The Best Australian Science Writing 2015 (12 page)

And this fitted with measurements Mulloney had made on the actual nerve circuit, where he found that the system reached an equilibrium with adjacent paddle pairs about a quarter of a cycle out of step.

‘We're very proud that it's mainly a mathematical paper and we've been able to figure out something important to biological science,' says Lewis.

I, wormbot: The next step in artificial intelligence

Copulate to populate: Ancient Scottish fish did it sideways

Global ‘roadmap' shows where to put roads without costing the earth

William Laurance

‘The best thing you could do for the Amazon is blow up all the roads.' These might sound like the words of an eco-terrorist, but it's actually a direct quote from Professor Eneas Salati, a forest climatologist and one of Brazil's most respected scientists.

Many scientists share Salati's anxieties, because we're living in the most explosive era of road expansion in human history. The International Energy Agency (IEA) predicts that by 2050 we will have 60 per cent more roads than we did in 2010. That's about 25 million kilometres of new paved roads – enough to circle the Earth more than 600 times.

In new research published in
Nature
, an international team of colleagues and I have developed a global ‘roadmap' of where to put those roads to avoid damaging the environment. Our maps are also available to the public on a new website: <
www.global-roadmap.org
>.

Roads today are proliferating virtually everywhere – and are used for exploiting timber, minerals, oil and natural gas; for promoting regional trade and development; and for building
burgeoning networks of energy infrastructure such as hydroelectric dams, power lines and gas lines.

Even national security and paranoia play a role. The first major roads built in the Brazilian Amazon were motivated by fears that Colombia or the US might try to annex the Amazon and steal its valuable natural resources. India's current spate of road building along its northern frontier is all about defending its disputed territories from an increasingly strident China.

According to the IEA, around 90 per cent of new roads will be built in developing nations which sustain the most biologically important ecosystems on Earth, such as tropical and subtropical rainforests and wildlife-rich savanna-woodlands.

Crucially, such environments also store billions of tonnes of carbon, harbour hundreds of indigenous cultures, and have a major stabilising influence on the global climate.

Killer roads

Why are roads regarded as disasters for nature?

Far too often, when a new road cuts into a forest or wilderness, illegal poachers, miners, loggers or land speculators quickly invade, unleashing a Pandora's box of environmental problems.

For instance, my colleagues and I recently found that 95 per cent of all forest destruction in the Brazilian Amazon has occurred within five kilometres of roads (notably, we also found that many Amazonian roads are illegal; for every kilometre of legal road, there were three kilometres of illegal roads). Other research has shown that major forest fires spike sharply within a few dozen kilometres of Amazon roads.

The Congo Basin is reeling from a spree of forest-road building by industrial loggers, with over 50 000 kilometres of new roads bulldozed into the rainforest in recent years. This has opened up the forest to a tsunami of hunting. The toll on wildlife has been appalling; in the last decade, for instance, around
two-thirds of all forest elephants have been slaughtered for their valuable ivory tusks.

In Peru, a new highway slicing across the western Amazon has led to a massive influx of illegal gold miners into formerly pristine rainforests, turning them into virtual moonscapes and polluting entire river systems with the toxic mercury they use to separate the gold from river sediments.

Avoid the first cut

Many road researchers believe the only safe way to protect a wilderness is by ‘avoiding the first cut' – keeping it road-free. This is because an initial road opens up a forest to deforestation, which then spreads contagiously, like a series of tumours.

And that cancer quickly grows. An initial road slicing into a wilderness typically spawns a network of secondary and tertiary roads, allowing deforestation to easily metastasise.

For instance, the first major highway in the Amazon – completed in the early 1970s to link the cities of Belem and Brasilia – was initially just a razor-thin cut through the forest. Today, that narrow incision has grown into a 400-kilometre-wide slash of forest destruction across the entire eastern Amazon.

But we need roads

And yet, for all the environmental perils of roads, they are also an indispensable part of modern societies. Most economists love roads, seeing them as a cost-effective way to promote economic growth, encourage regional trade and provide access to natural resources and land suitable for agriculture.

How do we balance these two competing realities, between road-lovers aspiring for wealth and social development, and road-fearers hoping to avoid ecological Armageddon?

This vexing question has been the focus of a talented group of researchers I've been leading over the past two years, from
Harvard, Cambridge, Melbourne, Minnesota, Sheffield and James Cook Universities and the Conservation Strategy Fund.

A global roadmap

Our scheme has two components. The first is a map that attempts to illustrate the natural values of all ecosystems worldwide. We built this map by combining data on biodiversity, endangered species, rare habitats, critical wilderness areas and vital ecosystem services across the Earth.

We added in parks and other protected areas, as these are also high priorities for nature conservation.

The second component is a road-benefits map. It shows where roads could have the greatest benefits for humankind, especially for increasing food production.

Focusing on food is vital because, with continuing rapid population growth and changing human diets, global food demand is expected to double by 2050.

