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Assessment of species diversity and state of Stipa tenacissima steppes

North African steppes are subjected to extreme degradation resulting in the reduction of their surface, genetic erosion of resources, and decrease in biodiversity. Stipa tenacissima steppes, which constitute one of the most representative vegetation types in the driest areas of the Mediterranean basin, are continuously degrading. | Turkish Journal of Botany Turk J Bot (2015) 39: 227-237 © TÜBİTAK doi:10.3906/bot-1404-57 http://journals.tubitak.gov.tr/botany/ Research Article Assessment of species diversity and state of Stipa tenacissima steppes 1, 2,3 3 1 Wahida GHILOUFI *, José Luis QUÉRO PÉREZ , Miguel GARCÍA-GÓMEZ , Mohamed CHAIEB Unit of Plant Biodiversity and Ecosystems in Arid Environments, Faculty of Sciences, University of Sfax, Sfax, Tunisia 2 Department of Forestry Engineering, School of Agricultural and Forestry Engineering, University of Cordoba, Córdoba, Spain 3 Area of Biodiversity and Conservation, Department of Biology and Geology, Graduate School of Experimental Sciences and Technology, University of Rey Juan Carlos, Móstoles, Spain 1 Received: 05.05.2014 Accepted: 24.09.2014 Published Online: 16.03.2015 Printed: 10.04.2015 Abstract: North African steppes are subjected to extreme degradation resulting in the reduction of their surface, genetic erosion of resources, and decrease in biodiversity. Stipa tenacissima steppes, which constitute one of the most representative vegetation types in the driest areas of the Mediterranean basin, are continuously degrading. With the aim of contributing to a better knowledge of the floristic composition and diagnosing the state of degradation of these steppes, we conducted a phytoecological analysis of 10 S. tenacissima sites in Tunisia. Floristic inventory compiled a systematic list of 46 vascular plant species belonging to 43 genera and 26 families. Species richness ranged from 4 to 18 species per 900 m2. Total vegetation cover was moderate and fluctuated between 22.8% and 49.9%. Our results revealed also a decreasing trend in species richness with increasing elevation (ρ = –0.585). Indeed, species richness was negatively correlated with slope (ρ = –0.19) and positively correlated with sand content (ρ = 0.262). Biological types were dominated by chamaephytes; this chamaephytization is due to the phenomenon of aridization and .