Image: Amber Wyard, Interventions in Wild Animal Health 2024

Why is Wildlife Health Key to Protecting Biodiversity?

It is now widely acknowledged that there is a fundamental interdependence between biodiversity – the variety of animals, plants, fungi and micro-organisms found in any one habitat - and climate change. Essentially, biodiversity is key to healthy ecosystems, which in turn act as carbon sinks, removing CO2 from the atmosphere, while providing essential services like flood and erosion regulation, and the purification of water. Healthy ecosystems in turn are likely to be more resistant to climate-related shocks like drought or extreme heat, which can have a positive impact on the resilience of both human and non-human animal populations.

However, climate change simultaneously operates in the opposite direction, negatively affecting biodiversity. Rising temperatures and extreme weather events can alter habitats and force species to migrate to avoid extinction. Altered sea and precipitation levels, wild fires and other unprecedented changes can disrupt food webs and established interactions between species, like pollination. The ocean is becoming more acidic as it absorbs excess CO2, harming marine life. Wildlife species that are already limited in their distribution or have specialised habitats are especially at risk of extinction as a result of this interplay between climate change and biodiversity. It is generally accepted that our planet is now experiencing a sixth mass extinction event, associated with the Anthropocene age, where many of the drivers of extinction are the result of human activity and we are witnessing the loss of species at a rate never experienced before. According to the UN, more than 1 million animal and plant species are now threatened with extinction over coming decades.[1] This is unprecedented.

It has never been more vital to weave wildlife health into the fabric of conservation efforts. Slowing down and preventing the extinction of wildlife species – both local populations and across their global ranges - is fundamental to addressing the twin challenges of biodiversity loss and climate change. While many of us are passionate about supporting conservation efforts, traditional approaches have tended to focus on addressing poaching and the illegal wildlife trade, loss and destruction of habitat and climate change mechanisms. But that leaves out a vital piece of the puzzle: the role of disease and the urgent need to simultaneously safeguard the health of wild animals, because the spread of disease is also intricately linked to extinction, biodiversity loss and climate change. Disease is, of course, a natural regulator of wildlife populations in healthy, balanced ecosystems. But as human activity encroaches more on vital habitat, the possibility for transmission of infectious disease increases dramatically and disproportionately – both as more and more people, along with their domestic animals and livestock, come into close contact with wildlife, and as wildlife species come into contact with each other in ways that were not previously possible, through, for example, global travel, urbanisation and the illegal wildlife trade. On average, three new infectious diseases emerge in humans every year, and 75% of all emerging diseases in humans are now zoonotic. The last four decades of the 20^th Century in particular saw a substantial increase in the proportion of human diseases emerging from wildlife hosts.[2] The Covid19 pandemic was a particularly stark illustration of what can happen as the interface between people, their animals and wildlife continues to expand.

But while there has been a tendency to view wildlife as the source of diseases which impact humans, like Ebola, Covid19 or rabies, and therefore focus on the need to protect people and their livestock, there has not always been an appreciation of the importance of viewing wildlife as victims of disease – and yet infectious disease is a significant driver of extinction with the power to decimate numbers of a threatened species, as well as cause terrible suffering to individuals. Ebola, for example, is believed to have wiped out around one third of the global gorilla population.[3]  A staggering 200,000 Endangered[4] Saiga antelope – two thirds of the global population - died suddenly in Kazakhstan in 2015, as the result of changes in the behaviour of the normally harmless Pasteurella bacteria due to sustained high air temperatures and humidity.[5] Other well documented examples of significant disease outbreaks include Canine Distemper Virus in the black footed ferret and African lions (thought to have been transmitted originally by domestic dogs[6]), which is now present in many other large carnivore species, squirrel pox in the UK’s red squirrels (contracted through contact with invasive grey squirrels), toxoplasmosis in sea otters (as a result of domestic cat litter being discharged into the ocean), lead poisoning of Californian condors and scabies in mountain gorillas (who had become habituated to the close presence of humans). One of the most devastating pathogens to emerge in recent years has been chytrid fungus, which has been apocalyptic for amphibians, wiping out an estimated 200 species. Its origins remain unclear but it is thought that it may have been spread to species which had never been exposed to it before through the international pet trade[7]. When local populations of a species are particularly small and fragmented, a disease outbreak can quickly result in local extinction; modelling has predicted that small populations of Amur tigers are as much as 65% more likely to be wiped out when Canine Distemper Virus is present.[8]  These examples are a stark illustration of the urgent need to integrate wildlife health considerations and mitigations into species conservation programmes.

