Reconciling cattle, conservation and culture: The challenge of grazing, controlling and communicating about Gamba grass

Gamba grass Andropogon gayanus is an African perennial introduced for pasture trials at Katherine in the Northern Territory during the 1940s. While it has been successful as a pasture it has also become a serious environmental weed. Gamba grass produces flammable material up to five times greater than fuel loads in native grasses (typically 2 - 4 t/ha), cures later in the year (June-July versus April) and maintains a tall, upright structure. Fire intensities and flame heights are increased and these conditions have severe impacts on the less fire-tolerant native grasses, shrubs and trees. Recovery by the exotic perennial is rapid. On the rural/urban interface, where development and disturbance coincide, the growth and spread of this grass is prolific. The threat to property, residents and firefighters is also significantly increased. Some ecologists (Bowman 1999; Flores 1999) have expressed concern about the widespread threat to northern Australian savannas, and the evidence to support that view is mounting. Given the usefulness of gamba grass as a pasture, there has been considerable debate about its status as an environmental weed, the extent and seriousness of the problem, and the manner in which the issues should be tackled.