The nearly magical properties of fig trees

In Cherrapunji, India, locals mold the roots of the fig species Ficus elastica tree into living bridges. Credit: Flickr (CC BY 2.0)

Living bridges made of fig tree roots in Cherrapunji, India

When the Indonesian island volcano Krakatoa erupted in 1883, the waves it sent forth crashed into Bantam, some 50 kilometers away in western Java, and flattened forest for a distance of more than 300 meters inland. All that remained standing, said French scientists who visited a year later, were tall fig trees, their bare branches reaching skyward.

Back on Krakatoa there was no trace of life. Much of the island had vaporized, and what was left was buried under a 60-meter deep blanket of ash. Yet before long, several species of fig trees grew there too. They had arrived as seeds defecated by wandering birds and bats. They soon produced figs that drew in more flying animals, which in time carried the seeds of dozens of other tree species. And so, from black lava, a forest grew anew.

The physical strength, resilience and animal magnetism of fig trees are powers we can tap as we grapple with the Earth’s fast-changing climate. As my book Ladders to Heaven (US title: Gods, Wasps and Stranglers) shows, humanity has long benefited from these trees as sources of materials and medicines, food, shade and security. As the world warms, we may need them more than ever.

That’s certainly true in the Indian state of Meghalaya, the most rain-soaked inhabited place on Earth. The Khasi and Jaintia people who live in the forested hills there train the aerial roots of Ficus elastica fig trees into living nets that prevent landslides and living bridges that save lives when monsoon rains turn streams into raging torrents.

Some of these bridges are thought to be centuries old. By contrast, steel suspension bridges last just a few decades. Bangalore-based architect Sanjeev Shankar says fusing fig roots with steel bridges could create stronger, longer-lasting hybrid structures. He also thinks people in other countries could use the living roots of their own local Ficus species to create structures that build resilience to extreme weather.

But fig trees aren’t only valuable in wet places like Meghalaya. They are also helping people adapt to the growing threat of drought. Farmers in Ethiopia, for instance, are embracing a fig species called Ficus thonningii. These trees need no irrigation, yet their leaves provide vital moist fodder for livestock. They enrich the soil with leaves that fall and decay, and they improve the growth of crops planted in their shade instead of the blazing sun.

Research by Mulubrhan Balehegn and colleagues at Mekelle University shows that planting this species instead of the usual fodder crops can boost production by 500 percent, while reducing inputs of water by 95 percent. Goats that eat the fig tree’s leaves produce more and better quality meat than those given only commercial feed.

Over the past decade, Balehegn and his colleagues have encouraged 20,000 households to plant this tree. They hope farmers will follow suit in the 33 other African countries where Ficus thonningii grows, and urge people to take similar approaches with fig trees in arid areas of India and China.

Crucially, planting fig trees doesn’t just improve livelihoods and help people adapt to the changing climate. By storing carbon, the trees can also play a part in slowing the rate of warming. All trees store carbon as they grow, but—as on Krakatoa—fig trees also encourage the growth of other tree species because their figs attract a diverse range of seed dispersers. In Costa Rica, Thailand and South Africa, researchers are harnessing this power by planting fig trees to accelerate reforestation on logged and mine-scarred land.

Elsewhere, people have traditionally used the presence of Ficus species to divine water, helping them decide where to plant crops or dig wells. Others have planted, or left standing, large fig trees as natural umbrellas against the heat, or have stored dried figs to turn to in times of drought and famine.

In fact, fig trees were among the first plants people domesticated. They have been helping people survive in hot and arid lands for thousands of years. As the world warms, the edible fig (Ficus carica), now grown in at least 70 countries, will grow in importance.

Rising temperatures also pose challenges to fig trees and the tiny wasps they depend on to pollinate their flowers. But this relationship between the plants and their pollinators has endured for 80 million years longer than humans have walked the Earth. The fig trees survived the extinction event that saw off the giant dinosaurs, and lived through periods warmer than what we experience today.

By contrast we are new here. Our future is made insecure by the slow pace at which we are removing carbon from the atmosphere, and our limited capacity to adapt to the resulting climatic change. The good news is that fig trees can help us to do both.

This post was first published (here) by Scientific American.

