45 bird species, eleven mammal species and seven fish species have arrived in Sweden since the 19th century, according to a report produced by the SLU Species Database on behalf of WWF.
"The number of species does not always say much about the state of nature, and sometimes it's directly negative when more arrive," says Emelie Nilsson, expert on Swedish nature conservation policy at WWF, in a press release.
Although there are invasive species that can threaten other species and ecosystems, many of the new species do not pose a threat to native ones. The twelve species that have disappeared are instead signs of how major landscape changes are affecting species richness, according to the report.
