Effects of fire protection on savanna structure in Central Brazil

Aim Fire protection gradually changes the density of woody plants in numero us savannas around the world. In this study changes of structure in two tro pical savanna areas with contrasting history of fire protection in the cent ral Brazilian Cerrado is documented. Location Vegetation was sampled with line intercept transects in two adjace nt sites in Brasilia, Federal District. These transects were located within a nature reserve protected from fire since 1972 and within an adjacent res erve area that burns every 2 years. Methods Five savanna physiognomies, from a low forest ('cerradao') to an op en savanna ('campo sujo'), were sampled in both sites. Results Fire protection increased the abundance of woody plants and favoure d fire-sensitive species. With some exceptions, shrubs tended to be less af fected by fire than trees. Species distribution was affected by a complex i nteraction of fire and physiognomy. Fire had the strongest effect on 'campo sujo' savanna, and a less significant effect on the intermediate physiogno mies. Main conclusions Protection permits the establishment of fire sensitive spe cies. A long enough protection against fire could lead to the appearance of more wooded physiognomies in the Cerrado.