Hidden in the marshes and mountains of southwestern Europe’s Iberian Peninsula, the last Iberian lynx may be quietly padding into history.
The lynx’s future depends on whether its sole prey, the European rabbit, can survive an outbreak of a disease known as rabbit hemorrhagic disease virus (RHDV). A new variant of RHDV has arrived with a vengeance, leaving dead rabbits across Iberia—and lynx with little to eat. RHDV has appeared at least twice before in other variants, and has caused precipitous declines in rabbit populations. The new strain will further bottom-out rabbit numbers.
As a result, the critically endangered Iberian lynx may be the first feline to go extinct since the saber-toothed tiger millennia ago. Iberian lynx are on the brink, according to the International Union for Conservation of Nature.
Former Heyday of a Rabbit-Hunter
In the 1800s, lynx were found across the Iberian Peninsula from Portugal through Spain and into southern France. A century later, life for Iberian lynx was still reasonably good. As recently as the 1980s, more than 1,100 lynx in Spain successfully hunted rabbits. Then came habitat fragmentation from agricultural and industrial development. Now just two or three small groups of Iberian lynx likely survive, all in Spain.
To the west in Portugal, the only Iberian lynx are ghosts. A search conducted in 2002 found a landscape empty of lynx.
In 2009, things began to turn around. Through a captive-breeding and reintroduction program in Spain, Iberian lynx rebounded from a low of about 100 to 319 cats. Most prowl in marshes in Donana National Park and brushlands in the Sierra Morena Mountains, the species’ stronghold—for now.
“In the last year, the effects of the rabbit disease began to be seen,” said Ramon Perez de Ayala, species program director at the World Wide Fund for Nature (WWF) in Spain. “If the trend continues, 2014 will be disastrous. Iberian lynx will decline if the situation doesn’t improve.”
An annual Iberian lynx census gets underway this month; a rabbit count is planned for fall.
Felled By Its Rabbit Prey
Rabbits make up 90 percent of an Iberian lynx’s diet. A lynx requires at least one rabbit each day; mother lynx with young need about three. But for lynx on the hunt, catching rabbits has become almost impossible. The new strain of RHDV, often fatal, gets there first.
In 2011, the variant was identified in rabbits in Spain. It was similar to one found in 2010 in France. Then in late 2012 and early 2013 it jumped to rabbits in Portugal.
“The rapid spread of this variant into Iberian wild rabbit populations raises questions about their survival, and that of Iberian lynx,” said biologist Pedro Esteves of the Universidade do Porto in Portugal. He and other scientists detailed the strain’s emergence in the journal Emerging Infectious Diseases.
Two subspecies of wild European rabbits live on the Iberian Peninsula: Oryctolagus cuniculus algirus and Oryctolagus cuniculus cuniculus. They’re both susceptible to RHDV; 80 to 90 percent have already succumbed.
Conservation concerns are at fever pitch for Oryctolagus cuniculus algirus. The rabbit lives only on the southwestern part of the peninsula; its range overlaps neatly with that of the Iberian lynx.
“Monitoring the spread and evolution of the new RHDV variant is crucial for rabbits and for lynx,” said Esteves. “What we don’t know for certain is if the virus, which is very specific to rabbits, could be transmitted to Iberian lynx. ” It’s unlikely, he added. “It would take a huge mutation in the virus, but no one has really looked at this yet, at least in Iberia.” Earlier studies of RHDV in Australia showed that the virus didn’t infect species beyond rabbits.
For Iberian lynx, it’s winner take all in a game not of cat-and-mouse, but virus-and-rabbit. Will RHDV forever close the golden-green eyes of the Iberian lynx?