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RESEARCH ARTICLE

Geographic distribution of the short-tailed river stingray (Potamotrygon brachyura): assessing habitat loss and fishing as threats to the world’s largest obligate freshwater elasmobranch

Luis O. Lucifora A H , Santiago A. Barbini B , Sabina Llamazares Vegh C , Pablo A. Scarabotti D , Facundo Vargas E , Agustín Solari A F , Ezequiel Mabragaña G and Juan M. Díaz de Astarloa G
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- Author Affiliations

A Instituto de Biología Subtropical – Iguazú, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Misiones, Casilla de Correo 9, Puerto Iguazú, Misiones, N3370AVQ, Argentina.

B Laboratorio de Ictiología, Instituto de Investigaciones Marinas y Costeras, CONICET, Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Mar del Plata, Buenos Aires, B7602YAL, Argentina.

C Dirección de Pesca Continental, Dirección Nacional de Planificación Pesquera, Subsecretaría de Pesca y Acuicultura, Ministerio de Agricultura, Ganadería y Pesca, Alférez Pareja 125, Ciudad Autónoma de Buenos Aires, C1107, Argentina.

D Instituto Nacional de Limnología, CONICET, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, Santa Fe, Santa Fe, S3001XAI, Argentina.

E Departamento Fauna y Pesca, Dirección de Fauna y Áreas Naturales Protegidas, Remedios de Escalada 46, Resistencia, Chaco, H3500BPB, Argentina.

F Centro de Investigaciones del Bosque Atlántico, Bertoni 85, Puerto Iguazú, Misiones, N3370BFA, Argentina.

G Laboratorio de Biotaxonomía Morfológica y Molecular de Peces, Instituto de Investigaciones Marinas y Costeras, CONICET, UNMdP, Funes 3350, Mar del Plata, Buenos Aires, B7602YAL, Argentina.

H Corresponding author. Email: luis.lucifora@conicet.gov.ar

Marine and Freshwater Research 67(10) 1463-1478 https://doi.org/10.1071/MF15003
Submitted: 5 January 2015  Accepted: 9 April 2015   Published: 28 September 2015

Abstract

Freshwater elasmobranchs are threatened but little is known about them. Potamotrygon brachyura is the world’s largest obligate freshwater elasmobranch. This makes it popular among fishermen and suggests a susceptibility to anthropogenic threats. We collected records of P. brachyura (n = 70) from media, fishermen and scientific sampling, to estimate its global geographic distribution (using both generalised additive and MaxLike models). Then, we estimated the species’ exposure to habitat modification and fishing pressure, by applying multinomial ordinal models with threat levels as response and the presence or absence of P. brachyura as an independent variable. Distance to coast, depth, water temperature range, salinity range and mean water temperature were the main determinants of the distribution in the Río de la Plata. This resulted in a narrow coastal distribution. In the Uruguay and Paraná River basins, the probability of occurrence was positively associated with flow accumulation, percentage of open water and submerged vegetation, and lowland ecoregions, and negatively to wetness index and altitude. This limited the distribution to large lowland rivers. Approximately 41% of the range of P. brachyura in the Río de la Plata was subject to high habitat modification. In the Uruguay and Paraná River basins, this percentage reached 7%; however, the overlap with high fishing pressure was 59%. For conservation purposes, P. brachyura may function as an umbrella species.

Additional keywords: Chondrichthyes, Pantanal, Paraná River, Río de la Plata basin, South America, species distribution modelling, wetlands.


References

Abell, R., Thieme, M. L., Revenga, C., Bryer, M., Kottelat, M., Bogutskaya, N., Coad, B., Mandrak, N., Contreras Balderas, S., Bussing, W., Stiassny, M. L. J., Skelton, P., Allen, G. R., Unmack, P., Naseka, A., Ng, R., Sindorf, N., Robertson, J., Armijo, E., Higgins, J. V., Heibel, T. J., Wikramanayake, E., Olson, D., López, H. L., Reis, R. E., Lundberg, J. G., Sabaj Pérez, M. H., and Petry, P. (2008). Freshwater ecoregions of the world: a new map of biogeographic units for freshwater biodiversity conservation. Bioscience 58, 403–414.
Freshwater ecoregions of the world: a new map of biogeographic units for freshwater biodiversity conservation.Crossref | GoogleScholarGoogle Scholar |

Aceñolaza, P., Zamboni, L. P., Sione, W., and Kalesnik, F. (2008). Caracterización de la región superior del complejo litoral del río Paraná: grandes unidades de ambiente. Instituto Superior de Correlación Geológica Serie Miscelánea 17, 293–308.

Agostinho, A. A., and Zalewski, M. (1996). ‘Upper Paraná River Floodplain: Importance and Preservation.’ (Editora da Universidade Estadual de Maringá: Maringá.)

