They’re rabbits, but they’re not multiplying.
The New England cottontail, the region’s only native rabbit species, is in decline, and researchers from the University of New Hampshire recently identified a non-invasive method to more accurately count the rabbits and assess the status of the population. To do that, they’re using fecal pellets.
“It’s our only native rabbit,” said Adrienne Kovach, one of the study’s researchers and a UNH professor of wildlife population ecology. “It’s our responsibility to try and conserve the species that we have and conserve biodiversity in general. If we lost this specialist species, we’re losing a piece of our biodiversity.”
It’s essential to know the rabbits’ population status and be able to monitor them to detect trends over time, Kovach said.
“We survey them in the wintertime, look for their fecal pellets in the snow, and sample their pellets,” she said. “From that, we can extract DNA, and identify unique individuals.”
It’s a fairly common wildlife research method, but the UNH researchers are the first to modify it to the cottontail population, she said.
During the study, they focused on three plots in Maine and three plots in Connecticut, and went back-and-forth through the patches at about 30-meter increments to find the fecal pellets, she said.
The New England cottontail population has decreased by about 86 percent in the past several decades, and has lost more than 80 percent of its habitat in the last 50 years, according to the New England Cottontail Conservation Initiative. They’re also endangered in Maine and New Hampshire.
The problem stems from a steady decline in their shrubland habitat, which consists of young trees, bushes, shrubs, and dense vegetation, Kovach said.
“Historically, they used to be more common … and more diverse,” she said. “There used to be a mix of habitat types and different ages of forest. Now our landscape is less like that, so a lot of the shrublands have grown up into more mature forests, or these types of habitats have been developed.”
While development has contributed to habitat destruction, the lack of shrubland also comes from fewer and fewer natural disturbances. As humans increasingly control fires, windstorms, and other animal lifestyles — such as beavers chewing through trees — they’re preventing nature from running its course, she said.
“We’ve suppressed them. We’ve changed the ecosystems dramatically,” she said. “So much has changed about our landscapes and ecosystems with humans modifying it in our own way, and we sort of try to control what else can happen there.”
Without low-to-the-ground shrubs and plants, it’s difficult for rabbits to find food and, just as importantly, shelter from predators, which can include foxes, coyotes, raptors, and hawks, she said.
The next step is to implement the surveying method into conservation and management scenarios, she said.
“The cottontail is a sign of a larger issue,” Kovach said. “By bringing back the habitat and hopefully having more thriving cottontail populations, we’ll also have other thriving species that use that habitat.”Elise Takahama can be reached at firstname.lastname@example.org. Follow her on Twitter @elisetakahama.