SHORT-TERM RESPONSE OF RIPARIAN VEGETATION TO 4 GRAZING TREATMENTS

The Sheep Creek watershed of northcentral Colorado provided an ideal s ite to collect baseline trend data and to estimate foliar cover respon ses of montane riparian vegetation. Percent relative cover data were c ompared with Sorensen's similarity index and were analyzed with a 2-st age nested analysis of variance (ANOVA) to assess differences among 4 grazing treatments: long-term grazing (G), protection from livestock g razing since 1956 (P), recent protection following long-term grazing ( P88), and recent livestock grazing following protection (G88). This st udy utilized 3 replications of each treatment. Data were collected in August 1988, June 1989, and August 1989, employing permanent and rando mly placed transects and plots. When percent foliar cover means were p aired using Sorensen's similarity index, long-term grazing and short-t erm grazing treatments were least similar in August 1988. Long-term pr otection and short-term grazing were most similar in June 1989. Averag e percent cover of bare ground, common dandelion (Taraxacum officinale Wiggers), white Dutch clover (Trifolium repens L.), and legumes group ed as lifeforms were significantly different among treatments, with lo ng-term grazing being significantly different from long-term protectio n. Average sedge and forb cover was least affected. However, responses of individual sedge species varied with treatments. Average percent g rass cover increased under short-term protection after a history of lo ng-term grazing. Short-term grazing stimulated foliar cover of forbs, grasses, and sedges after more than 30 years of cattle exclusion.