摘要：Livestock grazing influences arid rangelands greatly with important effects on vegetation dynamics. Two areas traditionally grazed by sheep and goats in southern Tunisia were sampled to evaluate the vegetation response to grazing management. A continuous grazing (CG) area was sampled in March 2007. A 2000 ha exclosure that had been rested for 3 years (2004–2007), grazed for 2 months (July and August 2007), and then rested for 7 months (September 2007 to February 2008) was sampled before and after grazing, and again after the 7 months’ rest. Results show that vegetation dynamics in arid rangelands respond strongly to changes in grazing management. Our results suggest that even previously overgrazed rangelands are resilient and are able to recover if given rest periods. In the studied Tunisian rangeland that has been moderately or lightly grazed, we found that recovery improved faster compared with continuously grazed. In practice, excluding grazing livestock and the use of a rotational grazing system are available ways to restore vegetation affected by CG. Therefore, a stocking rate not exceeding the carrying capacity is vital to maintain grazing operations under changing conditions and sustain rangeland resources over the long term. Increased stocking rates generally promote rangeland degradation.
