, Volume 28, Issue 4, pp 938–950 | Cite as

Environmental processes, water quality degradation, and decline of waterbird populations in the Rio Cruces wetland, Chile

  • Nelson A. Lagos
  • Pedro Paolini
  • Eduardo Jaramillo
  • Charlotte Lovengreen
  • Cristian Duarte
  • Heraldo Contreras


Changes in wetland ecosystems may result from the interactions of endogenous processes with exogenous factors such as environmental fluctuations and anthropogenic influences. Since mid-2004, the Río Cruces wetland, a Ramsar site located in southern Chile (40°S), exhibited a sudden increase in mortality and emigration of the largest breeding population of Black-necked swans in the Neotropics, a massive demise of the dominant macrophyte Egeria densa (the main food of swans and several aquatic birds), and a seasonal appearance of turbid waters. We compared annual variation in rainfall, river flow, and radiation over the period 2000–2005 to assess the role of environmental factors on these wetland changes. Those factors, with the exception of a decrease in river flow during 2004, did not show significant inter-annual differences. However, when comparing Landsat images, we found in the visible and near-infrared spectrum, a corresponding increase and decrease in water reflectance for 2005 with respect to 2003 and 2001, respectively. These results may reflect the appearance of turbid waters and the decrease in cover of E. densa. All temporal changes were restricted to the northern and central zones of the wetland. In addition, spatial analysis showed a gradient in turbidity across the wetland waters, which was enhanced by estuarine influence during spring-tides. Censuses of aquatic birds (1999–2005) showed that only herbivorous birds exhibited a pronounced decrease in population abundance after mid-2004, while piscivorous birds continued normal cycling, with even some positive trends in abundance during 2004–2005. Population declines in herbivorous birds may be related to the demise of E. densa and suspension of sediments during periods of reduced river flow (2004) that gave rise to the turbidity in the wetland waters. Environmental changes could be related to changes in water quality after a new pulp mill, built upstream of the wetland, initiated operations during February 2004.

Key Words

aquatic birds Landsat image macrophytes Ramsar site 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Literature Cited

