What are the Risks of Bringing Species Back from Extinction?

Biodiversity is declining at unprecedented rates in human history. Drastic declines call for ambitious mitigation measures. Would management be going too far by bringing species back from extinction? Leaving moral concerns for a later discussion, what are the practical risks and implications of de-extinction?

The current heavily exploitative human activities are causing species extinctions at thousands times the natural rate. Our species has become the single most influential organism on the planet, and this has brought many scientists to rename the current geological period the Anthropocene – the era of the humans.

In the recent decades, technology has improved drastically. Especially genetic laboratories have been exponentially improving their techniques and refining their tools. Such improvements have meant that today we may be able to bring back (long-)lost species from extinction. This controversial idea is known as de-extinction and it may be achieved through two separate approaches: either by using well-preserved cells of extinct species to make clones, or through creating and inserting gene sequences that resemble the traits of lost species into the genetic make-up of their alive counterparts (i.e., of taxonomically-close extant species).

Bringing back species could have several benefits, such as the restoration of lost ecological processes and the provision of invaluable ecosystem services to people. But what are the risks? A new paper1 published in the Journal for Nature Conservation explored them.

The pair of co-authors, Dr Piero Genovesi Chair of the IUCN Invasive Species Specialist Group, and Prof Daniel Simberloff based at the University of Tennessee, used their insights as ecologists specialised in invasion biology – the study of how non-native species affect the landscapes where people introduce them – to answer this question.

While ultimately the two authors do not strictly oppose de-extinction, they bring up four main issues which would need to be carefully evaluated before considering such intervention.

The first issue is that by bringing back extinct species, and especially those that have been extinct for a long time and we know little about, we would risk to jeopardise the functioning of entire ecosystems and even threaten biodiversity. In other words, we may cause more damage than good.  “De-extinction and release of recreated proxies in nature is a form of introduction, and would bring, as would any introduction, the possibilities of benefits but also risks of unintended consequences”, the authors say. Similar to when introducing non-native species in novel environments, the authors say that before considering bringing species back from extinction management should conduct rigorous feasibility assessments and “balance the probability of conservation benefits (likelihood of successful establishment plus magnitude of benefits gained) against the costs and risks (likelihood of undesired outcome plus magnitude of harm caused if realised) of the introduction”.

Second, the authors worry that the money invested in the exciting idea of de-extinction could siphon already limited funds and resources available for nature conservation globally. Furthermore, if the public and private attention is diverted from nature conservation to techno-fixes and de-extinction, this could be a final blow to today’s biodiversity and ecosystems. Would our societies become less worried, and thus less concerned, about extinctions at the sight of a species being brought back from the dead? Would you?

Third, de-extinction could also cause and exacerbate social conflicts, as not everyone may agree on whether or not a species should be brought back. For instance, would Australian or Tasmanian farmers be happy to see reappear their native large predator the thylacine (portrayed in the cover photo) in their landscapes, while this animal poses a potential additional threat to livestock? Or, should the proxy of an extinct plant with apparent weedy traits that would represent an agricultural burden to farmers be revived? These emerging conflicts would be extremely difficult to resolve, as we learn from other examples of conservation conflicts today.

Lastly, the authors stress that bringing species back from extinction could also provide new pathogen transmission pathways from wildlife to people, and could thus pose a serious threat to human health. “De-extinction also carries health risks both to other species and to humans. All organisms have some level of infection with micro-organisms or parasites, and the release of a species, especially following some inevitable period of captivity before release, could spread a disease”, explain the authors. “There is also a limited but not negligible risk that de- extinction would resurrect endogenous retroviruses residing in the genome of the target species, with health risks that are impossible to evaluate”, they continue.

While we want to avoid a Jurassic Park effect, our ability to predict the impacts of revived proxy species is limited, also because our ecological knowledge of extinct species tends to often be minimal. These issues make de-extinction a particularly risky tool for management to use, and any intervention of this kind would need to be deeply evaluated and heavily scrutinised, the authors conclude.

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  1.  Genovesi, P. and Simberloff, D., 2020. “De-extinction” in conservation: Assessing risks of releasing “resurrected” species. Journal for Nature Conservation, p.125838. https://doi.org/10.1016/j.jnc.2020.125838

Cover image credits: https://bit.ly/3fBEzBq

2 thoughts on “What are the Risks of Bringing Species Back from Extinction?

  1. The authors don’t seem to outrightly oppose the idea, but the number of concerns they’ve highlighted shows that they are extremely apprehensive. Probably not a good idea, in my opinion.


    1. Hi Saurab, thanks for your comment. You are right that the authors are not positioning themselves strictly against this type of intervention. It is a multifaceted (and controversial) idea and it would be incautious of us to rush into it. It necessitates a lot of thought, analysis and discussion just like many other conservation issues – if this can even be considered a “conservation” issue.

      Liked by 1 person

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