Bison, the Netherlands and Romania

In May, Dutch and Romanian European bison reintroduction programmes were declared successful after several years of conservation efforts. The Dutch project began back in 2007; the wild cattle had been extinct in that region for two centuries. Now, though, both national parks in question are reaping great environmental benefits from the bisons’ grazing, with a consequent flourishing of flora and fauna.

Photograph: Alamy Stock Photo

Grey wolf, US

Perhaps the most famous – and controversial – case of wildlife reintroduction is Yellowstone National Park’s thriving wolf population. Eleven packs and 108 wolves are reported, as of 2016, while there were none before the 1995 reintroduction of 14 Canadian wolves. The project was sparked by rampant elk overpopulation.

Photograph: Alamy Stock Photo

Beaver, UK

Rewilding is a seemingly constant fixture on the UK horizon: rewildingbritain.org.uk lists lynx, boar, wolves, bison, moose and a great many birds and fish as potential candidates for reintroduction to our island. The most recent success story, though, is the humble beaver. Since a late-2017 reintroduction, the Forest of Dean has already benefited from improvements to soil, and the creatures’ dams are a natural buffer to floods.

Photograph: Alamy Stock Photo

Giant tortoise, Galápagos Islands

Hunters and invasive species decimated the Galápagos giant tortoise from the 16th century onwards. The Española species was one of the worst affected. Conservationists were able to round up the remaining 14, however, before non-native rats and pests were eradicated over several years. The tortoises were then reintroduced. In 2010, it was estimated that more than 1,500 specimens were extant.

Photograph: Alamy Stock Photo

Siberian tiger, South Korea

When DNA tests revealed that the extinct, near-mythical, Korean tiger was the same species as the Siberian tiger, South Korea made the decision to bring them back. A “tiger forest” opened on 3 May, which will contribute towards WWF’s aim of having 6,000 tigers in the wild, globally, by 2022.