RESPONSE OF ANNUAL PLANTS AND COMMUNITIES TO TILLING IN A SEMIARID TEMPERATE SAVANNA

Despite the obvious importance of savannas, the response of semi-arid temperate savannas to disturbance has hardly been studied. The objecti ve of this study was to determine the response of annual plants and ve getation to severe disturbance (tilling) in the grassland phase of a s emi-arid savanna characterized by perennial bunchgrasses. Most species of annual plants responded positively to tilling; however, 25 % of th e species did not respond or responded negatively. Response of plants and vegetation was more strongly influenced by precipitation than dist urbance, even for the severe disturbance used in this study. Tilling-i nduced differences were negligible during a relatively dry year. Respo nse of annuals to disturbance in semi-arid temperate savannas may not be consistent with response in other systems.