Abstract
This study was carried out on the transported bed soil dredged from the outlet of Lake Burullus to the Mediterranean Sea and deposited nearby, forming by this way new land that underwent a primary plant succession. The multi-methodological approach comprised floristic inventories, vegetation sampling and soil composition analyses of the study site in order to detect the crucial parameters controlling the plant resettlement on recently deposited soil as related to time, local micro-topography and substrate characteristics. Floristic composition was assessed for the first 10 years of primary succession (2001-2010) on 18 stands of the area, distributed on basement, slope stands and plateau of the landfill, respectively. Vegetation surveys were the basis of multivariate analyses of the vegetation and soil data using TWINSPAN, DCA and CCA. Relationships between the edaphic gradients, floristic composition and species diversity were assessed.
Forty-one species were identified (22 annuals and 19 perennials) after ten years development compared with 7 species at the first year. After application of TWINSPAN and DCA on the data of the first year of establishment, two simple vegetation groups were recognized and named after their dominant species, Senecio glaucus and Bassia indica. In comparison, the multivariate analysis of the last year (i.e. after 10 years of succession) led to identify 4 more advanced vegetation groups: Senecio glaucus-Cakile maritima-Zygophyllum album, Bassia indica-Mesembryanthemum nodiflorum, Arthrocnemum macrostachyum and Phragmites australis-Limbarda crithmoides. These plant communities are comparable to the other communities in the same region, showing the tendency to establish the climax vegetation of Mediterranean coastal areas. The notable edaphic variables that affect the succession of the vegetation groups in the study area were moisture, salinity, organic matter, minerals (Ca, Na, K, Cl, SO4), soil texture and human disturbance. (C) 2012 Elsevier GmbH. All rights reserved.