Dismantling feral ecosystems

Basalt escarpent, overrun with serrated tussock

I’ve been privileged to work for a few weeks on a basalt escarpment in Melbourne’s western suburbs. The area is spectacular; I love the views and geology and flora of the escarpments. Even this one, which is seriously infested with invasive exotic species.

The section I’m working on is overrun with serrated tussock (Nasella trichotoma), a South American native that causes big problems in agriculture and native grasslands. It’s an attractive species, but tends to smother everything around it – and its seeding panicles (seedheads) break off and blow in the wind, spreading it far and wide. Native animals, stock, and even rabbits barely touch it, preferring to eat almost anything else including all the native species. So it has a great competitive advantage, and easily takes over (especially under heavy grazing). It sets thousands of seed per plant, building up a huge reservoir in the soil seed bank. Continue reading


Autumn burning

Here’s a few photos of an ecological burn I was privileged to be on for work. Hopefully I can explain a bit of the why and how as far as burning native grasslands goes.

The grasses here were forming a thick thatch of dead matter, which can smother out all the smaller plants, annuals, and even the grasses themselves eventually. I arrived early so I had a bit of a walk around and although it was a great patch of Themeda triandra (kangaroo grass), it was getting a bit rank. You couldn’t see a single square centimetre of bare ground.

Autumn burns remove all that mostly dead biomass so that the winter growing C3 grasses have a chance, and many of the herbaceous plants (think: wildflowers). Come next summer, the Themeda will also take off again. It may be choking everything out again within a couple of years, needing another burn; if the local climate is dry, it might take a bit longer. Continue reading

Grasslands: every bit counts

Dumbarton St grassland

I visited the Dumbarton St grassland in Reservoir the other day. It was brought to my attention via an online petition asking the government not to sell it off for housing (please go there and sign!). It’s a large vacant block in a residential street, backing onto a linear reserve for a pipeline/aqueduct.

It doesn’t look much from the street, although grasslands often have that problem. The front half is mown and the back half is dominated by rank exotic grasses of the kind that tend to infest wasteland everywhere.

But in the centre is a small Eucalyptus tree (I think it was a River Red Gum), and in a halo around it, a spread of native grassland plants with few weeds among them. The Eucalypt probably takes enough moisture from the soil that the fast-living exotic invaders don’t bother with that area. So here there’s some mat-rush (Lomandra species), Bindweed (Convolvulus angustissimus), Nodding Saltbush (Einadia nutans), native tussock-grass (Poa species) and quite a lot of the once-ubiquitous Kangaroo Grass (Themeda triandra). And even among the weedy grasses, closer inspection reveals patches of Themeda are scattered here and there, and Convolvulus twining around the grass stems. Continue reading

The lilies of the valley

Blue Squill Chamaescilla corymbosa and others

I recently was blessed to visit a remnant grassland in a little valley on the plains of western Victoria during a mass spring blooming of various lilies, orchids and other wildflowers. This site was once a sheoak and banksia woodland/savannah (I’m told) but most of them are gone, having been cleared. The derived grassland is, nevertheless, spectacular in its own right. This mass flowering is something not many people in modern Australia would have seen, although it would have once been typical of our temperate plains and grassy woodlands. A few photos might at least start rectifying the sad state of public appreciation. Continue reading

Melbourne’s western grasslands: going, going…

Suburban developments, assuming they are necessary, can occur in many places. Endangered species and ecological communities do not have that luxury. It’s time to protect all the remaining grasslands.

An edited and updated version of this essay has been published at Green Left Weekly

Although about 99% of Victoria’s volcanic plains grasslands have been destroyed by development, some outstanding remnants of this unique ecosystem persist, especially on the plains just west of Melbourne (see for eg Smith 2015). This ecological community was Federally listed in 2008 as critically endangered (DEWPC 2011). Yet at the same time, the the then Labor government of Victoria was initiating an expansion of Melbourne’s Urban Growth Boundary that would severely impact the exact same areas. (DPCD 2008).

The government nominated two areas totalling 15,000 hectares to the west of the new growth boundary, called the Western Grassland Reserves (WGR). (DPCD, 2010). Developers are to purchase offsets within these areas in exchange for grassland destroyed by new developments (DEPI, 2013). Sadly these bold sounding deals are falling into disarray, with little conservation to show for it as development goes ahead even at the expense of endangered species (Arup 2015).

Continue reading