Grazing animals affect rangeland vegetation structure and function both directly and indirectly.
These effects can be assessed in exclosures. In this study, vegetation changes inside and outside of
exclosures of Tanglaybid rangelands, located in south-western part of Yazd province, have been
investigated. Vegetation changes study was carried out in 3 key areas inside and also 3 key areas
outside of exclosure and lasted for 5 years (2000-2005). Every key area included 3 transects of 100
meters long and 40 meters intervals. The transects were selected vertical to slope, including 10
fixed plots (2×1 m2). Vegetation cover, density and frequency percentage of each plot species were
measured annually. The random- systematic method was applied as a sampling method. Vegetation
changes inside and outside of exclosure were assessed, in a completely random plan, applying
Duncan's test (P < 0.05). The results showed that vegetation cover percentages increased
significantly (P < 0.05), inside the exclosure comparing to outside of it. Mean coverage of annual
and perennial grasses and also bushes, inside the exclosure comparing to its outside increased 47,
38 and 7%, respectively. Thus, in present research, exclosure has positive effects on vegetation
cover changes of several species. Frequency percentage results showed that there was no significant
difference, inside against outside the exclosure in 2000, 2001, 2002, 2003, and 2004. Regarding
density, there was significant difference only in 2001.The results can be considered in future
management of the area's rangelands and similar regions throughout Iran