Assessing the impact of beach nourishment on the intertidal food web through the development of a mechanistic-envelope model
Vanden Eede, S.; Van Tomme, J.; De Busschere, C.; Vandegehuchte, M.; Sabbe, K.; Stienen, E.; Degraer, S.; Vincx, M.; Bonte, D. (2013). Assessing the impact of beach nourishment on the intertidal food web through the development of a mechanistic-envelope model, in: Vanden Eede, S. Impact of beach nourishment on coastal ecosystems, with recommendations for coastal policy in Belgium = Impact van zandsuppleties op kustecosystemen met aanbevelingen voor het Belgische kustbeleid. pp. 97-116 In: Vanden Eede, S. (2013). Impact of beach nourishment on coastal ecosystems, with recommendations for coastal policy in Belgium = Impact van zandsuppleties op kustecosystemen met aanbevelingen voor het Belgische kustbeleid. PhD Thesis. Ghent University: Gent. ISBN 978-90-90278-4-38. xxx, 301 pp., more |  |
| Keywords | Accretion > Beach accretion > Beach nourishment
Fauna > Aquatic organisms > Aquatic animals > Fish
Macrobenthos
Organisms > Eukaryotes > Animals > Chordata > Vertebrates > Birds
Marine/Coastal | | Author keywords | Species envelope modelling |
| Abstract | Beach nourishment is widely applied as a coastal protection measure because of its reduced ecological impact relative to hard coastal protection. In order to predict expected ecological impact on the sandy beach ecosystem, we developed a simulation model that integrates species envelope-based projections for the dominant macrobenthos species and mechanistic food web modules for higher trophic levels.Species envelopes are estimated by using Bayesian inference of species’ biomass relationships according to the three main determining abiotic variables, i.e. median grain size, total organic matter and the intertidal elevation, obtained from multiple independent sampling campaigns along the Belgian coast. Maximal possible abundances of higher trophic levels, being birds, shrimp and flatfish, are estimated based on their functional and energetic relationships with macrobenthos as an important food item.After validation, we demonstrate that sediment grain size is the most important factor determining beach-level diversity and production, with strong deterioration after nourishment with too coarse sediment (e.g. >> than 300 µm). Nourishment slope had a smaller impact on the species zonation patterns compared to the sediment grain size. Patterns for higher trophic levels do not follow the decreasing patterns in macrobenthos abundance and biomass.The advised gradient in sediment grain size for nourishment of fine-grained beaches is defined as 200 – 300 µm. This modelling approach shows that the assessment of ecosystem health needs to include the evaluation of different species richness and biomass variables. Focusing solely on for instance the potential abundance of species from higher trophic levels might lead to deceptive conclusions due to the dominance of opportunistic prey species. |
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