1. Introduction to rivers of South AmericaManuel A.S. Grac¿a, Edgardo M. Latrubesse, Marcos Callisto, Franco Teixeira de Mello, and Douglas Rodri¿guez-Olarte2. Rivers of the CaribbeanSamuel E. Segnini-Flores, Douglas Rodri¿guez-Olarte, Jose E. Rinco¿ n, Juan F. Blanco-Libreros, and Sara R. Lo¿ pez-Rodri¿guez3. MagdalenaJose Ivän Mojica, Edith Gonzälez-Afanador, Jhon Donato-Rondo¿ n, and Gabriel Hernando Guillot-Monroy4. OrinocoDouglas Rodri¿guez-Olarte, Judith Rosales, Jesu¿ s Manuel Väsquez-Ramos, Hernando Rami¿rez-Gil, Cri¿spulo J. Marrero, and Carlos DoNascimiento5. Rivers of the North AtlanticJan H.A. Mol, Raphael Covain, and Philip W. Willink6. AmazonasNaziano Filizola, Rogerio Marinho, Carlos Freitas, Camila Ribas, Jansen Zuanon, Philip Fearnside, and Patricia Moreira-Turcq7. Amazonian Rivers from the Guiana ShieldMaria Teresa Fernandez Piedade, Pia Parolin, Aline Lopes, Florian Wittmann, Wolfgang J. Junk, Amanda Mortati, Thiago Andre, and Jochen Schongart8. Rivers from the Western AmazonNatalia C. Piland, Claire F. Beveridge, Joa~o V. Campos-Silva, Carlos Can~ as, Sandra B. Correa, Thiago B.A. Couto, Andrea C. Encalada, Daniel Escobar-Camacho, Silvia Lo¿ pez-Casas, Benjamin Webb, and Elizabeth P. Anderson9. MadeiraCarolina Rodrigues da Costa Do¿ ria,Jorge Molina-Carpio, Gislene Torrente-Vilara, Aline Andriolo, Maria Madalena de Aguiar Cavalcante, Carmen Graci¿a-Dä vila, Hernän Ortega, and Paul Andre van Damme10. Amazonian Rivers from the Brazilian Shield: Xingu and Tapajo¿ sLuciano F.A. Montag, Leandro M. Sousa, Andre L. Netto-Ferreira, Andre O. Sawakuchi, Gustavo Hallwass, Renato A.M. Silvano, Jose Max B. Oliveira-Junior, and Tiago M.S. Freitas11. Tocantins and AraguaiaFernando M. Pelicice, Hasley R. Pereira, Priscilla Carvalho, Davi B. das Chagas, and Dilermando P. Lima-Junior12. Rivers of the North EastJose Etham de Lucena Barbosa, Juliana dos Santos Severiano, Silvia Yasmin Lustosa Costa, Biancade Freitas Terra, Elvio Sergio Figueredo Medeiros, and Rosemberg F. Menezes13. Sa~o FranciscoPaulo S. Pompeu, Diego R. Macedo, Carlos B.M. Alves, and Lafayette D. da Luz14. Rivers of the Central AtlanticFrancisco A.R. Barbosa, Diego G.F. Pujoni, Carlos E. Rezende, Alisson F. Barbieri, and Francisco Ricardo de Andrade Neto15. UruguayFranco Teixeira de Mello, Christine Lucas, Hugo Inda, Mariana Ri¿os, and Ivän Gonzä lez-Bergonzoni16. ParanäPablo A. Scarabotti, Isabel T. Leli, Luis O. Lucifora, Edgardo M. Latrubesse, Cläudia C. Bonecker, and Mercedes R. Marchese17. ParaguayKarl M. Wantzen, Yzel Rondon Su¿ arez, Julio C.J. Solo¿ rzano, Fernando R. Carvalho, Lucia A.F. Mateus, Mari¿a Fätima Mereles Haydar, Pierre Girard, and Jerry Magno F. Penha18. Rivers draining the Southern Gran ChacoHugo R. Fernändez, Luis A. Fernändez, Mario A. Caria, Yzel Rondon Su¿ arez, Jerry Magno F. Penha, andEduardo Domi¿nguez19. Pampean riversAlberto Rodrigues Capi¿tulo, Nestor A. Gabellone, Adonis Giorgi, Leandro Rodrigues Capi¿tulo, andNora Go¿ mez20. Colorado River systemPablo A. Macchi, Patricia Peralta, Marisa Cogliati, Nerina Canale, Heber Sosa, Ricardo Go¿ mez, andYeny Labaut21. Southern Atlantic riversMiguel A. Pascual, Juana Aigo, Natalia L. Pessacg, Boris G. Diaz, Pedro Tiberi, and M. Laura Miserendino22. Rivers flowing to the Southern PacificJorge Nimptsch, Pablo Fierro, Konrad Go¿ rski, Nicole Colin, and Jorge Leo¿ n Mun~ oz23. Rivers of the Central PacificIrma Vila, Pablo Rojas, Hernän Ortega, Mari¿a C. Sabando, Rodrigo Pardo, Cristina Dorador, and Francisco Meza24. Rivers of the northern PacificBlanca Ri¿os-Touma, Magnolia Longo, Christian Villamari¿n, Yesid Carvajal-Escobar, Jaime Cantera-Kintz, Daniela Rosero-Lo¿ pez, Pedro Jimenez-Prado, and Jose Ivän Mojica25. An agenda for conservation of South American riversManuel A.S. Grac¿a, Karl M. Wantzen, Franco Teixeira de Mello, Marcos Callisto, and Douglas Rodriguez-Olarte