Saving tropical forest carbon stocks won’t protect biodiversity

A team of experts led by Lancaster University has been investigating whether protecting the carbon storage of tropical forests will also protect biodiversity. The researchers have found that investments designed to prevent carbon losses will be the least effective in safeguarding wildlife across the most ecologically valuable forests.

In these particular regions, up to 77 percent of species remain vulnerable when conservation efforts are focused solely on protecting carbon stocks.

“Securing tropical forest carbon should remain a central conservation objective,” said study co-lead author Dr. Gareth Lennox.

“Not only will this slow climate change but it also has the potential to safeguard the unique and irreplaceable wildlife that inhabits these ecosystems. However, to ensure that those species survive, biodiversity needs to be treated as a priority – alongside carbon – of conservation efforts.”

More than a third of the the world’s terrestrial carbon is stored in tropical forests, which is why these regions have become an important target of international efforts to mitigate climate change and have attracted billions of dollars in funding.

Tropical forests are also the world’s most biodiverse ecosystems, harboring more than two-thirds of Earth’s land species.

The researchers wanted to understand how projects focused on protecting carbon stocks may affect biodiversity. The international team spent 18 months measuring the carbon content and species richness of plants, birds, and dung beetles in 234 tropical forests across the Brazilian Amazon.

For the first time, carbon and biodiversity levels were assessed in forests that ranged from minimally-disturbed by human activities to those recovering after vegetation had been completely cleared.

The analysis of this data confirmed that more carbon would mean more biodiversity in severely damaged forests. The study also revealed that, where human impacts were less intense, more carbon would not lead to more species.

*The changing relationship between carbon and biodiversity across forests that have suffered different kinds of human disturbances explain our findings,” said co-lead author Dr. Joice Ferreira.

“As cleared and highly disturbed sites recover from the effects of agricultural use and severe wildfires, biodiversity also recovers. However, this linkage between carbon and biodiversity breaks down mid-recovery.”

“The result: Forests with the greatest carbon content do not necessarily house the most species, meaning carbon-focused conservation can miss large swathes of tropical forest biodiversity.”

According to study co-author Dr. Toby Gardner, carbon and biodiversity conservation efforts must be combined for the best results.

“Although trade-offs are inevitable, conflicts between carbon and biodiversity can be reduced by more integrated planning,” said Dr. Gardner.

“By considering carbon and biodiversity together, we found, for example, that the number of large tree species that can be protected can be increased by up to 15% relative to a carbon-only approach for just a 1% reduction in carbon coverage.”

Study co-author Professor Jos Barlow explained why climate change mitigation requires the protection of biodiversity.

“Biodiversity and climate change are inextricably linked in tropical forests. A warming climate and changing rainfall patterns will lead to the extinction of many tropical species, while it is within tropical biodiversity itself that forest carbon resides,” said Professor Barlow.

“Species-poor forests will eventually become carbon-poor. Therefore, tackling the climate crisis requires that both tropical forest carbon and tropical forest species are protected together.”

The study is published in the journal Nature Climate Change.

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By Chrissy Sexton, Earth.com Staff Writer

Image Credit: A. Lees