Sweden saw promising jumps in all four predator species measured, explained researcher Guillaume Chapron from the Swedish University of Agricultural Sciences. He said Sweden's performance overall was pleasing and could be likely explained by a good habitat and prey base.
"Scandinavia is doing very well with the lynx and brown bears, but much less so when it comes to wolves. There are 2,400 wolves in Spain, for example, where there is a high human population density, but only 400 or so in Scandinavia where there is a lower human population density," he told The Local.
"But I would say the success of Scandinavia is good, it's effective for the lynx and the brown bears."
The French researcher, who has lived in Sweden for seven years, added that the data was collected over 2011 and 2012 over 26 European countries. He said that the trends in Sweden have changed slightly since then, with the numbers of lynx and brown bears declining and the wolf figures growing at a slower rate.
But the study's results came as a surprise, he added.
"I'd say the results are unexpected. If you think: 'Where can I find large predators in the world, where are they likely to do well, then Europe isn't the first idea that comes to mind."
"It's unexpected in that we very often have bad news, doom and gloom, and a sense that everything is hopeless when it comes to this kind of thing. But now we have a place where it's not so bad – Europe – and this is unexpected. And the fact that it's carnivores is even more unexpected."
When probed as to whether human intervention played a role in the increasing figures, Chapron said a tip of the hat was in order for the Habitats Directive, a European legislation that mandates member states to have thriving populations of flora and fauna.
"These are striking results, and you could say that the fact the carnivores are recovering is partly due to this legislation – it's definitely had a strong effect. Who knew before this data that Europe has twice as many wolves as the US? We tend to under appreciate this conservation success story."
The study was published in the journal Science, detailing the work of over 50 biologists, several of whom work with Chapron in the Department of Ecology at the Swedish University of Agricultural Sciences.
Researchers found that around one third of mainland Europe plays host to at least one large carnivore species. The study's authors suggested Europeans could expect promising conservation prospects going forward.
"The reasons for this overall conservation success include protective legislation, supportive public opinion, and a variety of practices making coexistence between large carnivores and people possible. The European situation reveals that large carnivores and people can share the same landscape," the authors explained.