The tropics at tipping point | University of Oxford
Image Credit: Matthias  Dehling
A flock of Blue-headed Parrots in the Peruvian Amazon. Image Credit: Matthias Dehling

The tropics at tipping point

Global biodiversity is at tipping point and on the verge of collapse, according to a major research collaboration. The team caution that urgent, concerted action is needed to reverse species loss in the tropics and prevent an environmental catastrophe.

In a new study, published today in Nature, the international team, including researchers from Oxford University, Lancaster University – who led the work and the Universities of Hong Kong, Manchester Metropolitan and partners in Brazil, reveal that without quick, decisive action, the risk of species loss in the most diverse parts of the planet will be unprecedented and irrevocable - with severe knock-on effects for wildlife and people alike.

The paper is the first in-depth review of all four of the world’s most diverse ecosystems – savannas, tropical forests, lakes and rivers and coral reefs.

The findings reveal that despite covering only 40% of the earth’s surface, they are home to more than three quarters of the world’s species - including almost all shallow water corals and more than 90% of bird species.

Dr Erika Berenguer, a researcher at the Oxford School of Geography and Environment, Environmental Change Institute, said: ‘We know that species diversity is much higher in the tropics than in temperate zones, but this paper puts into context how diverse the tropics are and exactly how much of the Earth’s species depend on them for home and sanctuary. For example, from the 151,466 flowering plant species, 75% of them occur in the tropics.'

Across tropical ecosystems many species face the ‘double jeopardy’ of being at risk from both local and human pressures, such as over fishing, selective logging and extreme weather such as droughts and heatwaves, heightened by climate change.

Dr Alexander Lees, from Manchester Metropolitan University explained that while over-harvesting of wildlife was responsible for the loss of millions of highly trafficked animals such as pangolins, each year, it also affects many other less-well known species.

He said: ‘Even many small songbirds are at risk of imminent global extinction due to their capture for the pet trade in South East Asia. The rainforests where they live are increasingly falling silent.’

Damage to tropical ecosystems not only affects wildlife, but, millions of people across the planet are also at risk, as lead author Professor Jos Barlow from Lancaster University explains: ‘Although they cover just 0.1% of the ocean surface, coral reefs provide fish resources and coastal protection for up to 200 million people. And between them, humid tropical forests and savannas store 40% of the carbon in the terrestrial biosphere and support rainfall in some of the world’s most important agricultural regions.’

The team’s disheartening predictions are balanced with recommended actions that if implemented sooner rather than later, could prevent the unthinkable. They include a step-change in efforts to support sustainable development and effective conservation interventions that could preserve and restore these tropical habitats.

Professor Barlow adds: ‘Fifty years ago biologists expected to be the first to find a species, now they hope not to be the last. The fate of the tropics will be largely determined by what happens elsewhere in the planet. While most of us are familiar with the impact of climate change on the polar-regions, it is also having devastating consequences across the tropics – and without urgent action could undermine local conservation interventions.’

Dr Joice Ferreira, a researcher from the Brazilian government´s agricultural research institution Embrapa, emphasized that a big part of the solution lies in in strengthening the capacity of research institutions in the tropics.

She said: ‘Despite some notable exceptions the vast majority of biodiversity-related data and research is concentrated in wealthy, non-tropical countries. 

‘An international approach to science is vital to help avoid the loss of tropical biodiversity.’