Roads affect food because large expanses of the planet – especially in Sub-Saharan Africa and expanses of Asia and Latin America – are populated by small-scale farmers who produce much less food than they could if they had new or better roads. Such roads could give them ready access to fertilisers, modern farming methods and urban markets to sell their crops.

In these regions, most of the native vegetation has already been cleared, so intensifying farming shouldn't have major environmental costs. In these contexts, new or better roads (along with other investments in modern farming methods) are a key way to help struggling farmers to boost their productivity.

A potential bonus of this strategy is that, as farming becomes more productive and rural livelihoods more prosperous, regions with better roads tend to act as magnets – attracting people from elsewhere, such as the margins of vulnerable forests.

In this way, investing in better roads in appropriate areas can
help to focus and intensify farming, accelerating food production while hopefully helping to spare other lands for nature conservation.

Conflict zones, but reasons to hope

By intersecting our environmental-values and road-benefits maps, we have estimated the relative risks and rewards of road building for Earth's entire land surface – some 13.3 billion hectares in total.

In our map, green-toned areas are priorities for conservation where roads should be avoided if possible, and red-toned areas are priorities for agriculture.

Dark-toned areas are ‘conflict zones', where environmental and agricultural priorities are likely to clash (light-coloured areas are lower priorities for both environment and farming).

The good news is that there are substantial areas of the planet where agriculture can be improved with modest environmental costs.

But there are also massive conflict zones: in Sub-Saharan Africa, expanses of Central and South America, and much of the Asia-Pacific region, among others. These hotbeds of conflict often occur where human population growth is rapid and there are many locally endemic species – those with small geographic ranges that are especially vulnerable to intensive development.

Our global roadmap is, admittedly, an exceedingly ambitious effort. Yet our hope is that our strategy can be incorporated with finer-scale local information to help inform and improve planning decisions at national and regional scales.

Our effort is a first step toward a vital goal: a global plan for road expansion. We're not so naïve as to believe everyone will immediately adopt it, but such efforts are unquestionably a crucial priority.

There is precious little time to lose if we don't want to see the
world's last wild places overwhelmed by an onslaught of roads, destructive development and the roar of fast-moving vehicles.

Playing God

Small mammals vanish in northern Australia

An uneasy alliance

Messages from Mungo

John Pickrell

It's almost silent, but all around me shift the sands of time. I am sitting on a dune 50 metres above the saltbush plains at Mungo National Park, in south-western NSW. A cool breeze carries with it fine grains of silica, and the soft glow of first light is beginning to illuminate a series of emu tracks that trail past me and disappear over the crest of the dune. Just a little while earlier, the Milky Way had been a clear streak across the sky, and Venus, Mars and Saturn were all bright points of light. There was even the brief and exciting flare of a shooting star – a distant traveller met with a fiery demise.

Aboriginal people have camped here on this very dune and on others like it in the Willandra Lakes Region World Heritage Area (WHA) for more than 50 millennia, beginning long before modern humans had even arrived in Western Europe. On countless occasions, they have looked out at the rising sun and seen the same night sky awash with twinkling stars. Beneath me in the dune are their stone tools, the baked hearths of their cooking fires, and their carefully buried or cremated human remains.

Here, perhaps more than anywhere else in Australia, you can feel a connection to the first people who arrived more than 60 000 years ago. They were at the front of a wave of migration that
carried small bands of travellers on an almost implausible journey, by foot and over many generations, from Africa and along the coasts of Asia. Eventually – via an ocean crossing from Indonesia that was shorter than it would be today due to lower sea levels – they made their way to northern Australia.

The first occupation sites in Australia are below today's sea level, so we're unlikely to ever find traces of them. Perhaps the earliest evidence of these migrants is a rock shelter, known as Malakunanja II, located about 50 kilometres inland from the Arnhem Land coast. Here, alongside rock art, the remains of stone tools, grinding stones, ochre and charcoal have been found, the oldest of which are about 55 000 years old.

The next evidence we have of people living in Australia comes from Mungo National Park and the wider Willandra Lakes area – and here it is abundant. In geological layers dated as far back as 50 000 years, there are stone tools and hearths, shellfish middens and butchered animal bones.

Australia's Aboriginal people have the oldest continuous culture on the planet and today we take its great antiquity for granted, but this wasn't always so. When now-retired professor Jim Bowler stumbled upon the cremated remains that came to be known as Mungo Lady, in 1969, it suggested Aboriginal people had been here far longer than scientists suspected. But it was his 1974 discovery of Mungo Man that really startled the world.

* * * * *

In 1974 Jim was working as a geologist with the Australian National University (ANU), in Canberra, looking at rocks in the south-western corner of NSW to find clues about ancient climate change; he wasn't an archaeologist and he hadn't set out to find human remains. ‘I wanted to unwrap the story of the climatic legacy written in the Australian landscape,' Jim tells me when I
meet him at Mungo on a warm autumn day, the air thick with flies. ‘My agenda was to explore the … dry inland country, the dune systems and salt lakes. I was reconstructing the impact of Ice Age climatic change.'