The IUCN lists the European rabbit (Oryctolagus cuniculus) as an endangered species. For many residents of Europe, this may come as a surprise. Where I live in the UK, some fields are potted and pitted with burrows and it would take genuine effort to avoid see the long-eared fuzzballs wiggle their noses in the air before rocketing into the undergrowth. Even in places outside Europe, rabbits are so common that they are considered a serious pest species. With such a large and widespread population, classing European rabbits as in danger of extinction seems laughable, so how has an organisation as trusted as the IUCN come to this weird conclusion? Explaining this requires a quick trip through European history with stops in the Colonial Era, the Roman Empire and the last Ice Age, a journey reviewed in brilliant detail by Lees & Bell (2008).

First let’s address the proboscidian in the corner. European rabbits are native to Europe. They have a wide-scattered presence in Australia, New Zealand, South Africa, Central and South America, as well as numerous islands, but it’s all down to humans. They made landfall in the New World some time in the late 17^th Century hopping around Columbus’ freshly-made footprints. Fast-breeding and tasty, rabbits were brought by settlers as a self-sustaining food source to add the flavour of home to their new surrounds. The rabbits proved adaptable, wielding their broad diet, ability to spread and tendency to multiply with great enthusiasm. Remarkably, Delibes & Delibes- Mateos (2015) report that Fernández de Oviedo warned of the invasiveness and voraciousness of rabbits back in 1535, reflecting on their impacts on crops in the Canary Islands after their introduction there. European rabbits are more infamously a problem in Australia where no native rabbit species exist and where, since their mid-19th Century introduction, they have earned a reputation for destroying crops, decimating fresh plant growth and supporting invasive predator populations.

So outside of Europe, European rabbits are an introduced species. No surprise there. But I want to focus on rabbits within Europe. Even here they are abundant, so how can they be endangered?

In the latter half of the Pleistocene, crazy fluctuations in temperature saw ice caps and glaciers reach across much of Europe, steamrolling everything in the northern latitudes and pushing the rest towards the Mediterranean on a bow wave of advancing biomes. The Iberian Peninsula became a refuge for a number of species, where they were cut off from the rest of Eurasia. Rabbits were one such refugee, according to fossil evidence, existing through much of Europe in the interglacials but beaten back by encroaching ice caps. (Early evidence of European rabbits in western North Africa may represent trade by people rather than wild populations.)

This describes the rabbit’s entire range up to only a couple of thousand years ago, when they were carried across the Pyrenees through south and central Europe by the Phoenicians and Romans. Being soft, quick-breeding, easy to raise and delicious, rabbits were seen as an invaluable resource. By the time of the Normans in the 13^th Century, they would finally be carried to the UK and Ireland. Surprisingly then, most populations in Europe are also introduced.

In their natural range, the Iberian populations have faced a harsh decline with disease at the top of the suspect list. Myxomatosis was intentionally released on ‘pest’ rabbits in parts of Western Europe in the ‘50s and hit so hard it took out 90% of the French population and, temporarily, hit mortality rates of 99% in the UK. This uncontrolled onslaught is steeped in irony: the disease is itself invasive, brought from South America, and has now largely confined itself to the rabbit’s only native range in Spain and Portugal. Then rabbit haemorrhagic disease (or ‘RHD’) erupted in the ‘90s, with a novel strain emerging in the ‘10s to kick ‘em while they’re down. Habitat loss by urbanisation, agricultural changes, climate change and unsustainable hunting play supporting roles in this collapse.

Regarded as pests of croplands and gardens, they are not bestowed with the sympathy or value they deserve. Their dwindling numbers have been linked to the sorry state of iconic predators like the Spanish imperial eagle and the Iberian lynx, both also endangered. Rabbit numbers also correlate with a number of predatory bird species. Worse still, the European rabbit’s population is divided between two distinct subspecies (and perhaps more on Mediterranean islands). So distinct, after 2 million years of division, that they may be wholly-separate species. Either way, the loss of a (sub)species spells the termination of a unique evolutionary unit. Reintroduction may not be easy: most of the global introduced population is of the O. c. cuniculus subspecies and could have suffered outbreeding, where a population evolves (or has been bred for) features unsuitable for its native habitat. Mixing the two subspecies in captivity or reintroduction programs can also contribute to this. And wherever a species is eradicated, the sands can shift from under them: a cascade of effects caused by their removal can lead to a new stable state in which the lost species no longer finds a place. This new state is simpler and usually less environmentally ‘healthy’, with multiple species caught in the landslide of habitat and biodiversity loss.

So there we have it. European rabbits are really Iberian-refugees-turned-European-travellers-turned-international-globetrotters and now they’re facing disease and persecution from their own homeland.

This situation begs a number of questions: if European rabbits had been widespread in Europe before the last glacial maximum, are they not merely being reintroduced to their past range? What stopped rabbits from naturally re-expanding their range out of Iberia? If rabbits were introduced to much of Europe, should they be removed and beaten back to Spain and Portugal where they apparently belong?

