Species conservation successes and reasons for hope in the midst of biodiversity decline
This blog post was written by Ashley Simkins, PhD Student in the Conservation Science Group, University of Cambridge and Dr Nigel Taylor, Research Associate with Conservation Evidence
The world is facing a global biodiversity crisis. Of more than 160,000 assessed species, 28% are threatened with extinction [1]. An estimated one million species are facing this fate due to human activities [2,3]. There is evidence that conservation action can work [4,5] and that targeted efforts for species are needed [6]. However, a more holistic understanding of the consequences of past conservation efforts on species is essential to inform future maintenance and recovery actions.
In their recent study, Ashley and colleagues used from the IUCN Red List – the world’s largest database of species conservation status – to assess whether conservation measures had been put in place for more than 67,000 different animal species, and whether those actions had a positive impact on a given species’ conservation status. They analysed all comprehensively assessed animal species in the Red List (where >80% of group had been assessed), including vertebrates, dragonflies and damselflies, horseshoe crabs, and some sub-groups of crustaceans, gastropods and warm-water reef-building corals.
The study [7] found that targeted conservation efforts are helping bring many species back from the brink of extinction. Conservation actions have driven improvements in status in more than 100 species.For example, captive breeding and reintroduction have led to the recovery of the Mauritius kestrel Falco punctatus. A population increase from 4 to >250 individuals meant it could be downlisted from Critically Endangered to Vulnerable. And the European bison Bison bonasus, which was hunted to extinction in the wild in the early 20th century, now roams parts of Eastern Europe thanks to sustained conservation efforts over decades. Humpback whales Megaptera novaeangliae and blue whales Balaenoptera musculus, once driven to the brink of extinction by commercial whaling, have made a comeback after an international moratorium on whaling. Yet more species have benefited from conservation action, even if these effects are not yet reflected in their Red List status.
Importantly, almost all recovering species (that have moved from a more threatened category to a less threatened category) have conservation actions in place, and species with actions are more likely to have improved status than those without. This is a strong signal that conservation works.
While there is no ‘one size fits all’ solution, the study identifies some connections between conservation success stories. Many of the species that have benefitted from conservation action live in isolated areas, such as islands, where intensive conservation efforts – such as habitat protection, captive breeding and reintroductions – can be fully implemented. Collaborative, locally driven action can also lead to better conservation outcomes for both wildlife and people. In Papua New Guinea, for example, conservationists worked with local communities to replace tree kangaroo hunting with sustainable forms of animal protein including farming of chickens and fishing [8].
However, despite these success stories, few species fully recovered from the brink of extinction (i.e. back to Least Concern status). The study also found that six times more species are experiencing a decline in their Red List status than are improving. Crucially, only around half of species examined have been subject to any conservation actions. To ensure conservation supports a wider range of species, emergency conservation action that addresses the symptoms of biodiversity loss needs to be supported by action that addresses the root causes. Like human healthcare, preventative measures in conservation are generally preferable to, and more cost-effective than, emergency interventions.
While biodiversity loss is a genuine crisis, it’s vital that we celebrate the success stories wherever and whenever we can. It’s so hard for a species to improve its conservation status, but with the right effort, we can turn things around. Conservation works if given the chance.
References
[1] The IUCN Red List of threatened species, 2023. https://www.iucnredlist.org/en
[2] IPBES (2019) Global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. https://doi.org/10.5281/ZENODO.3831673
[3] Purvis A, Butchart SHM, Brondízio ES, Settele J & Díaz S (2019) No inflation of threatened species. Science, 365, 767. https://doi.org/10.1126/science.aaz0312
[4] Bolam FC et al. (2020) How many bird and mammal extinctions has recent conservation action prevented? Conservation Letters, 14, e12762. https://doi.org/10.1111/conl.12762
[5] Langhammer PF et al. (2024) The positive impact of conservation action. Science, 384, 453–458. https://doi.org/10.1126/science.adj6598
[6] Bolam FC et al. (2022) Over half of threatened species require targeted recovery actions to avert human‐induced extinction. Frontiers in Ecology and the Environment, 21, 64–70. https://doi.org/10.1002/fee.2537
[7] Simkins AT et al. (2025) Past conservation efforts reveal which actions lead to positive outcomes for species. PLoS Biology, 23, e3003051. https://doi.org/10.1371/journal.pbio.3003051
[8] Tenkile Conservation Alliance (2025) https://tenkile.com/saving-people/
