The role of fire in germinating Wild Rice (Oryza meridionalis), an annual grass of northern Australian wetlands threatened by exotic grass invasion

摘要

Para Grass (Urocbloa mutica (Forssk.) Nguyen) has invaded large areas of north Australian wetlands, out-competing native flora. Post-fire observations indicated that the native grass, Wild Rice (Oryza meridionalis Ng), re-established where gaps in Para grass mats had been created by burning. We tested whether it was fire itself or simply the removal of Para Grass that promoted Wild Rice, by subjecting comparable buried seed batches to one of three treatments: fire (at two intensities) and no fire. Subsequent germination tests confirmed current laboratory research that suggests post-fire promotion of Wild Rice is not a function of fire per se (neither heat or smoke) but is likely to be due to the removal of the smothering grass layer, even though fire is a efficient way of removing Para Grass.