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The saga of the swamp rabbit

Decline of an ‘indicator species’ could mean problems for Oklahoma ecosystems

The “charismatic” swamp rabbit (Sylvilagus aquaticus) can be found in portions of eastern Oklahoma

Zay Shaeffer

In 1979, President Jimmy Carter was fishing in his home state of Georgia when he was nearly attacked by a “killer rabbit” that attempted to board his boat. Thankfully, the rabbit never made it aboard, as Carter’s defensive use of his oar was enough to scare it away. When it was recounted to the Associated Press by Carter’s press secretary, the story became something of a viral sensation—an odd but memorable moment in his short presidency.

In reality, President Carter was unlikely to be attacked, and the rabbit was not in fact a “killer,” but rather a swamp rabbit (Sylvilagus aquaticus), the largest species of cottontail. They have webbed feet for swimming, and despite their size and relative abundance, are usually difficult to spot in the wild thanks to their effective camouflage and skittishness, making this high-profile encounter with a U.S. president all the more unusual.

“Swamp rabbits are also pretty charismatic,” said Hayley Lanier, Assistant Curator of Mammals at the Sam Noble Museum in Norman. “They’re fairly similar to the eastern cottontail—the bunnies we see around much of Oklahoma—but these guys are larger and have more yellowish tones to their faces and rumps.” Lanier studies lagomorphs, the order to which all rabbits belong. She has been working with other scientists on revising the conservation assessment this year.

The swamp rabbit lives throughout the south central U.S., its habitat stretching from Georgia to Oklahoma and north all the way to parts of Indiana. They make their homes in lowland hardwood forests, flood plains, marshes, and of course swamps through the eastern half of Oklahoma up to the cross timbers ecoregion.

The cross timbers are a natural border between the forests of the eastern U.S. and the Great Plains that stretches from north central Texas through Oklahoma, including parts of the western Tulsa metro. Comprised mainly of blackjack and post oak, these woodlands mark the transition between environments and ecosystems, and represent the outermost edge of habitats like those of the swamp rabbit. It is a unique habitat befitting a unique creature.

Although the overall swamp rabbit population is robust in the U.S., Oklahoma is one area where their numbers are apparently in decline. They once spread across a wide range throughout the eastern half of the state, but a recent Natural Heritage status report for the state lists the swamp rabbit at a rank of S3, meaning that they are now a species of concern.

“Our best guess on their species status is they appear to be declining [in Oklahoma], but we don’t even know how much,” Lanier said. One thing that is known, however, is that there has been a dramatic decrease in where swamp rabbits are found. According to a survey of mammals in southeastern Oklahoma published by Texas Tech University in 2012, it has been nearly 50 years since the last study targeting swamp rabbits in Oklahoma. Until there is a targeted study, the exact extent of the decline will likely remain unclear.

Why should we care about swamp rabbits? After all, the International Union for Conservation of Nature (IUCN) lists their status as “least concern” in terms of conservation overall. There are vast areas of the country where they still thrive. It’s important for the health of the ecosystem to keep up their numbers.

“Because they are abundant now, we assume they always will be,” Lanier said. But that isn’t necessarily the case. Past experience shows us that destructive human activity can have disastrous effects on once bountiful animal populations. With that in mind, the fact that swamp rabbits are in decline at the fringes of their habitat is a worrying trend.

Since Oklahoma sits at the edge of the swamp rabbits’ range, populations in the state are particularly vulnerable. What once was an abundant population throughout the eastern half of Oklahoma has been reduced to small area in the southeastern corner.  “We certainly have some populations in other areas, but we don’t have a good handle on how widespread they are in the state or just how rare they are,” Lanier said. “For example, I would guess that they’re not found near Norman now, although we’ve got good records of them in Cleveland County through 1959.”

The U.S. as a whole has been losing its lowland forests and wetlands at an alarming rate. According to the U.S. geological survey, nearly two-thirds of Oklahoma’s original wetlands have been lost. Craig Davis is a professor and Bollenbach Chair of Wildlife Management at Oklahoma State University. He said that nearly all of the wetlands Oklahoma has lost are the types of bottomland hardwood forests swamp rabbits inhabit. “[They] are some of the more rare wetlands we have in the U.S. and probably worldwide as well,” Davis said.

If all signs point to swamp rabbit populations in decline, it might mean declines in biodiversity—and further degradation of wildlife populations—but there are practical consequences for people as well. Wetlands provide was Davis calls “ecosystem services.”

“They’re important for groundwater recharge,” Davis said. “They are critically important for alleviating flooding and for reducing flooding … so, they basically act as a sponge.”

Davis points to the loss of wetlands combined with the channelization of rivers as two things that not only have a major impact on wildlife, but also on flood control. “We’ve lost all of that capacity to slow the flooding down and more gradually release water into the river system,” he said. “We get much more devastating floods because we just don’t have the wetlands to capture all of that flood water.”

When rivers and creeks breach their banks, these areas contain that excess water, which then permeates the soil and recharges the aquifer. If these habitats are gone, then the natural barriers to floods are gone too. By further degrading the natural systems that keep flood waters in check, we are both opening ourselves up to more natural disasters and eliminating wildlife habitat.

According to a WWF report, wildlife populations worldwide were reduced by 60 percent between 1970 and 2014—and that trend is continuing—but it is unlikely that the swamp rabbit will be an early casualty of this loss.  These rabbits are resilient, and their overall population is still healthy. Species, like whooping cranes, that rely on similar environments as the swamp rabbit are in more imminent danger. “As we lose more and more wetlands, a lot of those species that rely on wetlands decline as well,” Davis said.

It’s disheartening to read about emaciated  polar bears, or huge bleached swaths of the Great Barrier Reef. In these instances, people feel helpless to do anything. There is probably not much we can do about those things directly in landlocked Oklahoma. We can be mindful of our habits of consumption; we can support politicians and organizations that make environmental issues a priority.

We can have the greatest impact, however, in our own backyard. When it comes to wetlands, Davis said, something everyone can do is to visit them, enjoy them, and protect them. “They’re not just something that’s an impediment to development, and a ‘cesspool’… they truly are amazing ecosystems that are critical, ultimately, to our survival.”

Swamp rabbits are doing fine on a national scale, but in Oklahoma they are in trouble because their habitat is disappearing. That should worry us because it means we are not acting as good stewards of the natural world—and because the lives of animals are important, even those of a peculiar “killer rabbit.”