Stream Channel and Vegetation Responses to Late Spring Cattle Grazing
Journal of Range Management , 52 , 1999
A 10-year riparian grazing study was conducted on a cold, mountain meadow riparian system in central Idaho in response to cattle grazing-salmonid fi'sheries conflicts. Six pastures were established along Stanley Creek to study the effects on riparian habitat of no grazing, light grazing (20-25% utilization), and medium grazing (35-50%) during late June. Stream channels narrowed, stream width-depth ratios were reduced, and channel bottom embeddedness decreased under all 3 grazing treatments as the area respond- ed to changes from heavier historic grazing use. Streambank stability increased and streamside willow communities (Salix spp. L.) increased in both height and cover under all 3 treat- ments. Plant species richness increased on both streamside and dry meadow areas during the years of grazing and mod- erate drought. The numbers of species receded to near origi- nal levels in the ungrazed and light grazed pastures in 1996, a wet post-grazing year, primarily due to a decrease in forb species. Streamside graminoid height growth was similar among treatments after 1 year of rest. Most measurements of streamside variables moved closer to those beneficial for salmonid fisheries when pastures were grazed to 10 cm of graminoid stubble height; virtually all measurements improved when pastures were grazed to 14 cm stubble height, or when pastures were not grazed. Many improvements were similar under all 3 treatments indicating these riparian habi- tats are compatible with light to medium late spring use by cattle.