A. ABABOU, M. CHOUİEB, A. BOUTHİBA, D. SAİDİ, M. Mâ€™hamedi BOUZİNA, K. MEDERBAL

Analysis of vegetation assemblage in the salted plain of the lower Chelif, Algeria

In order to establish the relationships between the plants communities and environmental gradients that prevail in the arid plain of the lower Cheliff, one of the largest salted alluvial plain in North Africa, we examined vegetation composition and the environmental variables, using 20 species sampled in 111 stands, followed by a direct gradient analysis. Classification of the vegetation using modified TWINSPAN classification resulted in the recognition of four vegetation units, each of these four units with a definite floristic composition, highly significantly different according to ANOSIM test, was linked to a specific habitat. Multivariate analyses including detrended correspondence analysis (DCA) and correspondence analysis (CCA) showed that vegetation distribution pattern was mainly related to conductivity and soil structure. CCA axis 1 (45.7% of variance explained) was mainly positively correlated to conductivity, Na+, clay and Ca++, with an exclusive appearance of halophilous species characteristic of the extreme salinity conditions. While it was negatively correlated mainly with soil structure and pH, these conditions were accompanied by the highest plant diversity in the study area, with the appearance of two vegetation units, adding up 13 species belonging to 8 families. CCA axis 2 (20.1% of variance explained) was positively correlated with soil structure and Na+, while it is negatively correlated mainly with Ca++, with the occurrence of three species indicating the worst soil structure conditions

Keywords:

Anosim, Conductivity, Correspondence analysis, Twinspan, Vegetation units,

PDF

___

Chytry, M., Tichy, L., Holt, J. & Botta-Dukat, Z. (2002). Determination of diagnostic species with statistical fidelity measures. Journal of Vegetation Science (pp. 79-90).
Chytry, M. & Tichy, L. (2003). Diagnostic, constant and dominant species of vegetation classes and alliances of the Czech Republic: a statistical revision. Folia-Biologia (pp. 1-231).
Flahault, C. & Schroter, C. (1910). Rapport sur la nomenclature phytogeographique. in Proc. 3rd International Botanical Congress, Brussels (pp. 131-164).
Hill, M.O. & Gauch, H.G. (1980). Detrended correspondence analysis, an improved ordination technique. Vegetatio (pp. 47-58).
Jongman, R.H.G., ter Braak, C.J.F. & Van Tongeren, O.F.R. (1995). Data analysis in community and landscape ecology, Cambridge University Press, New York.
Legendre, P. & Gallagher, E.D. (2001). Ecologically meaningful transformation for ordination of species data. Oecologia (pp. 271-280).
Legendre, P. & Legendre, L. (1998). Numerical ecology, Elsevier, Amsterdam. Leps, J. & Smilauer, P. (2003). Multivariate analysis of ecological data using CANOCO, Cambridge University Press, Cambridge.
McDonald, D.J., Cowling, R.M. & Boucher, C. (1996). Vegetation-environment relationships on a species-rich coastal mountain range in the fynbos biome (South Africa). Vegetatio (pp. 165–182).
MC Donald & B.N.E.D.E.R (1990). Etude de l’avant projet détaillé des extensions de Guerouaou et de Sabkhat Benziane et du réaménagement du Bas Cheliff, Bureau National d’Etude pour le Développement Rural, Tome I. Etude du milieu physique.
Orloci, L. (1967). An agglomerative method for classification of plant communities. Journal of Ecology (pp. 193-206).
Rao, C.R. (1995). A review of canonical coordinates and an alternative to correspondence analysis using Hellinger distance. Questiio (pp. 23-63).
Rolecek, J., Tichy, L., Zeleny, D. & Chytry, M. (2009). Modified TWINSPAN classification in which the hierarchy respects cluster heterogeneity. Journal of Vegetation Science (pp.596-602).
ter Braak, C.J.F. (1986). Canonical correspondence analysis: a new eigenvector technique for multivariate direct gradient analysis. Ecology (pp. 1167-1179).
Van der Maarel, E. (1979). Transformation of cover-abundance values in phytosociology and its effects on community similarity. Vegetatio (pp. 97-114).
Wang, G.G. (1995). White spruce site index in relation to soil, understory vegetation, and foliar nutrients. Canadian Journal of Forest Research (pp. 29-38).
Westhoff, V. & van der Maarel, E. (1973). The Braun-Blanquet approach, in Ordination and Classification of Plant Communities, Whittaker, R. H., Ed. The Hague: Dr. W. Junk Publisher (pp. 617-737).
Zuur, A.K., Ieno, E.N. & Smith, G.M. (2007). Analysing ecological data. Springer, New York.