located around periurban centers along or close to the coast­line of the East China Sea and the South China Sea. Major hotspots, with the highest concentrations of nitrogen and phosphorus overloads from livestock systems, have been found in the Mekong Delta, the mouth of the Red River and along the whole Chinese coast of the South China Sea. One report has suggested that animal manure accounts for 47% of the P and 16% of the N in these areas. The chemical oxygen demand from untreated piggery effluent accounted for 28% of the current urban industrial chemical oxygen loads in 1996, with the expectation that this will increase to 90% by 2010 (LEAD, 2006).
     Increasing concern about management of animal wastes has increased attention by ESAP governments to minimize the effect of nutrient pollution on the landscape and coastal marine systems. While anaerobic digest works on small-scale production systems, such as in the Pacific Islands, large-scale commercial livestock farmers of Southeast Asia will require different technology to adequately treat, dispose of and re­cycle livestock waste.
     Discharge of water excessively laden with organic mat­ter into rivers and canals, especially from intensive aquacul-ture ponds, was a cause of river water pollution in leading aquaculture countries. However, most destructive aquacul-ture has been the result of ignorance or nonadherence to "responsible aquaculture practice," also known as good aquaculture practice or best aquaculture practice.

2.4.3.4  Loss of agrobiodiversity ESAP harbors one of the world's richest reservoirs of biodi­versity. It is the point of origin of many crop and livestock varieties economically important to humankind. Resource-poor farmers are hugely dependent for their livelihoods on this agrobiodiversity of minor crops, wild plants, wild animals and medicinal plants. They might be insignificant in national statistics but are critically important locally. Biodiversity has been associated with farmer production choices and food security and is a mechanism for coping with environmental uncertainties by spreading and reducing potential risks.
     Genetic variability of species comes from genetic re­sources. Breeders identify desirable genetic traits from gene-pools and incorporate them into mainstream varieties to pro­duce crops with desirable characteristics, such as improved yield, quality, pest resistance and tolerance to environmental constraints. It is estimated that half the increase in yield of major crops is from genetic improvements through breeding (Chang, 1984).
     Agrobiodiversity is being threatened by simplification of ecosystems and species and by varietal replacement. Monocropping has displaced many local and traditional va­rieties, resulting in genetic erosion. In Indonesia, 1,500 rice varieties disappeared from 1975 to 1990. High-yield rice replaced traditional varieties in about 80 to 82% of fields in Burma, Indonesia, the Philippines and Thailand. The thou­sands of farmer-developed rice varieties planted in mosaic pattern in agricultural landscapes are no longer planted. Likewise, genetically uniform livestock and poultry breeds have replaced many traditional breeds (Thrupp, 1998). The predominant agricultural approach of monocropping and specialization has often been reinforced by government poli-

cies using input subsidies, agricultural extension messages or widespread distribution by governments of modern seeds (Cromwell et al., 1997).
     Loss of forest cover, coastal wetlands and other wild, un­cultivated areas has further exacerbated the loss of wild rela­tives and wild foods essential for providing food (Cromwell et al., 1997). Habitat loss has been serious in China, India, the Philippines, Thailand and Viet Nam (ESCAP, 1995).
     Cultural diversity, a fourth dimension of biodiversity, has been least appreciated. Traditional and local knowl­edge is key to using and conserving biodiversity because it embodies the coping mechanisms of local people under the varied and rigorous circumstances that make unique areas productive and sustainable. Local knowledge has been ig­nored in dominant agricultural systems and much of it is rapidly disappearing (Cox, 2000).
      AKST in aquaculture has had both positive and negative effects on the environment. Technology to produce fry of cultivable species obviated using wild fry for farming, saving biodiversity. Many previously fallow water bodies covered with water hyacinth, which used to be the abode of mosqui­toes, were now free of the insects. However, coastal shrimp aquaculture was responsible for mangroves being destroyed in many ESAP countries.

2.4.3.5  Pest and disease incidence and pesticides
Pests, diseases and weeds have remained significant prob­lems, despite the use of more pesticides. Pesticides may even cause pest problems, when beneficial insects are eliminated or if pest resistance to pesticides evolves. Agronomic prac­tices have their share in causing greater incidence of pests and diseases. For example, outbreaks of the brown plant hopper in rice during the 1980s occurred because pesticides, high nitrogen fertilization, dense planting and continuous ir­rigation eliminated their natural enemies (Ishii and Hirano, 1959; Heinrichs et al., 1982). Currently, some 500 insect pests, 150 plant pathogens and 133 weed species already have become resistant to insecticides (Brattsten et al., 1986; Altieri and Rosset, 1999).
     IPM, developed in the 1980s, was quite successful on selected crops in the ESAP region. Indonesia officially ad­opted IPM as national policy in 1986 and after five years, it reported a 70% reduction in pesticide use while rice yield increased by 10 percent.
     The drive by livestock growers to serve urban markets has led to intensive production, bringing problems of live­stock waste, land management and distribution. Greater awareness rose for the potential for transmission of disease from animals to humans. Major diseases that can be trans­mitted from animals to humans include bovine tuberculosis, Creutzfeldt-Jakob disease and various internal parasitic dis­eases (Steinfeld et al., 2006). Other examples of the potential dangers of disease transmitted through increased food trade include a 1997 outbreak of foot-and-mouth disease that vir­tually ruined the pig industry in Taiwan (China). The strain was closely related to strains found in Hong Kong (China) and the Philippines (WHO, 2002). There were also concerns about the rising demand for livestock feed, increased need for veterinary services and training, loss of genetic resources and the need to extend opportunities to small-scale produc­ers to earn cash from livestock (FAO, 2006c).