Fire-induced damage to Qualea multiflora Mart. seeds depends on fruit protection and the position in the tree crown.

Abstract

Although the Cerrado vegetation is adapted to fire, anthropogenic fires may impair the reproduction of some species. This study aimed to test the role of fruits of Qualea multiflora and their position in the tree crown in protecting the seeds during fires. Ten trees were selected in an area protected from fire (NB) and ten in a biannually burned area (B). Fruits were counted before the 2008 fire and weekly thereafter for 5weeks. Fruit dehiscence, damage and position in the tree crown were recorded. Seed germination was assessed for seeds from both areas. In NB, 5.7% of fruits were located higher than 2m, while in B 49.5% were located at this height. One week after the fire, the proportion of dehiscent fruits was lower in NB (19.5%) than in B (34.5%). Five weeks after the fire, all fruits in NB had dispersed their seeds, whereas in B only 47% of the fruits had. Immediately before the fire, the germination rate of seeds collected in NB was 80% (0-1m), 97% (1-2m) and 92% (≥2m). Fifteen days after the fire, the germination rate of seeds in the B area was 3% (0-1m), 13% (1-2m) and 78% (≥2m). Protection of Q.multiflora seeds from high temperatures is related to the fruit position in the tree crown rather than to fruit protection. Therefore, the results suggest that fire may alter the recruitment of new individuals.