A mega-nourishment creates novel habitat for intertidal macroinvertebrates by enhancing habitat relief of the sandy beach. (31st July 2018)

• Record Type: Journal Article
• Authors: van Egmond, E.M.; van Bodegom, P.M.; Berg, M.P.; Wijsman, J.W.M.; Leewis, L.; Janssen, G.M.; Aerts, R.
• Is Part Of: Estuarine, coastal and shelf science. Volume 207(2018)
• Page Start: 232
• Page End: 241
• Publication Date: 2018-07-31
• Subjects: Community composition -- Benthos -- Soft-sediment beach -- Beach management -- Zonation; The Netherlands -- Scheveningen; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2018.03.003
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: Globally, sandy beaches are subject to coastal squeeze due to erosion. Soft-sediment strategies, such as sand nourishment, are increasingly applied to mitigate effects of erosion, but have long-term negative impacts on beach flora and fauna. As a more ecologically and sustainable alternative to regular beach nourishments, a mega-nourishment has been constructed along the Dutch coast by depositing 21.5 Mm 3 of sand, from which sand is gradually redistributed along the coast by natural physical processes. The 'Sand Motor' mega-nourishment was constructed as a long-term management alternative for coastal protection and is the first large-scale experiment of its kind. We evaluated the development of intertidal macroinvertebrate communities in relation to this mega-nourishment, and compared it to species composition of beaches subject to regular beach or no nourishment. We found that a mega-nourishment resulted initially in a higher macroinvertebrate richness, but a lower macroinvertebrate abundance, compared to regular beach nourishment. As there was no effect of year after nourishment, this finding suggests that colonization and/or local extinction were not limiting macroinvertebrate richness at the mega-nourishment. In addition, a mega-nourishment does not converge to an intertidal macroinvertebrate community similar to those on unnourished beaches within a time scale of four years. Beach areas at the mega-nourishment sheltered from waves harbored a distinct macroinvertebrate community compared to typical wave-exposed sandy beach communities. Thus, a mega-nourishment temporally creates new habitat for intertidal macroinvertebrates by enhancing habitat relief of the sandy beach. We conclude that a mega-nourishment may be a promising coastal defense strategy for sandy shores in terms of the macroinvertebrate community of the intertidal beach. Graphical abstract: Image 1 Highlights: Higher richness but lower abundance at mega-nourishment than beach nourishment. Dissimilar wave-exposed community at mega-nourishment than at unnourished beaches. Distinct community at sheltered, mudflat-like beach parts of the mega-nourishment. Hook-shaped mega-nourishment creates habitat relief, attracting new species. A mega-nourishment is a new promising coastal defense strategy at sandy beaches.