PRESERVAR ou USUFRUIR? O debate sobre a melhor forma de proteger a natureza

LUISA RIVERA FOR YALE E360

Sparing vs Sharing: The Great Debate Over How to Protect Nature

What is the best way to save nature – to cordon off areas for parks and open space or to integrate conservation measures on working lands? Recent research makes a case for each of these approaches and has reignited a long-standing debate among scientists and conservationists.

BY FRED PEARCE

It is one of the biggest questions in conservation: Should we be sharing our landscapes with nature by reviving small woodlands and adopting small-scale eco-friendly farming? Or should we instead be sparing large tracts of land for nature’s exclusive use – by creating more national parks and industrializing agriculture on existing farmland?

The argument between “sparing” and “sharing” as a conservation tool has been raging since researchers first coined the terms more than a decade ago. Arguably it began almost half a century before when Norman Borlaug, the father of the Green Revolution of high-yielding crop varieties, declared that “by producing more food per unit of cultivated area, more land would be available for other uses, including recreation and wildlife.”

E.O. Wilson’s 2016 book Half-Earth upped the ante by calling for us to extend protected areas from the current 15 percent of the earth’s land surface to 50 percent. Research studies and critiques have flourished on both sides.

So where do things stand today? It begins to look as if the sparers are winning the narrow scientific argument by showing that locally, and in the short term, more species are usually saved by segregating conservation from agriculture and other human land uses. But critics say that begs more questions than it answers, overlooking the issue of the long-term sustainability of such islands of biodiversity and failing to address whether we actually need to grow more food.

“Most species will have larger populations if food is produced on as small an area as possible,” says one researcher.

Leading the argument for the sparers is Benjamin Phalan, who in 2011 while studying zoology at Cambridge University in the UK, looked at the relationship between crop yields and the number of bird and tree species in the forests of Ghana and the Ganges floodplain in India. In both places, he found that biodiversity did best where intensified cropping left space for unfarmed habitats, and less well where farmland was more wildlife-friendly but more extensive.

Since then, other studies have reached similar conclusions. In a region of southern Uganda where banana and coffee are the main crops, bird biodiversity was richest if the farming was done intensively in smaller areas. The same was true for birds and dung beetles in the Colombian Andes; for birds on the steppes of the former Soviet Union and the pampas grasslands of southern Brazil and Uruguay; and for dung beetles, trees, and birds in the grazing pastures of Mexico’s Yucatan peninsula.

In a review of this research, published in May, Phalan, now at Oregon State University, concluded that “most species will have larger populations if food is produced on as small an area as possible, while sparing as large an area of native vegetation as possible.” The finding was “especially true for species with small global ranges, which are often those of most conservation concern.”

The problem for those advocating “sharing” the land, he said, was that all farming was bad for nature, and adopting more benign methods did not help much. Agroforestry was no substitute for real forests; pampas grasses lost species quickly even at low levels of grazing; and organic farming protected insects no better than conventional farming, while taking more land.

Game over?

A farmer walks through his coffee plantation, which is integrated into the forest, in Lampung province, Indonesia. ULET IFANSASTI/CIFOR

Not so fast. A leading proponent of wildlife-friendly farming, Claire Kremen of the University of California Berkeley, has come out fighting. She says the research findings cited by Phalan are misleading. They are snapshots that “don’t assess the long-term consequences of isolating species in protected areas surrounded by inhospitable matrices.” Other research shows, she says, that “even very large protected areas will lose species if they remain isolated over time.” So in the long run, sparing on its own won’t work.

In a manifesto for “working lands conservation” in Science in October, Kremen and colleague Adina Merenlender say that “it is a fallacy that [intensive farming] will ultimately spare more land for nature conservation or feed the world indefinitely… To avoid mass extinction and ecosystem collapse, we must integrate biodiversity conservation into the landscape we use.”

The manifesto brought a combative response from eco-modernists at the Breakthrough Institute, who accused the sharers of engaging in “magical thinking.” “Organic farming requires 25 percent more land to grow the same amount of food… adding 25 percent of global cropland is equivalent to 300 million hectares, almost the size of Western Europe,” wrote Linus Blomqvist. That would be a lot of potential wilderness to lose.

But this zero-sum approach is not widely accepted, even among sparers. Several of the pro-sharing studies cited by Phalan argued that agricultural intensification won’t deliver more land for nature unless there are tough rules to protect land not yet farmed.

Otherwise, the result might be an agricultural version of what is known as the Jevons Paradox, after the British 19th-century economist William Jevons, who noticed that more efficient coal-powered engines of his day did not reduce coal burning but massively increased it by kick-starting the industrial revolution. Following that paradigm, the result of agricultural intensification will inevitably be more land going under the plow.

Large protected areas will lose species unless surrounding landscapes are managed to provide connectivity among parks.

As Phalan concedes in his review paper, land savings from the Green Revolution “were far less than predicted by Borlaug, in the region of 20 million hectares rather than 560 million… The higher yields were used primarily to produce more, cheaper, food, not to spare land for nature.” Brazil shows this well. The Amazon rainforest and cerrado grasslands have been converted to intensive croplands in recent decades, not to feed Brazilians but to export beef and soybeans that have brought “wealth and political influence to a small group of wealthy landowners,” Phalan writes.

