The New Nature Read online

  But what are we saving, anyway? Species have become the currency of conservation, although they are not always as real as people think. Biologists disagree endlessly about how to carve up nature’s variation into species, subspecies and varieties. DNA work suggests there may be many more species than we think, although this depends partly on definitions. In any event, subspecies and varieties matter too. Crimson rosellas in north-west Victoria are lemon-yellow, and something unique would be lost if they disappeared, although no species would go extinct.

  Genetic issues deserve a lot more consideration by the conservation community. Gene pools should not be jumbled up, if possible, but where do we draw the lines? When habitats are replanted, how far away can seed be collected and still count as ‘local provenance’? Five kilometres? Fifty kilometres? Is it a question of numbers? Plants with seeds spread widely by birds and winds probably vary less over distance than other plants, implying that seed can be collected more widely. But seldom are such matters discussed. Genetic purity can become as rigid and unrealistic a goal as preservation of pure nature and pure wilderness. Geneticists have told me it’s not a worthwhile guiding ideal. Hybridisation occurs naturally, after all. One geneticist who rails at the idea that genetic purity equates with naturalness is Neil Murray: ‘There is no such thing as naturalness any more, if there ever was. Everything has been radically affected by people, it’s all different. If we are going to conserve things, we need a better objective than naturalness.’ What that may be remains a challenge for the future.

  ‘I know it’s wrong but I’ve started something I can’t stop.’

  Brisbane resident who feeds wildlife

  In 1981 Martin and Hillary Boscott, a Brisbane brother and sister, both artists, found a pair of green tree-frogs (Litoria caerulea) mating in their swimming pool, at a time when the chlorine level was low. They scooped out the eggs and reared the young. In 1982 the frogs came back and more eggs were laid. The next spring was different: instead of a pair of frogs, dozens of young adults came to breed, presumably the offspring from 1981. The Boscotts had 2000 tadpoles on their hands. But this was only the beginning. By 1984 the pair had 300000 tadpoles to deal with, and they began giving them away.

  Their giveaways caught the eye of journalists and they found themselves on the 7.30 Report and the Midday Show, and in newspapers and the Reader’s Digest. Suddenly they were celebrities. Hundreds of people were clamouring for their tadpoles. Many older folk remembered a time when green tree-frogs smiled out from toilets and laundries, and the Boscotts’ vision of a frog-fond city struck a resonant chord. Green tree-frogs weren’t exactly rare in Brisbane, but their numbers had certainly fallen over the years. ‘From the mid-1980s to the early 1990s the number of people who wanted tadpoles was overwhelming,’ Martin told me. ‘There were toddlers and grandparents, teachers and customs officers and bikies and judges. People came from every conceivable age group and walk of life [I was one of them]. The word of mouth was phenomenal. Someone would ring up from work and say he’d got seventy workmates who wanted tadpoles. Usually when we did a television story members of the media crew would take some.’

  The Boscotts found they had to structure their giveaways. ‘It was extraordinary,’ Martin said. ‘We had organised sessions to give them away. Up to 200 people would come in a single afternoon. We put a limit of one parent and one child per collection. We’d give a fifteen-minute talk, quickly give them the tadpoles, get rid of the people who wanted to ask the extra questions, pause to have a quick cold drink, then another crowd would arrive. It was exhausting.’ Notes given with the tadpoles explained the basics of pond design, and frog ponds are now common features in Brisbane gardens.

  Frogs pervaded the Boscotts’ lives. Martin was painting them in every pose. Hot summer nights were riotous. On one side of the pool the males would roar in unison, like footy fans goading the other side. A few frogs would sometimes hop across the road to a neighbour’s swimming pool and call from there, luring the others over. The Boscotts would bring them back. The neighbour, fortunately, was sympathetic – he was their greengrocer supplying the lettuce their tadpoles ate.

  Frogs can’t use well-maintained swimming pools because chlorine kills their young. The Boscotts let the chlorine levels drop each spring before any frogs came. Even so, they tried to prevent spawning in the pool, moving mated pairs to water-filled bins for laying. Tadpoles in a swimming pool are a nuisance. During the month or six weeks they take to mature, the pool goes green. ‘The thing is, you can’t easily get tadpoles out of a swimming pool,’ Martin said. ‘If you have three tadpoles in the water they will all swim in different directions. When they are in there it’s easy to get half of them out, but the other half all learn about the net. They will sit on the bottom after taking a breath.’