Photo credit: Flickr (CC BY 2.0)

Read more about fig trees in my book Ladders to Heaven (published in North America as Gods, Wasps and Stranglers). For a summary and reviews from Annie Proulx, Deborah Blum, Michael Pollan, Sy Montgomery, Simran Sethi, David George Haskell and others, visit this page.


Guns, gangs and gold: A brewing social and environmental crisis in Venezuela


Beneath the rainforest to the south of Venezuela’s mighty Orinoco River lie vast reserves of gold, coltan and other minerals. While some say these resources should fund the country’s development, others say they should stay put and that Venezuela should diversify its economy away from resource extraction. But neither is happening. Instead, lawlessness and extreme violence reign.

A social and environmental crisis is unfolding, say researchers who publicly shared their findings for the first time on 26 July in Trinidad, at the Latin America and Caribbean Congress for Conservation Biology. Dutch criminologist and independent researcher Bram Ebus called it the “biggest mining conflict in the making in Latin America”.

The situation stems from a decree signed by President Maduro in 2016 to open up a vast area to mining. Dubbed the Orinoco Mining Arc, the zone encompasses 112,000 square kilometres, or 12% of the country. The region is home to 198 indigenous communities and has several protected areas that are rich in wildlife including jaguars, giant anteaters and 850 bird species. All are now under threat.

The decree invites multinational companies to form joint ventures with state-owned mining companies. While few multinationals have yet shown interest, plenty of other actors have. Ebus says the military, national guard and police, as well as Venezuelan organised criminal syndicates and ELN guerrillas and FARC dissidents from across the border in Colombia, all have mining interests in the area. They are adopting the methods of small-scale illegal miners already present in the region and are implementing them on a grand scale.

“The mining arc decree is a legal jacket put on illegal mining,” says Ebus. He explains that criminal gangs, often backed by state forces, fight each other for access to mining areas. There are frequent massacres – in July the burned corpses of 20 murdered miners were found in a mass grave. Armed groups now control thousands of workers, some of whom are effectively slaves, says Ebus — tattooed with numbers and forcibly moved around and made to work.

The situation comes amid an economic crisis in Venezuela, whose inflation rate the IMF expects to reach one million percent by the end of the year. Tens of thousands of urban Venezuelans — even doctors and lawyers — have rushed south of the Orinoco, desperate to earn a living. Many local indigenous people have also succumbed to gold fever having initially resisted. Women who recently farmed crops now sell their bodies in brothels.

Although the Mining Arc impinges on indigenous territories, these people were not consulted about the plans, nor given an opportunity to give their free, prior informed consent as required under the Indigenous and Tribal Peoples Convention, to which Venezuela is a signatory.

“Of course, most miners know they are doing something very damaging,” says Ebus. “But they are living on a day-to-day basis and need money for food and medicines.” This makes them ripe for exploitation. The work itself is dangerous. Miners spend long hours in deep pits or tunnels that are at risk of collapse. Mercury, despite being banned in Venezuela, is widely used to extract gold. Workers exposed to the chemical are suffering serious health effects, including Minamata disease.

The mercury also enters waterways and accumulates in the food chain. As a result, more than 90% of indigenous Yek’wana and Sanema women have mercury levels in their bodies beyond the World Health Organisation’s safe limits, says Francoise Cabada-Blanco of Universidad Simón Bolívar. Children are being born with neurological disorders and missing limbs.

A deadly outbreak of measles among the Yanomami people who live near the border with Brazil has been linked to the arrival of illegal miners. And there has also been a huge upsurge in malaria cases, linked to the artificial water bodies that mining creates, and in which mosquitoes breed. In 1960s, Venezuela had virtually eradicated the disease, but in 2016 there were more than 240,000 reported cases. By 2017, that number had risen by 69%, with many cases still unreported.

Mining is also polluting rivers that are home to more than a thousand fish species and causing widespread deforestation. But the Mining Arc decree was passed without an environmental impact assessment. “The only thing sustainable about mining in Venezuela is its environmental impact, because it is going to last a long time,” says Ebus.