Likewise, Phalan notes, most of the huge area of the United States given over to corn is devoted to “wasteful uses such as biofuels and livestock production.” As Kremen noted to Yale Environment 360, “the data do not suggest that intensified agriculture has had any nature-sparing effect in recent years.”

The conclusion from both sides in the sparing versus sharing debate seems to be that intensive agriculture can only work as a conservation strategy if there is effective action to ensure that land spared is turned over to conservation rather than profit-making commodity farming. But Kremen says that still leaves open the question of how effective islands of conservation can be in a landscape still dominated by industrialized agriculture.

For one thing, nature does not recognize the boundaries of national parks. Whether migrating elephants in Kenya or monarch butterflies in North America, much nature exists predominantly in human-made agricultural landscapes. As the author of a study of Australian biodiversity published this year, Stephen Kearney of the University of Queensland found that “it is not enough to just place land in a protected area and then walk away… simply reserving land will remove all threats to very few species – only 3 percent in fact.”

More than 1.5 million wildebeest migrate annually across Tanzania's Serengeti National Park, which covers 5,700 square miles. DANIEL ROSENGREN /WIKIMEDIA

More than that, say Kremen and Merenlender, in the long run “even the largest protected areas will lose species… unless surrounding landscapes can be managed to provide connectivity among parks… If [protected] areas are isolated from one another by inhospitable land uses and are faced with a rapidly changing climate [they will] continue to lose species.”

Some researchers believe we are already seeing the failure of strategies based on islands of nature protection. In recent years, the global area of protected land has grown significantly, but wild populations of vertebrates are down 60 percent from half a century ago. Since 1990, Germany has increased its protected areas, yet seen a 76 percent decline in insect biomass.

Kremen says saving the planet’s biodiversity requires a combination of protected areas and the creation of a wider landscape that is sympathetic to nature, a task she terms “working lands conservation.” She cites the example of the Mesoamerican Biological Corridor, stretching from Mexico to Panama, an initiative that aims to link more than 650 small protected areas with a filigree of forest fragments along river banks and across pastures and fields.

Elsewhere she points to mangrove forest restoration in Asia, community stewardship of land along the Great Eastern Ranges of Australia, from Cairns to Melbourne, and the revival of forests in patches of former farmland across central Europe, which has nurtured increasing populations of carnivores, especially wolves.

The argument between sparing and sharing opens up a debate about the kind of environment we want to live in.

The argument between sparing and sharing also opens up a debate about the kind of environment we want to live in. Kremen argues that sharing would allow more low-income people to have access to open spaces and nature within an urban environment, whereas sparers stress the need for high-density urban environments that leave more land open and free of people.

Phalan says that in some senses the scientific argument between sparing and sharing can be cover for a more ethical debate. The sparers are “ecocentric,” seeking to protect nature for its intrinsic value, while the sharers are more “anthropocentric,” wanting to serve humanity’s needs and desires. Sparers may not care as much whether an intensified, commercialized farming system may be better at producing profitable crops than feeding the hungry, so long as nature is spared. Sharers want fair shares between people as well.

But a new argument has opened up in the past couple of years about the nature of the food supply system that has been responsible for most of the loss of nature. Sharers say the sparers misunderstand both the supply and demand sides of food production. On the supply side, they argue, the idea that high-intensity, large-scale commercial agriculture is more efficient and productive is often a myth. Vincent Ricciardi of the University of British Columbia reported in August that smallholders with less than 2 hectares of land produce 30 to 34 percent of the world’s food on just 24 percent of the agricultural area. They achieve this because they devote a greater proportion of their production to food, rather than non-food crops such as cotton.

A farming village surrounded by undeveloped forests in the province of Quang Ninh, Vietnam. TERRY SUNDERLAND/CIFOR

Many smallholders also use low-intensity techniques that incorporate substantial elements of wild vegetation and rely on bees to pollinate and birds to eat pests. Kremen reckons that if all smallholder farmers adopted more “sharing” techniques — such as agroforestry and growing two or more crops close together, a practice known as “intercropping” — they could both preserve more nature and raise global food production: a win/win for working lands conservation undreamed of by zero-sum sparers.

And on the demand side, much of the push to embrace intensified agriculture as an essential conservation tool has been predicated on United Nations forecasts that we will need to double global food production as early as 2050. But recent research suggests this forecast is “grossly inflated,” Fabrice DeClerck of Bioversity International, a Rome-based research agency for agricultural biodiversity, told Yale e360.

We already grow enough food to feed a world of more than 10 billion people. The problem is that a third of harvested food crops are thrown away uneaten, and a further third is fed to livestock, an inefficient method of feeding the world. Reductions in waste and less livestock-intense diets are what is needed – not more food.

So the potential to share the land without sacrificing nature’s last wild places is much greater than once thought. “We can spare 50 percent and share the rest,” DeClerck believes.

Fonte: Yale 360°