Keep Them Safe – Including Citizens in Practical Conservation Work

It is obvious for some time and to many that biodiversity continues to decline. Despite numerous conservation efforts throughout the past decades, all indices measuring biodiversity show the same pattern. Over time and throughout all regions, the area and quality of natural habitats decline and decrease (IPBES 2019), landscape fragmentation increases (Romanillos et al. 2024), the number of wild populations decreases (WWF 2024), the number of threatened species increases (IUCN Red List 2026), biodiversity intactness declines (Scholes & Biggs 2005), etc. Consequently, numerous known and countless unknown species have become extinct during the last decades. Unfortunately, once a species is extinct, it is gone forever. So far, all efforts to resurrect lost species have failed. Therefore, it is of utmost importance to prevent species from disappearing completely. To ensure that, all available measures must be used. The IUCN One Plan Approach details that this requires in-situ conservation (conservation of species in their natural habitats, e.g. through protected areas) and ex-situ conservation (conservation of species outside their natural habitats, i.e. under human care, e.g. in zoological and botanical gardens) to work hand in hand. In addition, all parties and stakeholders affected must be involved (Byers et al. 2013).

Ex-situ conservation has successfully prevented species from becoming extinct. A very prominent example is the European bison (Bison bonasus) (Figure 1). The species was already considered threatened in 1920, and the last free-roaming individual was shot in 1927. Thus, the species was declared "extinct in the wild". However, 12 individuals survived in zoological gardens and became the founders of an ex-situ conservation breeding programme (Krasińska & Krasiński 2007). The first reintroductions in Poland took place in 1952, and by 2019, 1792 individuals were already counted in ex situ, and 6819 individuals belonging to 31 populations were living in natural habitats (in situ) (Dănilă et al. 2022). This shifted the IUCN Red List category for the species from EW ("extinct in the wild") to currently NT ("near threatened") (IUCN Red List 2026).

Amphibians are considered the most threatened vertebrate class (IUCN Red List), and there are also several successful conservation stories. The Kihansi Spray Toad (Nectophrynoides asperginis) (figure 2) has its natural distribution in a single gorge in Tanzania, where it lived in the spray zone of waterfalls (Channing et al. 2006). Due to the construction of a hydropower dam upriver of the gorge in 1999, water flow was reduced, which led to a change in habitat and the introduction of invasive species. Furthermore, the chytrid fungus Batrachochytrium dendrobatidis (Bd) was introduced too. Kihansi Spray Toad numbers declined, and the species was declared "extinct in the wild" in 2005 (IUCN Red List 2026). Fortunately, 499 individuals were taken to the United States of America in 2001, and Bronx Zoo as well as Toledo Zoo managed to establish reproducing populations. After some lessons learned, the conservation breeding programme took off, and 100 toads were flown to Tanzania in 2010, where they formed two new populations at two locations. So far, all reintroduction efforts have failed, despite large-scale technical efforts, such as the installation of a sprinkler system (see summaries in Nahonyo et al. 2017, Newmark 2025). However, the species is not extinct, reintroductions are still possible and might succeed one day.

Both examples show that the timely establishment of a so-called "backup population" (ex-situ conservation breeding programme) is crucial. Zoological and botanical gardens have been doing this for decades. Nevertheless, their resources are limited, and too many species require ex-situ conservation assistance. At the same time, there are a huge number of other institutions (e.g. schools, museums) and private enthusiasts who successfully keep and breed countless smaller species of vertebrates and insects. This group has acquired a vast amount of expertise and provides a unique resource in many ways. To use that potential, Citizen Conservation was founded in 2018. The simplified idea being that instead of keeping, for example, a goldfish, people can also keep and breed threatened species and thereby contribute to their conservation (provided they have the right expertise and resources). After intense discussions, the first ex-situ conservation breeding programmes in Citizen Conservation started in 2018 with selected species of amphibians. Citizen Conservation quickly became a success (Figures 3 and 4) and by 2026 over 5700 individuals of 37 species and subspecies of fish, amphibians and reptiles are kept (Table 1) by nearly 300 participants. Around two thirds of all participants are private persons who devote their own resources and spare time to saving species from extinction (Figure 5) and have a great positive impact with their detailed accumulated knowledge.

Successful conservation breeding programmes with such a variety of participants with diverse backgrounds require a well-defined set of rules and guidelines. In Citizen Conservation, an advisory board of experts has been discussing and suggesting which species should be included. Among others, the criteria are whether a species is threatened, what the situation is in its natural habitat and whether Citizen Conservation can have a positive impact. One central puzzle piece is that all animals and their offspring remain property of Citizen Conservation. This is necessary to ensure that scientific management is possible and allows the correct distribution (and thus pairing) of individuals. All participants are by contract required to report their numbers regularly (currently twice per year). Species in Citizen Conservation are classified into three categories: I – Require special programme management; II – For advanced keepers only; III – Keeping and breeding knowledge is required but practical experience is not mandatory. While surplus animals of categories II and III can be transferred or sold outside the programme, transfers of category I species underly individually specified restrictions. A functioning programme also requires health and safety guidelines which are developed by veterinary experts and published together with keeping and breeding recommendations on our webpage and are free for download. All participants must provide proof of expertise.

