If you've travelled across the Eden Monaro districts recently, you may have noticed great swathes of land covered by African Lovegrass (Eragrostis curvula). It's an attractive plant, with soft feathery seed-tops and generic tussock round leaves.
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It's an example of a "transformational weed", which get their name from the drastic changes they bring to a landscape. Similar examples are Gamba grass (Andropogon gayanus) and Buffel grass (Cenchrus ciliaris).
Transformational weeds such as Lovegrass are early and rapid colonisers of degraded country. As the drought has laid bare so much land, Lovegrass has hopped in to displace other plants.
From there, it smothers competitors, turning the rich blend of what was once there into a monoculture. The loss of diversity disrupts the local ecology, with knock-on effects on other plants, insects and wildlife.
Categorising these things can be contentious because one person's weed can be another person's treasure. Buffel grass is a "declared plant" in South Australia, which prohibits its sale and movement. Meanwhile, the Queensland Department of Agriculture and Fisheries website promotes its use, saying "Buffel is more productive than the native grasses when soil nitrogen levels are high".
The NSW Department of Primary Industries site suggests the Consol cultivar of Lovegrass is a "hardy perennial grass with special attributes as both a pasture plant and a soil binder". Consol differs from the naturalised Lovegrass which is unpalatable. It cannot be sown where African Lovegrass is a declared weed.
Fortunately, there appears to be an effective control for the invasive form of Lovegrass that uses a combination of fire and herbicide.
Transformational weeds are a subcategory of invasive species. In Australia, we are plagued with many others, often deliberately introduced. As "acclimatisation societies" sought to make the country more like Britain, in came rabbits, goats, carp and numerous birds that still cause ongoing destruction. That includes as many as 500,000 feral sambar deer now roaming through Victoria.
Also on the list of All Time Bad Ideas was Baron Ferdinand von Mueller, filling his pockets with blackberry seeds to spread across the countryside. Von Mueller was Victoria's first government botanist and was involved in planning Burke and Wills' ill-fated exploration. Dr Pete Minard's book, All things Harmless, Useful and Ornamental describes how von Mueller thought the explorers might've survived if they'd had access to plants such as blackberries.
One wonders whether it crossed his mind that Aboriginal people had been living here for thousands of years without them.
Even if weeds can transform a landscape, their influence is easily surpassed by humans. After all, they wouldn't be here without us.
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