Climate change vs. Easter bunnies

By Dean Kuipers

April 5, 2012 12 AM PT

Easter is still a great day for worship, candy in baskets, pagan equinox rituals and running around the yard finding eggs, but every year it gets quite a bit worse for bunnies.

And no, not because the kids like to pull their ears. The culprit is climate change, and the folks at Climate Nexus found that rising temperatures are having adverse effects on at least five species of rabbit in the U.S.

Take the Lower Keys Marsh rabbit, for instance. An endangered species that lives in the Lower Florida Keys, this breed of cottontail is a great swimmer – it lives on the islands! – but it is already severely affected by development and now by rising sea levels. According to the Center for Biological Diversity’s 350 project, which highlights species that are most directly impacted by global warming, an ocean level rise of only .6 meters will send these guys hopping for higher ground and a .9 meter rise would wipe out their habitat completely. As creatures go, they are about as charismatic as can be – they’re even named after Playboy eminence Hugh Hefner (Sylvilagus palustris hefneri) – but that’s not going to help them with this problem.

The snowshoe hare, on the other hand, has a color issue. Most of these hares change their fur color from a brilliant white in the wintertime to a rusty brown in the summer, each designed to give them better cover from predators. As the number of days with snow decreases all across the country, however, more and more bunnies are being left in white fur during brown dirt days of both fall and spring, making them an easier mark for predators. According to Science Daily, researchers know that the color change is controlled by the number of hours of sunlight, but whether the rabbit will be able to adapt quick enough to survive is a big question. The National Wildlife Federation has reported that hunters have noticed their numbers are already markedly down.

American pikas or rock rabbits, a relative of rabbits and hares, might be the first of these species to go extinct due to climate change. Rodent-like creatures about 7-8 inches long, pikas live high in the cool, moist mountains west of the Rocky Mountains, in the alpine zone above the treeline. As global temperatures rise, they would naturally migrate to higher elevations – but they already occupy the mountaintops and high ridges. They can’t go any higher. The National Wildlife Federation reports that they might not be able to withstand the new temperatures as their habitat heats up.

The incredibly named volcano rabbit (Romerolagus diazi) has the same issue. These rabbits live on the slopes of volcanoes in Mexico, and recent studies have shown that the lower range of their habitat has already shifted upward about 700 meters, but there’s not suitable vegetation for them to move higher, so they’re squeezed in the middle. Scientists are concerned about their populations.

Most Easter-y of all are the pygmy rabbits, tiny bunnies native to the U.S. that weigh less than 1 pound and live in sagebrush territory in the American West. They are believed to be the smallest rabbits in the world. More and more, the pine-juniper woodlands have encroached on the sage, or their habitats have been destroyed by development. Several populations, such as the Columbia Basin pygmy, almost went extinct and were saved by zoo breeding programs. Great burrowers, pygmy rabbits also rely on winter cover by digging tunnels through the snow to escape predators, but lesser snowfall is leaving them exposed.

All of this gives new meaning to dressing up in a giant bunny costume this Sunday. Do it!

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