Albert, J. S., Petry, P., and Reis, R. E. (2011). Major biogeographic and phylogenetic patterns. In ‘Historical Biogeography of Neotropical Freshwater Fishes’. (Eds J. S. Albert and R. E. Reis.) pp. 21–57. (University of California Press: Berkeley, CA.)

Allan, J. D., Abell, R., Hogan, Z., Revenga, C., Taylor, B. W., Welcomme, R. L., and Winemiller, K. (2005). Overfishing of inland waters. Bioscience 55, 1041–1051.
Overfishing of inland waters.Crossref | GoogleScholarGoogle Scholar |

Anderson, D. R., Burnham, K. P., and Thompson, W. L. (2000). Null hypothesis testing: problems, prevalence, and an alternative. The Journal of Wildlife Management 64, 912–923.
Null hypothesis testing: problems, prevalence, and an alternative.Crossref | GoogleScholarGoogle Scholar |

Araújo, M. L. G., Almeida, M. P., Rincon, G., Charvet-Almeida, P., and Rosa, R. S. (2009). Potamotrygon orbignyi. In ‘IUCN Red List of Threatened Species. Version 2013.1’. (International Union for Conservation of Nature and Natural Resources.) Available at http://www.iucnredlist.org/details/161609/0 [Verified 10 July 2013].

Baigún, C. R. M., and Oldani, N. O. (2006). La ictiofauna y los recursos pesqueros. In ‘La Situación Ambiental Argentina 2005’. (Eds A. Brown, U. Martinez Ortiz, M. Acerbi and J. Corcuera.) pp. 144–147. (Fundación Vida Silvestre Argentina: Buenos Aires.)

Baigún, C. R. M., Oldani, N., and Van Damme, P. A. (2011). Represas hidroeléctricas en América Latina y su impacto sobre la ictiofauna: lecciones aprendidas. In ‘Los Peces y Delfines de la Amazonía Boliviana: Hábitats, Potencialidades y Amenazas’. (Eds P. A. Van Damme, F. M. Carvajal-Vallejos and J. Molina Carpio.) pp. 397–416. (Editorial Inia: Cochabamba.)

Baigún, C. R. M., Colautti, D., López, H. L., Van Damme, P. A., and Reis, R. E. (2012). Application of extinction risk and conservation criteria for assessing fish species in the lower La Plata River basin, South America. Aquatic Conservation: Marine and Freshwater Ecosystems 22, 181–197.
Application of extinction risk and conservation criteria for assessing fish species in the lower La Plata River basin, South America.Crossref | GoogleScholarGoogle Scholar |

Baigún, C., Minotti, P., and Oldani, N. (2013). Assessment of sábalo (Prochilodus lineatus) fisheries in the lower Paraná River basin (Argentina), based on hydrological, biological, and fishery indicators. Neotropical Ichthyology 11, 199–210.
Assessment of sábalo (Prochilodus lineatus) fisheries in the lower Paraná River basin (Argentina), based on hydrological, biological, and fishery indicators.Crossref | GoogleScholarGoogle Scholar |

Barbini, S. A., Lucifora, L. O., and Hozbor, N. M. (2011). Feeding habits and habitat selectivity of the shortnose guitarfish, Zapteryx brevirostris (Chondrichthyes, Rhinobatidae), off north Argentina and Uruguay. Marine Biology Research 7, 365–377.
Feeding habits and habitat selectivity of the shortnose guitarfish, Zapteryx brevirostris (Chondrichthyes, Rhinobatidae), off north Argentina and Uruguay.Crossref | GoogleScholarGoogle Scholar |

Barletta, M., Jaureguizar, A. J., Baigún, C., Fontoura, N. F., Agostinho, A. A., Almeida-Val, V. M. F., Val, A. L., Torres, R. A., Jimenes-Segura, L. F., Giarrizzo, T., Fabré, N. N., Batista, V. S., Lasso, C., Taphorn, D. C., Costa, M. F., Chaves, P. T., Vieira, J. P., and Corrêa, M. F. M. (2010). Fish and aquatic habitat conservation in South America: a continental overview with emphasis on neotropical systems. Journal of Fish Biology 76, 2118–2176.
Fish and aquatic habitat conservation in South America: a continental overview with emphasis on neotropical systems.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3crhtlensg%3D%3D&md5=e0902e9cb4206be3c3bf61142d1ea0f8CAS | 20557657PubMed |

Barua, M. (2011). Mobilizing metaphors: the popular use of keystone, flagship and umbrella species concepts. Biodiversity and Conservation 20, 1427–1440.
Mobilizing metaphors: the popular use of keystone, flagship and umbrella species concepts.Crossref | GoogleScholarGoogle Scholar |

Baumgartner, G., Pavanelli, C. S., Baumgartner, D., Bifi, A. G., Debona, T., and Frana, V. A. (2012). ‘Peixes do Baixo Rio Iguaçu.’ (Editora da Universidade Estadual de Maringá: Maringá.)