Europe’s wilderness was quite different before the last glacial maximum. The climate had become increasingly unstable but was on average colder and drier than today. This means that, though there is some debate, dense woodland was probably less widespread in Western and Central Europe during this time, providing the nice open habitat rabbits need. As temperatures warmed, humidity increased and the forests spread back, closing up the open habitat on which the rabbits depended. Under non-human conditions, much of modern Europe would be unsuitable for them. This answers the question of how they came to break out of Iberia: with widespread deforestation, Europe opened up for rabbits once more. The erupting civilisations transported rabbits across the continent, through dense patches of forest into ideal open environments. The Pyrenees weren’t the problem; rabbits have successfully made their way across the Andes from Chile to Argentina, so a mountain range clearly isn’t enough to stop them. There simply wasn’t space for rabbits to live in before humans made room for them.

Across the oceans, European rabbits cause all kinds of issues like grazing away the native vegetation, encouraging the spread of invasive plants and providing a food source to invasive predators. But removing them is easier said than done. Much as pulling out a knife leaves a big hole and makes everything worse without due care, killing them off now might do irreparable damage before it does any good. Paradoxically, removing the rabbits’ grazing pressure can let other introduced plant species spread like wildfire and provide habitat for fellow invasive species like black rats, as was found on Carnac Island in Australia. To further complicate matters, rabbits are now a staple in the diet of many native predators in their introduced range, especially where native prey species are overhunted. The result is a messy dependence on rabbits like a drug, which could be kicked only with a great deal of effort and a lot of careful management. The metaphorical nicotine patch is the re-establishment of native prey species paired with the eradication of invasive plants and predators. That’s a tall order, and takes a serious effort.

Within Europe, it seems the rabbits have been less a narcotic and more a medicine. Many take to labelling them as ‘naturalised’ – that is, they’ve integrated themselves into ecosystems and aren’t worth removing. In fact, as Lees & Bell explain, it’s believed that their grazing habits may be functionally similar to those of extinct native grazers, keeping habitats like native grassland open for a variety of species. Costly to evict, rabbits have made themselves useful and earned their place as an exotic-but-permanent piece of wider European ecology.

Even within Europe, then, the European rabbit’s history and residency are complicated. They are in a way a relic from another time, finding new life again in a modern world. Rabbits have been carried far and spread themselves further but ironically in their native range, where they are most valuable, they are close to the edge. The scenario of rabbits existing only in human-altered or non-native landscapes, so becoming a human-dependent species, is accelerating towards reality. They are denizens of the anthrosphere, now woven into the complex ecosystems they have invaded, and yet they may lose the only place they naturally call home.

References

Abbott I, Marchant N & Cranfield R. 2000. Long-term change in the floristic composition and vegetation structure of Carnac Island, Western Australia, Journal of Biogeography, 27(2), pp. 333-346 | Link

Adams J. 1998. Europe during the last 150000 years. Retrieved from https://www.esd.ornl.gov/projects/qen/nercEUROPE.html (Accessed 07/09/2020)

Delibes R & Delibes-Mateos M. 2015. Linking historical ecology and invasion biology: some lessons from European rabbit introductions in the new world before the nineteenth century, Biological Invasions, 17, pp. 2505-2515 | Link

Delibes-Mateos M, Redpath SM, Angulo E, Ferreras P & Villafuerte R. 2007. Rabbits as a keystone species in Southern Europe, Biological Conservation, 137, pp. 149-156 | Link

Ferreira CC, Castro F, Piorno V, Barrio IC, Delibes-Mateos M, Rouco C, Mínguez LE, Aparicio F, Blanco-Aguiar JA, Ramírez E, Iriarte C, Ríos-Saldaña, Cañadilla J, de Reyna LA, Ferreras P, Alves PC & Villafuerte R. 2015. Biometrical analysis reveals major differences between the two subspecies of the European rabbit, Biological Journal of the Linnean Society, 116(1), pp. 106-116 | Link

Ferrer M & Negro JJ. 2004. The near extinction of two large European predators: super specialists pay a price, Conservation Biology, 18(2), pp. 344-349 | Link

Flux JEC & Fullagar PJ. 1992. World distribution of the rabbit Oryctolagus funicilus on islands, Mammal Review, 22(3-4), pp. 151-205 | Link

Forrester NL, Trout RC, Turner SL, Kelly D, Boag B, Moss S & Gould EA. Unravelling the paradox of rabbit haemorrhagic disease virus emergence, using phylogenetic analysis; possible implicaitons for rabbit conservation strategies, Biological Conservation, 131(2), pp. 296-206 | Link

Lees AC & Bell DJ. 2008. A conservation paradox for the 21^st century: the European wild rabbit Oryctolagus cuniculus, an invasive alien and an endangered native species, Mammal Review, 38(4), pp. 304-320 | Link

Rabbit Free Australia. (No date). The Rabbit Problem. Retrieved from http://www.rabbitfreeaustralia.com.au/rabbits/the-rabbit-problem/ (Accessed 11/09/2020)

Villafuerte R & Delibes-Mateos M. 2019. Oryctolagus cuniculus (errata version published in 2020). The IUCN Red List of Threatened Species 2019: e.T41291A170619657. Retrieved from https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T41291A170619657.en (Accessed 14/09/2020)