Impact of Rosa persica Controlling Methods on Species Richness and Diversity in Steppe Vegetation, Arak, Iran

Rosa persica Michx. ex Juss. is an aggressive plant species in Iranian rangelands. Several controlling methods have been suggested to stop its expansion. This study examined the short-term effects of fire, tilling, cutting, and herbicides as a means of controlling Rose persica on the richness, evenness and diversity of R. persica communities in rangelands of Iran. The experiment was arranged using a split-plot design with fire (burning and control) as main plot and four treatments (cutting, tilling and glyphosate herbicide and control) as subplots based on a completely randomized block design with four replications over three years (2013-2015) in khosbijan, Iran. The Margalef, Sheldon, and Shannon-Wiener indices were used to assess the species richness, evenness, and diversity, respectively. We found that treatments had a different effect on the plant community composition. Prescribed fire coupled with other treatments had a significant effect on species diversity rather than control (p <0.01). This finding indicated the significant effect of prescribed fire on the plant diversity indices. Mean of diversity was higher in burning alone (3.181). The highest value of evenness was related to the chemical treatment without fire (0.582) and the highest richness was related to the control (11.114). Also, the lowest values of diversity, evenness and species richness occurred by cutting without burning (2.582), control area without applying other treatments (0.258) and herbicide without burning (7.921), respectively. Therefore, plant diversity was increased using each treatment. This may be due to reduction of R. persica frequency. Despite the increasing of species diversity after applying treatments, it should be acknowledged that due to lack of desirable species gene pools and colonization of ruderal species, the vegetation composition won't be necessarily desirable. Therefore, in R. persica communities, the restoration of these communities should be considered after the controlling of the R. persica.