, Volume 790, Issue 1, pp 141–155 | Cite as

Coastal saltpans as foraging grounds for migrating shorebirds: an experimentally drained fish pond in Portugal

  • Afonso R. Rocha
  • Jaime A. Ramos
  • Tânia Paredes
  • José A. Masero
Primary Research Paper


Worldwide, low-salinity ponds of coastal saltpans are often drained for artisanal fishing, at which time shorebirds feed opportunistically on the drained ponds. This case study sought to examine how shorebirds exploit this food supply after experimentally draining a large pond (9.1 ha) used for artisanal fishing at the Tagus estuary, Portugal. Shorebirds rapidly increased after draining (reaching 156 birds ha−1), and the pond provided a suitable foraging ground for a high density of shorebirds during 6–12 days after the study site was drained, supporting up to 6% of the total population using the estuary. The benthic invertebrate community was dominated by polychaete worms, and their high density (2215.0 ± 329.9 ind m−2) apparently explained the relatively large percentage of feeding birds in the pond. Most shorebirds fed on polychaete worms at high intake rates throughout the experiment, probably because they increased their searching effort. Bird predation contributed to the food supply decrease during the first 3–6 days, and desiccation was presumably the major factor in 8–15 days. The drainage of low-salinity ponds by artisanal fishing is a traditional activity in coastal saltpans that might play a significant role in providing suitable foraging grounds for migrating shorebirds.


Artisanal fishing Benthic invertebrates Foraging behaviour Saltpans Shorebirds 



We are grateful to Daniela Fonseca for the help during bird surveys and sediment sampling, the volunteers of roost counts for the unpublished shorebird data, Naomi Treble and Jessica Hey for correcting the English, and two anonymous reviewers for valuable reviews. We thank the Salinas do Samouco Foundation for allowing us to work on Samouco complex and to the facilities. A. Rocha acknowledges the support given by ‘Fundação para a Ciência e Tecnologia’ (Portugal, SFRH/BD/74228/2010). This study benefited from the strategic programme of MARE—financed by FCT (MARE—UID/MAR/04292/2013).

Supplementary material

10750_2016_3025_MOESM1_ESM.docx (59 kb)
Supplementary material 1 (DOCX 59 kb)


