AbstractIn northern Australia, the biology and ecology of native grasses in relation to their suitability for revegetation of disturbed areas is poorly understood. Introduced grasses have traditionally been used for revegetation but this practice is often in conflict with the rehabilitation objective of developing self-sustaining native ecosystems. This study, located at Ranger Mine near Jabiru in the Northern Territory, evaluated the potential of four native grasses for revegetation. The species consisted of three perennial species Ectrosia leporina R.Br., Eriachne schultziana F. Muell. and Dichanthium sericeum (R.Br.) A. Camus, and one annual species, Pseudopogonatherum contortum (Brongn.) A. Camus. These were compared with the introduced grass that has been commonly used for revegetation at Ranger and across northern Australia, Chloris gayana Kunth (pioneer rhodes grass).
Seed of the perennial species was dormant for at least six months while the annual Pseudopogonatherum was dormant for only two months. To maximise field germination, seed of perennial species should stored for at least 12 months and seed of annual species should be stored at least five months prior to sowing.
All species, except Dichanthium, established well from direct seeding. Eriachne, and to a lesser extent Ectrosia, demonstrated the best potential for revegetation because they had high maximum germination (>65%), produced relatively high foliage cover without fertiliser (40-50%) and, importantly, they resprouted successfully following both dry season drought and fire. Thus, once established, their populations will be resilient and self-sustaining. In contrast, the introduced Chloris had relatively low maximum germination (42%), required fertiliser to produce similar cover to the native species, and populations did not recover from the dry season drought and were decimated by fire.
This study has shown that, provided that the species-specific germination and field establishment characteristics are known, using native grasses for revegetation can be highly successful. Revegetation with native grasses is also an ecologically and economically attractive alternative to revegetation with introduced species.
|Date of Award||May 2002|