Comparison between Some Vegetation Traits and Bioindicators in Two Grazing and Exclosure Areas (Case Study: Sorkhe-Graz and Valikbon Rangelands)

Abstract

Overgrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. In order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this effect with exclosure area, and proving of the excluded area effects on plant diversity; two sites of Kojour rangeland, Mazandran province, Iran. Four transects, 50 m were systematic-accidentally established on two different aspects including along of slope (two transects) and staple on steep slope side. Cover percentage was recorded by 10 plots 1m2 in each transect. Rangeland condition and trend was determined by 6-factor and Trending Balance methods, respectively. Diversity indices in each area, by analysing of vegetation parameters, were calculated using PAST software. Vegetation traits and bioindicators were analysed by independent T-test using SPSS software. The result showed that percentages of all life-forms in rangeland were different between the exclosure and grazing areas, especially, grasses and forbs were meaningfully remarked. Regarding to bioindicators, diversity-Shannon index and richness-Menhinick index values were higher in the exclosure area than open area (P<0.01). Dominance index in grazing area was significantly higher than exclosure area (P<0.05). Evenness index, however, has not punctual difference in both areas.