Behr, E. R. (2005). Estrutura da comunidade de peixes do rio Ibicuí, Rio Grande do Sul, Brasil. Ph.D. Thesis, Pontifícia Universidade Católica do Rio Grande do Sul.

Bó, R. (2006). Situación ambiental en la ecorregión Delta e Islas del Paraná. In ‘La Situación Ambiental Argentina 2005’. (Eds A. Brown, U. Martinez Ortiz, M. Acerbi and J. Corcuera.) pp. 131–143. (Fundación Vida Silvestre Argentina: Buenos Aires.)

Brazeiro, A., Acha, M., Mianzan, H., Gómez-Erache, M., and Fernández, V. (2003). Aquatic priority areas for the conservation and management of the ecological integrity of the Río de la Plata and its maritime front. Technical Report PNUD Project GEF RLA/99/G31. (FREPLATA: Montevideo and Buenos Aires).

Casciotta, J., Almirón, A., and Bechara, J. (2005). ‘Peces del Iberá: Hábitat y Diversidad.’ (Fundación Ecos: Corrientes.)

Charvet-Almeida, P., and Almeida, M. P. (2009). Potamotrygon magdalenae (Magdalena freshwater stingray, Magdalena river stingray). In ‘IUCN Red List of Threatened Species. Version 2013.1’. (International Union for Conservation of Nature and Natural Resources.) Available at http://www.iucnredlist.org/details/161385/0 [Verified 10 July 2013].

Charvet-Almeida, P., Soto, J. M. R., and Almeida, M. P. (2009) Potamotrygon brachyura (giant freshwater stingray). In ‘IUCN Red List of Threatened Species. Version 2013.1’. (International Union for Conservation of Nature and Natural Resources.) Available at http://www.iucnredlist.org/details/161687/0 [Verified 10 July 2013].

Chebez, J. C., López, H. L., and Athor, J. (2009). Peces de agua dulce amenazados de la Argentina. In ‘Otros que se Van’. (Ed. J. C. Chebez.) pp. 32–54. (Editorial Albatros: Buenos Aires.)

Collen, B., Whitton, F., Dyer, E. E., Baillie, J. E. M., Cumberlidge, N., Darwall, W. R. T., Pollock, C., Richman, N. I., Soulsby, A.-M., and Böhm, M. (2014). Global patterns of freshwater species diversity, threat and endemism. Global Ecology and Biogeography 23, 40–51.
Global patterns of freshwater species diversity, threat and endemism.Crossref | GoogleScholarGoogle Scholar |

Compagno, L. J. V. (1990). Alternative life-history styles of cartilaginous fishes in time and space. Environmental Biology of Fishes 28, 33–75.
Alternative life-history styles of cartilaginous fishes in time and space.Crossref | GoogleScholarGoogle Scholar |

Compagno, L. J. V. (2002). Freshwater and estuarine elasmobranch surveys in the Indo-Pacific region: threats, distribution and speciation. In ‘Elasmobranch Biodiversity, Conservation and Management: Proceedings of the International Seminar and Workshop’, July 1997, Sabah, Malaysia. (Eds S. L. Fowler, T. M. Reed and F. A. Dipper.) pp. 168–180. (IUCN: Gland, Switzerland.)

Compagno, L. J. V., and Cook, S. F. (1995). The exploitation and conservation of freshwater elasmobranchs: status of taxa and prospects for the future. Journal of Aquariculture and Aquatic Sciences 7, 62–90.

da Graça, W. J., and Pavanelli, C. S. (2007). ‘Peixes da Planície de Inundação do Alto Rio Paraná e Áreas Adjacentes.’ (Editora da Universidade Estadual de Maringá: Maringá.)

Davidson, N. C. (2014). How much wetland has the world lost? Long-term and recent trends in global wetland area. Marine and Freshwater Research 65, 934–941.
How much wetland has the world lost? Long-term and recent trends in global wetland area.Crossref | GoogleScholarGoogle Scholar |

de Resende, E. K. (2003). Migratory fishes of the Paraná–Paraguay basin excluding the upper Paraná basin. In ‘Migratory Fishes of South America: Biology, Fisheries and Conservation Status’. (Eds J. Carolsfeld, B. Harvey, C. Ross and A. Baer.) pp. 99–155. (World Fisheries Trust–The World Bank–International Development Research Centre: Ottawa, ON, Canada.)

Devincenzi, G. J., and Teague, G. W. (1942). Ictiofauna del río Uruguay medio. Anales del Museo Nacional de Historia Natural de Montevideo (Serie 2) 5, 1–100.

