GROWTH OF PROSOPIS-CALDENIA SEEDLINGS IN THE FIELD AS RELATED TO GRAZING HISTORY OF THE SITE AND IN A GREENHOUSE AS RELATED TO DIFFERENT LEVELS OF COMPETITION FROM STIPA-TENUIS

In temperate semi-arid rangelands of Argentina grazing by domestic liv estock is apparently linked with the conversion of open grasslands to dense shrublands. Prosopis caldenia and Stipa tenuis are dominant spec ies of the shrub and grass life-forms, respectively. Research was cond ucted to determine the growth responses of P. caldenia seedlings to gr azing history of the site and competition from S. tenuis, at different levels of water availability. The Prosopis seedlings grew better (p < 0.05) in long-term protected than in long-term grazed sites, and at l ow rather than high levels of competition from S. tenuis. Both overgra zing and high levels of grass competition may limit the establishment of P. caldenia seedlings in grasslands, particularly under conditions of water shortage. (C) 1996 Academic Press Limited