DIVERSITE FLORISTIQUE EN RELATION AVEC LES GRADIENTS ABIOTIQUES DANS LA ZONE HUMIDE DE LA MACTA (QUEST D'ALGERIE)

Floristic diversity in relation to abiotic gradients in La Macta wetland (West Algeria). The Macta marshes are classified as a Ramsar site and currently profit at the same time from the attention of both authorities and scientists. The aim of this article is to make a study on the relationship between the environmental factors and the plant groupings along a transect. Factorial analysis of correspondences allows the individualization of three principal groupings: maritime, of sebkhas and succulent salted steppe. Canonical analysis highlights the superposition of edaphic gradients, physiographical variables and anthropic pressure. Results suggest that the distribution and variation of species abundance are mainly ordered according to salinity, texture of soil, degree of immersion, altitude and human pressure. The use of biodiversity indices with techniques of coordination leads to a good discrimination between the plant communities and a better comprehension of the state of these marshes.