Juan Carlos Amilibia, a scientist working with the Venezuelan NGO Provita, presented data showing that between 2000 and 2015 the area deforested doubled every five years. Much of the forest loss coincides with new open-pit mines which resemble a lunar landscape, or bombsite. “Since 2010, illegal mining has grown without control within the Venezuelan Amazon, resulting in larger impacts and further forest loss,” says Amilibia. “The Orinoco Mining Arc creates great uncertainty in the region and likely even greater deforestation rates.”

Critics says the Orinoco Mining Arc decree violates Venezuela’s constitution, as well as national and international regulations on the environment. “In Venezuela, there is no efficient institution for environmental control,” says José Rafael Lozada of the University of the Andes, in Mérida, Venezuela. “That is why the Mining Arc must be rejected.” Chances of that happening are slim. The Venezuelan government claims the Mining Arc has the world’s second largest gold reserves (worth US$200 billion) and the largest reserves of coltan (another US$100 billion), as well as diamonds and other resources.

“This is a government you can’t work with on environmental issues,” says Ebus. He says the state mining company Minerven is buying gold from illegal miners, rather than mining itself. But according to Ebus, in 2017 less than 10% of the gold reached the central bank. The rest, he says, is sold on the black market or smuggled across the border to Colombia or over the sea to Dutch Caribbean islands where it is easy to launder.

Venezuela’s Ministry for the Development of Ecological Mining, set up by President Maduro to oversee the Mining Arc, did not respond to questions about the claims made by the researchers. Contrary to the Government’s stated intentions, gold is not being used for social development, says Ebus. “It’s stolen, absolutely stolen. The Government is not interested in cash for the good of the country. It is a kleptocracy. They are going to be thieving what’s left until they’re not in power anymore.”



In August 2018, the Latin America and Caribbean Section of the Society for Conservation Biology issued its first ever formal statement, urging action to reduce the threats the Orinoco Mining Arc poses.

Photo credits: Bram Ebus / Creative Commons

Brilliant birds and the mystery of the mutating mangroves


As dusk falls in the Caroni Swamp on the west coast of Trinidad, hundreds of scarlet ibises fly in from their feeding grounds to roost in the mangrove trees that grow in the dark, brackish water. The birds settle in the trees like glowing embers.

For generations, local people hunted these birds for their meat and used their feathers for Carnival costumes. By the 1860s, colonial records warned that “a fierce war” had been waged on the ibis, and that it would soon be rare. Yet it is thanks to a hunter that the bird has a haven today.

In the 1930s, Simon Nanan started guiding fishermen and duck hunters into the maze of waterways in the Caroni Swamp – some 6000 hectares of marshes, mudflats and mangrove forest. Many of Nanan’s clients marvelled at the scarlet ibis, so he began offering tours to see the birds and these proved more popular than his hunting trips. And so, ecotourism in Trinidad was born.

In time, Nanan convinced the colonial authorities to create a sanctuary to protect the scarlet ibis. The bird now shares its umbrella of security with a rich variety of wildlife that includes silky anteaters, crab-eating raccoons, spectacled caimans and nearly 200 bird species. The Caroni Swamp also provides key services to local people. It protects the coastline from storm surges, provides a nursery for fish and shellfish, and supports a thriving tourism industry.

When Trinidad gained its independence in 1962, it made the scarlet ibis its national bird and banned hunting of the species. But old habits die hard and poaching has continued to the present day. Serving and eating the bird has apparently become a status symbol. In response, the government this week increased protection for the species.

Anyone caught harming, trading or possessing the species now faces a fine of 100,000 Trinidad and Tobago dollars (about US$15,000) and two years in prison. The penalties apply to possession of even a single feather. What few people realise is that those scarlet feathers have another story to tell.

In the late 1990s, researchers noticed harmful genetic mutations in mangrove trees in areas where the ibises roosted. They showed that the sediments beneath the trees had abnormally high levels of mercury, as did the feathers of the scarlet ibises — unlike those of some other birds in the swamp.

The researchers noted that, unlike the other birds, the scarlet ibises travelled to wetlands in Venezuela each year, where they fed on crustaceans and other animals. They concluded that mercury used by gold miners far inland had entered the country’s rivers and made its way into the food chain. Feeding on contaminated animals is what led the mercury to build up in the bodies of the scarlet ibises, they surmised.

