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Deadly Rabbit Disease May Have Doomed Iberian Lynx

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Iberian lynxThe 1988 arrival of viral hemorrhagic disease (VHD) in Spain devastated that country’s European rabbit (Oryctolagus cuniculus) population and, in the process, possibly doomed the local species most adapted to hunt rabbit, the Iberian lynx (Lynx pardinus).

The wildcat is now critically endangered, with an estimated 100 to 200 animals remaining in the wild. That makes them the world’s most endangered feline species. The species numbered 4,000 animals in 1960.

One of the few areas where Iberian lynx still reside is Spain’s Doñana National Park. According to research published in the March 2011 issue of Basic and Applied Ecology, the lynx was the only predator in the park not able to adapt to eating other prey when the rabbit population crashed.

“All the carnivores reduced their consumption of rabbits following the arrival of VHD, although this reduction varied from one species to another,” lead author Pablo Ferreras, a researcher at the Research Institute on Cynegetic Resources in Ciudad Real, Spain, said in a prepared statement.

According to the research, predators such as the badger (Meles meles), fox (Vulpes vulpes) and Egyptian mongoose (Herpestes ichneumon) all turned to other small mammals, birds and ungulate carrion for food when the rabbits became less plentiful. Badgers, for example, reduced the amount of rabbit in their diets from 71.8 percent to 26.2 percent.

But the Iberian lynx was not able to make that switch; it still relies on rabbits for 75 percent of its diet.

Why was the lynx unable to adapt? Ferreras told me that the lynx evolved on the Iberian Peninsula during the Pleistocene epoch glacial periods at the same time as the European rabbit. “The body size of the Iberian lynx, smaller than its evolutionary ancestor, is a result of its adaptation to preying upon rabbits, smaller than the ungulates, which constituted the main prey of its ancestor,” Ferreras says. “Also the hunting behavior of the Iberian lynx—by ambushing and stalking—is an adaptation to hunting rabbits in patchy Mediterranean shrubs, where large rabbit densities originally occurred.”

According to Ferreras, the lynx uses Mediterranean scrubland more than any other habitat, and relies on the presence of both rabbits and shrubs to thrive. “Lynx cannot survive in areas with high rabbit densities but without Mediterranean shrubs,” Ferreras says. Much of the lynx’s former scrubland habitat has been lost to human development.

The shrinking supply of its major prey source has not only affected the lynx’s ability to feed itself, it has altered the species’s social structure. Ferreras and his team found that female lynx increased the size of their territories, whereas juvenile lynx did not disperse from their nesting areas the way they used to. The researchers are calling on managing the rabbit population either through restocking or habitat improvement in order to save the cat from extinction.

Ferreras says that restocking the park with rabbits would not present an ecological problem, as most famously happened when rabbits were introduced to Australia, because the species is native to the region and there are so many other predators to help control their numbers. The Iberian Peninsula is “a large community of 30 to 40 natural predators, from reptiles to raptors and carnivores,” Ferreras says. “The few places where rabbits are perceived (probably subjectively) as a pest in the Iberian Peninsula are mostly agricultural areas, where predators are very scarce. This is not the case of the landscapes where lynx can be recovered and where we propose to increase rabbit numbers.”

VHD is the second plague to hit rabbits in Spain. The first was myxomatosis, a rabbit-specific disease that was purposefully released in France in 1952 by a doctor who wanted to keep rabbits out of his garden. It spread to Spain a couple of years later, where it killed 95 percent of the country’s rabbits and kick-started the precipitous decline of the Iberian lynx. VHD, which also only affects rabbits, was first observed in China in 1984. Its origins are unknown.

Photo by José María Alvarez. Used under Creative Commons license

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  1. 1. scientific earthling 1:41 am 07/13/2011

    We are living the sixth extinction, a man made event. Man has spread across the surface of this planet like a plague of locusts eating his way through one species after another. Excavations in the Pacific islands are revealing how the arrival of man resulted in the extinction of many local species, mainly by man eating them to extinction.

    Now you try to blame a virus that kills rabbits for the near extinction of the Iberian lynx. Man may be more to blame that your article indicates. The Myxoma virus causes Myxomatosis in rabbits and was used as a pest control in Australia, it did not work; nor will VHD kill off all the rabbits in Spain. Natural selection always eliminates the more toxic or susceptible specimens of a pathogen and its host. Eventually host and pathogen learn to live with each other.

    A deeper study could show that man was responsible for moving VHD to Spain, also loss of habitat my be more relevant than just less rabbits.

    There is no living organism on planet earth more destructive of the biosphere than the ignorant Homo sapien.

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  2. 2. oldvic 3:37 am 07/13/2011

    As a local (Portugal) I’m well placed to observe directly many of the factors involved in the decline of the Iberian lynx. Sadly, the various rabbit diseases are only one among many such problems.

    Habitat destruction is the most important. We’ve paved, planted, urbanized and otherwise "landscaped" most of our nature into oblivion. It’s hard, if not impossible, to find a significant patch of reasonably undisturbed eco-system: our wetlands are now fields, our "forests" are single-species tree plantations (mostly pine and eucalyptus, which dutifully burn in the summer) largely devoid of any biodiversity.

    The problem is compounded by a strange urban myth that sees the rural world as an environmental paradise, oblivious to the fact that a picturesque meadow filled with cows is about as close to nature as a Versailles-type city garden.

    We might yet get out of this bind in time if we were to recognize that we need to abandon significant areas of territory to the natural processes, starting with those that are marginal for human habitation (mountains, wetlands, arid scrubland, and such).

    Instead, we get hysterical cries about "desertification" whenever the media find a small village with only a few people, which is ironic since it’s the presence of large numbers of humans that tends to create a biodiversity desert.

    We continue to be transfixed by the sight of our navel instead of looking around us at the wider world.

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  3. 3. jgrosay 12:38 pm 07/13/2011

    Many point that myxomatosis, a deadly rabbit viral disease spread by a french laboratory man trying to protect his vegetables from the voracity of rabbits was first. Anyway, whatever the cause, linx are starving as they have very few rabbits to feed on. Vaccinating wild rabbits against both diseases may make growth the rabbit population, but the farmer’s pockets will be very seriously hit. Making an experimental local spread of live vaccine innoculated rabbits is a possibility, but you never know how far the vaccine will spread. An old spanish author stated: "The experiments must be done with soda" – as opposed to with Champagne -

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