Fire effects on germination of soil seed bank in a semi-arid rangeland (a case study in Darehshahr, Ilam Province)

Abstract

The size and longevity of soil seed bank in rangeland ecosystem change continuously due to natural and anthropogenic disturbances such as seed mortality, decomposition, consumption by seedivores, fire, and germination. This study aimed to examine the influence of human-induced fire on seeds germination rate in soil seed bank of a semi-arid rangeland. The study was carried out in Darehshahr, southeast of Ilam Province, western Iran in 2016 with two treatments, i.e. burned and unburned sites, in three replications. Soil samples was randomly taken at two different layers of 0-5 and 5-10 cm. Totally, 30 soil samples were taken in each soil layers at each site. Soils were spread on 15 × 20 cm sterilized sand bed and germinated seed was monitored for 3 months. Seedlings were counted every 10 days and then removed from the trays. Diversity and richness of seedling were calculated using respective indices. The Repeated Measure Analysis of Variance was used to compare the diversity and richness of seedlings. The values of the Margalef and Menhinick richness indices in the burned site were 31.12 and 25.15% greater than that in unburned site. In addition, the values of the Simpson's and also Shannon-Wiener diversity indices in the burned site were 26.6 and 23.27% greater than that in the unburned site, respectively.