Back in Trinidad, moulted feathers accumulating around the roost over decades appear to have polluted the sediments and resulted in the genetic mutations in the mangrove trees. This 20-year old scientific detective story takes on new relevance given the massive increase in mining and illegal use of mercury underway in Venezuela.

If Trinidad’s new penalties do not deter poachers and consumers of ibis meat, perhaps the risk of exposure to mercury will.


Reference: Klekowski, E.J. et al. 1999. An association of mangrove mutation, scarlet ibis, and mercury contamination in Trinidad, West Indies. Environmental Pollution 105: 185-189.

Photo credits: Bottom — Top left — Charles J Sharp / Wikimedia Commons; Top right — Fernando Flores / Creative Commons; Aaron Maizlish / Creative Commons

Sit down, chase some coral, then get up and act


If you’ve not yet seen the award-winning documentary Chasing Coral, I urge you to watch it as soon as you can. It is a powerful illustration of what we are doing to the planet and why we need to wake up and act. It is inspiring, illuminating and even funny in places.

Coral reefs sustain a quarter of all marine life and directly support the livelihoods of more than half a billion people. They are a source of medicines, such as cancer drug prostaglandin. And they protect coastal communities from storms because the skeletons they form create a living breakwater that constantly grows and rebuilds itself.

But corals are in big trouble. The biggest threat they face come from global warming. That’s because the oceans absorb most of the heat our greenhouse gas emissions are trapping in the atmosphere. As the seas warm, the corals eject the tiny plant cells that live within their tissues. Without the plant cells, the corals turn white — they ‘bleach’ — and then they die.

Chasing Coral follows a team on a quest to record the first ever footage of this process unfolding in real time. There’s a poignant moment in the film when team member Zack Rago is scuba diving on Australia’s Great Barrier Reef. He turns to the camera to show a note he has written with his underwater pen. It reads: “This is the hardest dive I’ve ever had to do.”

Rago, a self-identifying ‘coral nerd’, was stung by the effect of going into the sea each day for a month and seeing corals die from one day to the next, of seeing “flesh, living tissue, rotting away”. He was filming in 2016, the year in which 29 percent of the corals on the reef died. The following year another 22 percent perished.

Coral bleaching is now a worldwide phenomenon. At current rates of global warming, all of the world’s corals will be gone in 30 years, or as Ove Hoegh-Guldberg, Director of the Global Change Institute at the University of Queensland, puts it: “In our lifetime, on our watch”.

The film also follows Rago as he meets his childhood hero, Australian coral expert John ‘Charlie’ Veron, who has been diving on the Great Barrier Reef for 45 years. Veron tells Rago to never quit raising awareness of the threats to corals. “You have to keep at it,” he says. “Otherwise you’re not going to like yourself when you’re an old man. You’re going to like yourself much more if you can say, well, I sure tried to turn that around.”

I feel the same. I’ve been talking and writing about the damage we are doing to the planet for a long time now and I’m not going to stop. But sometimes it feels like nobody is listening, that everyone thinks someone else is going to solve these problems for them.

After the screening of Chasing Coral I saw yesterday, host Anjani Ganase of Wild Tobago and the Global Change Institute pointed out that people often ask what individuals can to do change anything. That’s the wrong way of thinking about it, she said. It is when we are vocal, when we come together that we can build a better future. “There’s no individual in this game,” she said. We are all in this together.

If you have Netflix you can watch Chasing Coral now. If not, you can get a free licence for a public screening.

Photo credit: Daviddarom / Wikimedia Commons

Scientists reveal yet another reason fig trees are titans of biodiversity


Biologist David Mackay got a surprise when he began studying the birds visiting fig trees in his native Australia: While he expected to see plenty of species coming to eat the figs, he didn’t expect the insect eaters to outnumber them two-to-one.

Mackay already knew that figs feed more bird species than any other fruit. His research, published in June, would show that fig trees are disproportionately important for insect-eaters too. It adds to growing evidence that fig trees are titans of biodiversity with important roles to play in conservation.

