Floristic diversity and vegetation patterns along disturbance gradient in arid coasts in southern Mediterranean: Case of the Gulf of Gabès, southern Tunisia

Knowledge about vegetation patterns along disturbance gradients is essential for conservation and management of coastal habitats in arid regions. This study focuses on the floristic diversity and the factors controlling the vegetation structure in the Gulf of Gabes (Tunisia). For this purpose, the floristic diversity of 120 releves belonging to three coastal sites with different disturbance levels (40 releves per site) was analyzed in relation with 10 environmental and anthropogenic factors. Therophytes constitute 54% of the 237 plants species belonging to 44 families identified in the present study. The species richness and floristic diversity indices exhibited a similar trend and peaked in the slightly disturbed site (H′ = 3.38; S = 176). The similarity between sites was relatively low and reached its maximum between the little and the highly disturbed sites. Two-way indicator species analysis and detrended correspondence analysis applied on the floristic data resulted in groups mainly determine...