by Tim Low
Brushtail possums get fed too. These likeable chaps try our affections by stealing fruit, munching plants, peeing on ceilings, and thumping on roofs in hobnailed boots. I never resented the odd apple they took from my kitchen, but the broken crockery! Now I keep my windows shut. A few possums are fine, but our cities are overrun. Screeching feuds over accommodation are a common urban sound. Possums probably prey on many nesting birds, contributing to the toll exacted by currawongs and crows.1 People deal with them in topsy-turvy ways. Boxes in trees are supposed to lure them out of buildings, but all they do is accommodate more possums. They only work if the possums are also evicted from nearby homes. In The New Native Garden (1999) Paul Urquhart and Leigh Clapp get possums completely wrong. ‘It’s mostly where natural foods have diminished, due to habitat destruction (usually for housing tracts), that conflicts occur,’ they suggest. ‘The simple solution is to grow some food for them.’ This may be simple, but it’s wrong. Animal problems are seldom so easily solved.
In Melbourne possums fed in parks are multiplying and stripping treasured elms. In Curtain Square, North Carlton, two dying trees had to be removed, and others were dressed in metal collars to keep possums away. A few possums were separated from their holes in the trees, outraging Animal Liberation, which dropped a road-killed possum on the doorstep of Yarra’s mayor.
Bird boxes are wonderful when they work, but too often they only aid the enemy. A study in Canberra’s bushland parks reported Indian mynas in thirty-five boxes, starlings in five, feral honeybees in seven, and native birds (rosellas) in only seventeen. Tough-minded mynas will pile their straw over hapless parrot eggs. Hugo Phillipps recommends boxes only if they are actively managed. ‘This means removing the eggs and nestlings of Common Starlings and Common Mynas and destroying the nests of feral Honeybees or European Wasps,’ he writes on the Birds Australia web site, noting that ‘deterring Mynas and Starlings from renesting is not easy; these pests are very persistent, and constant vigilance is necessary.’ You must climb the tree and empty the box, over and over, killing chicks and eggs, until the bad birds give up. It’s not what most people have in mind when they put up a box.
For this reason, Brisbane City Council won’t allow any more boxes into parks. Senior manager Jim McDonnell speaks of their ‘dubious merit’ and the ‘difficult dilemma’ they pose. ‘The fundamental issue, in my personal view, is that nest boxes aren’t achieving anything.’ He cites a local survey showing that boxes were occupied only by very common birds – mainly lorikeets and rosellas – and by pests. He knows of one reserve with nest boxes all over the place and nothing in them but bees. ‘There’s a lot of good intentions but not a lot of science behind it,’ he complains. ‘For example, if you put in possum boxes, are you artificially increasing the brushtail possum population at the expense of other species? Are they going to compete with gliders?’ He wants boxes in reserves only if clear benefits to some declining species can be shown. That’s certainly possible in some bushland remnants, but not at all likely for a box nailed in a garden.
Bat boxes don’t do any harm, but they may not be much good either. Monika Rhodes said they often remain empty for years on end, and many are probably never used. We don’t know for sure because our little insect bats are very shy and transient. Boxes are based on foreign designs that may not suit our species. European and American bats show differing tastes for plywood and paint. The narrow slits keep out possums and birds and end up looking nothing like tree holes. Bats may fail to recognise them, or may be deterred by the scents of humans, paint and glue. Boxes are proving their worth in some bushland settings, including Organ Pipes National Park near Melbourne, but whether they work in city gardens remains to be seen. Monika has boxes in place to find out. She suspects it may take fifty years of trial and error to perfect suitable designs here.
Reptiles can certainly be helped by installing rocks, logs and groundcover plants, and by embracing disorder. My garden teems with lizards, but my tenants are mostly grass skinks, lizards that weren’t here before the houses went up. Nothing I could do would bring back the fleet forest skinks that scampered here before. I love my lizards, and my lizards love my garden, but I can’t pretend I’ve created a refuge for reptiles displaced by development.
