The Global 200 : a representation Approach to Conserving the Earth’s Distinctive Ecoregions
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- Afrotropical
- Neotropical igh Andean Lakes [183]
- Palearctic
Large LakesScattered across the Earth’s surface are a number of Large Lakes, characterized as such by large surface areas and often by very deep water. Many of these lakes are quite old and contain a high diversity of habitats. These systems support fishes and other aquatic organisms that are uniquely adapted to these lacustrine conditions. Some of these lakes support abundant animal populations, species with unusual morphologies, or diverse species assemblages. Afrotropical
ift Valley lakes [182] - Burundi, Democratic Republic of Congo, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Tanzania, Uganda, Zambia Geographic Location: East-central Africa Biodiversity Features: The Great Rift Valley, created by the moving of tectonic plates beneath the crust of Africa, is home to many lakes that harbor extraordinary endemic species assemblages. Some, such as Lakes Malawi (>800 m deep) and Tanganyika (>1400 m deep), have formed in the rifts, but the vast Lake Victoria is actually located in a shallow depression between the two rifts. Several small soda lakes in the eastern rift represent a globally rare habitat type. Upwards of 800 cichlids live in the lakes, with many more species yet to be discovered. The lakes also support high numbers of endemic molluscs and crustaceans. Lake Tana hosts one of only two known flocks of cyprinid fish species in the world and is the only one that remains intact. The species radiations of cichlids in the Rift Valley lakes rival radiations of terrestrial fauna in the Galápagos and serve as a classic example of evolutionary adaptation. Globally outstanding adaptive radiations of fish in tropical lakes, extraordinary levels of endemism
Selected Species: The Rift Valley lakes are primarily known for the extensive radiations of fish species in the family Cichlidae. Endemic species of the Clariidae, Claroteidae, Mochokidae, Poecilidae, Mastacembelidae, Centropomidae, Cyprinidae, Clupeidae and other families are also found in these lakes. A unique pelagic fish community has evolved in Lake Tanganyika including two endemic clupeids, Limnothrissa miodon and Stolothrissa tanganicae, that feed on zooplankton in the pelagic zone and, in turn, provide food for the four predatory centropomids, Lates angustifrons, L. mariae, L. microlepis, and L. stappersii. These aquatic habitats are also important to the persistence of a number of frogs, including Bufo kisoloensis, B. keringyagae, Cardioglossa cyaneospila, and Nectophryne batesii. General Threats: The introduction of exotic fishes (tilapia, Oreochromis niloticus, and Nile perch, Lates niloticus) has decimated the native cichlids of Lake Victoria, with nearly 200 species of cichlids estimated to have been lost. Overfishing has been a substantial force leading to declines in species abundance. Runoff from urban areas, pollution from industrial activities, and deforestation on steep banks also threaten the health of the lakes. Harvesting of species for the aquarium trade is a potential threat to fish populations, although the impact is unknown. Neotropical igh Andean Lakes [183] – Argentina, Bolivia, Chile, Peru Geographic Location: Western South America Biodiversity Features: Freshwater and saline lakes are scattered throughout this ecoregion, including some of the highest elevation lakes in the world. These high altitude lakes, such as Lake Titicaca in Peru and Bolivia, are not particularly rich in species but they contain many endemic fish and molluscs. For example, Lake Titicaca hosts 23 endemic species of the fish genus Orestias and 15 endemic gastropods. Some of the lakes also support huge colonies of flamingos (Phoenicoporrus spp.). Unique high-altitude freshwater lake biota and saline lake communities, important radiations in several fish taxa Selected Species: Numerous Orestine fishes occur in these still-water habitats, such as Orestias chungarensis, O. laucaensis, and O. pentlandii. The climbing (Astroblepidae) and pencil (Trichomycteridae) catfishes are also characteristic of the high-altitude lakes and streams of the Andes. The threatened James (Phoenicopterrus jamesi) and Andean (P. andinus) flamingoes, as well as the endemic horned coot (Fulica cornuta) and more common Chilean flamingo (P.chilensis), live in the lake environs. General Threats: The fragile systems of these high elevation lakes are threatened by runoff of sediments and contaminants from mining, agriculture, and livestock grazing activities. Water quality has declined in several lakes due to the input of untreated sewage and pollution from industrial sources. Overfishing and introduction of exotic species threaten fish populations, particularly in Lake Titicaca. Palearctic
ake Baikal [184] – Russia Geographic Location: Central Asia
Biodiversity Features: Due to 25 million years of isolation and a diversity of deep-water habitats, the biodiversity of Lake Baikal (also the deepest lake in the world, at 1,741 m) is unrivaled. There are about 2,500 species of known plants and animals in the lake, of which 1,500 are endemic. Underwater "reefs" of giant sponges, a unique biological phenomenon, support a great diversity of fish, crustaceans, molluscs, and other invertebrates. Several large endemic fish inhabit deeper waters and form part of the prey base of the endemic Baikal seal (Phoca sibirica), the only entirely landlocked seal species in the world. Among the lake’s many habitats are recently discovered hydrothermal vents at a depth of about 400 meters that support sponges, bacterial mats, snails, transparent shrimp, and fish. Ancient cold temperate lake of central asia with unique sponge reefs and associated invertebrate and fish communities, deep and open water communities unusual as well, very high richness and endemism for habitat type, including endemic freshwater seal Selected Species: The Baikal seal (Phoca sibirica) may be the best-known endemic species of this ecoregion. Lake Baikal’s fish are distinguished by a flock of 36 species in the sculpin family Cottidae, an endemic family (Comephoridae), and distinct stocks of Coregonus, Thymallus, and Lota species. The amazing aquatic diversity of the lake includes 147 species of gastropods, 255 species of shrimp-like amphipod species, and 80 species of flatworm. General Threats: Although industrial development is significant, natural habitats are not as highly fragmented as in other regions of Russia. Major threats stem from pulp, aluminum, and other industrial enterprises that dump pollutants into the lake, its tributaries, and the atmosphere. Forest clearance, fires, agriculture, and grazing also pose significant threats. ake Biwa [185] – Japan Geographic Location: Far-eastern Asia Biodiversity Features: Lake Biwa is one of the oldest lakes in the world, estimated to have originated some 4 million years ago. It is surrounded by mountains and is fed by 460 streams. It has high species richness and endemism, with 38 gastropods (19 endemics), 16 bivalves (9 endemics), 4 endemic fish species; and 70 aquatic plants. The coastal areas of the lake are also important wintering areas for waterfowl, with over 50,000 birds arriving in a typical year. high levels of endemism for temperate lake Selected Species: Fish species include sunayatume (Lampetra mitsukurii), ayu (Plecoglossus altivelis), deme-moroko (Squalidus japonica), Rhinogobius similis, and unagi (Anguilla japonica). Four of the fishes endemic to this lacustrine system are a catfish (Silurus biwaensis), isaza (Chaenogobius isaza), honmoroko (Opsaiichthys uncirostris), and Gnathopogon caerulescens. Endemic molluscs of the genera Heterogen, Semisulcospira, Radix, Gyraulus, Anodonta, Corbicula, and Pisidium are present in the lake. General Threats: The lake is the largest in Japan and is relied upon to supply water for 14 million people, as well as industrial and other uses within the watershed. Although the lake is located in a protected area, it suffers from threats associated with recreational use, flood-control measures, overfishing, and eutrophication from excess nutrient inputs. More than one-fourth of the watershed has been converted for paddy field agriculture and conifer plantations. 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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