Dudgeon, D., Arthington, A. H., Gessner, M. O., Kawabata, Z.-I., Knowler, D. J., Lévêque, C., Naiman, R. J., Prieur-Richard, A.-H., Soto, D., Stiassny, M. L. J., and Sullivan, C. A. (2006). Freshwater biodiversity: importance, threats, status and conservation challenges. Biological Reviews of the Cambridge Philosophical Society 81, 163–182.
Freshwater biodiversity: importance, threats, status and conservation challenges.Crossref | GoogleScholarGoogle Scholar | 16336747PubMed |

Dulvy, N. K., Fowler, S. L., Musick, J. A., Cavanagh, R. D., Kyne, P. M., Harrison, L. R., Carlson, J. K., Davidson, L. N. K., Fordham, S. V., Francis, M. P., Pollock, C. M., Simpfendorfer, C. A., Burgess, G. H., Carpenter, K. E., Compagno, L. J. V., Ebert, D. A., Gibson, C., Heupel, M. R., Livingstone, S. R., Sanciangco, J. C., Stevens, J. D., Valenti, S., and White, W. T. (2014). Extinction risk and conservation of the world’s sharks and rays. eLife 3, e00590.
Extinction risk and conservation of the world’s sharks and rays.Crossref | GoogleScholarGoogle Scholar | 24448405PubMed |

Dunne, T., and Mertes, L. A. K. (2007). Rivers. In ‘The Physical Geography of South America’. (Eds T. T. Veblen, K. R. Young and A. R. Orme.) pp. 76–90. (Oxford University Press: New York.)

Faraway, J. J. (2006). ‘Extending the Linear Model with R: Generalized Linear, Mixed Effects and Non-Parametric Regresion Models.’ (Chapman and Hall/CRC: Boca Raton, FL.)

Ferrer-Paris, J. R., Sánchez-Mercado, A., Rodríguez-Clark, K. M., Rodríguez, J. P., and Rodríguez, G. A. (2014). Using limited data to detect changes in species distributions: insights from Amazon parrots in Venezuela. Biological Conservation 173, 133–143.
Using limited data to detect changes in species distributions: insights from Amazon parrots in Venezuela.Crossref | GoogleScholarGoogle Scholar |

Ferretti, F., Worm, B., Britten, G. L., Heithaus, M. R., and Lotze, H. K. (2010). Patterns and ecosystem consequences of shark declines in the ocean. Ecology Letters 13, 1055–1071.
| 20528897PubMed |

Fitzpatrick, M. C., Gotelli, N. J., and Ellison, A. M. (2013). MaxEnt versus MaxLike: empirical comparisons with ant species distributions. Ecosphere 4, art55.
MaxEnt versus MaxLike: empirical comparisons with ant species distributions.Crossref | GoogleScholarGoogle Scholar |

Fowler, S. L. (2002). Elasmobranch biodiversity, conservation and management in Sabah. In ‘Elasmobranch Biodiversity, Conservation and Management: Proceedings of the International Seminar and Workshop, Sabah, Malaysia, July 1997’. (Eds S. L. Fowler, T. M. Reed and F. A. Dipper.) pp. 9–14. (IUCN: Gland, Switzerland.)

Freeman, E. A., and Moisen, G. (2008). PresenceAbsence: an R package for presence–absence model analysis. Journal of Statistical Software 23, 1–31.

FREPLATA (2004). Análisis Diagnóstico Transfronterizo del Río de la Plata y su Frente Marítimo. Documento Técnico. Proyecto Protección Ambiental del Río de la Plata y su Frente Marítimo. Proyecto PNUD/GEF/RLA/99/G31. (FREPLATA: Montevideo and Buenos Aires).

García, V. B., Lucifora, L. O., and Myers, R. A. (2008). The importance of habitat and life history to extinction risk in sharks, skates, rays and chimaeras. Proceedings. Biological Sciences 275, 83–89.
The importance of habitat and life history to extinction risk in sharks, skates, rays and chimaeras.Crossref | GoogleScholarGoogle Scholar |

Garrone-Neto, D. (2010). Considerações sobre a reprodução de duas espécies de raias (Myliobatiformes, Potamotrygonidae) na região do Alto Rio Paraná, Sudeste do Brasil. Pan-American Journal of Aquatic Sciences 5, 101–111.

Garrone-Neto, D., and Uieda, V. S. (2012). Activity and habitat use of two species of stingrays (Myliobatiformes: Potamotrygonidae) in the upper Paraná River basin, southeastern Brazil. Neotropical Ichthyology 10, 81–88.
Activity and habitat use of two species of stingrays (Myliobatiformes: Potamotrygonidae) in the upper Paraná River basin, southeastern Brazil.Crossref | GoogleScholarGoogle Scholar |

Garrone-Neto, D., Haddad, V. Jr, Vilela, M. J. A., and Uieda, V. S. (2007). Registro de ocorrência de duas espécies de potamotrygonídeos na região do Alto Rio Paraná e algumas considerações sobre sua biologia. Biota Neotropica 7, bn00707012007.
Registro de ocorrência de duas espécies de potamotrygonídeos na região do Alto Rio Paraná e algumas considerações sobre sua biologia.Crossref | GoogleScholarGoogle Scholar |