  Over the years, the concerts in the pool lured in new tenants. Graceful tree-frogs (Litoria gracilenta) appeared in 1984, followed by striped marsh-frogs (Limnodynastes peronii) two years later. These are common frogs around Brisbane, but they weren’t found in most gardens. The Boscotts distributed these frogs’ tadpoles as well. Green tree-frogs were more popular because they are big and ‘friendly’ and enter houses, but many people accepted tadpoles of all three types.

  ‘We could not fill the demand for tadpoles,’ Martin told me. ‘We must have had millions of tadpoles by the end. Even so, we never had enough. We always had to ration them. In the end we even turned away some of the media coverage.’ His sister has moved away and he no longer distributes tadpoles, but frogs remain important in his life, their faces smiling out from large canvases in his home.

  Brisbane is now a city of frogs. The people who put in ponds soon attracted frogs of their own. They passed tadpoles on to friends, the spawn radiating outwards like an endless chain letter. Independently of the Boscotts, the CSIRO Double Helix Club also promoted distribution of tadpoles. The results today are astounding. On hot steamy nights frogs call from almost every street. Brisbane was never this way before. The Boscotts initiated a remarkable ecological and social phenomenon, one that has few parallels in Australia. They were thoroughly selfless, never seeking to profit from the queues of callers at their door.

  But everything did not go exactly as expected. Green tree-frogs did not benefit as much as everyone hoped. Although their tadpoles did well enough in buckets and ponds, they seldom returned as adults. They seem to be fussy breeders, and possibly sensitive to disease. Their numbers have dropped dramatically around the Boscotts’ pool. The real winners were the striped marsh-frogs that came in 1984. Given away as tadpoles of third choice and sometimes taken reluctantly, they now dominate most pools. Better suited to city life than other species, they are the frogs that call in greatest numbers. Graceful tree-frogs and dwarf sedge-frogs are also doing well. Green tree-frogs show up here and there around Brisbane, croaking from drainpipes and bounding across roads on wet nights, but they seldom appear in ponds.

  Marsh-frogs are handsomely marked, but instead of a smiley grin they sport a rat-like snout. They don’t inspire emotional attachment. But they do incite emotion. Their incessant ‘pok-pok-pok-pok-pok’ calls have become a new form of sound pollution. More vocal than other frogs, they call relentlessly, even on mild winter nights. Irate residents often phone the Brisbane City Council and frog groups to complain. ‘I’ve been getting that many complaints it’s not funny,’ Wayne Winter of the RANA Frog Group told me. One caller he could barely hear over the frog noise echoing in the background. Maureen, a friend of mine, recalled the night two crazed men called at her door. ‘Lady,’ one said. ‘I can’t eat, I can’t sleep, I’m going crazy. What is that noise going on in your front yard?’ Maureen now regrets ever getting ‘marshies’ because they sometimes annoy her as well. She tidied her inner-city yard and found twenty or more. She told me about one woman who, angered by a neighbour’s loud dog, installed a frog pond against the fence for revenge. Brisbane City Council can’t act against frogs because they count as natural noise.

&nbs
p; Some frog-lovers now remove marsh-frog spawn from their ponds; others even kill adult frogs. One pond-owner, Steve Rhodes, told me he scoops out hundreds of thousands of the eggs each year to give other species a better chance. Biologist Arthur White suspects that marsh-frog tadpoles poison the water they swim in. He founded a colony of endangered bell-frogs in Sydney that did well until marsh-frogs swamped the pond and his bell-frog colony ‘crashed’. Back in the lab he put bell-frog tadpoles into water once used by marshie tadpoles, and they stopped growing. Marshie tadpoles may secrete a toxin that stunts the competition. Some foreign tadpoles do this, it’s a form of natural water pollution. Marsh-frogs are now important links in the urban food chain. In inner-city gardens they fall prey to white-faced herons and kookaburras, and water skinks devour their tadpoles. Someone I know lost all her marsh-frogs, and when she drained the pond an eel emerged. Eels are good overland travellers and this one had slithered up from across a park.