What makes fig trees so crucial is their ancient relationship with tiny wasps. The trees depend on the wasps to pollinate their flowers, while the wasps can only breed and lay eggs inside their partner’s figs. Thanks to this partnership, figs are available year-round and have been called ‘keystone’ resources for fruit eaters. Mackay’s study is the first to show that fig-wasps emerging from figs before they ripen are also valuable year-round resources for a diverse variety of insect-eating birds.

Altogether, Mackay recorded 55 bird species visiting Ficus rubiginosa fig trees to feed on insects. They included ten species — such as the superb fairy-wren and the shining bronze-cuckoo —whose recent declines in numbers have concerned conservationists. Mackay and his colleagues say fig trees are “very likely” to be similarly important to insect-eating birds throughout tropical, subtropical, and temperate regions globally.

To support this view, Mackay points out that in just his study and two others in localised areas of India and Costa Rica, researchers have already identified more than a hundred insect-eating birds visiting fig trees. “The presence of avian insectivores in figs in these three continents strongly suggests their occurrence in figs is ubiquitous,” he says.

“I can hazard a wild guess that there are at least several hundred species of insectivorous birds that forage in fig trees worldwide,” Mackay told me. “This has important implications for the conservation of insectivores, many of which have suffered and continue to suffer declines in response to habitat loss and fragmentation.”

As Mackay points out, the number of fig-wasps emerging from figs on a single Ficus rubiginosa tree in just a few weeks could approach ten million. He adds that insect-eating bats would also relish fig-wasps, many of which fly at night. His study adds to a growing body of evidence that fig trees are centrepieces of vast food webs that include tens of thousands of species.

“I suspect fig trees could play an important role in conservation of declining insectivores as well as contributing to the conservation of other species in the wider communities they inhabit, including frugivores and the other plants that depend on them for seed dispersal,” Mackay said.

Increasingly, researchers and conservationists are turning to fig trees to boost rainforest regeneration by attracting seed-dispersers. Mackay said that using fig trees could also slow or even reverse declines of insect-eating birds: “If we don’t do these restoration projects with figs then we stand a chance of losing these birds altogether.”

This post was first published by on 6 July 2018 and is reproduced here under a Creative Commons licence.

Read more about the ecological and cultural importance of fig trees in my book, published in the UK as Ladders to Heaven and in North America as Gods, Wasps and Stranglers.


Mackay, K.D., Gross, C.L. & Rossetto, M. 2018. Small populations of fig trees offer a keystone food resource and conservation benefits for declining insectivorous birds. Global Ecology and Conservation. Published online on 20 June 2018.

Photo credits

Left to right —  Superb fairy wren (Malurus cyaneus): Patrick_K59 / Wikimedia Commons; Eastern yellow robin (Eopsaltria australis): Graham Winterflood / Wikimedia Commons; Eastern spinebill (Acanthorhynchus tenuirostris): DavidFrancis34 / Wikimedia Commons

Infographic: 5 ways fig trees are titans of biodiversity

To mark the International Day for Biological Diversity, here’s an infographic I made to highlight how fig trees are so important to life on Earth. Please feel free to use it/share it.


Read more about fig trees in my book Ladders to Heaven (published in North America as Gods, Wasps and Stranglers). For a summary and reviews from Annie Proulx, Deborah Blum, Michael Pollan, Sy Montgomery, Simran Sethi, David George Haskell and others, visit this page.


Religion + fig trees = a boost for biodiversity


A sacred fig tree at a Hindu temple in Bengaluru (Bangalore) – credit Anoop Negi

When Tarsh Thekaekara and Shruti Agarwal spotted a lone fig tree in sea of tea bushes in southern India, they knew it had to be special. The researchers were documenting sacred groves in tea plantations to see if they helped conserve wild species. They learned that the fig tree was all that remained of a grove consecrated by local Paniya people who, for generations, had convinced tea estate managers not to fell the tree.

As in many other countries, fig trees have been sacred species in India for thousands of years. Wherever they grow, figs are also key resources for wildlife. Thanks to their curious biology, they feed more bird and mammal species globally than any other fruit and so sustain the seed dispersers of thousands of other plant species. In India, and in many other countries, fig trees could play key roles in protecting biodiversity and regenerating lost forests — but policies to protect these trees are rare.

