PhD Reza Erfanzadeh 2009 - Ghent Ecology - Universiteit Gent

Table of contents
CHAPTER 1 GENERAL INTRODUCTION ............................................................................................... 1
1.1 WHAT IS SUCCESSION? ......................................................................................................................... 2
1.1.1 Temporal and spatial aspects of succession.................................................................................... 2
1.2 GENERAL CONSIDERATIONS ON SUCCESSION IN SALT-MARSH HABITAT................................................ 3
1.2.1 The facilitation mechanism ............................................................................................................. 4
1.2.2 The tolerance mechanism................................................................................................................ 4
1.2.3 The inhibition mechanism ............................................................................................................... 5
1.3 WHAT IS KNOWN ABOUT SALT-MARSH SUCCESSION ............................................................................. 6
1.3.1 Which species are able to be the first colonizers in a salt-marsh?.................................................. 7
1.3.2 Inundation, vegetation and succession.......................................................................................... 10
1.3.3 Grazing and succession................................................................................................................. 11
1.3.4 The effect of soil conditions on vegetation in different successional stages.................................. 14
1.3.5 Seed bank and succession ............................................................................................................. 16
1.4 THE REASONS WHY TO STUDY SUCCESSION IN A RESTORATION PROGRAM.......................................... 17
1.5 MATERIAL AND METHODS .................................................................................................................. 18
1.5.1 The recently history of the study area ........................................................................................... 18
1.5.2 Materials ....................................................................................................................................... 24
1.6 THE RESTORATION INTEREST OF SALT-MARSHES ................................................................................ 26
1.7 WHY PERMANENT PLOTS?................................................................................................................... 28
1.8 OBJECTIVES AND OUTLINE OF THE THESIS .......................................................................................... 29
CHAPTER 2 FACTORS AFFECTING THE SUCCESS OF EARLY SALT-MARSH COLONIZERS:
SEED AVAILABILITY RATHER THAN SITE SUITABILITY AND DISPERSAL TRAITS ................. 33
2.1 ABSTRACT .......................................................................................................................................... 34
2.2 INTRODUCTION ................................................................................................................................... 36
2.3 MATERIAL AND METHODS.................................................................................................................. 38
2.3.1 Study area ..................................................................................................................................... 38
2.3.2 Seed production in the reference site ............................................................................................ 40
2.3.3 Seed bank in the restoration site ................................................................................................... 40
2.3.4 Vegetation cover within the restoration and reference sites ......................................................... 41
2.3.5 Plant traits and site suitability ...................................................................................................... 42
2.3.6 Statistical analyses........................................................................................................................ 42
2.4 RESULTS ............................................................................................................................................. 43
2.4.1 Seed production at the reference site ............................................................................................ 43
2.4.2 Seed bank at the restoration site ................................................................................................... 44
2.4.3 Vegetation cover within the restoration site and adjacent local salt-marsh ................................. 44
2.4.4 Plant traits..................................................................................................................................... 47
2.5 DISCUSSION ........................................................................................................................................ 47
2.6 CONCLUSIONS..................................................................................................................................... 52
CHAPTER 3 INUNDATION FREQUENCY DETERMINES THE POST-PIONEER
SUCCESSIONAL PATHWAY IN A NEWLY CREATED SALT-MARSH................................................. 53
3.1 ABSTRACT .......................................................................................................................................... 54
3.2 INTRODUCTION ................................................................................................................................... 56
3.3 MATERIAL AND METHODS .................................................................................................................. 59
3.3.1 Study area ..................................................................................................................................... 59
3.3.2 Data collection.............................................................................................................................. 59
3.3.2.1 Vegetation..................................................................................................... 59
3.3.2.2 Inundation frequency.................................................................................... 60
3.3.3 Data analysis................................................................................................................................. 60
3.4 RESULTS ............................................................................................................................................. 62
3.4.1 Variation in cover (and frequency) of individual species.............................................................. 62
3.4.2 Change in richness, the cover of growth forms and composition (DCA1 and DCA2) .................. 64
3.4.3 Curve estimation ........................................................................................................................... 66
3.4.4 Species turnover and inundation frequency .................................................................................. 68
3.4.5 Change in plant communities........................................................................................................ 70
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