Sure, it can be legitimately argued that our level of knowledge increases (we didn´t anticipate that some species were threatened, and others we even might not know) and the criteria for individual species to be included to the Red List are changing. Unfortunately a great deal of research shows that the number of threatened species is growing rapidly and also that the abundance of common species is declining significantly. Only in the last two weeks the results of such two research reports were published. According to the first, the global population of vertebrates has fallen by half during the last 40 years. According to the second, over four hundred billion individual members of common species of birds have disappeared in Europe during last 30 years.

Based on these data we could succumb to the impression that the fight for preservation of biodiversity is lost – but even if it were, it doesn´t mean that we should give up. It is a key task of modern zoological gardens and their opportunities are considerable. It is estimated that they hold in their collections three and a half billion individuals drawn from 13,000 species of vertebrates. It is a very large Noah´s Ark. But not large enough, and not only regarding the growing number of threatened species, but also because one half of these kept individuals belong to a mere ten species.

But by that I do not wish to diminish the importance of creating back up populations of threatened animal species in zoological gardens and their reintroduction back to the wild. Not in the least! After all, it was our Zoo which played key role in the preservation of Przewalski´s Horse and its return to Central Asia. But even all the zoos of the world united in one Noah´s Ark simply can´t save more than only a tiny fraction of threatened species. Not to mention the sad fact that in most cases there would be nowhere to return them anyway. Semi-arid deserts, where Przewalski´s Horses once lived, have been preserved without any major changes, but as the tropical rain forest disappears, Lowland Gorillas surely will not find a surrogate home in palm oil plantations.

Yes, modern zoological gardens should serve as a lifeboat – the ambition to be Noah´s Ark is excessive – yet their strength of determination I see in something else. In Europe the member zoos of the European Association of Zoos and Aquaria (EAZA) are visited by one hundred and forty billion people each year. Globally, the number is seven hundred billion visitors. It is thanks to them and through them that zoological gardens can change public opinion and create pressure on politicians and entire governments, and in this way contribute to changes in favour of nature protection and the conservation of biodiversity. At the same time, due to the funds they have at their disposal or which they can raise, the zoos have the possibility to develop conservation projects in situ, meaning in localities where threatened species are prevalent. And in cases like that it usually is not about just the preservation of one species – let´s say the popular gorilla – but also of its habitat and, together with it, the entire range of less visible and less attractive animals.

During the next 50 years of its existence the Red List, to speak metaphorically, will likely not become shorter. Still, using the best options we have, we must strive for this goal relentlessly.

The author is the Chair of the Union of Czech and Slovak Zoological Gardens and the Director of Prague Zoo.