Effects of cessation of grazing on vegetation and soil characteristics
Consistent with our expectations, across all sites, cessation of grazing had strong effects on plant community composition (Figure S1). In general, cessation of grazing resulted in plant communities becoming more dwarf-shrub or fern dominated on acid soils, or dominated by tall grasses (e.g ., Deschampsia cespitosa) on more alkaline soils. Sites where grazing was excluded had marginally higher aboveground biomass (F(1,73)3.28, p=0.07), although this varied strongly by site (F(11,73)2.77, p = 0.004). Across sites, cessation of grazing caused the litter layer depth to increase on average by 28% or 4 cm (F(1,60), P=0.04). Cessation of grazing also resulted in changes in soil abiotic properties, including lower mean soil temperature (F(1,53)22.0, p <0.001) and reduced electrical conductivity (F(1,53)8.8, p =0.004). Grazing removal resulted in slightly higher soil inorganic nitrogen concentrations (F(1,69)4.4, p=0.04), but we detected no changes in rates of potential N mineralization (p > 0.1) nor in pH (p > 0.1). Soil bulk densities varied across sites (F(11,88)8.84, p < 0.001), but were not affected by cessation of grazing (p > 0.1).