Weeds usually occur where grazing and farming activities have been concentrated – around stock yards, dams and along tracks. Many start as introduced pasture grasses or arrive on vehicles, in stock feed, or with cattle and sheep.
When not controlled, weeds can out-compete native plants, smother native vegetation and have the potential to change fire regimes by providing fuel for wildfires.
At each of our reserves different weeds provide different challenges. Here are just a few.
Siam and Lantana (Yourka Qld)
At Yourka Reserve in the Upper Herbert River catchment, Reserve Managers Paul and Leanne Hales have been working on the control of Siam weed for almost a decade.
It occurs alongside Lantana, along creek lines and can be hard to spot until it's almost ready to seed. After trialling a range of control methods, they've established an effective cyclical approach using fire to reduce the plants and trigger seeds to germinate, then returning to spray the juveniles.
With the help of contractors and volunteers, they’ve reduced weed numbers by over 90% across the treatment area.
Importantly, this work at the top end of the river catchment has had a significant regional impact, helping to protect other areas such as the wet tropics downstream.
Buffel Grass (Bon Bon, SA)
Buffel grass came to Australia about 150 years ago with Afghan camel trains. It was soon the pasture grass of choice in the north as it can withstand heavy grazing and drought conditions.
It's a dangerous and invasive weed that produces wildfires so hot it has the potential to transform entire woodlands into grasslands of a single species.
At our Bon Bon Station Reserve in South Australia, Buffel Grass infestations along a 65km stretch of the Stuart Highway have been a focus, to prevent further spread onto the reserve. Tens of thousands of litres of herbicide have been used in a significant joint project by Bush Heritage volunteers, SA Main Roads, the SA Arid Lands NRM Board and the Native Vegetation Council.
It's a battle that's likely to continue for many years, with vigilant monitoring and support for community efforts to control the weed in surrounding areas.
We remove weeds by hand, burn, spray or inject them with herbicide. In the case of highly invasive pasture grasses such as Serrated Tussock and Buffel Grass, we've sometimes used grazing to reduce the amount of seed produced and to reduce the density of the plants (alongside other control measures).
How the land responds
Once weeds are removed or reduced, native species can recolonise the areas naturally or we spread native seed or replant seedlings to help re-establish native habitats.