Protecting the iron-grass natural temperate grasslands of South Australia
While native grasslands were once found in landscapes the world over, many of these ecosystems are under threat from land clearing. Parts of South Australia were once dominated by a unique native grassland - the iron-grass natural temperate grasslands (INTG) - but grazing of livestock had a significant impact on this ecosystem and today only 1% of the original footprint remains. In order to preserve and enhance remaining parts of INTG, specialist ecologists from the Murraylands and Riverland Landscape Board have been working with local landholders and First Nations communities.
What is an iron-grass temperate natural grassland?
Iron-grass temperate natural grasslands (INTG) are a community of plants dominated by grasses with no or few trees and tall shrubs. This ecosystem is highly diverse with a mix of grasses and wildflowers including herbs, lilies, orchids and small shrubs.
Where are iron-grass natural temperate grasslands found?
Mixed with grassy woodlands, iron-grass previously occupied the area from the base of the eastern Mount Lofty Ranges across to the Mallee and from Callington northwards to Terowie and beyond. Iron-grass grasslands occur in the transition zone between the higher rainfall forests and woodlands and the drier Mallee areas.
Poonthie Ruwe Conservation Park at Tailem Bend is home to one of the last remaining INTG grasslands and, like many native ecosystems, is under threat from invasive pest species including rabbits.
Wild rabbits are declared pest animals under the Landscape South Australia Act, causing damage to native vegetation by eating bulbs and plants, and directly competing with native wildlife for food and shelter. Their digging and feeding leads to a loss of vegetation cover and soil erosion.
What are we doing to protect iron-grass temperate natural grasslands?
To protect INTG grasslands from the effects of rabbits, the landscape board’s landscape ecology team managed a rabbit baiting program in late summer 2023, working to control the rabbit population in Poonthie Ruwe Conservation Park and on the adjacent Dukes Highways Roadside.
To ensure that no native flora was damaged, the team used a variety of baiting techniques including hand-baiting in sensitive areas. In patches where the environment was more degraded, bait was distributed using bait layers.
The program’s success was mixed but overall rabbit numbers are now significantly lower. This more manageable level will allow better results from follow up control treatments in the following seasons.
Statistically, it takes only 0.5 rabbits per hectare to prevent new native plants growing, so focussing on managing rabbit warrens over winter has become more of a focus for landscape board ecologists. Our team is currently monitoring warrens in the park for rabbit activity and ascertaining the level of native fauna that might use the warrens as shelter. This is an important step so we can prevent damaging native fauna when fumigating or destroying the warrens.
Work to bait rabbits was undertaken by staff from our district team in conjunction with staff from National Parks and Wildlife Service with co-funding from the Department of Infrastructure and Transport.
This project is supported by the Murraylands and Riverland Landscape Board through funding from the Australian Government’s National Landcare Program.