Results
Full version of report
A full version of the report of this project can be downloaded here (in Dutch). For further details please contact Jeroen Speybroeck.
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Summary
This study was conducted by a consortium of experts with as main objectives (1) to provide an integrated overview of the Belgian beach ecosystem and all its components, (2) to conduct a first evaluation on what is known on the ecological impact of beach nourishment and (3) to identify gaps in the scientific knowledge on both matters.
Although sandy beaches are often considered of less biological value, they are the habitat of a number of beach specific organisms and play an important role in providing food and serving as breeding grounds, resting area and nursery for several plants and animals. An integrated overview of the Belgian sandy beach ecosystem has been made, divided into three altitudinal zones: the supralittoral, the littoral and the infralittoral zone. Besides sedimentology and hydrodynamics, five ecosystem components were taken into account: microphytobenthos, vascular plants, terrestrial arthropods, zoobenthos and avifauna.
A review of prior studies indicates that the impact of nourishment is rather case-specific and that it is difficult to draw general conclusions (Nelson, 1993). Nevertheless it seems very likely that potential recovery from the impact of nourishment will be limited to two essential, species specific pathways: (1) survival by resident organisms and (2) recolonisation by immigrating individuals, the latter depending on both the dispersal capacities and habitat demands of the organisms. Considering the current practice of beach nourishment, the first option is non-existent. The large quantity of deposited sand excludes survival for all organisms (Löffler & Coosen, 1995; Essink, 1999; Greene, 2002). Thus the restoration of the natural values of a replenished beach will largely depend on post hoc recolonisation (Menn, 2002).
Further research is needed to explore possibilities for reducing detrimental ecological effects. Specific studies are needed towards the survival options, the dispersal abilities and habitat demands of the species present on Belgian beaches. These should allow for management guidelines to be drawn in terms of preferable nourishment sediment characteristics, timing and practice of the deposition of the sand.
This project has been commissioned and supported by AWZ, Coastal Waterways Division.
References:
- Essink, K. 1999. Ecological effects of dumping of dredged sediments; options for management. J. Coast. Conserv. 5:69-80.
- Greene, K. 2002. Beach Nourishment: A Review of the Biological and Physical Impacts. ASMFC Habitat Management Series # 7. Washington DC. 69 pp.
- Löffler, M. and Coosen, J. 1995. Ecological Impact of Sand Replenishment. In: Healy & Doody (eds.). Directions in European Coastal Management. Samara Publishing Ltd., Cardigan. 291-299.
- Menn, I. 2002. Beach morphology and food web structure: comparison of an eroding and an accreting sandy shore in the North Sea. Helgol. Meersunters. 56(3):177-189.
- Nelson W.G. 1993. Beach Restoration in the Southeastern US: Environmental Effects and Biological Monitoring. Ocean Coast. Manage. 19:157-182.
