ecology of macrobenthos as a baseline for an ecological adjustment of beach nourishment

205 Pages·2007·6.93 MB·English

FACULTY OF SCIENCES

E
COLOGY OF MACROBENTHOS AS

A BASELINE FOR AN ECOLOGICAL ADJUSTMENT OF

BEACH NOURISHMENT

ECOLOGIE VAN MACROBENTHOS ALS EEN BASIS VOOR EEN ECOLOGISCHE BIJSTURING VAN STRANDSUPPLETIES

JEROEN SPEYBROECK

Thesis submitted in partial fulfillment of the requirements for
the degree of Doctor in Sciences: Biology

Promotor: Prof. dr. Magda Vincx
Co-promotor: dr. Steven Degraer

Academic year 2006-2007

MEMBERS OF THE READING COMMITTEE:

Prof. dr. Magda Vincx, promotor (UGent, B)
dr. Steven Degraer, co-promotor (UGent, B)
dr. Gerard Janssen (RIKZ, NL)
dr. ir. Jan van de Graaff (TU-Delft, NL)

MEMBERS OF THE EXAMINATION COMMITTEE:

Prof. dr. Wim Vyverman, chair (UGent, B)

Prof. dr. Magda Vincx, promotor (UGent, B)
dr. Steven Degraer, co-promotor (UGent, B)
dr. Gerard Janssen (RIKZ, NL)
dr. ir. Jan van de Graaff (TU-Delft, NL)
Prof. dr. Jean-Pierre Maelfait (UGent and INBO, B)
dr. Jan Seys (VLIZ, B)
dr. Maaike Steyaert (UGent, B)
dr. Eric Stienen (INBO, B)

Table of contents

DANKWOORD

SUMMARY – SAMENVATTING . . . . . . . . 3
Summary . . . . . . . . . . 3
Samenvatting . . . . . . . . . . 7

OUTLINE . . . . . . . . . . . 13
Rationale . . . . . . . . . 13
Thesis contents and structure . . . . . . . 16
Candidate’s contribution to the different chapters . . . . . 18

I. INTRODUCTORY CHAPTERS

Chapter 1. The Belgian sandy beach ecosystem – a review . . . . . 21
Abstract . . . . . . . . . . . 23
Introduction . . . . . . . . . . 24
The physical environment . . . . . . . . . 24
The Belgian coast . . . . . . . . 24
General features of beaches sampled within this thesis research (Chapters 3 and 4) . 28
The biological environment . . . . . . . . . 32
Vascular plants . . . . . . . . . 32
Terrestrial arthropods . . . . . . . . 33
Microphytobenthos . . . . . . . . 36
Zoobenthos . . . . . . . . . 37
Avifauna . . . . . . . . . . 39
Discussion . . . . . . . . . . 43
Acknowledgements . . . . . . . . . 44

Chapter 2. Beach nourishment: an ecologically sound coastal defence alternative? A review . 45
Abstract . . . . . . . . . . . 47
Introduction . . . . . . . . . . 48
Ecological effects of beach nourishment . . . . . . . 50
Differential ecological effects of beach nourishment related aspects . . . 51
Activities during construction . . . . . . 51
Quality characteristics of the nourishment sediment . . . . 52
Sediment composition . . . . . . 52
Shells and other coarse material . . . . 52
Fines . . . . . . . 53
Grain size distribution . . . . . 54
Beach morphology . . . . . . 55
Presence of toxic substances and/or dead organisms . . . 55
Sediment colour . . . . . . . 55
Quantity characteristics of the nourishment sediment . . . . 56
Factors determining scale of impact . . . . . . . 57
Timing, place and size of beach nourishment . . . . . 57
Nourishment strategies and techniques . . . . . 57
Nourishment strategies . . . . . . 57
Nourishment techniques . . . . . . 59
Indirect and cumulative effects . . . . . . . 59
Conclusions . . . . . . . . . . 60
Guidelines for an ecologically good practice of beach nourishment . . . 61
Sediment . . . . . . . . 61
Timing . . . . . . . . . 61
Size . . . . . . . . . 61
Nourishment strategy . . . . . . . 62
Shortcomings of former research and options for future research . . . 62
Acknowledgements . . . . . . . . . 63

II. FIELD RESEARCH – PATTERNS: LIFE CYCLE, POPULATION DYNAMICS AND ZONATION

Chapter 3. Understanding the life of a sandy beach polychaete of functional importance - Scolelepis
squamata (Polychaeta: Spionidae) on Belgian sandy beaches (northeastern Atlantic, North Sea) 65
Abstract . . . . . . . . . . . 67
Introduction . . . . . . . . . . 68
Material & methods . . . . . . . . . 69
Sampling . . . . . . . . . 69
Lab procedures . . . . . . . . . 69
Data analysis . . . . . . . . . 70
Results . . . . . . . . . . . 71
Physical environment . . . . . . . . 71