Patchy vegetation is the main characteristic of arid and semi-arid lands. Gaps between patches in some cases are covered with biological soil crust such as lichens and these crusts have important ecological roles such as influence on germination and plant survival. In this research, effects of lichens as an important biological crust on the germinations of some rangeland species were investigated in Golestan national parks. Seeds of 4 plant species including Stipa caucasica, Bromus tectorum, Melica ciliate, and Taeniatherum caput-medusae were collected and in a laboratory experiment effects of live lichen and removed lichen versus control were studied on germination percentage and speed (T₅₀) of these species. Results showed that germination percentage of Stipa caucasica and B. tectorum had significant differences among treatments and mean germination percentage of B. tectorum, M. ciliata, S. caucasica and T.caput-medusae were 86.4, 95.47, 51.2 and 94.13 percent respectively. Germination speed of S. caucasica, M. ciliata and T. caput-medusae varied significantly and the mean germination speeds of B. tectorum, M. ciliata, S. caucasica and T. caput-medusae were 0.57, 2.62, 6.06 and 2.75 days.

Keywords: Biological soil crust, Lichen, Germination, Steppe Rangelands, Golestan National Park.

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