dams, diversions), and aquaculture development (e.g. inland fish farming). Those IAS species are a major threat to wetlands and livelihoods in the LMB (IUCN, 2006). For instance, Giant Mimosa ( Mimosa pigra) is one of the worst environmental weeds of the Mekong River Basin, also on the list of 100 of the world’s worst IAS, and can be found in upland agricultural systems in Northern Provincesofthe Lao PDR (Miththapala, 2007). IUCN (2006) highlighted that “It is a serious agricultural weed in the LMB often establishing in areas along streams and canals and then invading adjacent rice fields” (.p3). Moreover, some aquatic fauna have been introduced for aquaculture in Lao PDR.
They have proven to be negative to the native species (Miththapala, 2007). Tilapia (Oreochromis spp.) is a native from Africa, this fish species have been introduced as aquaculture in Lao PDR where it has been declared an invasive species . Miththapala (2007) also highlighted that IAS are directly and indirectly affecting human livelihoods; especially inland water systems are particularly vulnerable. Pollution: Environmental pollutants can generate various toxicities that can prevent normal growth of biological organisms and their reproductive and survival capabilities.
Water pollution from industrial sources has been identified in the Lower Mekong Basin (LMB), especially in the capital cities of Vientiane and Phnom Penh, and more generally in northeast Thailand and the Mekong Delta. Elevated levels of heavy metals have been found mainly, down-stream of Phnom Penh and on the Mekong Delta, in areas with heavy boat traffic and high population densities (MRC, 2010) . Forms of pollution that affect biodiversity in the Lao PDR include nutrient and chemical run-off from agricultural areas and urban lands.
For example, excessive fertilizer, pesticide, and herbicide use leads to excessive levels of nutrients in soil, and has also caused increasing environment pollution. Likewise, pesticides deter beneficial insects. Therefore, it can be seen that the aquatic systems are affected with water pollution from domestic, aqua cultural and agricultural sectors. Moreover, pesticides and agro-chemicals can have a negative impact on water quality which can affect aquatic biodiversity and other forms of biodiversity. Lao Farmers have used pesticide in their agricultural activities. The GoL has addressed the above issues by adopting the integrated water resources management (IWRM) approach, among others.
Moreover, the GoL has recently passed the Fisheries and Aquaculture Law and is also promoting the role of community-based resource management that build on regulatory systems. 20