In East African savanna grasses, as the growing season progressed, there was a systematic decline in nutritional value at all sites, as indicated by fibre properties, but fibre nutritional values were at all times higher in areas of high herbivore use intensity (HUI) than of low HUI. There were few differences in fibre properties between soil types. There were marked differences in element contents between samples from different soil types, and relatively less variation in element contents with time and HUI. Much of the between-site variation was due to different plant species compositions. Grazing animals can apparently regulate plant nutritional properties by increasing soil nutrient levels and by changing species composition. -from Authors