|Inundation frequency determines the post-pioneer successional pathway in a newly created salt-marsh|
|Erfanzadeh, R.; Maelfait, J.-P.; Hoffmann, M. (2009). Inundation frequency determines the post-pioneer successional pathway in a newly created salt-marsh, 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. 53-74|
|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|
Community composition; Frequency; Inundation; Salt marshes; Species diversity; Succession (ecological); Marine
The effect of inundation frequency on plant community composition, species turnover, total and growth form cover, species richness and abundance of individual common species was investigated. The study area was a newly created salt-marsh located along the Belgian coast with a more or less continuous gradient of inundation frequencies from 0.01% of all high waters for highest elevations to 100% for lowest elevations. Cover of all plant species was estimated in 119 permanent 2m × 2m plots along six randomly chosen transects perpendicular to the main inundation gradient with a 3m distance between the plots in 2003, 2005 and 2007. Detrended correspondence analysis (DCA) scores were used as a proxy for plant composition. Total cover, the cover of annuals and perennials, total species richness, species richness of annuals and perennials and species turnover was calculated for each plot. Repeated measurements and LSD were used to compare all variables in three different years for different inundation frequencies. In addition, TWINSPAN was used to distinguish plant communities in different years.
The results showed that plant composition changed differently according to inundation frequency. The cover of annual species increased at a higher pace at higher inundation frequencies. The cover of perennials increased at higher pace at lower inundation frequencies. In total, species richness and the abundance of most species increased in time, indicating absence of a competitive exclusion among species. Nevertheless, the abundance and frequency of Atriplex spp., Chenopodium spp. and Salsola kali strongly decreased in time, indicating a declining natural succession. It seems that perennial species (e.g. Elymus athericus) are spreading by vegetative propagules from upward to downward. Frequent inundations hampered plant species turnover, because of the low number of species that can tolerate that environmental condition. The frequencies of communities dominated by Elymus athericus and Salicornia procumbens strongly increased in time, indicating that these species are getting more and more spatially separated, leading to a stronger separation of plant communities and an appearance of a salt-marsh zonation.