  1. Alcorn, M. & R. Alcorn, 2000. Seasonal migration of banded stilt Cladorhynchus leucocephalus to the natimuk-douglas salt pans in Western Victoria, Australia. The Stilt 36: 7–10.Google Scholar
  2. Alves, J. A., W. J. Sutherland & J. A. Gill, 2012. Will improving wastewater treatment impact shorebirds? Effects of sewage discharges on estuarine invertebrates and birds. Animal Conservation 15: 44–52.CrossRefGoogle Scholar
  3. Amaral, M. J. & M. H. Costa, 1999. Macrobenthic communities of saltpans from the Sado estuary (Portugal). Acta Oecologica 20: 327–332.CrossRefGoogle Scholar
  4. Arias, A. M. & P. Drake, 1994. Structure and production of the benthic macroinvertebrate community in a shallow lagoon in the Bay of Cadiz. Marine Ecology Progress Series 115: 151–168.CrossRefGoogle Scholar
  5. Britton, R. H. & A. R. Johnson, 1987. An ecological account of a Mediterranean salina: the Salin de Giraud, Camargue (S. France). Biological Conservation 42: 185–230.CrossRefGoogle Scholar
  6. Catry, T., J. A. Alves, J. Andrade, H. Costa, M. P. Dias, P. Fernandes, A. I. Leal, P. M. Lourenço, R. C. Martins, F. Moniz, S. Pardal, A. Rocha, C. D. Santos, V. Encarnação & J. P. Granadeiro, 2011. Long-term declines of wader populations at the Tagus estuary, Portugal: a response to global or local factors? Bird Conservation International 21: 438–453.CrossRefGoogle Scholar
  7. Cordova, L. R. M. & L. F. E. Ocaña, 2007. Study of benthic fauna in the discharge lagoon of a shrimp farm with special emphasis on the polychaetes. Online Journal of Biological Sciences 7: 12–17.CrossRefGoogle Scholar
  8. Davis, J., 2000. Structure, function, and management of the biological system for seasonal solar saltworks. Global Nest 2: 217–226.Google Scholar
  9. De Medeiros Rocha, R., D. F. S. Costa, M. A. Lucena-Filho, R. M. Bezerra, D. H. Medeiros, A. M. Azevedo-Silva, C. N. Araújo & L. Xavier-Filho, 2012. Brazilian solar saltworks – ancient uses and future possibilities. Aquatic Biosystems 8: 8.CrossRefPubMedPubMedCentralGoogle Scholar
  10. Delany, S., D. Scott, T. Dodman & D. Stroud, 2009. An Atlas of Wader Populations in Africa and Western Eurasia. Wetlands International, Wageningen.Google Scholar
  11. Dias, M. P., J. P. Granadeiro, M. Lecoq, C. D. Santos & J. M. Palmeirim, 2006. Distance to high-tide roosts constrains the use of foraging areas by dunlins: Implications for the management of estuarine wetlands. Biological Conservation 131: 446–452.CrossRefGoogle Scholar
  12. Dias, M. P., J. P. Granadeiro & J. M. Palmeirim, 2009. Searching behaviour of foraging waders: does feeding success influence their walking? Animal Behaviour 77: 1203–1209.CrossRefGoogle Scholar
  13. Dias, M. P., M. Lecoq, F. Moniz & J. E. Rabaça, 2014. Can human-made saltpans represent an alternative habitat for shorebirds? Implications for a predictable loss of estuarine sediment flats. Environmental Management 53: 163–171.CrossRefPubMedGoogle Scholar
  14. Drent, R., C. Both, M. Green, J. Madsen & T. Piersma, 2003. Pay-offs and penalties of competing migratory schedules. Oikos 103: 274–292.CrossRefGoogle Scholar
  15. Durell, S. E. A. L. V. D., J. D. Goss-Custard & R. T. C. McGrorty, 2008. Density-dependent mortality in oystercatchers Haematopus ostralegus. Ibis 142: 132–138.CrossRefGoogle Scholar
  16. Dwyer, R. G., S. Bearhop, H. A. Campbell & D. M. Bryant, 2013. Shedding light on light: benefits of anthropogenic illumination to a nocturnally foraging shorebird. Journal of Animal Ecology 82: 478–485.CrossRefPubMedGoogle Scholar
  17. Ens, B. J. & J. D. Goss-Custard, 1984. Interference among oystercatchers, Haematopus ostralegus, feeding on mussels, Mytilus edulis, on the exe estuary. Journal of Animal Ecology 53: 217–231.CrossRefGoogle Scholar
  18. França, S., C. Vinagre, M. A. Pardal & H. N. Cabral, 2009. Spatial and temporal patterns of benthic invertebrates in the Tagus estuary, Portugal: comparison between subtidal and an intertidal mudflat. Scientia Marina 73: 307–318.CrossRefGoogle Scholar
  19. Gill, J. A., K. Norris & W. J. Sutherland, 2001. Why behavioural responses may not reflect the population consequences of human disturbance. Biological Conservation 97: 265–268.CrossRefGoogle Scholar
  20. Goss-Custard, J. D., 1977. Optimal foraging and the size selection of worms by redshank, Tringa totanus, in the field. Animal Behaviour 25: 10–29.CrossRefGoogle Scholar
  21. Goss-Custard, J. D., R. W. G. Caldow, R. T. Clarke & A. D. West, 1995. Deriving population parameters from individual variations in foraging behavior. II. Model tests and population parameters. Journal of Animal Ecology 64: 277–289.CrossRefGoogle Scholar
  22. Granadeiro, J. P., M. P. Dias, R. C. Martins & J. M. Palmeirim, 2006. Variation in numbers and behaviour of waders during the tidal cycle: implications for the use of estuarine sediment flats. Acta Oecologica 29: 293–300.CrossRefGoogle Scholar
