PhD Reza Erfanzadeh 2009 - Ghent Ecology - Universiteit Gent

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with one or more reference sites (Thom et al. 2002; Edwards & Proffitt 2003). In the present study, the rate of appearance of salt-marsh species present on the adjacent old salt-marsh could be used as an evaluation criterion for restoration success. 1.7 Why permanent plots? 28 Permanent plot studies have a long history (Austin 1981) and long-term permanent plots are important as they can help in separating trends and seasonal fluctuations (Huisman et al. 1993), and are needed to test ecological models that are often based on assumptions and not derived from solid field studies (Bakker et al. 1996). The study of long-term permanent plots has made it clear that vegetation development in many ecosystems under restoration was different from the final state that was anticipated. This may generate new hypotheses (Klotzli & Grootjans 2001). Furthermore, long-term recordings are needed to validate the effects of management measures. Even, experimental changes in salt-marsh management (Bos et al. 2002) revealed clear changes after some years, stressing the importance of long-term monitoring (Bakker 2005). Permanent plots are useful in studies of climate change (Petriccione 2005), in field experiments (Brys et al. 2005) and in the restoration projects (Bekker et al. 1996; Kiehl & Wagner 2006). Measuring sequential percent cover and species composition in permanent plots allows the trajectory of vegetation change to be quantified by multivariate methods and similarity measures (del Moral 2007). Bakker et al. (1996) stressed that permanent plot studies permit both internal and external driving forces to be explored. Such studies can lead to new hypotheses and offer clues to appropriate experiments to test these hypotheses (Odland & del Moral 2002). The size of vegetation relevés may differ according to the structural characteristics of the vegetation. Dutch ecologists have used permanent plots 2m × 2m in size for decades to
show cyclical and directional vegetation dynamics in salt-marshes (Leendertse et al. 1997; Smits et al. 2002). Consequently, we also used plots 2m × 2m in our study. 1.8 Objectives and outline of the thesis Understanding the driving factors of succession is still a matter of great interest in ecological science, despite countless studies that deal with succession in all kinds of habitats. One of those habitats is salt-marsh environment in which drivers determine plant species turnover in time and changes in spatial plant arrangement during the succession process. General primary succession determinants in naturally developing salt-marshes are relatively well described, although the vast literature on this matter shows that local plant succession is unique for each salt-marsh environment, since biotic and abiotic factors always differ among localities. Additionally, relatively little knowledge is available on the specific drivers in restoration conditions, which will always differ from natural conditions, in which spontaneous salt-marsh vegetation would develop. Knowledge of succession patterns and processes in these restoration conditions is essential though, when one wants to be able to estimate potential success of restoration initiatives that aim at the creation or restoration of a diverse salt-marsh environment in general. This thesis uses the restoration initiative taken in 1999- 2004 along the right bank of the IJzer estuary (province of West-Flanders, Belgium) to learn about the specificity of succession processes at a salt-marsh restoration site. Primary succession on a newly created salt-marsh starts with colonization of species from the local and regional species pool from the seed bank or from seed rain. Seed dispersal from the local species pool is more important than from the regional species pool, since it may take several years to disperse seeds from the regional species pool to newly created salt-marsh (Wolters et al. 2008). Nevertheless, species present in the local species pool show different colonization abilities. In the study area, no seed bank existed because of the huge quantities of slurry material deposited on the former salt-marshes, removed in 2001. This was proven in a 29
Page 1: Ghent University Faculty of Science
Page 5: Spatio-temporal aspects of early ve
Page 9 and 10: Acknowledgements The accomplishment
Page 11: List of Abbreviations ADF Acid Dete
Page 14 and 15: XII 3.5 DISCUSSION ................
