Effect of fire and grazing on vegetation and biological soil crusts in eastern Montana. Muscha, Jennifer^*,1, Vermeire, Lance², Haferkamp, Marshall³, ¹ USDA-ARS Fort Keogh Livestock and Range Research Laboratory, Miles City, MT² USDA-ARS Fort Keogh Livestock and Range Research Laboratory, Miles City, MT³ USDA-ARS Fort Keogh Livestock and Range Research Laboratory, Miles City, MT

ABSTRACT- Little information exists about fire and grazing effects on biological soil crusts in the northern Great Plains. Four permanent quadrats (20 x 50 cm) were selected based on presence of lichens and mosses to measure canopy cover in each of 4 blocks and 3 treatments in a randomized block design. Treatments were autumn fire, moderate grazing (50% removal) in May and June and a non-burned, non-grazed control. Plots were 15 x 39 m. Dominant herbaceous species were needle-and-thread, western wheatgrass, junegrass and threadleaf sedge. The dominant lichen, Cladonia pocillum, other lichens and grass cover decreased 1 year post-treatment. Cladonia pocillum cover decreased from 10.8% to 9.3%, other lichens decreased from 2.5% to 2%, and grass decreased from 18.8% to 8.5%. Burning and grazing reduced moss cover. Across treatments, moss cover decreased from 1% to 0.5% the second year. Litter cover was similar across plots before treatments were applied (∼60%). Litter increased in the second year for all treatments, but at a slower rate in the burned plots. Bare ground cover was lower in the burned plots (4%) before treatment and increased to 7% after treatment. Control and grazed plots had more bare ground cover before treatments (8%) and decreased to 4% after treatment. There was no effect on forbs. Seven lichen and 2 moss species were encountered at this site. Delayed fire effects may be expected for lichens.

KEY WORDS: moss, lichen, northern great plains