Short-term effects of fire frequency on vegetation composition and biomass in mixed prairie in south-western Manitoba

摘要: The net effects of one, two, and three spring burns in consecutive yearson the aboveground biomass, species composition, soil variables wereassessed two different mixed-grass prairie sites south-western Manitoba.Precipitation first year was greater than 30-year average but lowerduring next years. site (Area 6) characterized byBouteloua gracilis, Stipa spartea,Selaginella densa lichens, while second, somewhatdrier 10) dominated by B. gracilis andCarex spp. Each burn treatment applied to 15 plots inarandom block design. Vegetation data collected following thirdburnare presented. In general, repeated burning were more pronouncedin drier Area 10, where litter significantly reduced with eachadditional burn. 6, only after threeyears burning. both sites, cumulative effect fire had nosignificant on total standing crop, even yearsofburning. however, biomass several componentsshifted such that increasedsignificantly forb decreased burns. Plantcover also affected 10. cover B.gracilis, dominant C4 grass, increasedand Carex thedriersite. most significant a reduction inSelaginella lichen cover. Bare ground increased inbothsites as number increased. There little change soilnutrients burning, moisture somewhat surfacetemperature