Changes in soil properties and vegetation following livestock grazing exclusion in degraded arid environments of South Tunisia

In this study, characteristics of vegetation and soil properties under continued grazing and exclusion of livestock for 6 and 12 years were examined in a degraded Stipa tenacissima steppe in South Tunisia Exclosures enhance the total plant cover, the dry matter yield, the number of species per unit area and the Shannon-Wiener diversity. Some palatable species were frequently found inside the protected site In the continually grazed site, these species are being replaced by less desirable species. Contents of soil organic matter, total nitrogen, Ca2+ and K+ in soils, as well as, water infiltration rate and basal soil respiration showed an increasing trend as time of grazing exclusion increased, from minimum values in the continually grazed area (Gr) to the maximum levels in 12 years protected area (12ex), while there was an opposite trend for Na+ concentration, EC, pH and soil hydrophobicity values The results suggested that excluding grazing livestock on the arid degraded steppes has a great potential to restore vegetation and soil. Therefore, it must be encouraged as an alternative to stop further degradation and to combat desertification in arid and semi arid ecosystems (C.) 2009 Elsevier GmbH. All rights reserved.