THE EFFECTS OF FIRE AND COVER ON SEEDLING ESTABLISHMENT IN A NEOTROPICAL SAVANNA

1 It was hypothesized that if facilitation is important for seedling e stablishment in savanna, then fire should reduce seedling establishmen t. 2 This was tested in the cerrado savanna of Brazil with a factorial experiment designed to evaluate the effects of cover and prescribed b urning on seedling establishment. 3 Seeds of 12 species of trees and s hrubs were sown in plots located in sites providing three densities of woody cover and four times since last burning. 4 Seedling establishme nt generally was greater under the crowns of trees than in open grassl and, but individual species responded differently to cover. Eight of t he 12 species responded favourably to cover, but a single species show ed reduced establishment with increasing cover. 5 Burning had an overa ll negative effect on seedling establishment in the first year followi ng burning. By the second year following burning, establishment return ed to control levels. 6 An irrigation experiment with two species demo nstrated that rain-free periods within the wet season had negative eff ects on seedling establishment: 7 A litter-removal experiment with Mic onia albicans revealed that, at least for this species, litter has a n egative effect upon seedling establishment in densely wooded sites and positive effects in open grassland.