It worries me that many people have been led into thinking they are doing their share for conservation when they green up their gardens. If only it were that easy. ‘We can all do our bit for wildlife conservation by planting habitats for animals that would otherwise be displaced by housing developments,’ one book claims. This is well meaning, but wishful thinking, and more selfish than it seems. ‘You are helping yourself to feel good,’ said Ian Temby about bird feeding. ‘To an extent it’s about playing with nature and being seen to do something,’ said Jim McDonnell, with nest boxes in mind. When university reseachers Peter Howard and Darryl Jones interviewed people who feed birds (a third of households in Brisbane), the prime reason given was to ‘make up for the loss or destruction of habitat’. ‘Man’s greed’ came up, as did the greed of developers. At the same time, ‘many respondents expressed guilt that what they were doing was wrong’. They knew that, by creating bird-bludgers, they weren’t really helping.
Housing estates are very destructive, and no amount of tinkering in the garden can alter that. Most garden birds belong to species that thrive on destruction. People feed magpies, currawongs, noisy miners and crows. The losers from clearing – robins, whistlers, fantails, weebills – seldom come far into cities and never use food trays or bird boxes. We can’t really create genuine rainforests and wetlands up by the barbie – this is naïve. The real value of nature gardening is the contact it gives us with nature. We want birds and butterflies because they brighten up our lives. We don’t want grasshoppers and moths, not because they need conserving less, but because they don’t offer as much pleasure. Wildlife gardening, for most people, is more about personal gratification and flight from guilt than true conservation. We should not pretend that good deeds done in gardens atone for crimes committed elsewhere.
Earlier on I emphasised the importance of cities for wildlife – what about that? Let’s revisit some of the examples. The study on black flying-foxes found them feeding mainly on exotic trees, Asian figs especially. My white-headed pigeons ate exotic camphor laurel berries and nested in a foreign vine. Urban butterflies dote on foreign plants. Brown snakes eat house mice and black rats. Other animals rely on sewage and scraps. One tenet of wildlife-friendly gardening is that native plants be used, but often that’s not what animals want. Growing native plumbago for native butterflies doesn’t help as much as growing the exotic equivalent, which sprouts hundreds more flowers. And switching native animals over to native plants is often harder than it sounds.
Conservation does begin at home, but not so much in the garden. It’s that old refrain: consume fewer resources, create less waste. Too many people are taking too much, and nothing we do in the garden can atone for that. I think it’s only decent to use phosphorus-free detergents and recycle plastic bags. Less fun than shopping for native plants, I know, but a lot more helpful. Out in the garden the best thing we can do is not grow invasive plants. Years ago I wrote Dinkum Gardening, a booklet spouting all the wrong advice – on possum boxes, frog ponds and bird flowers (although I did warn about miners). I still believe wildlife gardening has a role to play, but first we should go back to square one and reassess its worth. What is it really achieving? We need studies to show us what’s working and what’s not. How often are we helping the wrong things? Often it’s a question of location. In the innermost suburbs, frog ponds and bird flowers are probably a good idea. Miners and marsh-frogs are better than nothing. It’s further out that questions arise.
Right now I’m working as a consultant, reviewing a vast housing project near Noosa. Right now (but not for long) there are scribbly gum forests alive with gliders and grey-headed flying-foxes, and wetlands chirping with rare wallum frogs (Crinia tinnula and Litoria olongburensis). S
oon houses will rise on the hills and gardens and ponds will go in. Noisy miners have claimed one forest edge, and they will thrive. So will marsh-frogs and dwarf sedge-frogs. Wallum frogs need acidic coastal waters to breed in and won’t use ponds. Soap seepage and fertilisers will eventually kill them off. Grey-headed flying-foxes will depart when urban fruit trees go in and the more successful black flying-foxes will take over. The gliders (four species) won’t survive unless we save a decent tract of forest for them. There are four rare plants here (one nationally endangered) but three of them need infertile soils and won’t do well in gardens. There are rare birds (glossy black-cockatoos) but not for long. But I did see swordgrass browns (Tisiphone abeona rawnsleyi), unusual butterflies, happy in a swamp, and they can be helped, I think. Tall sawsedge (Gahnia clarkei), their foodplant, is a messy, prickly-leafed swamp plant that gardeners won’t like. But the council will plant some in soggy places in parks and the butterflies will dance on for a while at least.
