Biotic and Abiotic Interactions Shape Seed Germination of a Fire-Prone Species

Abstract

Both biotic and abiotic environmental filters drive the occurrence, distribution, and persistence of plant species. Amongst drivers that influence the distribution of plants in harsh environments, seed predation and temperature are particularly important in habitats that are prone to fire. In this study, we highlight the combined effects of predation and high temperature simulating fire to understand its effects on the germination percentage and germination speed of the fire prone species Copaifera oblongifolia. Groups of seeds attacked by the beetles Rhinochenus brevicollis and Apion sp., seeds manipulated by the ant Atta laevigata, and seeds left intact were put to germinate in controlled environments. To evaluate the effects of abiotic filters, seeds with intact elaiosomes and seeds with elaiosomes removed by the ant Atta laevigata were exposed to temperatures of 27, 60, 100, and 200 °C. The results showed that only 2.8% of the seeds attacked by R. brevicollis germinated. Seeds attacked by Apion sp. germinated faster, followed by seeds with their elaiosomes removed and seeds with intact elaiosomes. Seeds attacked by Apion sp. had the lowest germination percentage. The temperature of 200 °C killed seed embryos, whereas seeds exposed to 100 °C took longer to germinate than seeds exposed to other temperatures. Our results reveal that fire intensity and seed damage are important drivers of seed germination of C. oblongifolia.