Impact on bird fauna of a non-native oyster expanding into blue mussel beds in the Dutch Wadden Sea

Published Date
October 2016, Vol.202:39–49, doi:10.1016/j.biocon.2016.08.007

Author 

• Andreas M. Waser ^a,b,c,,
• Symen Deuzeman ^d
• Arno K. wa Kangeri ^e
• Erik van Winden ^d
• Jelle Postma ^d
• Peter de Boer ^d
• Jaap van der Meer ^a,b
• Bruno J. Ens ^c

• aDepartment of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands
• bDepartment of Animal Ecology, VU University Amsterdam, Faculty of Earth & Life Sciences, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
• cSovon Dutch Centre for Field Ornithology, Sovon-Texel, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands
• dSovon Dutch Centre for Field Ornithology, P.O. Box 6521, 6503 GA Nijmegen, The Netherlands
• eInstitute for Marine Resources & Ecosystem Studies (IMARES), Wageningen University and Research Centre, P.O. Box 57, 1780 AB Den Helder, The Netherlands

Received 27 May 2016. Revised 1 August 2016. Accepted 8 August 2016. Available online 29 August 2016. 

Highlights

• •
  Half of the epibenthic bivalve beds in the Dutch Wadden Sea are a mix of Pacific oysters and native blue mussels.
• •
  Most bird species prefer bivalve beds over bare intertidal flats.
• •
  20 out of 24 of the bird species were not affected by the Pacific oyster occurrence.
• •
  Oysters negatively affected Common Gull, Dunlin, Oystercatcher, and Red Knot.
• •
  Removal of the Pacific oyster will not aid the avian community.

Abstract

Intertidal mussel beds are important for intertidal ecosystems, because they feature a high taxonomic diversity and abundance of benthic organisms and are important foraging grounds for many avian species. After the introduction of the Pacific oyster (Crassostrea gigas) into the European Wadden Sea, many mussel beds developed into oyster dominated bivalve beds. Despite the fact that oysters have been colonizing many European intertidal areas for about two decades, their impact on the ecosystem is still poorly understood. Here, we investigated the impact of oysters on the condition of mussels and on the spatial distribution of birds on 18 bivalve beds with different grades of oyster occurrence throughout the Dutch Wadden Sea. Moreover, in comparing bird densities on bivalve beds with densities expected on the total intertidal area, we could detect which species exhibit a preference for the structured habitat. Overall, 50 different bird species were observed on the beds, of which about half regularly frequent intertidal flats. Most of these species showed a preference for bivalve beds. The condition of mussels decreased with the oyster dominance, whereas the majority of bird species was not affected by the oyster occurrence. However, three of the four species that were negatively affected depend on intertidal mussels as food source. Even though the Pacific oyster is a nonnative species, attempts to fight it may do more harm to avian biodiversity than good.

Graphical asbtract

Keywords

• Oyster reef
• Crassotrea gigas
• Mytilus edulis
• Shorebirds
• Habitat complexity
• Species distribution

---

Fig. 1.

 Table 1

Table 1.

Fig. 2.

 Table 2

Table 2.

 Table 3

Table 3.

Fig. 3.

Fig. 4.

Fig. 5.

• PDF (525K)

• KML (14K)

Map

• ⁎ 
  Corresponding author at: Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research and Utrecht University, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands.

For further details log on website :
http://www.sciencedirect.com/science/article/pii/S000632071630310X