The primary role of veterinary medicine in conservation is often surveillance and base line sampling, so that infectious disease can be identified, monitored, predicted and mitigated against. In addition, when numbers are small, conservation strategies should give every individual the opportunity to breed and play a role in the survival of the species and the maintenance of a healthy gene pool. This means taking care of any that are injured, malnourished or otherwise ill is also a vital aspect of conservation, and requires wildlife vets with specialised knowledge of rehabilitation, including aspects like wound healing, nutrition and husbandry. In addition, there is a need for an understanding of how recovered animals, like sea turtles which have been trapped in fishing gear or vultures which have collided with power lines, can be safely returned to the wild.

Captive breeding and translocation (the planned movement of animals from one area to another, including reintroduction) of threatened species are also key tools when it comes to protecting threatened wildlife and restoring native populations which can then play a vital role in maintaining ecosystem health. The return of wolves to Yellowstone is a well-publicised example. Closer to home in the UK, recent captive breeding programmes have resulted in reintroductions of red-billed choughs, Scottish wild cats and beavers, while other translocations have involved pine martens and golden eagles. Wildlife vets have a crucial contribution to make as members of the teams responsible for these interventions, particularly with regard to the drawing up of essential Disease Risk Assessments which must be in place and up to date, and complemented by pre-release health checks, before any movement of animals to a new location can be undertaken.

There is an urgent need to recognise wildlife health as a cornerstone of species conservation. Healthy wildlife contributes to healthy ecosystems and the resilience of biodiversity, which in turn mitigates the impact of climate change. We need to ensure that wildlife health is routinely incorporated into conservation planning, and that wildlife vets, especially those working in regions of high biodiversity but lower incomes, can access the skills and knowledge they need to play their key role in multi and trans disciplinary conservation teams, so they can be a truly effective part of the solution. Good health is important to all who share the planet. It is a unifying force that underlines the interconnectedness of all living things and demonstrates the importance of adopting a One Health approach to conservation, where consideration of wildlife health needs to be woven into plans and policy.

FURTHER READING:

UN: Biodiversity: Our Strongest Natural Defence Against Climate Change

https://www.un.org/en/climatechange/science/climate-issues/biodiversity

The Lancet: One Health: A Call for Ecological Equity (2023)

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)00090-9/fulltext#:~:text=Nowadays%2C%20the%20term%20One%20Health,people%2C%20animals%2C%20and%20ecosystems.

WCS: The Manhattan Principles (2004) on “One World, One Health”

https://oneworldonehealth.wcs.org/About-Us/Mission/The-Manhattan-Principles.aspx#:~:text=Devise%20adaptive%2C%20holistic%20and%20forward,among%20species%20into%20full%20account.

World Economic Forum: Why Wildlife Health is the Missing Link in Conservation (2024)

https://www.weforum.org/stories/2024/03/wildlife-health-conservation/

All accessed 08/03/25

[1]https://www.un.org/sustainabledevelopment/biodiversity/#:~:text=A%20recent%20UN%20report%20on,ever%20before%20in%20human%20history.

[2] Cunningham, Andrew A., P. Daszak & J.L.N. Wood (2017) One Health, emerging infectious diseases and wildlife: two decades of progress? 2017 Philosophical Transactions of the Royal Society B: Biological Sciences 2017 Jul 19; 372(1725): 20160167 Published online 2017 Jun 5 http://doi.org/10.1098/rstb.2016.0167

[3] https://phys.org/news/2015-01-ebola-virus-population-chimps-gorillas.html#:~:text=Jan%2021%2C%202015-,Ebola%20virus%20has%20wiped%20out%20a%20third,population%20of%20chimps%20and%20gorillas&text=There%20is%20a%20side%20to,the%20great%20apes%20of%20Africa

[4] Thanks to concerted conservation efforts, the status of the Saiga antelope has since been changed to Near Threatened: https://www.ox.ac.uk/news/2023-12-12-unprecedented-conservation-triumph-saiga-antelope-return-red-list

[5] https://www.ox.ac.uk/news/science-blog/scientists-uncover-why-200000-antelope-suddenly-died

[6] Roelke-Parker, M., Munson, L., Packer, C. et al. A canine distemper virus epidemic in Serengeti lions (Panthera leo). Nature 379, 441–445 (1996)., p443 https://doi.org/10.1038/379441a0 (accessed 21/03/25)

[7] https://www.imperial.ac.uk/news/104234/frog-trade-linked-emergence-killer-fungus/

[8] https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110811

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