Jussi Murtosaari / Muskrat (Ondatra zibethicus) Espoo, Uusimaa, Finland, May. Introduced species.

Edwin Giesbers / Barbary ground squirrel (Atlantoxerus getulus) looking over rock, Fuerteventura, Canary Islands. Introduced from North Africa.

Edwin Giesbers / Barbary ground squirrels (Atlantoxerus getulus) fighting, Fuerteventura, Canary Islands. Introduced from North Africa.

Nigel Cattlin / Orange balsam (Impatiens capensis). Kennet and Avon Canal, Berkshire, England, UK. August.

Nigel Cattlin / Orange balsam (Impatiens capensis) flowering and seeding at edge of Kennet and Avon Canal, Berkshire, England, UK. August.

Colin Varndell / Grey squirrel (Sciurus carolinensis) preparing to jump. Dorset, England, UK. April.

Juan Manuel Borrero / Carvao aqueduct with Chilean rhubarb (Gunnera tinctoria) at base. Devasa mountain range, Sao Miguel Island, Azores, Portugal. 2019.

Juan Manuel Borrero / Japanese cedar (Cryptomeria japonica) seedling. Devasa mountain range, Sao Miguel Island, Azores, Portugal. 2019.

Juan Manuel Borrero / Chilean gunnera (Gunnera tinctoria) at edge of footpath, woman hiking along path. Devasa mountain range, Sao Miguel Island, Azores, Portugal. 2019.

Adrian Davies / Oak processionary moth (Thaumetopoea processionea) nest removal from infested Oak (Quercus sp) tree with cherry picker. Surrey, England, UK. July 2018.

Cyril Ruoso / Harlequin ladybird (Harmonia axyridis) group overwintering under bark in crack in tree, non-native invasive species. Bourgogne-Franche-Comte, France. March.

Cyril Ruoso / Signal crayfish (Pacifastacus leniusculus), non-native invasive species. On riverbed in woodland. La Cure river, Morvan, Bourgogne-Franche-Comte, France. May.