I recently returned from walking the Larapinta Track west from Alice Springs in the Tjoritja West MacDonnell National Park. One issue stood out above all others in terms of the ecological management of the park. Buffel Grass.
Buffel Grass was originally introduced into the NT inadvertently by the Afghan cameleers - it had been used to stuff the camel saddles (or at least this is what the guides on the walk told me). Subsequently, graziers in the north introduced several other Buffel Grass species. Buffel Grasses are ideally suited to spreading in the dry parts of Australia. They are deep rooted, resprout after fire, seed prolifically, germinate quickly, the seed has comb-like appendages which means in blows in the wind and can easily hitch a ride on a passing animal, and they are competitive with many of the sparser native grasses.
Unsurprisingly Buffel Grass grows better along the sandy creeklines than the driest slopes of the ranges. Indeed it grows so well in these locations that it creates an almost continuous cover, excluding native grasses, and building up a heavy fuel load of dry dead leaves around the base of each plant. This means, much more than any indigenous grass, that Buffel Grass creates more intense fires, and leads the fires along watercourses. There was plenty of evidence of this that I saw on the walk from the fires that burnt roughly half the park in January 2019. And distressingly, the creek beds are where almost all of the hollow-bearing trees are, and many of the oldest trees in the burnt areas were burnt to almost nothing but a pile of white ash.
So intense were the fires that the heat caused the quartzite rocks on parts of the range to flake off.
"In my opinion, buffel grass is the biggest threat to this part of the world." Jimmy Cocking, CEO of the Arid Lands Environment Centre, who also criticised the lack of fire management in the Park. He said to Alice Springs News that patch burning, breaking the country up, will protect the Park's assets in the long term, and without it "it will all burn in one hit".
- That hotter fires promoted by Buffel Grass can affect groundcover vegetation (including bush foods important to Indigenous communities) and carry into the canopy of keystone arid zone trees such as river red gums (Eucalyptus camaldulensis), corkwoods (Hakea species) and beefwoods (Grevillea striata) with flow-on effects to other plants and animals.
- A whole list of priorities for dealing with Buffel Grass.
But I have to say the case seems hopeless. The West MacDonnell National Park is 2500km2. There is no way that Gamba Grass can be directly targetted for control. Perhaps biological control might work, but powerful grazing interests would oppose that.
There is potential for Buffel Grass to invade Victoria too, however it doesn't appear to be even mentioned in the latest noxious weeds list on the Agriculture Victoria website. The last thing we want in Victoria is a fire-promoting weed invasion when climate change is already doing enough to cause bigger hotter fires.