green lizard and Aesculapian snake, have formed colonies probably due to a result of release from captivity. There have also been calls for the return of the European tree frog to the wild. Established in 2020, Celtic Reptile & Amphibian, aims to reintroduce the lost species of reptile and amphibian that once inhabited Britain, back to rewilding projects. These include the moor frog, European tree frog, agile frog and European pond turtle. They have already had significant success breeding the moor frog in captivity. The organisation also wants to see European pond turtles re-established within wetland restoration projects. The large blue butterfly has been successfully re-established from Swedish stock at several sites, but very few of these are open-access. There are also several successful cases of the establishment of new populations of heath fritillary. There have been calls for the reintroduction of the Eurasian lynx, brown bear and grey wolf to the UK, because no large predators are living in viable populations in Great Britain. It is theorized that a large predators presence could create a trophic cascade, thus improving the ecosystem. There are plans to reintroduce European bison into England in spring 2022. The initial reintroduction would consist of one male and three females being released into a 150-hectare area with no accessible footpaths. See also List of mammals of the British Isles Extinct animals from the Isle of Man List of extinct animals of Europe List of extinct plants of the British Isles Introduced species of the British Isles Timeline of prehistoric Britain References Further reading A Short History of the British Mammal Fauna (archived) The History of British Birds Buglife on bumblebees Joint Nature Conservation Committee – Invertebrates extinct in the last 100 years Britain Britain Extinct Extinct animals