Most species in UK zoos are non-native and not threatened, undermining conservation goals

A study involving British zoos and aquariums has revealed that a mere 9% of the vertebrate species held in captivity are native to the United Kingdom. Furthermore, just 2% of the species are considered high conservation priorities. These findings, published in the journal PLOS One on August 19, 2026, by researchers Justin Lennon of the University of Brighton and his colleagues, challenge the notion that zoos primarily serve as entertainment venues.

While zoos have evolved to encompass education, research, and conservation, their original purpose was to provide public amusement. However, the priorities for captive breeding and reintroduction programs often conflict with these new roles. Large, charismatic species tend to attract more visitors, which is crucial for a zoo's financial stability, yet these species are not always the most critical for conservation efforts.

The study examined data from 113 BIAZA members, analyzing the species diversity and size of captive vertebrate populations. Of the over 2,600 species, fish comprise 61% of the captive population, followed by birds (16%), mammals (15%), amphibians (5%), and reptiles (4%). Fish exhibit the highest species richness, whereas amphibians, despite being the most threatened vertebrate class, have the lowest diversity and smallest number of species in British zoos.

Only 28.5% of captive species are classified as vulnerable, endangered, or critically endangered according to the IUCN Red List, and their populations are smaller than nonthreatened species. The researchers emphasize that while BIAZA institutions may have a tendency to favor globally nonthreatened species, they are still contributing to the preservation of UK native and priority species.

Nonetheless, there is room for improvement in increasing the diversity and population sizes of threatened species within zoo collections.