Invasive species lurk just outside of most protected areas

A new study has revealed that most protected areas are at risk of being invaded by non-native species. The researchers found that across the majority of the world’s protected areas, there is an invasive animal species present less than 10 kilometers away that could easily adapt and become well-established. 

Study co-author Tim Blackburn is a professor in the Department of Genetics, Evolution & Environment at University College London. 

“One of the most harmful ways that people are impacting the natural environment is through the introduction of ‘aliens’ – species that do not occur naturally in an area, but have been taken there by human activities,” explained Professor Blackburn. 

“These species may kill or compete with native species, or destroy habitats, amongst other impacts. Invasions by alien species are regarded as one of the top five direct drivers of global biodiversity loss, and aliens are establishing themselves in new areas at ever increasing rates.”

“Protected areas are a cornerstone of biodiversity conservation, but aliens don’t know where their boundaries lie. It’s important to know whether these areas might protect against the spread of invasive species.”

The study was focused on 894 animal species that have previously established alien populations somewhere in the world, including mammals, birds, reptiles, and invertebrates. 

The experts investigated the proximity of these invasive species to 199,957 conservation areas, such as national parks and wilderness areas.  

The non-native animals were found to be present in less than 10 percent of the protected areas, which indicates that nature reserves are mostly effective in keeping out invaders.

On the other hand, 89 percent of protected areas had an alien species within 10 kilometers, and 99 percent had a neighboring invasive species within 100 kilometers. 

Furthermore, 95 percent of the protected areas consisted of habitat suitable for multiple alien species. 

The study showed that wildlife reserves were more vulnerable to invasion when they were influenced by humans or had human populations nearby. Older protected areas, which are usually in remote locations, were found to be less exposed to human activities and alien species. 

“At the moment most protected areas are still free of most animal invaders, but this might not last. Areas readily accessible to large numbers of people are the most vulnerable,” said study senior author Dr. Li Yiming.

“We need to increase efforts to monitor and record invasive alien species that people may bring into protected areas, deliberately or by accident, especially damaging species like the American bullfrog, brown rat and wild boar.”

The research did not produce evidence to suggest that areas with higher levels of biodiversity are more protected from invasive species.

“If alien species continue to spread – and we would expect many to do that – many more protected areas will have their boundaries reached, and potentially breached, by these alien species,” said Professor Blackburn.

The study is published in the journal Nature Communications.

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By Chrissy Sexton, Earth.com Staff Writer