Garrone-Neto, D., Haddad, V. Jr, and Gadig, O. B. F. (2014). Record of ascending passage of potamotrygonid stingrays through navigation locks: implications for the management of non-native species in the Upper Paraná River basin, southeastern Brazil. Management of Biological Invasions 5, 113–119.
Record of ascending passage of potamotrygonid stingrays through navigation locks: implications for the management of non-native species in the Upper Paraná River basin, southeastern Brazil.Crossref | GoogleScholarGoogle Scholar |

Giraudo, A. R., and Moggia, L. (2008). Entre el agua y la tierra: anfibios, reptiles, aves y mamíferos de Jaaukanigás. In ‘Sitio Ramsar Jaaukanigás: Biodiversidad, Aspectos Socioculturales y Conservación’. (Ed. A. R. Giraudo.) pp. 57–68. (Asociación de Ciencias Naturales del Litoral – Comité Intersectorial de Manejo del Sitio Ramsar Jaaukanigás: Santa Fe.)

Gómez, S. E., Gonzalez Naya, M. J., and Ramírez, L. (2009). Río Iguazú Superior: química del agua y comentarios biológicos sobre algunos de sus peces. In ‘Parque Nacional Iguazú: Conservación y Desarrollo en la Selva Paranaense de Argentina’. (Eds B. Carpinetti, M. Garciarena and M. Almirón.) pp. 211–222. (Administración de Parques Nacionales: Buenos Aires.)

Helfman, G. S. (2007). ‘Fish Conservation: a Guide to Understanding and Restoring Global Aquatic Biodiversity and Fishery Resources.’ (Island Press: Washington, DC.)

Hijmans, R. J. (2014). raster: geographic data analysis and modeling. R package version 2.3-0. Available at http://CRAN.R-project.org/package=raster [Verified 17 July 2015].

Hijmans, R. J., Cameron, S. E., Parra, J. L., Jones, P. G., and Jarvis, A. (2005). Very high resolution interpolated climate surfaces for global land areas. International Journal of Climatology 25, 1965–1978.
Very high resolution interpolated climate surfaces for global land areas.Crossref | GoogleScholarGoogle Scholar |

Humphries, P., and Winemiller, K. O. (2009). Historical impacts on river fauna, shifting baselines, and challenges for restoration. Bioscience 59, 673–684.
Historical impacts on river fauna, shifting baselines, and challenges for restoration.Crossref | GoogleScholarGoogle Scholar |

Hutchings, J. A., Myers, R. A., García, V. B., Lucifora, L. O., and Kuparinen, A. (2012). Life-history correlates of extinction risk and recovery potential. Ecological Applications 22, 1061–1067.
Life-history correlates of extinction risk and recovery potential.Crossref | GoogleScholarGoogle Scholar | 22827118PubMed |

Jenkins, D. G., Brescacin, C. R., Duxbury, C. V., Elliott, J. A., Evans, J. A., Grablow, K. R., Hillegass, M., Lyon, B. N., Metzger, G. A., Olandese, M. L., Pepe, D., Silvers, G. A., Suresch, H. N., Thompson, T. N., Trexler, C. M., Williams, G. E., Williams, N. C., and Williams, S. E. (2007). Does size matter for dispersal distance? Global Ecology and Biogeography 16, 415–425.
Does size matter for dispersal distance?Crossref | GoogleScholarGoogle Scholar |

Júlio Júnior, H. F., Tós, C. D., Agostinho, A. A., and Pavanelli, C. S. (2009). A massive invasion of fish species after eliminating a natural barrier in the upper rio Paraná basin. Neotropical Ichthyology 7, 709–718.
A massive invasion of fish species after eliminating a natural barrier in the upper rio Paraná basin.Crossref | GoogleScholarGoogle Scholar |

Junk, W. J., Bayley, P. B., and Sparks, R. E. (1989). The flood pulse concept in river–floodplain systems. In ‘Proceedings of the International Large River Symposium (Honey Harbour, Ontario, Canada, September 14–21, 1986)’. (Ed. D. P. Dodge.) Canadian Special Publication of Fisheries and Aquatic Sciences 106, 110–127. Available at http://publications.gc.ca/site/eng/114039/publication.html [Verified 7 September 2015].

Junk, W. J., da Cunha, C. N., Wantzen, K. M., Petermann, P., Strüssmann, C., Marques, M. I., and Adis, J. (2006). Biodiversity and its conservation in the Pantanal of Mato Grosso, Brazil. Aquatic Sciences 68, 278–309.
Biodiversity and its conservation in the Pantanal of Mato Grosso, Brazil.Crossref | GoogleScholarGoogle Scholar |

Last, P. R., White, W. T., Caira, J. N., Dharmadi, Fahmi, Jensen, K., Lim, A. P. K., Manjaji-Matsumoto, B. M., Naylor, G. J. P., Pogonoski, J. J., Stevens, J. D., and Yearsley, G. K. (2010). ‘Sharks and Rays of Borneo.’ (CSIRO Publishing: Melbourne.)

