Saving the forest on a shoestring

Landscape of Brazil

Around 80% of the Atlantic Rainforest has been lost, but a low-cost method could help restore biodiversity

28 November 2018 by Julia Horton

As a child growing up in Brazil, Cristina Banks-Leite spent most weekends on a farm about 60 miles from her home city of São Paulo, in one of the world's most beautiful but rapidly vanishing rainforests.

It gave her a lifelong passion for the natural beauty of tropical forests and the desire to find a compromise between farming and conservation to help all species, including humans, survive.

Although the Amazon rainforest is better known, Brazil's Atlantic rainforest is home to more unique species and millions more people. While 80% of the Amazon remains, roughly the same amount of the Atlantic rainforest has been lost as growers of lucrative crops, like sugar cane, have cleared trees to make way for plantations. Brazil's environmental laws on protecting forest are better than those of many other countries, including many European nations, Cristina says. For over half a century, farmers have been legally obliged to set aside at least 20% of their land for rainforest. But that target is hard to enforce and had no scientific basis, so no-one knew if it was enough for the forest and endemic species to survive.

The magic number

Determined to find out, Cristina - who now works at Imperial College London after fulfilling her childhood ambition to become an ecologist - began painstakingly assessing the rainforest, square kilometre by square kilometre. She found that birds, mammals and amphibians need a minimum of 30% forest cover to thrive. Other scientists had suggested that level before, but Cristina was the first to gather detailed data to prove it.

Dr Cristina Banks-Leite

Cristina then analysed the figures, to identify 37,000 priority areas, on farmland which, with minimal action, could reach the 30% threshold. She also calculated that compensating those farmers for restoring the land would cost the government around US$200 million (£157 million) annually. That is less than 0·01% of Brazilian GDP.

Getting back to nature

Now Cristina's pioneering work, published in 2014 and recognised by NERC in the 2018 Impact Awards, is set to make a real difference at ground level after the Brazilian government enshrined the 30% target in law last year.

Government officials are also currently considering her proposal for a priority version of existing compensation schemes, which are known as Payments for Ecosystem Services (PES).

Recalling how her childhood inspired her work, Cristina says:

I fell in love with the Atlantic rainforest. I was always going to be an ecologist. Our farm was mostly bare ground when my parents bought it, with little vegetation. We've had it almost 40 years now and it's very green. The trees are taller so they hold the soil better and we see animals coming back, like anteaters. Mostly we did nothing to the land and left it to return to rainforest.

While her parents had jobs in the city, as an engineer and a chef, and bought the farm for fun and a love of the rural land they grew up in, millions of people still living in the rainforest need their land to earn a living - so giving up any land is a significant ask. Industries in the Atlantic rainforest collectively generate 70% of Brazil's GDP, with farms growing crops like sugar cane making a significant contribution to that.

Cristina says:

There are lots of different payment schemes run by the government or non-governmental organisations, but they are dependent on individuals who are engaged in rural conservation, which means they are not necessarily done where they are most needed.

If you're planting sugar cane, no amount of PES will compete against that. Payments would go to farmers whose land is not so productive or is not being used. Some would just need to stop grazing cattle on land (which would return to forest naturally). More damaged land would need to be planted with new trees, so higher payments would be needed for buying and watering seeds.

Policymakers have really taken up the 30% threshold. The law was only enacted last year and I hope that in time they will use (the priority farmland version of) PES to achieve that.

She acknowledges that the 30% target is only based on biodiversity, one of many factors which the government is considering, including erosion and socio-economic needs, as it works out how best to meet forthcoming restoration targets.

Seeing the bigger picture

Meanwhile Edwin Montenegro, who mainly grows sugar cane on his plantation just under 200 miles from São Paulo city, is among the prosperous farmers who Cristina does not think it is realistic to target with any form of PES. He has nearly met the 20% target, but while he supports the government's environmental laws, he wants officials to help fund less destructive alternative crops instead of for setting aside land.

He said:

We have started growing macadamia, as well as sugar cane, as a more sustainable alternative crop. It's not native, but it will help us increase native crops in future.

Cristina said that while "any plantation would be better than sugar cane", none support the same biodiversity as natural rainforest.

The issues will not be resolved quickly, but next time she returns to Brazil she hopes it will look greener, as the impact of her work helps lost rainforest return on more farms, as it has on her family's land.