Comparison of the effect of three woody species of Daphne mezerum, Amygdalus scopaia and Ebenus stellata on the diversity, richness and production of understory herbaceous species

Study of the effect of woody plant species on the production, diversity and richness of substratum herbaceous species, especially in the arid and semiarid regions, is essential for the proper management of these ecosystems. Therefore, the rangelands of Chenarnaz region in Khatam city in Yazd province were selected and then, using 0.5m×0.5m quadrats, vegetation sampling was performed under the selected 15 sites from Daphne mezerum, Amygdalus scoparia and Ebenus stellate (growing in equal topographical conditions) canopies, and outside of the canopies (as control). In each quadrat, the cover percentage of each plant species was visually estimated and the productions were measured by clipping and weighing method. The species diversity and richness indices were calculated using Past software through introducing the plant covers into the software. The results showed that the most values of Shannon-Weaner and Simpson diversity indices were found under A. scoparia (2.07 and 0.80, respectively) and the lowest values were found under E. stellata (1.010 and 055, respectively). In addition, the highest values of Menhinik and Margalef richness indices were found under A. scoparia (4.90 and 3.43, respectively) and D. mezerum (4.25 and 3.12, respectively), while the highest production was found under E. stellata (64.76 g/m2). The results of this study showed that different woody species had the desired but different effects on the herbaceous species, in such, A. scoparia and D. mezerum had significant positive effects on species diversity and E. stellata increased significantly species production; therefore, conservation of all woody species is emphasized in the region.