13.1.1 The Indo-Australian Archipelago and its freshwater fauna Th e Indo-Australian Archipelago (IAA) houses one of the highest levels of spe-cies richness and endemism in the world, encompassing four of the world's 25 biodiversity 'hotspots', which coalesce within this region in Southeast Asia (Myers et al. 2000). Southeast Asia covers only around 4% of the earth's surface, but houses some 20–25% of global fauna and fl ora (Mittermeier et al. 1999 , 2005 , Myers et al. 2000). Freshwater biodiversity levels are also extremely high in Southeast Asia, although very understudied and undervalued (Dudgeon et al. 2006 , and refer-ences therein). Freshwater biodiversity within this species-rich region is often overlooked by conservationists; for example, only 0.6% of papers published in the conservation literature from 1992–2001 dealt with Asian freshwater biodiversity (Dudgeon 2003). Around 15% of global freshwater fauna are found in Indonesia