  1. Ahn, Y. H., P. Shanmugam, and J. Hyung-Ryu. 2004. Atmospheric correction of the Landsat satellite imagery for turbid waters. Gayana 68: 1–8.Google Scholar
  2. Antoine, D. and A. Morel. 1999. A multiple scattering algorithm for atmospheric correction of remotely sensed ocean color (MERIS instrument): principle and implementation for atmospheres carrying various aerosols including absorbing ones. International Journal of Remote Sensing 20: 1875–1916.CrossRefGoogle Scholar
  3. Chander, G. and B. Markham. 2003. Revised Landsat-5 TM radiometric calibration procedures and postcalibration dynamic ranges. IEEE Transactions on Geoscience and Remote Sensing 41: 2674–77.CrossRefGoogle Scholar
  4. Childers, D., J. Boyer, S. Davis, C. Madden, D. Rudnick, and F. Sklar. 2006. Relating precipitation and water management to nutrient concentration patterns in the oligotrophic “upside down” estuaries of the Florida Everglades. Limnology and Oceanography 51: 602–16.CrossRefGoogle Scholar
  5. Cisternas, M., B. Atwater, F. Torrejón, Y. Sawai, G. Machuca, M. Lagos, A. Eipert, C. Youlton, I. Salgado, T. Kamataky, M. Shishikura, C. Rajendran, J. Malik, Y. Rizal, and M. Husni. 2005. Predecessors of the giant 1960 Chile earthquake. Nature 437: 404–07.CrossRefPubMedGoogle Scholar
  6. Corti, P. and R. P. Schlatter. 2002. Feeding ecology of the blacknecked swan Cygnus melancoryphus in two wetlands of southern Chile. Studies on Neotropical Fauna and Environment 37: 9–14.CrossRefGoogle Scholar
  7. Curran, P. J. and E. Novo. 1988. The relationship between suspended sediment concentration and remotely sensed spectral radiance: a review. Journal of Coastal Research 4: 351–68.Google Scholar
  8. Engelhardt, K. and M. Ritchie. 2001. Effects of macrophyte species richness on wetland ecosystem functioning and services. Nature 411: 687–89.CrossRefPubMedGoogle Scholar
  9. Euliss, N., J. LaBaugh, L. Fredrickson, D. Mushet, M. Laubhan, G. Swanson, T. Winter, D. Rosenberry, and R. Nelson. 2004. The wetland continuum: a conceptual framework for interpreting biological studies. Wetlands 24: 448–58.CrossRefGoogle Scholar
  10. Gaudet, C. L. and P. A. Keddy. 1995. Competitive performance and species distribution in shoreline plant communities: a comparative approach. Ecology 76: 280–91.CrossRefGoogle Scholar
  11. Han, L. 1997. Spectral reflectance with varying suspended sediment concentrations in clear and algal-laden waters. Photogrammetric Engineering and Remote Sensing 63: 701–05.Google Scholar
  12. Huovinen, P., I. Gómez, and C. Lovengreen. 2006. A five-year study of solar ultraviolet radiation in southern Chile (39°S): potential impact on physiology of coastal marine algae? Photochemistry and Photobiology 82: 515–22.CrossRefPubMedGoogle Scholar
  13. Jaksic, F. 2004. El Niño effects on avian ecology: lesson learned from the southeastern Pacific. Ornitologia Neotropical 15: 61–72.Google Scholar
  14. Jaramillo, E., R. Schlatter, H. Contreras, C. Duarte, N. Lagos, E. Paredes, J. Ulloa, G. Valenzuela, B. Peruzzo, and R. Silva. 2007. Emigration and mortality of black-necked swans (Cygnus melancoryphus) and disappearance of the macrophyte Egeria densa in a Ramsar wetland site of southern Chile. Ambio 36: 607–10.CrossRefPubMedGoogle Scholar
  15. Keddy, P. and L. H. Fraser. 2000. Four general principles for the management and conservation of wetlands in large lakes: the role of water levels, nutrients, competitive hierarchies and centrifugal organization. Lakes and Reservoirs: Research and Management 5: 177–85.CrossRefGoogle Scholar
  16. Lagos, N. A., B. Broitman, and J. C. Castilla. 2008. Environmental spatial correlates of intertidal recruitment: a test using barnacles in northern Chile. Ecological Monographs 78: 245–61.CrossRefGoogle Scholar
  17. Lagos, N. A., S. Navarrete, F. Veliz, A. Masuero, and J. C. Castilla. 2005. Meso-scale spatial variation in settlement and recruitment of intertidal barnacles along the coast of central Chile. Marine Ecology Progress Series 290: 165–78.CrossRefGoogle Scholar
  18. Leonard, L. and M. Luther. 1995. Flow hydrodynamics in tidal marsh canopies. Limnology and Oceanography 40: 1474–84.CrossRefGoogle Scholar
  19. Mitsch, W. and J. Gosselink. 2000. Wetlands, third edition. John Wiley & Sons, Inc., New York, NY, USA.Google Scholar
  20. Mulsow, S. and M. Grandjean. 2006. Incompatibility of sulphate compounds and soluble bicarbonate salts in the Río Cruces waters: an answer to the disappearance of Egeria densa and black-necked swans in a Ramsar sanctuary. Ethics in Science and Environmental Politics 2006: 5–11.Google Scholar
