VEGETATION AND LITTER CHANGES OF A NEBRASKA SANDHILLS PRAIRIE PROTECTED FROM GRAZING

End of season components of biomass and litter were measured on a Nebraska Sandhills prairie site to follow vegetation changes during the 4 yr following the cessation of intense livestock grazing. The 1977-1980 mean annual end of season biomass at Arapaho Prairie, a sandhills prairie site, was 109 g/m2. Summer grazing on Arapaho Prairie was terminated in 1977, and as a result, significant increases in the biomass of the deep-rooted, palatable warm-season (C4) grasses, sand bluestem, little bluestem and switchgrass [Andropogon hallii, A. scoporius and Panicum virgatum, respectively], have occured since then. The biomass of the shallowly rooted C4 grama grasses [Bouteloua gracilis, B. hirsuta, Calamovilfa longifolia, Cyperus schwinitzii, Muhlenbergia pungens, Sporobolus cryptandrus] for the 4-year period was significantly correlated with growing season precipitation. Significant decreases in end of season biomass of the cool-season (C3) grasses [Carex heliophila, Festuca octoflora, Koeleria pyramidata, Stipa comata] during the same 4-yr period were highly correlated with yearly decreases in May precipitation. Following the removal of grazing, litter increased from 40 to 127 g/m2 from 1977 to 1980. A nonsignificant yearly increase in litter production occurred in the 3rd yr after grazing as a steady state of litter production and decomposition was approached.