Human threat hotspots revealed: study shows impact of hunting, land clearing on species

A University of Queensland-led study has delivered alarming results, signalling the imminent extinction of up to 1000 species of birds, mammals and amphibians, unless the mostly human threats are actively managed.

The team mapped destructive human activities including hunting, agriculture, urbanisation and other industrial land uses in the locations of 5,457 threatened species.

Published in PLOS Biology, the study found that species are affected across 84 per cent of the Earth’s surface, with global hotspots in South East Asia and South America where tropical forests contain the richest diversity of life.

James Allan, from UQ’s School of Earth and Environmental Sciences, said the crisis is severe, to say the least.

“We predict hundreds of extinctions will happen without conservation action, which really is shocking. This is new evidence that shows just how extreme the crisis is, and identifies the specific species in the most trouble.

“A quarter of those assessed [1,237 species] are impacted by threats covering more than 90 per cent of their habitat, and 395 species are impacted by threats across their entire range, including many charismatic large mammals,” he said.

“We only mapped threats within a location if those threats are known to specifically endanger the species.

“This means species will decline, and possibly die out in the impacted parts of their habitat without conservation action.

“Completely impacted species will almost certainly face extinction.”

Allan said while the findings were alarming, they were not surprising.

“Human activity is so pervasive across Earth and we really are leaving species no place to hide.

“We certainly expected to find the patterns that we did, but the bit that surprised us is just how extensive impacts were.”

The authors also mapped global ‘cool spots’ where species had not been affected, identifying the world’s last, threat-free refuges.

“Cool spots are places where many species are not threatened by human activity.

“Interestingly, cool spots can occur in the same place as hotspots simultaneously.

“This tends to happen in places with lots of species, where some species are sensitive to the threats, and others are not – so it is a cool spot for them.

“For example, a road might be catastrophic for amphibians or mammals trying to cross it but for birds flying high above it has no impact.”

Professor James Watson of UQ and the Wildlife Conservation Society said the results are a striking reminder of the severity of the biodiversity extinction crisis, but there is room for hope.

“All the threats we mapped can be stopped by conservation action, we just need the political will and funding to do it,” Watson said.

“We have shown, throughout the world, that actively tackling these types of threats works, with species bouncing back when conservation action is targeted and well-resourced.

“One obvious step is to secure species threat-free refuges, which are paramount for their survival, avoiding any initial human impacts in these places.”

The authors said the study provides essential information for conservation and development planning, and can help guide future national and global conservation agendas.

“It can also help us define the conservation strategy for different areas. In hotspots, we must manage threats and remove them. In cool spots we just need to prevent threats getting in,” said Allen.

“These strategies appeal to different organisations. We can also use the data to specifically identify which threat to remove where.

“Opening up space for species with large areas of their ranges impacted is key.”

Allen said studies such as these provide a framework for moving beyond just mapping threats – to actually mapping where they impact species.

“Others can adapt and improve this, adding in finer scale data, etc.

“The results of our analyses are a wake-up call telling us the situation is dire, but all the threats we map can be stopped by conservation action – we just need to fund it and get political will.”

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