Alice Springs lecturer gains grant to monitor effects of invasive grass 

Dr Christine Schlesinger measures the canopy

A CDU lecturer in environmental science has been successful in achieving a $7800 internal funding grant to help understand the effects of a major environmental weed in arid Australia.

Dr Christine Schlesinger, based at the Alice Springs campus, is working to determine the effect on native lizards of removing buffel grass from small areas by slashing and follow-up poison, and to evaluate the effort invested against biodiversity gains.

The grass’ effect on native plant communities is well established, but this program addresses the effects on native fauna.

Dr Schlesinger joins Professor Keith Christian, professor of Zoology at CDU and members of the Alice Springs Desert Park and Parks and Wildlife Service in the southern NT in this collaborative project.

Experimental sites will be located at the Alice Springs Desert Park and at Simpson’s Gap in the West Macdonnell National Park. High densities of buffel grass at Simpson’s Gap have affected fire regimes in recent years and there is already evidence that vegetation communities are changing, with fire-tolerant shrubs now dominating the canopy and long-lived corkwood trees dying.

An initial survey of reptiles and vegetation will be undertaken before any control of buffel grass.

Slashing will then take place during summer and reptile trapping will re-commence immediately after to detect any short-term effects.

If sufficient rain has fallen to produce a growth flush, poisoning will occur later in the year. Lizard trapping will continue later in 2008 to determine the longer term impacts of the control measures.

Controlling the grass can be challenging because there is only a brief period after rain when poisoning is effective. In the arid zone it is impossible to know when the next rain event will happen. Slashing immediately reduces the ground cover which lowers the risk of fire as well as changing the structural habitat for other plants and animals. But without follow-up poison, the grass will return with renewed vigour.

Buffel grass was introduced to arid Australia by Afghan cameleers and, more recently, was widely planted by pastoralists and government departments to increase productivity and reduce erosion by stabilising ground cover. It is still valued by the pastoral industry and so research into biocontrol has not been recommended as a management strategy for buffel grass.

But there is increasing concern, particularly in protected areas, about the effects of the grass on fire frequency and on plant and animal communities. Lizards were chosen as a target group to assess impacts on biodiversity because they live on the ground among the grass, and are known to respond closely to structural changes to their habitat.

The project will determine the short and longer term impacts on lizard communities from removing buffel in small areas on conservation reserves.

Dr Schlesinger said project aimed to help land managers decide if the slashing approach was the best way forward.

‘Because it’s not officially declared a weed in the Territory, there are some restrictions in how we deal with it,’ she said. ‘But this method will help to inform management of the grass in national parks where it is considered a big problem.’

Funding was made available through CDU’s Research Panel Project Grants and in-kind contribution from the Alice Springs Desert Park and a final paper will be submitted in early 2009.