  21. Munday, J. and P. Zudkoff. 1981. Remote sensing of dinoflagellates bloom in a turbid estuary. Photogrammetry Enginnering and Remote Sensing 47: 523–31.Google Scholar
  22. Oldham, C. E. and J. Sturman. 2001. The effect of emergent vegetation on convective flushing in shallow wetlands: experiments and scaling. Limnology and Oceanography 46: 1486–93.Google Scholar
  23. Palma, A. T., M. G. Silva, C. Muñoz, C. Cartes, and F. Jaksic. 2008. Effect of prolonged exposition to mill pulp effluent on the invasive aquatic plant Egeria densa and other primary producers: a mesocosm approach. Environmental Toxicology and Chemistry 27: 387–96.CrossRefPubMedGoogle Scholar
  24. Parslow, J. S. and G. Harris. 1990. Remote sensing of marine photosynthesis. p. 269–90. In R. J. Hobbs and H. A. Mooney (eds.) Remote Sensing of Biosphere Functioning. Springer-Verlag, New York, NY, USA.Google Scholar
  25. Pezzato, M. and A. Camargo. 2004. Photosynthetic rate of the aquatic macrophyte Egeria densa Planch (Hydrocharitaceae) in two rivers from the Itanhaém River Basin in São Paulo State. Brazilian Archive of Biology and Techology 47: 153–62.Google Scholar
  26. Ramírez, C., C. San Martín, R. Medina, and D. Contreras. 1991. Estudio de la flora hidrófila del Santuario de la Naturaleza “Río Cruces”. Gayana Botánica 48: 67–80.Google Scholar
  27. Rose, C. and W. Crumpton. 1996. Effects of emergent macrophytes on dissolved oxygen dynamics in a prairie pothole wetland. Wetlands 16: 495–502.Google Scholar
  28. Schlatter, R., R. Navarro, and P. Corti. 2002. Effects of El Niño Southern Oscillation on numbers of Black-necked swans at Río Cruces Sanctuary, Chile. Waterbirds 25: 114–22.Google Scholar
  29. Schlatter, R., J. Salazar, A. Villa, and J. Meza. 1991. Reproductive biology of Black-necked swans Cygnus melancoryphus in three Chilean wetland areas. In J. Sears and J. Baco (eds.). Proceedings of the Third IWRB International Swan Symposium. Wildfowl Supplement 1:268–71.Google Scholar
  30. Soto-Gamboa, M., N. A. Lagos, E. Quiroz, E. Jaramillo, R. Nespolo, and A. Casanova-Katny. 2007. Causes of the disappearance of the aquatic plant Egeria densa and blacknecked swans in a Ramsar sanctuary: comment on Mulsow and Grandjean (2006). Ethics in Science and Environmental Politics 2007: 7–10.Google Scholar
  31. Strickland, J. D. H. and T. R. Parsons. 1972. A Practical Handbook of Seawater Analysis. Bulletin No. 167, second edition, Fisheries Research Board of Canada, Ottawa, Canada.Google Scholar
  32. Teillet, P. M., G. Fedosejevs, K. J. Thome, and J. L. Barker. 2007. Impacts of spectral band difference effects on radiometric cross-calibration between satellite sensors in the solar-reflective spectral domain. Remote Sensing of Environment 110: 393–409.CrossRefGoogle Scholar
  33. UACH. 2005. Estudio sobre origen de mortalidades y disminución de aves acuáticas en el Santuario de la Naturaleza Carlos Anwandter, en la provincia de Valdivia, Chile. Final Report available at: http://www.sinia.cl/1292/article-31832.html.Google Scholar
  34. van Bodegom, P., C. Bakker, and H. D. van der Gon. 2004. Identifying key issues in environmental wetland research using scaling and uncertainty analysis. Regional Environmental Change 4: 100–06.CrossRefGoogle Scholar
  35. Wartenberg, D. 1989. SAAP 4.3: Spatial Autocorrelation Analyses Program. Exter Software, New York, NY, USA.Google Scholar
  36. Weiher, E., I. Wisheu, P. Keddy, and D. Moore. 1996. Establishment, persistence, and management implications of experimental wetland plant communities. Wetlands 16: 208–18.CrossRefGoogle Scholar
  37. Wilson, S. D. and P. Keddy. 1986. Species competitive ability and position along a natural stress/disturbance gradient. Ecology 67: 1236–42.CrossRefGoogle Scholar
  38. Woelfl, S., M. Mages, F. Encina, and F. Bravo. 2006. Trace metals in microcrustaceans and brazilian waterweed from a contaminated Chilean wetland using total reflection X-ray fluorescence spectrometry. Microchimica Acta 154: 261–68.CrossRefGoogle Scholar

Copyright information

© Society of Wetland Scientists 2008

Authors and Affiliations

  • Nelson A. Lagos
    • 1
  • Pedro Paolini
    • 2
  • Eduardo Jaramillo
    • 3
  • Charlotte Lovengreen
    • 4
  • Cristian Duarte
    • 3
  • Heraldo Contreras
    • 3
  1. 1.Centro de Investigación en Ciencias Ambientales (CIENCIA-UST)Universidad Santo TomásSantiagoChile
  2. 2.Centro de Estudios EspacialesUniversidad de ChileSantiagoChile
  3. 3.Instituto de Zoología Facultad de CienciasUniversidad Austral de ChileValdiviaChile
  4. 4.Instituto de Física Facultad de CienciasUniversidad Austral de ChileValdiviaChile

Personalised recommendations