Writing in the Indian Express, Thekaekara and Agarwal tell how they returned to the lone fig tree and set up camera traps to find out what wildlife visited. They soon recorded monkeys, many bird species, civets and a species of flying squirrel. “As the figs ripened and fell to the ground, the place really came alive,” they write. “Porcupine, wild boar, barking deer, sambhar deer, bear and, even, an elephant! A leopard also walked by, probably feeling like she was missing the party, and to try to dine on a couple of fig-eaters!”

Thekaekara and Agarwal highlight the important ecological role the tree plays in a landscape dominated by tea bushes. “The irony is that even with this knowledge, there is no official protection for the tree,” they write, “and it could legally be cut if the correct permissions are sought.” They note that, across their study area, many sacred groves had been reduced to just a solitary tree — most commonly a fig tree.

In India’s urban areas too, the loss of wildlife-friendly trees is elevating the importance of surviving fig trees. In a new study, Harini Nagendra and colleagues documented 5504 trees at religious sites— 62 temples, churches and Hindu, Christian and Muslim cemeteries — in Bengaluru (Bangalore).

Compared with trees in the city’s parks and streets, the trees at religious sites were far more likely to be native species, which offer more to local biodiversity. As in the tea plantation, fig trees (Ficus species) are disproportionately important in urban areas as they feed so many birds and mammals, and at least one fig species was present at 71% of the religious sites the researchers surveyed.

“Fig trees play a critical role in supporting Bangalore’s threatened biodiversity,” says Nagendra. “Bangalore’s tree cover is extremely fragmented, and Ficus trees act as keystone species, improving canopy-to-canopy connectivity and supporting a wide range of species, including birds, butterflies, bees, bats, macaques, and even the endangered slender loris.”

The researchers found 286 individuals of just one fig species — the banyan, Ficus benghalensis — at the religious sites, where it was the fourth most common tree species. But in the city’s streets and parks, all species of fig trees were relatively rare. None ranked in the top ten species the researchers counted there. Nagendra and colleagues says the large numbers of Ficus trees in sacred sites “demonstrate a strong potential” for urban conservation.

“Unfortunately, there is no policy to promote the planting or fig trees, or to conserve them,” Nagendra told me. “Many Ficus trees in Bangalore are heritage trees, decades and even centuries old. Yet many are now under threat, their branches pruned, the bases concreted, or are cut down for road expansion projects.”

In fields and cities in India and all across the tropics, fig trees play key roles in sustaining wildlife. The ecological importance of these trees results from their 80-million-year old relationship with their pollinator wasps, and it helps explain why fig trees have become embedded in religions in many countries.

Over millennia, diverse cultures have protected fig trees but few societies today value them in the same way. Yet, with the right policies in place, these trees could help us to address 21st century challenges — from conserving biodiversity to restoring forest cover.

Tarsh Thekaekara is a biodiversity conservation researcher with The Shola Trust. Shruti Agarwal worked with The Shola Trust before joining the Centre for Science and Environment in Delhi. Harini Nagendra is a professor of sustainability at Azim Premji University, Bengaluru.

Read more about the many ways fig trees have shaped our species and the world about us in my book, published in the UK as Ladders to Heaven: How fig trees shaped our history, fed our imaginations and can enrich our future, and in North America as Gods, Wasps and Stranglers. Readers in India can buy the book here.


Related posts

The majesty and mystery of India’s sacred banyan trees

Why one fig tree in the middle of nowhere has a 24-hour armed guard

Fresh evidence of the power of fig trees to sustain wildlife and restore lost forests

Photo credit

A fig tree (Ficus religiosa) alongside a Hindu temple dedicated to the monkey god Hanuman in Bengaluru (Bangalore) — Anoop Negi (reproduced with permission). See Anoop Negi’s website for more images.


Jaganmohan, M. et al. 2018. Biodiversity in sacred urban spaces of Bengaluru, India. Urban Forestry & Urban Greening 32: 64-70. [Read online]

Thekaekara, T. & Agarwal, S. 2018. The Ficus in the Tea: The fight for the lonely atti maram (fig tree). The Indian Express. 22 April 2018. [Read online]