Page 16 and 17: 1.1 What is succession? 2 Successio
Page 18 and 19: completely destroy the existing veg
Page 20 and 21: also occur in salt-marsh habitat, a
Page 22 and 23: seed production (Willson 1983; Pric
Page 24 and 25: 1.3.2 Inundation, vegetation and su
Page 26 and 27: affected plant species richness in
Page 28 and 29: 14 In chapter 4, the effects of she
Page 30 and 31: elationship between soil characteri
Page 32 and 33: areas which are re-colonized. They
Page 34 and 35: Fig. 1.4. The position of the newly
Page 36 and 37: 22 There are some photos available
Page 38 and 39: were collected systematically along
Page 40 and 41: Table 1.1. Materials and methods us
Page 44 and 45: pilot study performed in the area i
Page 46 and 47: Fig. 1.7. The conceptual framework
Page 48 and 49: 2.1 Abstract Restoration of salt-ma
Page 50 and 51: 2.2 Introduction The successful res
Page 52 and 53: physiological process depending on
Page 54 and 55: separated from it by a dike (with a
Page 56 and 57: scale (Londo 1976). According to th
Page 58 and 59: 2.4.2 Seed bank at the restoration
Page 60 and 61: Table 2.3. Average (± SE) species
Page 62 and 63: particular those species coming fro
Page 64 and 65: germinate, the seeds should have ap
Page 66 and 67: the restoration site along a strong
Page 68 and 69: 3.1 Abstract 54 The effect of inund
Page 70 and 71: 3.2 Introduction 56 Tidal marshes a
Page 72 and 73: more stable. Consequently, species
Page 74 and 75: 3.3.2.2 Inundation frequency 60 The
Page 76 and 77: and 2007) for those variables that
Page 78 and 79: maritima) increased over time (Fig.
Page 80 and 81: perennial species between years, wi
Page 82 and 83: 68 Perennial richness 1.4 1.2 1 0.8
Page 84 and 85: 70 Species turnover 1.2 1 0.8 0.6 0
Page 86 and 87: Reznicek 1986). They therefore play
Page 88 and 89: Suaeda maritima. Spartina is well k
Page 90 and 91: 4.1 Abstract 76 In this paper, the
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4.2 Introduction 78 Salt-marshes ar
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available on the influence of sheep
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consecutive months, sampling effort
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factor was applied. In case of sign
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Table 4.1. The result of repeated m
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88 Cover(%) 2.5 2 1.5 1 0.5 0 C a b
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90 2.5 2 1.5 1 0.5 0 a b a b Grazed
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succession leading to rapid vegetat
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(van Wijnen et al. 1997). In additi
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5.1 Abstract 96 It is generally acc
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5.2 Introduction 98 One of the main
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area started in 2002, when part of
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high and highly significant (see Ta
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104 Although the percentage of spec
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5.5 Discussion 106 Not surprisingly
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europaea zone as long as the elevat
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110
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6.1 Abstract 112 Seed bank density
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6.2 Introduction 114 The persistenc
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116 Our study area consists of thre
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were also placed randomly on the sh
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Seed density(m²) Seed density(m²)
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122 Plant species in the above-grou
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6.4.2 Seed bank properties and sali
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Seed density(m²) Seed density(m²)
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conclude that Suaeda seeds are most
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130 Both the similarity between sta
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marsh were found not to be fundamen
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134 Permanent plots in this study g
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(soil and elevation), and between v
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138 In literature it is generally a
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ecome extinct, some palatable and s
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production, but their massive produ
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144 Grazing in the entire year migh
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146
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Bakker, E.S. & Olff, H. 2003. The i
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Bertness, M.D., Wise C. & Ellison A
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Burrows, C.J. 1990. Processes of ve
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de Leeuw, J. 1992. Dynamics of salt
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Egler, F.E. 1954. Vegetation scienc
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Garbutt, A. & Wolters, M. 2008. The
Page 174 and 175:
Harper, J.L. 1961. Approaches to th
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Hoffmann, M. 2006a. 5. De natuurher
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Janssen, J.A.M. & Schaminée, J.H.J
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Klotzli, F. & Grootjans, A.P. 2001.
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Levine, J.M., Brewer, J.S. & Bertne
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Myster, R.W. & Pickett, S.T.A. 1990
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Packham, J.R. & Willis, A.J. 1997.
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Poschlod, P., Tackenberg, O. & Bonn
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Rozema, J. & Blom B. 1977. Effects
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Smith, T.B., Kark, S., Schneider, C
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Thompson, K., Bakker, J.P. & Bekker
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van Leeuwen, C.G. 1966. A relation
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Wijnen, H.J.V. & Bakker, J.P. 1999.
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186
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of a continuous water bridge betwee
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Appendix F - Continued Samolus vala
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Appendix G - Continued Rubus caesio
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PhD Reza Erfanzadeh 2009 - Ghent Ecology - Universiteit Gent

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