An agenda for conservation of South American rivers

Nature and its biodiversity provide benefits to human societies, some of which can be quantified in economic terms (e.g., fish for consumption), while others, though crucial, are harder to quantify and often neglected (e.g., the capacity of headwaters, wetlands, and floodplains to store and release water, thereby warranting perennial discharge and protecting from hydrological extremes floods and droughts). The Neotropics are among the most diverse systems on Earth, but human activities are threatening rivers and their ecosystems, thereby jeopardizing their vital services. Major threats to South American rivers, their biota, and ecosystem services include river damming and navigation projects, deforestation of drainage basins, agricultural and livestock activities, urban development, pollution, overexploitation of living resources, invasion by nonnative species, and human-influenced climate change. To maintain environmental health, human societies need to take actions to counteract environmental stressors. These actions include limit damming; designate large areas for effective conservation and include rivers and their riparian zones in protection schemes; use “Debt-for-Nature” schemes to assign new protected areas; Implement long-term monitoring programs, which should include the biological component and involve citizen associations; invest in wastewater treatment; and limit pollution from mining and agriculture. Given the transnational nature of many rivers, international cooperation is strongly needed. Finally, the results of scientific studies must reach the general public. Scientists also need to work with economists and jurists to implement scientifically sound decisions taking into account the needs of local populations.