrocephalus griseldis) and Iraq babbler (Turdoides altirostris). Other species unique to these wetlands include two species of mammal (Erythronesokia bunnii and Gerbillus mesopotamiae) and several subspecies of fish. More widespread freshwater-dependent mammals found in the ecoregion include common otter (Lutra lutra) and a subspecies of smooth-coated otter (Lutra perspicillatamaxwelli). Migrants such as pygmy cormorant (Phalacrocorax pygmaeus), lesser white-fronted goose (Anser erythropus), and red-breasted geese (Branta ruficollis) winter in the wetlands and numerous other species of waterbirds and birds of prey frequent the ecoregion. General Threats: Vast areas of wetlands have been degraded or destroyed as a result of channelization and damming, as well as water withdrawals and drainage schemes. Planned large dams and large-scale water withdrawals upstream of the delta would decrease the already low water levels in the delta and its associated floodplains. Much of the fighting during the prolonged Iran-Iraq War (1980-1988) and bombings during the Persian Gulf War occurred in and around the wetlands and caused considerable damage to the marsh ecosystems. Another serious threat to the wetlands is salinization, caused by the continuous flushing of salts from irrigated lands. The threat of large-scale oil pollution from oil production in the region is also a concern. Additionally, hunting and fishing pressure in the marshes continues to be heavy. anube River Delta [159] – Bulgaria, Moldova, Romania, Ukraine, Yugoslavia Geographic Location: Eastern Europe Biodiversity Features: The Danube delta contains some 11,000 km2 of wetlands, making it one of the largest wetlands in Europe. The delta is a unique habitat of canals, reedbeds, lakes, and ponds, where over 280 species of birds congregate. Historically, 73 native freshwater fish and an additional 9 brackish-water species were found in the lower Danube basin. The basin is also home to approximately 88 freshwater molluscs (with 18 endemics), 75 dragonfly species, and 18 amphibian species. one of the largest eastern eurasian river deltas with extensive BIRD populations, DIADROMOUS FISH Selected Species: The delta is an important site for breeding populations of a number of rare or imperiled waterbirds, including Dalmatian pelican (Pelecanus crispus), white pelican (Pelecanus onocrotalus), water rail (Rallus aquaticus), pygmy cormorant (Phalacrocorax pygmeus), and collared pratincole (Glareola pranticola). Historically, ten diadromous fish species occurred in the lower Danube River. These included five sturgeon species (Acipenser gueldenstaedtii, A. nudiventris, A. stellatus, A. sturio, and Huso huso), European eel (Anguilla anguilla), three shad (Alosa caspia, A. immaculata, and A. maeotica), and Tyulka sprat (Clupeonella cultiventris). Today, A. nudiventris and A. sturio are exinct in this ecoregion. Fish species endemic to the lower Danube basin are a loach, Cobitis megaspila, and the critically endangered, monotypic Romanichthys valsanicola. General Threats: The loss of two of this ecoregion’s migratory fish species and the imperilment of several more speaks to the modified nature of this ecoregion’s aquatic systems. Pollution, damming, and drainage of wetlands disrupt the fragile ecology of the delta. Industry, agriculture, livestock and urban settlements have all increased the input of sewage, agricultural and industrial waste, and pesticides into the Danube’s water. Over-exploitation of some birds and frogs may be a problem, as are exotic species. Impacts from recent human conflicts in the Danube basin have undoubtedly had negative impacts on this ecoregion.
ena River Delta [160] – Russia Geographic Location: Northern Asia Biodiversity Features: Siberia's Lena River rises west of Lake Baikal and eventually flows north before emptying into the Laptev Sea, an arm of the Arctic Ocean. The river spreads out over the alluvial plain of the delta into five major channels and hundreds of smaller streams and lakes, which provide habitat for abundant wildlife. This arctic ecoregion experiences seven months of winter before the snow-covered tundra transforms into fertile wetlands. Swans, divers, geese, ducks, plovers, sandpipers, snipes, phalaropes, terns, skuas, birds of prey, passerines and gulls are only some of the migratory birds that breed in the productive wetland. The rich delta also supports abundant populations of fish and five marine mammals. Some scientists think that the ciscos (fish genus Coregonus) originated here. globally outstanding delta of the arctic ocean, globally important for nesting birds Selected Species: Spawning fish reported from the delta include Arctic lamprey (Lethenteron japonicum), burbot (Lota lota), and Arctic cisco (Coregonus autumnalis). Several species of ciscos (Coregonus spp.) are also found in the delta, including C. tugun, C. sardinella, C. peled, C. muskun, and C. nasus. A few of the many birds that visit or breed in the delta are black brant (Branta bernicla), common (Somateria mollissima) and Steller’s (Polysticta stelleri) eiders, Sabine’s (Xema sabini) and Ross’s (Rhodostethia rosea) gulls, and peregrine falcon (Falco peregrinus). General Threats: The Lena Delta Reserve was expanded in 1995, making it the largest protected area in Russia (61,000 km2). This large expanse offers protection to the abundant wildlife of the delta. However, overfishing, particularly of cisco populations within the refuge, is reportedly a concern. Outside of the reserve, mining, forestry, grazing, expanding agricultural activities, water diversion for irrigation, and pollution from fertilizers and pesticides may threaten the water quality and quantity that reach the delta. Small Rivers 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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