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Nature

The Tropics Are Set For A Catastrophic And Irreversible Collapse In Biodiversity

author

Robin Andrews

Science & Policy Writer

clockJul 30 2018, 17:41 UTC

Frogs are a surprisingly good measure of the health of an ecosystem - and suffice to say, they aren't doing particularly well as of late. Dirk Erken/Shutterstock

The tropics – which include a plethora of habitats between the Tropics of Cancer and Capricorn – are the perma-balmy home to more than 75 percent of all known species, including 90 percent of terrestrial birds, pretty much all shallow-water corals, and three-quarters of all amphibians. They act as a barometer for the state of biodiversity on the planet, which is why a new Nature review makes for such a profoundly disheartening read.

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The international endeavor – led by Lancaster University – aimed to quantify the global importance of biodiversity in the tropics, while assessing their vulnerability to current antagonizing factors. These include climate change, pollution, deforestation, weak governance, overfishing, unsustainable product demands, poaching, and an increasingly large and affluent population.

From the forests and savannahs to the coastlines, the team not only found that they are likely to be more richly diverse than we’ve previously estimated, but that without urgent action, those antagonizing factors will likely trigger a collapse in biodiversity.

The review’s lead author, Jos Barlow – a professor of conservation science at Lancaster University – doesn’t hold out much hope for the future either.

“Unfortunately, over the coming 20 years I suspect we'll see more of the same – an increasingly warm and unpredictable climate, ongoing land-use change, growing pressure on protected areas, and woefully insufficient investment in socially-just and sustainable development pathways,” he told IFLScience.

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Describing the prognosis as “sobering,” he added that he’d “love to be wrong.”

90 percent of all birds are either endemic to the tropics, or use it for part of their life cycle. David Carillet/Shutterstock

Between 15,000 and 19,000 new species are classified in the tropics every single year. That’s around 47 new species per day. One researcher suggests it would take three centuries to properly catalog all the biodiversity, which hints at what’s at stake here.

Even if how we describe it is up for some debate, the precipitous decline in biodiversity levels all over the planet is increasingly well documented. As every living thing is connected with intricate ecological strands, a speedy decline in biodiversity, particularly in the areas surrounding the Equator, is decidedly unwelcome but increasingly probable.

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It cannot be overstated that the tropics also provide, as the team’s paper phrases it, “incalculable benefits to humanity.” They are where the fields of ecology, biogeography, and evolutionary biology sprang from, and provide much of the planet with vital, economy-driving natural resources.

Take coral reefs, which are perennially threatened by climate change: Covering just 0.1 percent of the ocean’s surface, they provide fish for 275 million people. The tropics also provide a much-needed buffer against anthropogenic warming by acting as a carbon sink, with tropical forests storing 25 percent of the terrestrial biosphere’s carbon.

This isn’t an esoteric issue or one that’s exclusive to wildlife. The tropics support a vast number of humans too, and their destruction is clearly a sobering example of humanity shooting itself in the collective foot. Without swift and effective action, there is a huge risk for “unprecedented and irrevocable species loss” in the region.

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As spotted by The Guardian recently, one paper looking at how we should best communicate this loss highlighted a particularly evocative, pertinent phrase: we are "burning the library of life.”

So what’s to be done? Barlow suggests that an uptick in environmental sustainability and social equality movements, along with much more involvement from developed nations, could turn back the tide somewhat.

Examples of good conservation do exist, after all – something the team refer to as “bright spots” – and it’s important to find out how they can be both publicized and scaled up. The paper underscores the importance of pluralism, noting that there is no one-size-fits-all solution to what the tropics are experiencing.

The tropics experience half the world's rainfall. Gustavo Frizao/Shutterstock

As well as improving the integration between natural and social sciences to bolster the idea of sustainable co-existence, scientists need to up their game too: Too often, they apply ecological models elsewhere in the world to vastly different, hyperdiverse tropical areas. Scientific authors from low-income nations are less than half as likely to be published as those from wealthier nations, suggesting that there's a well of conservational knowledge currently being untapped.

It’s not an entirely hopeless situation. The team point out that accords like the Paris Agreement hint at an “awakening of environmental consciousness” – but unless we back up words with decisive action, a cataclysmic loss awaits us.


Nature
  • climate change,

  • biodiversity,

  • pollution,

  • species,

  • overfishing,

  • loss,

  • collapse,

  • tropics,

  • habitat destruction,

  • globalization,

  • catastrophic,

  • governance