New research suggests that, as well as enhancing bird diversity inside their borders, large national parks also support a higher variety of wildlife species in adjacent unprotected areas.
The new study, published in Nature, recruited scientists from 10 countries to conduct a comprehensive analysis of bird and mammal diversity inside and outside of national parks across South-East Asia – one of the most biodiverse regions on Earth. The scientists compiled a massive database of observations across the region that demonstrated the protective features of national parks.
"We knew that protected areas can reduce logging – you can see that from satellite imagery – but you can't see the animals in the forest from space," said the study's lead author Dr Jedediah Brodie, the UM Craighead Chair of Conservation. "Our new analysis shows that parks benefit forest wildlife, too."
The researchers compiled a vast database of observations across South-East Asia that demonstrated protective features of national parks (Gumsaku).
Brodie said that some scientists argue that conservation success inside some parks can come at the expense of neighbouring unprotected habitats. Conversely, marine parks often report biodiversity spillover, meaning that species protected within park boundaries produce an abundance of eggs, larvae and adults that then disperse and increase the biodiversity in surrounding habitats. The question the researchers faced was whether or not land parks displace biodiversity losses or provide spillover.
Brodie added that the findings are especially timely for the UN, which recently announced ambitious biodiversity conservation targets that include significant expansions of global protected areas. The UN strategy is to conserve 30% of Earth's lands and waters by 2030.
"Massive expansions to global protected area coverage will be difficult and expensive, but our results show that it's worth it," Brodie said.
The study provides justification to designate protected areas that are as large as possible, as larger parks had significantly stronger influence on mammal diversity in the surrounding landscape. Recent work in the region suggests that some wildlife species are persisting in small parks, but this apparently doesn't scale up to such areas having landscape-scale spillover effects.
"Not all parks are equal," said co-author Dr Mairin Deith of the University of British Columbia, Canada. "Larger parks routinely had higher bird diversity. Considering the UN's goal of increasing protected area to 30% of the world's surface, these findings support the creation of fewer larger parks compared to many smaller ones, where it is possible to do so."
Reference
Brodie, J F, Mohd-Azlan, J, Chen, C, et al. 2023. Landscape-scale benefits of protected areas for tropical biodiversity. Nature. DOI: 10.1038/s41586-023-06410-z
