Protected Areas All Over the World Vulnerable to Invasive Alien Species

Protected areas around the world are protected from invasive species. However, most of them are still vulnerable to invasion, according to research conducted by scientists from China and the UK, with the involvement of the University College London (UCL).

The study, spearheaded by the Chinese Academy of Sciences, was published in the journal Nature Communications. It showed how the majority of protected areas are no more than 10 kilometers away from an area with the presence of invasive species.

Tim Blackburn, a co-author of the study and UCL Genetics, Evolution and Environment Research Department and Institute of Zoology, ZSL professor, said that introducing invasive species is among the worst damage that humans can inflict to the natural environment.

Invasive alien species or IAS can harm an ecosystem by competing with or killing native species and destroying habitats, among many impacts. Aliens are species that are not naturally occurring in a particular area and are introduced through human agency. Invasion by such species is considered as among the five worst direct drivers of biodiversity loss worldwide. Aliens establish populations at more new areas at an ever-increasing pace. 

The study looked at 894 species of terrestrial fauna, including both vertebrates and invertebrates, which are known aliens in some areas in the world. The researchers assessed if these aliens are in or near the boundary of a protected area. A total of 199,957 protected areas were considered, as identified by the IUCN or International Union for Conservation of Nature. These include wilderness, natural features of monuments, and national parks.

The researchers discovered that lower than ten percent of protected areas have the 894 surveyed invasive species within them, which suggests that, in general, protected areas are effectively shielded against invasion.

However, all of them are still at risk from IAS, because at least one alien species was found within 100 kilometers of 99% of the surveyed protected areas' boundaries. In 89% of these areas, an alien can be found within 10 kilometers of their boundaries. Over 95% of these areas were considered environmentally suitable for some aliens, which means they can quickly establish themselves in these areas.

The research team also looked into the variables present within the protected areas that have aliens and discovered that protected regions that contain more invasive animal species experience a more significant influence or presence of humans, otherwise known as the human footprint index. This is caused by factors like adjacent or nearby large human populations and transport links.

In addition, protected areas that have been established more recently and are more extensive have a more significant number of IAS. The older protected areas are usually in more remote locations, which provide them better protection from human impacts.

Dr. Li Yiming of the Institute of Zoology, Chinese Academy of Sciences, and senior study author, said that for now, the majority of protected areas are free from IAS. Still, it may not be true for long. He adds that those areas which are easily accessible to many people count as the most highly vulnerable.

The study does not imply that the rich biodiversity in these areas is the barrier preventing invasion because the relationships of native flora and fauna with IAS are mixed.