Academic year 2012 – 2013 IMPACT OF BEACH NOURISHMENT ON COASTAL ECOSYSTEMS WITH RECOMMENDATIONS FOR COASTAL POLICY IN BELGIUM IMPACT VAN ZANDSUPPLETIE OP KUSTECOSYSTEMEN MET AANBEVELINGEN VOOR HET BELGISCHE KUSTBELEID Sarah Vanden Eede Promotors: Prof. Dr. Magda Vincx Prof. Dr. Steven Degraer IMPACT OF BEACH NOURISHMENT ON COASTAL ECOSYSTEMS WITH RECOMMENDATIONS FOR COASTAL POLICY IN BELGIUM ISBN 9789090278438 EAN 9789090278438 Marine Biology Research Group Campus Sterre – S8 Krijgslaan 281 B-9000 Gent Belgium Academic Year 2012 – 2013 Publically defended on September 20th 2013 Co-authored one or more chapters: Joke Van Tomme, Dries Bonte, Lia Laporta, Klaas Deneudt, Sofie Derous, Jeroen Speybroeck, Charlotte De Busschere, Martijn Vandegehuchte, Eric Stienen, Koen Sabbe, Steven Degraer, Magda Vincx For citation to published work reprinted in this thesis, please refer to the original publications (as mentioned in the beginning of each chapter). Vanden Eede S (2013) Impact of beach nourishment on coastal ecosystems with recommendations for coastal policy in Belgium. Ghent University (UGent), pp. 301 IMPACT OF BEACH NOURISHMENT ON COASTAL ECOSYSTEMS WITH RECOMMENDATIONS FOR COASTAL POLICY IN BELGIUM IMPACT VAN ZANDSUPPLETIE OP KUSTECOSYSTEMEN MET AANBEVELINGEN VOOR HET BELGISCHE KUSTBELEID Sarah Vanden Eede Promotors Prof. Dr. Magda Vincx Prof. Dr. Steven Degraer Academic year 2012 – 2013 Thesis submitted in partial fulfilment of the requirements for the degree of Doctor in Science, Marine Sciences Members of the reading committee Dr. Angel Borja (AZTI, Spain) Dr. Jeroen Speybroeck (INBO, Brussels, Belgium) Dr. Jan Vanaverbeke (Ghent University, Belgium) Members of the examination committee Dr. Angel Borja (AZTI, Spain) Dr. Jeroen Speybroeck (INBO, Brussels, Belgium) Dr. Jan Vanaverbeke (Ghent University, Belgium) Prof. Dr. Dries Bonte, Chairman (Ghent University, Belgium) Prof. Dr. Magda Vincx, Promotor (Ghent University, Belgium) Prof. Dr. Steven Degraer, Promotor (Ghent University, Belgium) Dr. Gert Van Hoey (ILVO, Ostend, Belgium) Prof. Dr. Ann Vanreusel (Ghent University, Belgium) Table of contents Table of contents Table of contents ........................................................................................................................................... xi Dankwoord ................................................................................................................................................. xvii Summary ................................................................................................................................................... xxiii Samenvatting ............................................................................................................................................ xxvii Chapter 1: General introduction ................................................................................................................... 1 1. Coastal zones worldwide ................................................................................................................... 1 1.1 Sandy shores .............................................................................................................................. 2 1.2 Threats to coastal zones and sandy beaches ............................................................................ 5 2. Belgian coastal zone .......................................................................................................................... 5 3. Belgian coastal ecosystem ................................................................................................................. 7 3.1 Supralittoral zone: vascular plants and strandline fauna .......................................................... 8 3.2 Intertidal and shallow subtidal zone: benthos .......................................................................... 9 3.3 From supralittoral to shallow subtidal: birds and seals .......................................................... 12 4. Threats to the Belgian sandy beach ecosystem .............................................................................. 13 4.1 Coastal defence along the Belgian coastline ........................................................................... 14 4.2 Guidelines for ecologically good practice of beach nourishment along the Belgian coastline18 5. Governance in the Belgian coastal zone ......................................................................................... 19 6. Current coastal governance status in Belgium and Flanders .......................................................... 23 7. Aims of the PhD thesis ..................................................................................................................... 26 8. Outline of the PhD thesis ................................................................................................................. 28 Chapter 2: Assessment of the ecological characteristics of the Belgian beaches prior to the implementation of the Belgian Master Plan for Coastal Safety .................................................................. 31 Abstract ....................................................................................................................................................... 32 1. Introduction ..................................................................................................................................... 33 2. Material and methods ..................................................................................................................... 35 2.1 Study Area ............................................................................................................................... 35 2.2 Data ......................................................................................................................................... 36 xi Table of contents 2.3 Sampling method .................................................................................................................... 37 2.4 Laboratory procedures ............................................................................................................ 38 2.5 Data analysis ............................................................................................................................ 38 3. Results ............................................................................................................................................. 39 3.1 Partitioning of abiotic and macrobenthic variance on Belgian beaches ................................. 40 3.2 Spatial and temporal macrobenthos variation........................................................................ 41 3.3 Variation within beaches ......................................................................................................... 45 3.4 Niche properties of the dominant species .............................................................................. 48 4. Discussion ........................................................................................................................................ 52 4.1 Partitioning of abiotic and macrobenthic variance on Belgian beaches ................................. 52 4.2 Spatial and temporal variation ................................................................................................ 53 4.3 Variation within beaches ......................................................................................................... 53 4.4 Niche properties of the dominant species: a synthesis .......................................................... 54 5. Conclusion ....................................................................................................................................... 56 Chapter 3: The monitoring of ‘ecological’ beach nourishment impacts on macrobenthos, within a Special Area of Conservation (SAC) along the Belgian coast ................................................................................... 59 Abstract ....................................................................................................................................................... 60 1. Introduction ..................................................................................................................................... 61 2. Material and methods ..................................................................................................................... 63 2.1 Study Area ............................................................................................................................... 63 2.2 Data ......................................................................................................................................... 64 2.3 Sampling method .................................................................................................................... 65 2.4 Lab procedures ........................................................................................................................ 65 2.5 Data analysis ............................................................................................................................ 66 3. Results ............................................................................................................................................. 67 3.1 Habitat changes ....................................................................................................................... 68 3.2 Impacts on macrobenthos and recovery ................................................................................