Legault, A., Theuerkauf, J., Chartendrault, V., Rouys, S., Saoumoé, M., Verfaille, L., Desmoulins, F., Barré, N., and Gula, R. (2013). Using ecological niche models to infer the distribution and population size of parakeets in New Caledonia. Biological Conservation 167, 149–160.
Using ecological niche models to infer the distribution and population size of parakeets in New Caledonia.Crossref | GoogleScholarGoogle Scholar |

Lévêque, C., Oberdorff, T., Paugy, D., Stiassny, M. L. J., and Tedesco, P. A. (2008). Global diversity of fish (Pisces) in freshwater. Hydrobiologia 595, 545–567.
Global diversity of fish (Pisces) in freshwater.Crossref | GoogleScholarGoogle Scholar |

Liu, C., White, M., and Newell, G. (2013). Selecting thresholds for the prediction of species occurrence with presence-only data. Journal of Biogeography 40, 778–789.
Selecting thresholds for the prediction of species occurrence with presence-only data.Crossref | GoogleScholarGoogle Scholar |

Llompart, F., Paracampo, A., Solimano, P., and García, I. (2012). Peces de la Reserva Natural Punta Lara. In ‘Inventario de los Vertebrados de la Reserva Natural Punta Lara, Provincia de Buenos Aires, Argentina’. (Eds I. Roesler and M. G. Agostini.) pp. 57–70. (Aves Argentinas: Buenos Aires.)

Loboda, T. S., and de Carvalho, M. R. (2013). Systematic revision of the Potamotrygon motoro (Müller & Henle, 1841) species complex in the Paraná–Paraguay basin, with description of two new ocellated species (Chondrichthyes: Myliobatiformes: Potamotrygonidae). Neotropical Ichthyology 11, 693–737.
Systematic revision of the Potamotrygon motoro (Müller & Henle, 1841) species complex in the Paraná–Paraguay basin, with description of two new ocellated species (Chondrichthyes: Myliobatiformes: Potamotrygonidae).Crossref | GoogleScholarGoogle Scholar |

López, H. L., Menni, R. C., Donato, D., and Miquelarena, A. M. (2008). Biogeographical revision of Argentina (Andean and Neotropical Regions): an analysis using freshwater fishes. Journal of Biogeography 35, 1564–1579.
Biogeographical revision of Argentina (Andean and Neotropical Regions): an analysis using freshwater fishes.Crossref | GoogleScholarGoogle Scholar |

López, L., Paradeda, C., Ferrero, B., and Arach, O. (2009). Aspectos socioeconómicos. In ‘Uso Sostenible de Peces en la Cuenca del Plata. Evaluación Subregional del Estado de Amenaza, Argentina y Paraguay’. (Eds J. Capatto and A. Yanosky.) pp. 47–63. (IUCN: Gland, Switzerland.)

Loureiro, M., Zarucki, M., González, I., Vidal, N., and Fabiano, G. (2013). Peces continentales. In ‘Especies Prioritarias para la Conservación en Uruguay. Vertebrados, Moluscos Continentales y Plantas Vasculares’. (Eds A. Soutullo, C. Clavijo and J. A. Martínez-Lanfranco.) pp. 91–112. (Sistema Nacional de Áreas Protegidas: Montevideo.)

Martínez Achenbach, G., and Valentinis de Martínez Achenbach, S. (1976). Notas acerca de algunas especies de ‘raya fluvial’ (Batoidei, Potamotrygonidae), que frecuentan el sistema hidrográfico del río Paraná medio en el Departamento La Capital (Santa Fe – Argentina). Comunicaciones del Museo Provincial de Ciencias Naturales, Florentino Ameghino 8, 1–34.

Menni, R. C. (2004). Peces y ambientes en la Argentina continental. Monografías del Museo Argentino de Ciencias Naturales 5, 1–316.

Monasterio de Gonzo, G. (2003). ‘Peces de los Ríos Bermejo, Juramento y Cuencas Endorreicas de la Provincia de Salta.’ (Museo de Ciencias Naturales y Consejo de Investigación Universidad Nacional de Salta: Salta.)

Murguía, D., Daniele, C., Dabas, M., and Frassetto, A. (2006). Escenario ambiental de los ríos navegables de la Argentina: problemáticas actuales e iniciativas para su análisis y solución. In ‘La Situación Ambiental Argentina 2005’. (Eds A. Brown, U. Martinez Ortiz, M. Acerbi and J. Corcuera.) pp. 464–468. (Fundación Vida Silvestre Argentina: Buenos Aires.)

Nestler, J. M., Baigún, C. R. M., Oldani, N., and Weber, L. J. (2007). Contrasting the Middle Paraná and Mississippi rivers to develop a template for restoring large floodplain river ecosystems. International Journal of River Basin Management 5, 305–319.
Contrasting the Middle Paraná and Mississippi rivers to develop a template for restoring large floodplain river ecosystems.Crossref | GoogleScholarGoogle Scholar |

Oddone, M. C., Velasco, G., and Rincon, G. (2008). Occurrence of freshwater stingrays (Chondrichthyes: Potamotrygonidae) in the Uruguay River and its tributaries, Uruguay, South America. Aqua 14, 69–76.

