https://www.sciencedaily.com/releases/2020/06/200608093000.htm

The research, led by the Chinese Academy of Science and published in Nature Communications, show that for most protected areas, there is an invasive animal species living less than 10km away that is well suited to the protected area's environment.

Co-author Professor Tim Blackburn (UCL Genetics, Evolution & Environment and the Institute of Zoology, ZSL) said: "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.