The foundation of scientifically managed ex-situ conservation breeding programmes are their goals. In Citizen Conservation, these are currently calculated in order to ensure that 90 % of the species' genetic diversity is safeguarded for 40 years. Besides the underlying models, the goals take into account whether there are complementary and cooperating other programmes for the species, and risk spreading (e.g. not having all individuals at a single holding). These goals guide our management and ensure that capacities are well used (see Table 1).

Working with voluntary organisations and persons has also other positive impacts than just increasing capacities. It raises awareness for the biodiversity crisis and the threats many species are facing. Thus, all participants act as multipliers. The key message is, that we can only succeed in slowing down the species extinction crisis, if we focus on the human abilities that led us to become the dominant species on earth: our capacity for cooperation and for sharing information and knowledge across time and space. To enforce that point, Citizen Conservation runs a professional campaign to raise awareness and reach as many people as possible. Of course, keeping the peer group up to date is crucial, at the same time it's of utmost importance to communicate outside the already engaged community and reach out to the majority of society that doesn't have any personal link to wild animals. Therefore, during the Covid-19 pandemic we launched a series of podcasts (and later on a book) that explored the topic in a humorous and literary manner, presented by German-speaking celebrities from cultural and show-biz sector. The aim was not to turn everyone into animal-breeders, but to convince non-animal-breeders of the need for ex situ conservation breeding. We can only succeed with our approach with a backing of the majority of the society.

We believe that as many species as possible should be protected from extinction (not only because we like animals, but for the sake of humanity). Unfortunately, a lot of them won't survive without effective ex-situ measures. Professional scientific and zoological institutions can provide a lot of expertise through the work they are doing, but we'll only be able to manage this challenge, if we effectively use all available capacities and tackle this historical societal challenge through cooperation. We simply need every helping hand. And by the way, fighting extinction can be fun. It provides you with direct success and thus hope – a very rare currency these days. It is awesome to be part of a group of people who directly experiences reproduction success in the species they keep, thus successfully taking care of a threatened species, even (or for some folks especially) if it's a frog.

The efforts of Citizen Conservation significantly increase the amount of scientifically managed ex-situ conservation breeding programmes for taxonomic groups which are highly threatened but often neglected in conservation, i.e. amphibians, reptiles and fish. For some species, e.g. the Mangarahara Cichlid (Ptychochromis insolitus) (Figure 6) and the Demonic Poison Frog (Minyobates steyermarki) (Figure 7), there is the fear that both might be extinct in the wild. For others, such as the European Fire Salamander (Salamandra salamandra in Central Europe, Figure 8), the recent spread of the chytrid fungus Batrachochytrium salamandrivorans (Bsal) threatens their genetic diversity. The Rio Pescado Stubfoot Toad (Atelopus balios) (Figure 9) was considered extinct and rediscovered by our Ecuadorian colleagues from Centro Jambatu de Investigación y Conservación de Anfibios and Wikiri Sapoparque, both in Quito. We have established the first backup populations in Europe for this highly threatened genus which suffers heavily from habitat decline and the chytrid fungus Bd. Sometimes species are also included for reasons other than being threatened. The Oriental Fire-bellied Toad (Bombina orientalis) (Figure 10) is included not because of its threat status but because wild-caught individuals are regularly imported, though the species is easily bred under human care. We believe that for this species there is no need to rely on large scale wild-caught imports.

Currently, the majority of participants come from German-speaking countries (Germany, Austria and Switzerland). However, participants from other European countries (Belgium, Czechia, France, Hungary, Latvia, Netherlands, Poland, Sweden, and UK) are also contributing significantly. Members in Italy will join in the near future. The development of Citizen Conservation over the last years is very positive, with numbers of species, individual animals and participants continuing to rise over the years (see Figures 3 and 4).

Naturally, many readers might have many more questions than can be answered in this article. We invite everyone to check out our webpage, which contains much useful information, documents and a well-developed FAQ section, where further answers can be sought. We hope to continue our growth in the future, further professionalise our management (e.g. through a dedicated platform), inspire more people to join Citizen Conservation and ensure that species do not disappear but survive for future generations.

Table 1. Overview of ex-situ conservation breeding programmes currently being managed by Citizen Conservation, split across two coordinated panels so that all nine columns remain legible in print. Table 1a gives the scientific and common names and the numbers of males, females and undetermined individuals counted during the inventory in the first half of 2026 (as of 1 May 2026). Table 1b gives the holdings counted in the same inventory, the calculated goals to safeguard 90 % genetic diversity for a period of 40 years, and the average status in reaching these two goals.

Table 1a. Individuals held, inventory of the first half of 2026 (as of 1 May 2026).

Table 1b. Programme goals and progress towards them.

Acknowledgements

We are deeply grateful to the shareholders of Citizen Conservation Foundation gGmbH for their support, these are the Association of Zoological Gardens (in German speaking countries) "Verband der Zoologischen Gärten – VdZ", the German Society for Herpetology and Terraristics "Deutsche Gesellschaft für Herpetologie und Terrarienkunde – DGHT" and the NGO Frogs & Friends e.V. We are also indebted to the numerous zoos, institutions (and the people behind these) and private persons who provide financial support but also who are the heart and machine of Citizen Conservation by keeping and breeding Citizen Conservation animals in such a successful and dedicated manner.

References

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