  Brisbane’s love affair with frogs is an extraordinary, heart-warming phenomenon, but it’s one that also raises serious ecological questions. Should tadpoles be moved around? Some of Martin’s tadpoles have found their way down to Sydney and up to Cairns, muddling up the gene pool for no good reason. In 1999 I was weeding my garden when I uncovered something that made me gasp. Crouched under a tuft of grass was a black-soled frog (Lechriodus fletcheri), a rare denizen of montane rainforest. Someone had taken some tadpoles from an upland forest, probably from a national park, to rear in a pond near me. Not only were they depleting a national park, they might also be creating a new feral population: black-soled frogs don’t belong in Brisbane. Nor do orange-eyed tree-frogs (Litoria chloris), another upland jungle frog now sighted around Brisbane pools. Another concern is that hordes of pond-reared striped marsh-frogs will descend upon natural wetlands and displace dwindling colonies of rarer frogs. People who move tadpoles also risk spreading the chytrid fungus (Batrachochytrium dendrobatidis), implicated in the extinction of several frog species. This fungus is rife in Brisbane ponds, turning up at times on dead green tree-frogs. It was first recorded in Australia in 1978, on a graceful tree-frog caught near Brisbane. In the mountains west of me, two frogs have recently become extinct. Queensland changed its laws in 1994, outlawing the movement of tadpoles (in line with other states). Ponds are legal, but frogs are meant to seek them out. Most pond-owners don’t know this, however.

  Frog-lovers want to help frogs, but only five or six of Brisbane’s twenty-four species have benefited. And these are tough frogs that already do well in parks, farms and battered bushland. Garden ponds help winners, not losers. Marsh-frogs and dwarf sedge-frogs even breed in polluted industrial zones. Green tree-frogs, helped along by ponds to some extent, do well in farmland, often occupying water tanks around homesteads. In Sydney, where ponds are proliferating, only one species – the striped marsh-frog – is prospering. But Martin Boscott says all frogs benefit indirectly from breeding, and I can see his point: children who rear frogs grow up concerned for the plight of all species, including vanishing rainforest frogs. Frog ponds bring people to nature, and that is their main value. We should not assume they also achieve environmental goals. Sometimes, surely, they do, but often they don’t. They are another example (like island arks) of well-meaning actions returning unexpected results.

  The pond issue brings into question the very idea of fauna-friendly gardens. Books and TV shows exhort us to help the environment by installing ponds and nest-boxes and growing native plants. We needn’t feel helpless about habitat destruction, the message goes: we can make amends. Let’s atone at home for the harm done elsewhere. But one of the worst eco-crimes we commit is helping winners displace losers. If wildlife-friendly gardens further that trend, we should reconsider their worth.

  Planting flowers for birds all too often encourages noisy miners. The outcome is ironic: by vying for more birds, you get fewer. Miners, like striped marsh-frogs, do best in damaged landscapes. Like weeds, they thrive where resources abound. Graham Pizzey, in A Garden of Birds (1988), serves up a bitter dose of realism: ‘The moral, for anyone contemplating establishing a bird garden, is to carefully check the whole vicinity for signs of their presence. If they are anywhere near your intended home, and particularly if the habitat of large open trees extends towards your intended location, tread carefully, and even consider living somewhere else, if you haven’t already bought.’ It’s brutal advice this, coming from the doyen of birdwatchers. Live somewhere else. Noisy miners dislike thickets, so you could try planting up thick rainforest and convince your neighbours to join in. But it probably wouldn’t work. I’ve seen miners in a patch of rainforest – a habitat they avoided in the past.

  Around Adelaide David Paton worries about garden flowers luring honeyeaters out of forests where native shrubs need pollinating. Typical garden choices, including bottlebrushes (Callistemon) and ironbarks (Eucalyptus sideroxylon), flower in winter or spring when forest shrubs also bloom. Birds don’t benefit greatly because nectar remains scarce in summer. But if more summer-flowering shrubs were grown, David fears birds would desert forests for good, depriving plants of their pollinators. Some years ago he studied dying red wattlebirds in Melbourne gardens, and the symptoms of head retraction, convulsions and anorexia suggested thiamine deficiency, a conclusion supported by blood tests. David believes wattlebirds traditionally migrated north in winter to feed on vitamin-rich insects, but now stay behind, seduced by sugary garden flowers to adopt a vitamin-poor and sometimes fatal diet. He published his findings back in 1983 but I’ve yet to see them mentioned in any wildlife gardening book. No-one wants to admit that maybe flowers can kill.