  23. Green, J. M. H., S. Sripanomyom, X. Giam & D. S. Wilcove, 2015. The ecology and economics of shorebird conservation in a tropical human-modified landscape. Journal of Applied Ecology 52: 1483–1491.CrossRefGoogle Scholar
  24. Hoegh-Guldberg, O. & J. F. Bruno, 2010. The impact of climate change on the world’s marine ecosystems. Science 328: 1523–1528.CrossRefPubMedGoogle Scholar
  25. Hua, N., K. Tan, Y. Chen & Z. Ma, 2015. Key research issues concerning the conservation of migratory shorebirds in the Yellow Sea region. Bird Conservation International 25: 38–52.CrossRefGoogle Scholar
  26. Hurlbert, S., 1984. Pseudoreplication and the design of ecological field experiments. Ecological Monographs 54: 187–211.CrossRefGoogle Scholar
  27. International Wader Study Group, 2003. Waders are declining worldwide. Conclusions from the 2003 International Wader Study Group Conference, Cádiz, Spain. Wader Study Group Bulletin 101/102: 8–12.Google Scholar
  28. Iwamura, T., R. A. Fuller & H. P. Possingham, 2014. Optimal management of a multispecies shorebird flyway under sea-level rise. Conservation Biology 28: 1710–1720.CrossRefPubMedGoogle Scholar
  29. Kloskowski, J., A. J. Green, M. Polak, J. Bustamante & J. Krogulec, 2009. Complementary use of natural and artificial wetlands by waterbirds wintering in Doñana, south-west Spain. Aquatic Conservation: Marine and Freshwater Ecosystems 19: 815–826.CrossRefGoogle Scholar
  30. Kuwae, T., E. Miyoshi, S. Sassa & Y. Watabe, 2010. Foraging mode shift in varying environmental conditions by dunlin Calidris alpina. Marine Ecology Progress Series 406: 281–289.CrossRefGoogle Scholar
  31. Luís, A., J. D. Goss-Custard & M. H. Moreira, 2002. The feeding strategy of the dunlin (Calidris alpina L.) in artificial and non-artificial habitats at Ria de Aveiro, Portugal. Hydrobiologia 475–476: 335–343.CrossRefGoogle Scholar
  32. Martins, R. C., T. Catry, C. D. Santos, J. M. Palmeirim & J. P. Granadeiro, 2013. Seasonal variations in the diet and foraging behaviour of dunlins Calidris alpina in a south European estuary: improved feeding conditions for northward migrants. PLoS ONE 8: e81174.CrossRefPubMedPubMedCentralGoogle Scholar
  33. Masero, J. A., 2003. Assessing alternative anthropogenic habitats for conserving waterbirds: salinas as buffer areas against the impact of natural habitat loss for shorebirds. Biodiversity and Conservation 12: 1157–1173.CrossRefGoogle Scholar
  34. Masero, J. A. & A. Pérez-Hurtado, 2001. Importance of the supratidal habitats for maintaining overwintering shorebird populations: how Redshanks use tidal mudflats and adjacent saltworks in Southern Europe. The Condor 103: 21–30.CrossRefGoogle Scholar
  35. Masero, J. A., M. Pérez-González, M. Basadre & M. Otero-Saavedra, 1999. Food supply for waders (Aves: Charadrii) in an estuarine area in the Bay of Cádiz (SW Iberian Peninsula). Acta Oecologica 20: 429–434.CrossRefGoogle Scholar
  36. Masero, J. A., A. Pérez-Hurtado, M. Castro & G. M. Arroyo, 2000. Complementary use of intertidal mudflats and adjacent salinas by foraging waders. Ardeola 88: 177–191.Google Scholar
  37. Masero, J. A., S. M. Estrella & J. M. Sánchez-Guzmán, 2007. Behavioural plasticity in foraging mode of typical plovers. Ardea 95: 259–265.CrossRefGoogle Scholar
  38. Méndez, N., J. Romero & J. Flos, 1997. Population dynamics and production of the polychaete Capitella capitata in the littoral zone of Barcelona (Spain, NW Mediterranean). Journal of Experimental Marine Biology and Ecology 218: 263–284.CrossRefGoogle Scholar
  39. Moreira, F., 1994. Diet, prey-size selection and intake rates of black-tailed godwits Limosa limosa feeding on mudflats. Ibis 136: 349–355.CrossRefGoogle Scholar
  40. Moreira, F., 1996. Diet and feeding behaviour of grey plovers Pluvialis squatarola and Redshanks Tringa totanus in a Southern European Estuary. Ardeola 43: 145–156.Google Scholar
  41. Myers, J. P., S. L. Williams & F. A. Pitelka, 1980. An experimental analysis of prey availability for sanderlings (Aves: Scolopacidae) feeding on sandy beach crustaceans. Canadian Journal of Zoology 58: 1564–1574.CrossRefGoogle Scholar
  42. Navedo, J. G., J. A. Masero, O. Overdijk, G. Orizaola & J. M. Sánchez-Guzmán, 2010. Assessing the role of multiple environmental factors on eurasian spoonbill departure decisions from stopover sites. Ardea 98: 3–12.CrossRefGoogle Scholar
  43. Navedo, J. G., G. Fernández, J. Fonseca & M. C. Drever, 2015. A potential role of shrimp farms for the conservation of nearctic shorebird populations. Estuaries and Coasts 38: 836–845.CrossRefGoogle Scholar
  44. Nebel, S., D. L. Jackson & R. W. Elner, 2005. Functional association of bill morphology and foraging behaviour in calidrid sandpipers. Animal Biology 55: 235–243.CrossRefGoogle Scholar