Oddone, M. C., Velasco, G., and Charvet, P. (2012). Record of the freshwater stingrays Potamotrygon brachyura and P. motoro (Chondrichthyes, Potamotrygonidae) in the lower Uruguay River, South America. Acta Amazonica 42, 299–304.
Record of the freshwater stingrays Potamotrygon brachyura and P. motoro (Chondrichthyes, Potamotrygonidae) in the lower Uruguay River, South America.Crossref | GoogleScholarGoogle Scholar |

Paira, A. R., and Drago, E. C. (2007). Origin, evolution, and types of floodplain waterbodies. In ‘The Middle Paraná River: Limnology of a Subtropical Wetland’. (Eds M. H. Iriondo, J. C. Paggi and M. J. Parma.) pp. 53–81. (Springer: Berlin.)

Pautasso, A. A., and Virasoro, C. A. (2011). Observaciones sobre la ictiofauna del AVP La Salamandra y zonas aledañas. In ‘La Fauna y su Conservación en los Bajos Submeridionales’. (Ed. A. A. Pautasso.) pp. 49–55. (Ediciones Biológica: Santa Fe.)

Peteán, J. (2009). Aspectos biológicos. In ‘Uso Sostenible de Peces en la Cuenca del Plata. Evaluación Subregional del Estado de Amenaza, Argentina y Paraguay’. (Eds J. Capatto and A. Yanosky.) pp. 15–46. (IUCN: Gland, Switzerland.)

Peteán, J., and Cappato, J. (2006). Equidad y sustentabilidad mediante el manejo de los humedales: la iniciativa del corredor fluvial. In ‘La Situación Ambiental Argentina 2005’. (Eds A. Brown, U. Martinez Ortiz, M. Acerbi and J. Corcuera.) pp. 147–152. (Fundación Vida Silvestre Argentina: Buenos Aires.)

Quirós, R. (2004). The Plata river basin: international basin development and riverine fisheries. In ‘Proceedings of the Second International Symposium on the Management of Large Rivers for Fisheries. Volume I’. (Eds R. L. Welcomme and T. Petr.) pp. 253–271. (FAO Regional Office for Asia and the Pacific: Bangkok.)

Quirós, R., Bechara, J. A., and de Resende, E. K. (2007). Fish diversity and ecology, habitats and fisheries for the un-dammed riverine axis Paraguay–Paraná–Río de la Plata (southern South America). Aquatic Ecosystem Health & Management 10, 187–200.
Fish diversity and ecology, habitats and fisheries for the un-dammed riverine axis Paraguay–Paraná–Río de la Plata (southern South America).Crossref | GoogleScholarGoogle Scholar |

R Core Team (2014). ‘R: a Language and Environment for Statistical Computing.’ (R Foundation for Statistical Computing: Vienna.)

Rincon, G. (2004). Potamotrygon henlei (bigtooth river stingray). In ‘IUCN Red List of Threatened Species. Version 2013.1’. (International Union for Conservation of Nature and Natural Resources.) Available at http://www.iucnredlist.org/details/39402/0 [Verified 10 July 2013].

Rodrigues Capítulo, A., Cortelezzi, A., Paggi, A. C., and Tangorra, M. (2002). Fitoplancton y bentos de la campaña de prospección ambiental del Río de la Plata. Informe 1 y 2. Parte B: Bentos. Technical Report PNUD Project GEF RLA/99/G31. (FREPLATA: Montevideo and Buenos Aires).

Rosa, R. S. (1985). A systematic revision of the South American freshwater stingrays (Chondrichthyes: Potamotrygonidae). Ph.D. Thesis, College of William and Mary in Virginia, USA.

Rosa, R. S., Charvet-Almeida, P., and Quijada, C. C. D. (2010). Biology of the South American potamotrygonid stingrays. In ‘Sharks and their Relatives. II: Biodiversity, Adaptive Physiology and Conservation’. (Eds J. C. Carrier, J. A. Musick and M. R. Heithaus.) pp. 241–281. (CRC Press: Boca Raton, FL.)