  Carla Catterall is another conservation biologist who doubts the value of gardening for birds. She surveyed gardens around Toohey Forest, the reserve we visited in the noisy miner chapter. Although plenty of native shrubs and trees have been grown, Carla found that gardens more than 50 metres from the forest carried only the usual garden regulars (magpies, butcherbirds and suchlike), not forest birds. Noisy miners, cats, dogs, roads, fences and noise conspire to keep them away. ‘You could make a bird garden on an average suburban block, with a wonderful vegetation structure with all the right heights, and with flowers and fruit, but the forest birds you would hope to see there would not come,’ she told me. ‘You might get the odd fantail but it’s not a sufficient area to provide the needs for most forest birds.’ Bird-scaping would only work if a large cluster of gardeners all agreed to do away with lawns, flowerbeds and pets – an unlikely scenario. Growing native plants also backfires when plants become weeds or spawn hybrids, as we’ve seen. The bush nearest me (Mt Coot-tha) is thick with feral wattles (Acacia macradenia), eucalypts (Corymbia torelliana), grevilleas (Grevillea banksii), ferns (Nephrolepis cordifolia), and umbrella trees.

  Many people feed birds in their gardens, a practice experts condemn. The food trays become disease hotspots where bacteria and worms are exchanged via soiled seed and water. The handouts keep alive sick birds that would otherwise die, including highly infectious aviary escapees (as well as birds released because they were ill). Natasha Taylor, a Currumbin Sanctuary vet, rattled off a long list of horror ailments – psittacosis, salmonella, lorikeet enteritis, giardia, coccidiosis, trichomoniasis, yeast infections, fatty liver, calcium deficiency, and vitamin E responsive deficiency. Some of these (notably psittacosis and salmonella) even harm people. Bacteria thrive in the warm stale water of sunlit bowls. Wild birds feed largely on green seed and suffer vitamin deficiencies when they switch over to dried grain. Natasha also worries about diseases jumping between species for the first time when birds crowd together at feeders. Birds may also suffer when their patrons go on holiday and the handouts stop. Meat attracts carnivores – butcherbirds, ravens, magpies, currawongs, kookaburras – which then turn upon smaller birds, converting gardens into killing fields. It makes no sense feeding meat to birds. In national parks you can see the predators lined up around the barbecue pits, and smaller birds conspicuous by the
ir absence. Currawongs take seed and fruit as well as meat, and anything encourages them, including berries on bushes and scraps in parks.

  On Mt Tamborine half the households feed birds, ranger Wil Buch told me. ‘Bird feeding is a major issue for us,’ he complained. ‘People feed kookaburras, magpies, all the wrong birds. One lady admitted spending $70 a week feeding birds. She was a pensioner. For four months of the year they feed the brush-turkeys, and for three months they want us to stop them wrecking their gardens.’ They also expect him to extricate all the pythons that coil around bird trays awaiting feathered fare.

  Seed-fed cockatoos regularly vandalise homes. Freed from the need to seek seed, they loaf on patios, sharpening their mandibles on timber fittings. Western red cedar is favoured for its soft (and pricey) wood. Ian Temby, Victorian government pest whiz, told me of $25000 worth of damage that was done to one house. One flock, pampered by an old lady, wrought thousands of dollars worth of damage to each of ten houses. The old lady refused to stop feeding her ‘pets’. Victoria is now enacting laws to control the feeding of problem birds, and New South Wales may follow suit. Wildlife management officer Geoff Ross told me about $32000 damage done to one Sydney building. The cockatoos chewed out window frames and gouged a hole through the wall. ‘Someone came into work and there was this cockatoo squarking at him.’ The damage bill did not include the cost of repairing ruined computer cables. He’s also heard of cockatoos destroying solar hot-water panels, and suspects that in forests around Sydney they steal nest holes from gliders.