  45. Ntiamoa-Baidu, Y., T. Piersma, P. Wiersma, M. Poot, P. Battley & C. Gordon, 2008. Water depth selection, daily feeding routines and diets of waterbirds in coastal lagoons in Ghana. Ibis 140: 89–103.CrossRefGoogle Scholar
  46. Pedro, P. & J. A. Ramos, 2009. Diet and prey selection of shorebirds on salt pans in the Mondego estuary, western Portugal. Ardeola 56: 1–11.Google Scholar
  47. Pienkowski, M. W., 1982. Diet and energy-intake of grey and ringed plovers, Pluvialis squatarola and Charadrius hiaticula, in the non-breeding season. Journal of Zoology 197: 511–549.CrossRefGoogle Scholar
  48. Rodríguez-Pérez, H. & A. J. Green, 2012. Strong seasonal effects of waterbirds on benthic communities in shallow lakes. Freshwater Science 31: 1273–1288.CrossRefGoogle Scholar
  49. Rosa, S., A. L. Encarnação, J. P. Granadeiro & J. M. Palmeirim, 2006. High water roost selection by waders: maximizing feeding opportunities or avoiding predation? Ibis 148: 88–97.CrossRefGoogle Scholar
  50. Sadoul, N., J. Walmsley & B. Charpentier, 1998. Salinas and Nature Conservation. Conservation of Mediterranean Wetlands. Station Biologique de la Tour du Valat, Arles.Google Scholar
  51. Sánchez, M. I., A. J. Green & E. M. Castellanos, 2006. Temporal and spatial variation of an aquatic invertebrate community subjected to avian predation at the Odiel salt pans (SW Spain). Archiv für Hydrobiologie 166: 199–223.CrossRefGoogle Scholar
  52. Sassa, S. & Y. Watabe, 2007. Role of suction dynamics in evolution of intertidal sandy flats: field evidence, experiments, and theoretical model. Journal of Geophysical Research 112: 1–15.CrossRefGoogle Scholar
  53. Sassa, S., Y. Watabe, S. Yang & T. Kuwae, 2011. Burrowing criteria and burrowing mode adjustment in bivalves to varying geoenvironmental conditions in intertidal flats and beaches. PLoS ONE 6: 1–11.CrossRefGoogle Scholar
  54. Silva, G., J. L. Costa, P. R. Almeida & M. J. Costa, 2006. Structure and dynamics of a benthic invertebrate community in an intertidal area of the Tagus estuary, western Portugal: a six year data series. Hydrobiologia 555: 115–128.CrossRefGoogle Scholar
  55. Simmons, R. E., H. Kolberg, R. Braby & B. Erni, 2015. Declines in migrant shorebird populations from a winter-quarter perspective. Conservation Biology 29: 877–887.CrossRefPubMedGoogle Scholar
  56. Sripanomyom, S., P. D. Round, T. Savini, Y. Trisurat & G. A. Gale, 2011. Traditional salt-pans hold major concentrations of overwintering shorebirds in Southeast Asia. Biological Conservation 144: 526–537.CrossRefGoogle Scholar
  57. Taft, O. W., M. A. Colwell, C. R. Isola & R. J. Safran, 2002. Waterbird responses to expiremental drawdown: implacations for the multispecies managment of wetland mosaics. Journal of Applied Ecology 39: 987–1001.CrossRefGoogle Scholar
  58. Takekawa, J. Y., C. T. Lu & R. T. Pratt, 2001. Avian communities in baylands and artificial salt evaporation ponds of the San Francisco Bay estuary. Hydrobiologia 466: 317–328.CrossRefGoogle Scholar
  59. Tavares, P. C., D. Alves & M. Shapouri, 2009. Structural changes in macroinvertebrate communities associated with reduction in the management of coastal saltpans. Journal of Marine Biology 2009: 1–13.CrossRefGoogle Scholar
  60. van de Kam, J., B. Ens, T. Piersma & L. Zwarts, 2004. Shorebirds. An Illustrated Behavioural Ecology. KNNV Publishers, Utrecht.Google Scholar
  61. Velasquez, C. R., 1992. Managing artificial saltpans as a waterbird habitat: species’ responses to water level manipulation. Colonial Waterbirds 15: 43–55.CrossRefGoogle Scholar
  62. Vieira, N. & F. Amat, 1997. The invertebrate benthic community of two solar salt ponds in Aveiro, Portugal. International Journal of Salt Lake Research 5: 281–286.CrossRefGoogle Scholar
  63. Warren, L. M., 1976. A population study of the polychaete Capitella capitata at plymouth. Marine Biology 38: 209–216.CrossRefGoogle Scholar
  64. Warwick, R. M. & R. Price, 1975. Macrofauna production in an estuarine mud-flat. Journal of the Marine Biological Association of the United Kingdom 55: 1–18.CrossRefGoogle Scholar
  65. Yasué, M. & P. Dearden, 2009. The importance of supratidal habitats for wintering shorebirds and the potential impacts of shrimp aquaculture. Environmental Management 43: 1108–1121.CrossRefPubMedGoogle Scholar
  66. Zwarts, L., B. J. Ens, M. Kersten & T. Piersma, 1990. Moult, mass and flight range of waders ready to take off for long-distance migrations. Ardea 78: 339–364.Google Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Department of Life Sciences, MARE – Marine and Environmental Sciences CentreUniversity of CoimbraCoimbraPortugal
  2. 2.Department de Anatomy, Cell Biology and ZoologyUniversity of ExtremaduraBadajozSpain

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