Stream channel and vegetation responses to late spring cattle grazing

A 10-year riparian grazing study was conducted on a cold, mountain meadow r iparian system in central Idaho in response to cattle grazing-salmonid fish eries conflicts. Six pastures were established along Stanley Creek to study the effects on riparian habitat of no grazing, light grazing (20-25% utili zation), and medium grazing (35-50%) during late June. Stream channels narr owed, stream width-depth ratios were reduced, and channel bottom embeddedne ss decreased under all 3 grazing treatments as the area responded to change s from heavier historic grazing use. Streambank stability increased and str eamside willow communities (Salix spp. L.) increased in both height and cov er under all 3 treatments. Plant species richness increased on both streams ide and dry meadow areas during the years of grazing and moderate drought. The numbers of species receded to near original 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 am ong treatments after 1 year of rest. Most measurements of streamside variab les moved closer to those beneficial for salmonid fisheries when pastures w ere grazed to 10 cm of graminoid stubble height; virtually all measurements improved when pastures were grazed to 14 cm stubble height, or when pastur es were not grazed. Many improvements were similar under all 3 treatments i ndicating these riparian habitats are compatible with light to medium late spring use by cattle.