Freshwater and estuarine ecosystems are among the most threatened in the world, are under-represented in protected area (PA) Policies and have the highest portion of species threatened with extinction. Freshwater and estuarine ecosystems are among the most threatened in the world, with the Millennium Ecosystem Assessment describing freshwater ecosystems as being over-used, under-represented in PAs and having the highest portion of species threatened with extinction. Freshwater, food and energy are inextricably linked on a global scale. Freshwater is essential for potable supply, producing food and agricultural products, for supporting subsistence communities, and to harness "renewable" energy. Agricultural practices over the past few centuries have caused wide-scale changes in land cover, watercourses, and aquifers, contributing to the loss and degradation of wetlands and undermining the ecological processes that support the provision of a wide range of ecosystem services. Fish, and other freshwater organisms, account for 72.4 per cent of all capture harvest in developing countries.