Effects of Clipping on Size and Tillering of Native and African Grasses of the Brazilian Savannas (The Cerrado)

Abstract

African grasses are becoming major invaders of crop fields, degraded rangelands, and natural reserves of the Brazilian savannas (the cerrado). One of the main hypotheses proposed to explain the successful spread of these species suggests that they are more grazing tolerant than native grass species. To test this premise I compared African and native grasses for tillering and size change responses after clipping. It was hypothesized that African species would tiller more but be shorter after clipping than native species. Four African and five native grasses were clipped in the field at three different periods: early wet season, late wet season, and dry season. Control plants were not clipped. Plant height and number of tillers were measured. Plant base circumference was also measured in the caespitose species to determine whether or not species were spreading laterally as a result of tillering