Herbicide control of exotic grasses in south-east Australian native grasslands: case study with serrated tussock (Nassella trichotoma)
Bram Mason and Colin Hocking, Ecology and Sustainability, Victoria University, PO Box 14428 MCMC, Melbourne, Victoria 8001, Australia.
Summary
Australia's south-eastern native grasslands are one of Australia's most threatened ecosystems. Limited knowledge of grassland dynamics in the land management and scientific fields in the past has contributed to native grasslands being in poor quality today. Native grasslands of poor quality usually exhibit senescing native grass tussocks that are deteriorating in structure. Native forbs are also swamped out by the senescing grass tussocks leading to the forbs struggling to survive and reproduce. Soil nutrient enrichment can also occur due to the native flora not able to assimilate the nutrients to the same extent as they would if they were growing in a healthy state - not senescing. Poor quality grasslands are unable to compete adequately with invasion from exotic weeds. Invasion by exotic grasses into native grasslands in poor condition is a very real problem that is intrinsically connected to the decreasing biodiversity and sustainability of our native grasslands.
To adequately control the spread of exotic grasses in native grasslands the authors present a checklist for weed control measures in native grasslands. The checklist incorporates the biology and ecology of both the native flora and the exotic invaders. Also, timing, type and mode of action of weed control are considered. These points can provide a window of control for a particular situation. However, this is not the end to the weed control problem. In most circumstances the same or another exotic will re-establish in the control zone. Allowances need to be made to reintroduce native species back into the control zone to compete with the exotic invaders. A case study is presented using the checklist of control with a prescribed herbicide to control serrated tussock in a native grass and forb matrix.
Plant Protection Quarterly (2003) 18 (2) 72-77.