|Assessment of the ecological characteristics of the Belgian beaches prior to the implementation of the Belgian Master Plan for Coastal Safety|
Vanden Eede, S.; Bonte, D.; Degraer, S.; Vincx, M. (2013). Assessment of the ecological characteristics of the Belgian beaches prior to the implementation of the Belgian Master Plan for Coastal Safety, 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. 31-56
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., meer
Natural variation; Mesoscale patterns
Sandy shores or beaches line 70 % of the world’s oceans, including the entire Belgian coastline (67 km). They have a multitude of ecosystem functions, constitute an important habitat for a variety of fauna and flora and hold important economic, social and cultural value as prime recreational assets. In order to protect the Belgian coastline against erosion and coastal flooding on a short and long term basis (up to 2050), the Belgian sandy beaches face a multitude of beach nourishment activities over the next years, as stipulated in the Belgian Master Plan for Coastal Safety. Monitoring the ecological characteristics of the Belgian beaches will aid in the detection of possible impact effects of past, current and future beach nourishment activities.To this end, 686 intertidal and 582 shallow subtidal samples from the period 1997 – 2011 were analysed to describe the macrobenthic communities and corresponding abiotic patterns on 16 Belgian beaches. The 15 intertidal and 9 shallow subtidal locations were treated separately. The partitioning of macrobenthic community structure within the Belgian beach ecosystem showed a large within beach variability, linked to elevation on the beach (intertidal: 44 % and shallow subtidal: 50 %) and median grain size of the sediment (intertidal: 35 % and shallow subtidal: 23 %), in both the intertidal and shallow subtidal zone. Large scale along-shore spatial (intertidal: 14 % and shallow subtidal: 13 %) and long-term temporal (intertidal: 5% and shallow subtidal: 12 %) variability clearly explained less variation. Several spatial and temporal trends in abiotic factors (overall median grain size between 150 and 300 µm) and in macrobenthic species richness (intertidal: 0 – 19 species; shallow subtidal: 0 – 28 species), abundance (intertidal: 0 – 3988.75 individuals.m-²; shallow subtidal: 0 – 1949.32 individuals.m-²) and biomass (intertidal: 0 – 6.95 g AFDW.m-²; shallow subtidal: 0 – 246.14 g AFDW.m-²) were measured. The mean macrobenthic abundance in the intertidal and shallow subtidal zone fluctuates between 0 and 350 individuals.m-² over the years. Furthermore, the realized niches of the dominant macrobenthic species of the Belgian beaches were defined as the area where these species really live during low tide, characterized by elevation on the beach and median grain size of the sediment.Since all sampling locations were considered to be outside the influence of major impacting activities, these findings improve our knowledge of the natural abiotic and macrobenthic variability of the Belgian beaches. As such, this study can be used as a preconceived basis (t0 situation) of ‘natural’ macrobenthic variability on the Belgian beaches.