Let’s go back to the claim that ‘We can all do our bit for wildlife conservation by planting habitats for animals that would otherwise be displaced by housing developments.’ If only that were true. Up near Noosa I’m trying to save a special place where most of the good things are doomed. Wildlife-friendly gardening has almost nothing to offer here. Residents can grow the one rare plant that likes rich soil and that’s about all. Houses are the enemy here, along with nutrient-enriched waste water running into gutters and flowing down drains. The most helpful thing a prospective home owner could do here would be to not buy a home.
Of course I’ve picked upon a stark example where eco-gardening can’t offer much. In some places it can play a useful role. Hobart residents can help endangered swift parrots by growing nectar-rich blue gums. In many places where noisy miners aren’t the problem they are elsewhere, gardeners – if they live near bushland – can help thornbills and wrens by installing dense shrubs. Growing velvety peppercress and other endangered plants makes sense, and growing plants for insects works. I put in a native mulberry (Pipturus argenteus) and soon had visits from the white nymph (Mynes geoffroyi), a scarce butterfly I’ve never seen here before. The butterflies to help are those in decline from loss of foodplants and with no exotic to turn to, and with no scruples about visiting suburbs. Unfortunately there aren’t many of these. I can think of Macleay’s swallowtail, birdwings, the nymph, and little else apart from tiny moth-like skippers.2 Some butterflies eschew cities no matter what you grow. Thousands of gardeners between Ballina and Noosa have put in vines for rare Richmond birdwings without achieving much so far. These butterflies seldom visit gardens far from rainforest. But opportunities to help bugs, beetles and skippers abound. I know of a very rare, flag-legged bug that uses sweet morinda, an attractive climber. Insects need less space than birds and frogs, and can seek out scarce foodplants by scent. But do gardeners want more bugs? Is ecogardening really about conservation, or is it more about gratification?
The key habitats in cities are usually parks, drains, creeks, sewage farms, golf courses, mudflats and remnant bushland – not gardens. Opportunities to help wildlife multiply as soon as we leave home. Robert Bender, who tends the bat boxes in Organ Pipes National Park, hears plenty of bat calls along the Yarra River (with an Anabat detector at night), but none at all around his Melbourne home, where his bat box remains empty. As for flying-foxes, they would eat more native figs if we grew more of them, but most fig trees are too big for the home, parks suiting them better. In parks we can create real reed-fringed wetlands for bitterns and crakes. Guided by proper research, we could redesign all our public places. Wildlife-friendly parks could do some of what wildlife-friendly gardens only pretend to do. But the challenge will always remain: how to help those in real need – the losers – rather than aiding ever more miners, magpies, marsh-frogs and mischievous possums.
1 The nest-egg survey mentioned in chapter 16 did not record possums attacking ‘eggs’ because their sense of smell is too keen to be fooled by eggs made of clay.
2 Australia has about 20 000 native insects, only 390 of which are butterflies. They are no more prone to become rare than any other insect group, although more is known about their conservation status because they are widely collected.
‘I must be cruel, only to be kind.’
William Shakespeare, Hamlet
Peter Mills sounds remarkably like a farmer when he points out ‘his cows’ in ‘his paddocks’. ‘I need my thirty to fifty cattle to just keep munching away on all these blocks,’ he says, waving at fenced fields, ‘hopefully for all of winter.’ But Peter is not quite a farmer. He’s a manager with Environment ACT, committed to saving priceless grassland remnants and the rare things they contain. ‘We’re proving that we can graze for conservation,’ he says proudly.
A few years ago ‘conservation grazing’ would have been branded as heresy, something cooked up by a country politician wanting grazing rights in national parks for his mates. I’d have damned it myself. Today it’s a fact of life in New South Wales, Victoria, Tasmania and the ACT. Cows and sheep are trucked into national parks and other reserves to manage growth of grass. Mowers and fires are used too. Managers are learning that grasslands can’t be saved by leaving them be, that wilderness goals don’t promote their protection.
Native grasslands and grassy woodlands are celebrations of diversity – rich in grasses, orchids, lilies, daisies and peas. ‘It’s absolutely fantastic stuff if you get down on your hands and knees and look at it,’ said Jamie Kirkpatrick about the Epping Forest understorey, and I know what he means, for I’m a grassland fan too. It’s a world in miniature down there, a festival of detail where dainty herbs in every shape and hue jostle for space among the tufts of domineering grass. Australia’s grasslands are among the richest in the world but they have suffered ignominiously at our hands. As the first lands seized by squatters and their flocks, they were ploughed, fertilised, overgrazed by stock and rabbits, oversown with foreign plants and invaded by weeds.
