Studying the Vegetation Changes of Natural Rangelands in Inche Shorezar of Agh Ghala, North Golestan Province, Iran

Abstract

Studies on vegetation changes of rangelands under grazed and non-grazed<br />conditions are of great importance in the range management planning programs. To determine<br />the change process of vegetation, this study was performed in Inche Shorezar site of Golestan<br />province for nine years (1997-2005). The vegetation parameters were measured every year in<br />several fixed plots inside and adjacent of exclosures. The canopy cover of each species was<br />estimated in each plot. Forage production was randomly measured on one meter square plots<br />in each year using the clipping and weighing method. Correlations between canopy cover of<br />species and growth forms with the rainfall of different months and periods were calculated<br />using SPSS software. Results showed that total canopy cover in 2005 was significantly higher<br />than 1997 both inside and adjacent of exclosures which has been mainly related to increased<br />annual plant cover but the perennial canopy cover was decreased in these years. Perennial<br />species of (class I) did not grow inside the fixed plots. Cover of increasers (class II) species<br />was reduced from the first year to the final one for both inside and adjacent of exclosures.<br />However, the cover of (class III) species in the final year was not significantly increased than<br />that for the first year. Forage production generally was higher inside than adjacent of<br />exclosures. Litter increased during the study period for both inside and adjacent. Litter was<br />significantly higher inside of exclosures than adjacent in 2005. Although the plant canopy<br />cover was affected by rainfall but correlation coefficient was statistically significant only for<br />total, annual and some perennial canopy cover species. Although total and annual cover was<br />high inside and adjacent of exclosures in 2005, the cover of perennials was decreased. By the<br />reduction of palatable species, unpalatable species were increased inside and adjacent.<br />Although by increasing the plant cover, the range condition was relatively improved, this<br />improvement was achieved by the increase in the annuals instead of perennials. It was<br />concluded that the exclosure cannot be used as a range improvement method to improve these<br />rangelands' conditions. For the rehabilitation of these areas, human interference is necessary.