SBR- Content.pmd - INBO

4 - Biota of the Mekong BasinA number of the mammal species within the basin are considered rare. One terrestrial mammalclosely associated with the river, the fishing cat (Prionailurus viverrinus), is considered globallynear-threatened. Of three species of otter – the hairy-nosed otter (Lutra sumatrana), the smoothcoatedotter (Lutrogale perspicillata) andthe oriental small-clawed otter (Aonyxcinerea), the first two are considered by theWorld Conservation Union (IUCN) to bevulnerable to extinction, and the latter“near-threatened”. 5 For all of these species,there is only anecdotal data on populationnumbers and distribution. For theIrrawaddy dolphin (Orcaella brevirostris),there is rather better data from populationsurveys. 6The smooth-coated otter (Lutrogale perspicillata) isconsidered by the World Conservation Union (IUCN) tobe vulnerable to extinctionWetland and riverine birds are declining in abundance,particularly those that rely on sandbars as breeding orfeeding habitatA number of aquatic or semi aquatic turtles, snakes andlizards occur within the basin, and many are hunted forsubsistence or sold for food or medicine in local marketsFor birds within the basin, there is also anabsence of quantitative data on populationabundance and distribution. Dudgeon 7 hasnoted that a high proportion of the birdspecies in the region that are known to havedeclined in abundance, are riverine orwetland birds. For example, 24 of 35species of bird identified as having declinedseriously in Lao PDR over the past 50 yearsare wetland birds. The decline has beenparticularly noticeable in species that relyon sandbars and large rivers as breeding orfeeding habitat. For example, the plainmartin (Riparia paludicola), which hasdeclined significantly in Lao PDR andThailand, nests in burrows on sandbars, ahabit probably shared with the now extinctwhite-eyed river martin (Pseudochelidonsirintarae). 8The largest of the reptiles in the basin arethe two species of crocodiles. The largestwild populations of the Siamese crocodile(Crocodylus siamensis) are thought to occurin Cambodia, particularly in the CardamomMountains area. Some estuarine(Crocodylus porosus) crocodiles may stillexist in the Mekong Delta, where amaximum number of 100 were estimatedin 1994. 9A number of aquatic or semi aquaticturtles, snakes and lizards occur within thebasin, many of which are hunted forsubsistence or sold for food or medicinein local markets. Of the lizards, the water31