Most of the grasses you see in southern Australia today are exotic. Native remnants linger here and there along railway lines, on road verges, in cemeteries, and in paddocks where stock never overgrazed and fertiliser never fell. Each year many disappear forever, ploughed under in order to grow grain, or smothered by weeds. The remnants that remain are not ‘natural’ in a purist sense, but they are hotspots for endangered plants as well as being priceless reminders of past landscapes. They charm their devotees, who peer with fine-tuned eyes at each dainty leaf and pastel petal.
The sorriest remnant that I ever saw was a tiny fenced plot bounded by railway lines in an industrial zone on Melbourne’s outskirts. About 30 metres long and flush with kangaroo grass (Themeda triandra), it’s the last place on earth where endangered fragrant doubletails (Diuris fragrantissima) grow naturally. These orchids once whitened like snow the plains where they bloomed. Gravel had just been dumped beside the grassy plot when I visited in 2000 – right on top of some kangaroo grass. Another memorable remnant is York Park in Canberra, a square of lawn set between the Department of Foreign Affairs and the Macquarie Hotel. Endangered golden sun moths (Synemon plana) meander through the wallaby grass here. Unfortunately railway grounds and mown lawns don’t excite most greenies – they look and just see grass.
Peter Mills’ cows graze the Gungahlin grasslands, a rare survivor of the habitat that once graced Canberra’s rolling plains. His management tool is Pro-Graze, a computer program for farmers that works on regular rotation of cows between paddocks to optimise pasture. He showed me a management plan like none I’ve seen before. ‘It’s just a spreadsheet,’ he said. ‘It gives us two years of management guidelines. We apply a completely different management plan to each block.’ When Environment ACT declared the reserve in 1996 after taking over old grazing blocks, the cows were kept in place and more fences and troughs put in. Apart from the sign at the gate, nothing about Gungahlin marks it out from a farm. Peter reckons he could stock at higher rates
than farmers nearby and still protect biodiversity. ‘Agriculture is a real science that in our case is inextricably linked with conservation.’ I assumed Peter had come from a farming background but he surprised me (one more time) by admitting he had loudly opposed conservation grazing at first. Why use it? To keep weeds down and stop native grasses thickening up. Surprisingly, it’s the second goal that matters most.
The need to thin out native grassland hit me on a visit to Epping Forest, a precious new reserve in Tasmania’s dry Midlands. Botanist Jamie Kirkpatrick told me the reserve – a rare-plant hotspot – had been a sheep farm for 150 years and still carried sheep. On an overgrazed knoll he pointed out tiny, ground-hugging rare plants sprouting in the eroded furrow of an old car track. Nearby was a small trial plot fenced off to exclude sheep. It carried a sea of dried kangaroo grass and nothing else. The contrast was shocking. Where sheep still fed, the understorey was clipped down to lawn height but looked green and diverse. Behind the fence loomed a monoculture of dried grass half a metre tall. ‘You can see it’s a mess,’ Jamie said. ‘There’s no green growth coming through, and eventually even the kangaroo grass will die. You really do need some form of biomass removal. And fire is actually not enough by itself.’
Fire was trialled at the Derrimut Grasslands, a nationally significant reserve in an industrial zone of western Melbourne. The results weren’t promising. Thistles invaded, their seeds wafting in from nearby wastelands. Only five native plants did well from the fire, and four of these proved to be ‘weedy’ species, three of them not belonging in grassland. Cattle had previously kept these unwanted plants away.
Kangaroo grass evolved alongside grazing. It puts out more leaf than it needs in order to feed kangaroos and other grazers. If it stays ungrazed the old leaves wither and shade the plant, as well as anything nearby. On fertile lands it may grow so thickly it smothers itself to death. Jamie’s exclusion plot showed this. Sheep will stay at Epping, to promote biodiversity and save rare plants. ‘You definitely do need the grazing, whether it’s by native animals or by sheep,’ Jamie concluded. ‘And the more fertile it is, the more you need the sheep.’ What about native grazers? I asked. ‘You could probably get enough wombats and wallabies in here to do the same thing but the neighbours wouldn’t like it as much,’ he said, looking in the direction of nearby farms.