|Factors affecting the success of early salt-marsh colonizers: seed availability rather than site suitability and dispersal traits|
|Erfanzadeh, R.; Garbutt, Angus; Pétillon, J.; Maelfait, J.-P.; Hoffmann, M. (2009). Factors affecting the success of early salt-marsh colonizers: seed availability rather than site suitability and dispersal traits, in: Erfanzadeh, R. (2009). Spatio-temporal aspects of early vegetation succession in a recently restored salt-marsh ecosystem: a case study of the IJzer estuary (Belgium). pp. 33-52|
|In: Erfanzadeh, R. (2009). Spatio-temporal aspects of early vegetation succession in a recently restored salt-marsh ecosystem: a case study of the IJzer estuary (Belgium). PhD Thesis. Ghent University. Faculty of Sciences. Department of Biology. Terrestrial Ecology Unit: Gent. xii, 206 incl. Appendices pp., more|
Colonization; Dispersal phenomena; Seeds; Marine
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Restoration of salt-marshes on newly created substrates provides an excellent opportunity to study plant colonization and its constraints. We evaluated the process of salt-marsh colonization in early successional stages and investigated how the sequence of species establishment is related to the abundance of species in neighbouring, long-existing saltmarshes, site suitability, seed production and dispersal traits of the involved plant species. Species distribution and colonization data were collected, using vegetation relevés, that were collected in the restoration site during three consecutive periods in 175 permanent 2m × 2m plots. The plots were located along eight randomly chosen transects which were established perpendicular to the shoreline. To describe the only local diaspore source for new salt-marsh plant species, vegetation data were also collected in the adjacent salt-marsh in 66 permanent plots in the same time sequence. We used seed length, width and mass as dispersal traits, and Ellenberg moisture, salinity and nutrient indices as indicators of site suitability. To describe the importance of seed availability on initial colonization, seed production in the reference site and seed bank in the restoration site were also investigated.
The results showed that the establishment of salt-marsh species in the restoration site was good and fast, the cover of new colonizers in the restoration site was unrelated to their cover in the adjacent salt-marsh. Seed availability appeared to be a more important factor in explaining the sequence of species establishment than salt and nutrient-limitation tolerance. The first colonizers are known as massive seed producers, shorter seed length and lower seed mass, which probably increased buoyancy. Among dispersal and site traits, seed length and mass, and in a less extent salinity and nutrients, indicated a relationship with new colonizers. Despite few species have not appeared in vegetation and seed bank in the restoration site yet, the existence of an old salt-marsh adjacent to the restoration site is shown to be vital for fast colonization of newly created intertidal areas.