Royle, J. A., Chandler, R. B., Yackulic, C., and Nichols, J. D. (2012). Likelihood analysis of species occurrence probability from presence-only data for modelling species distributions. Methods in Ecology and Evolution 3, 545–554.
Likelihood analysis of species occurrence probability from presence-only data for modelling species distributions.Crossref | GoogleScholarGoogle Scholar |

Sánchez-Mercado, A., Ferrer-Paris, J. R., García-Rangel, S., Yerena, E., Robertson, B. A., and Rodríguez-Clark, K. M. (2014). Combining threat and occurrence models to predict potential ecological traps for Andean bears in the Cordillera de Mérida, Venezuela. Animal Conservation 17, 388–398.
Combining threat and occurrence models to predict potential ecological traps for Andean bears in the Cordillera de Mérida, Venezuela.Crossref | GoogleScholarGoogle Scholar |

Sarre, S. D., MacDonald, A. J., Barclay, C., Saunders, G. R., and Ramsey, D. S. L. (2013). Foxes are now widespread in Tasmania: DNA detection defines the distribution of this rare but invasive carnivore. Journal of Applied Ecology 50, 459–468.
Foxes are now widespread in Tasmania: DNA detection defines the distribution of this rare but invasive carnivore.Crossref | GoogleScholarGoogle Scholar |

Sbrocco, E. J., and Barber, P. H. (2013). MARSPEC: ocean climate layers for marine spatial ecology. Ecology 94, 979.
MARSPEC: ocean climate layers for marine spatial ecology.Crossref | GoogleScholarGoogle Scholar |

Scarabotti, P. A., López, J. A., and Pouilly, M. (2011). Flood pulse and the dynamics of fish assemblage structure from neotropical floodplain lakes. Ecology of Freshwater Fish 20, 605–618.
Flood pulse and the dynamics of fish assemblage structure from neotropical floodplain lakes.Crossref | GoogleScholarGoogle Scholar |

Schaefer, S. A., and Arroyave, J. (2010). Rivers as islands: determinants of the distribution of Andean astroblepid catfishes. Journal of Fish Biology 77, 2373–2390.
Rivers as islands: determinants of the distribution of Andean astroblepid catfishes.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3M%2FksVajtA%3D%3D&md5=a99710e1c617d8d6184c878e31cb05a6CAS | 21155789PubMed |

Serra, S., Bessonart, J., Teixeira de Mello, F., Duarte, A., Malabarba, L., and Loureiro, M. (2014). ‘Peces del Río Negro.’ (Dirección Nacional de Recursos Acuáticos: Montevideo.)

Shibuya, A., Araújo, M. L. G., and Zuanon, J. A. S. (2009). Analysis of stomach contents of freshwater stingrays (Elasmobranchii, Potamotrygonidae) from the middle Negro River, Amazonas, Brazil. Pan-American Journal of Aquatic Sciences 4, 466–475.

Speranza, E. D., Cappelletti, N., Migoya, M. C., Tatone, L. M., and Colombo, J. C. (2012). Migratory behaviour of a dominant detritivorous fish Prochilodus lineatus evaluated by multivariate biochemical and pollutant data. Journal of Fish Biology 81, 848–865.
Migratory behaviour of a dominant detritivorous fish Prochilodus lineatus evaluated by multivariate biochemical and pollutant data.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38bmsFenuw%3D%3D&md5=5bdeec05c9787f13b9360894ea04f2bcCAS | 22803738PubMed |

Tuanmu, M.-N., and Jetz, W. (2014). A global 1-km consensus land-cover product for biodiversity and ecosystem modelling. Global Ecology and Biogeography 23, 1031–1045.
A global 1-km consensus land-cover product for biodiversity and ecosystem modelling.Crossref | GoogleScholarGoogle Scholar |

Venables, W. N., and Ripley, B. D. (2002). ‘Modern Applied Statistics with S’, 4th edn. (Springer: New York.)

Vitule, J. R. S., Skóra, F., and Abilhoa, V. (2012). Homogenization of freshwater fish faunas after the elimination of a natural barrier in the Neotropics. Diversity & Distributions 18, 111–120.
Homogenization of freshwater fish faunas after the elimination of a natural barrier in the Neotropics.Crossref | GoogleScholarGoogle Scholar |

Vörösmarty, C. J., McIntyre, P. B., Gessner, M. O., Dudgeon, D., Prusevich, A., Green, P., Glidden, S., Bunn, S. E., Sullivan, C. A., Liermann, C. R., and Davies, P. M. (2010). Global threats to human water security and river biodiversity. Nature 467, 555–561.
Global threats to human water security and river biodiversity.Crossref | GoogleScholarGoogle Scholar | 20882010PubMed |

Waller, T., Parera, A., Giraudo, A., Aprile, G., Bortoluzzi, A., Uhart, M., Solís, G., and Méndez, M. (2004). ‘Fauna del Iberá: Composición, Estado de Conservación y Propuestas de Manejo.’ (Fundación Biodiversidad Argentina: Corrientes.)

Wildlife Conservation Society and Center for International Earth Science Information Network, Columbia University (2005). Last of the Wild Project, Version 2, 2005 (LWP-2): Global Human Influence Index (HII) Dataset (IGHP). (NASA Socioeconomic Data and Applications Center (SEDAC): Palisades, NY.) Available at http://dx.doi.org/10.7927/H46W980H [Verified 31 March 2014].

Wood, S. N. (2006). ‘Generalized Additive Models: an Introduction with R.’ (Chapman & Hall/CRC: Boca Raton, FL.)