, Volume 282, Issue 1, pp 509–524

Changes in the waterbird populations of the Oosterschelde (SW Netherlands) as a result of large-scale coastal engineering works

  • Hans Schekkerman
  • Peter L. Meininger
  • Patrick M. Meire
Theme VII: The higher trophic levels

DOI: 10.1007/BF00024652

Cite this article as:
Schekkerman, H., Meininger, P.L. & Meire, P.M. Hydrobiologia (1994) 282: 509. doi:10.1007/BF00024652


Between 1982 and 1987, the construction of a storm-surge barrier and two secondary dams in the eastern and northern parts of the Oosterschelde/Krammer-Volkerak area resulted in the loss of 33% of the 170 km2 of intertidal area in the estuary. Consequences for non-breeding waterbirds were evaluated on the basis of monthly high-tide counts during five seasons before and three seasons after the construction period.

In the entire Oosterschelde/Krammer-Volkerak area, numbers of wintering waders decreased but those of ducks increased. Peak numbers and total number of bird-days changed little, but the seasonal pattern shifted from a midwinter maximum to a peak in autumn.

In the Oosterschelde (excluding the Krammer-Volkerak), where 17% of the tidal flats disappeared, species feeding mainly on open water remained stable or increased. Species dependent on intertidal areas for foraging (mainly waders and dabbling ducks) generally decreased. Total density of intertidal foragers decreased slightly. In most intertidal species, the Oosterschelde wintering population showed a stronger decrease, or smaller increase, than was shown during the same period by numbers in Britain and Ireland which were taken as an index of the total W-European winter populations. Changes varied considerably between species, and were correlated with their distribution within the estuary. Species concentrated in the eastern sector, where most habitat loss occurred, declined more than species with a more westerly distribution.

Results indicate that intertidal foragers forced to move from the enclosed parts of the estuary were not generally able to settle into the remaining intertidal areas. Both dispersal to adjacent areas (mainly by dabbling ducks) and mortality during severe winter weather (in some wader species) may have contributed to the declines. Populations of intertidal foragers apparently were (and consequently still are) close to carrying capacity, and further changes in capacity, as foreseen from geomorphological changes still under way in the estuary, are likely to be reflected in bird populations.

Numbers of waders moulting in the Oosterschelde in late summer declined strongly compared to numbers in other seasons. Increased disturbance due to recreational activities may have played a role during this time of the year.

Key words

carrying capacitycoastal engineeringestuaryhabitat losswaderswaterbirds

Copyright information

© Kluwer Academic Publishers 1994

Authors and Affiliations

  • Hans Schekkerman
    • 1
  • Peter L. Meininger
    • 3
  • Patrick M. Meire
    • 4
    • 1
  1. 1.Netherlands Institute of Ecology, Centre for Estuarine and Coastal EcologyYersekeThe Netherlands
  2. 2.IBN-DLOWageningenThe Netherlands
  3. 3.National Institute for Coastal and Marine Management/RIKZMiddelburgThe Netherlands
  4. 4.University of GhentGentBelgium
  5. 5.Institute for Nature ConservationHasseltBelgium