Influences of patch-burn grazing on headwater prairie streams and subsequent recovery

1. Patch-burn grazing (PBG) can promote terrestrial heterogeneity and biodiversity, but can temporarily increase stream nutrients, ecosystem metabolism, and alter macroinvertebrate assemblages. The impacts of grazing on stream channel morphology and post-PBG recovery patterns are unclear. 2. We assessed the influence of grazing in PBG managed grassland streams in Missouri, USA, and subsequent recovery when grazing ceased for two years. We hypothesized that grazing would degrade water quality, stream biotic integrity, and channel morphology, but that riparian fencing would mitigate these effects. We predicted that biological and chemical variables in unfenced streams would return to pre-PBG levels within two years after grazing ceased, but channel morphology would not. 3. Six small headwater streams (two in ungrazed control watersheds, two in PBG watersheds with 10 m fenced riparian zones, and two in unfenced PBG) were sampled over seven years; 2 years before PBG, 3 years during PBG, and...