By TODD McLEISH/ecoRI
News contributor
Photo by Will Collette |
Millions more animals than usual survived their often-treacherous attempts to cross roadways to reach breeding grounds and foraging habitat or to escape predators.
That is the conclusion of a study by
scientists at the Road Ecology Center at the University of California, Davis. They found that 45
percent fewer wild animals were killed by vehicles in Maine compared to the
previous month, and roadkill declined by 38 percent in Idaho and 21 percent in
California during the same period.
The study noted
that about 1 million wild creatures typically die on U.S. roads every day, so
it’s likely that tens of millions escaped a crushing death. Most were probably
small animals such as frogs, snakes, and salamanders for which road mortality
is a leading cause of death, according to Fraser Shilling, the director of the
Road Ecology Center.
But many large animals were spared as well. In California, for instance, the study found that 58 percent fewer mountain lions were killed by vehicles over a 10-week period beginning with the state’s stay-at-home order compared with the previous 10 weeks.
“This is the biggest conservation
action that we’ve taken, possibly ever, certainly since the national parks were
formed,” Shilling told The Atlantic. “There’s not a single other action that
has saved that many animals.”
In Rhode Island, there is little
data available to assess the impact of the pandemic on the road mortality of
wildlife. But anecdotal evidence suggests that local animals have benefited.
Dylan Ferreira, a senior wildlife biologist for the Rhode Island Department of Environmental Management who monitors the state’s deer herd, believes there was a decrease in the number of deer struck by vehicles during the peak months when most Rhode Islanders were staying home.
“However, the majority of our road kills occur during the fall during the breeding season when deer are most active,” he said.
Scott Goodwin, the animal control
officer in North Smithfield who disposes of an abundance of road-killed animals
every year, observed far fewer dead animals on northern Rhode Island roads this
spring.
“But it’s starting to pick up again now,” he said, noting that spring is usually a busy time for dead raccoons, skunks, and opossums because that’s when young ones are becoming active.
The only scientific effort underway
in the Ocean State to assess the impact of reduced traffic on wildlife
mortality is by a University of Rhode Island graduate student. Noah Hallisey
has been studying road-killed reptiles and amphibians since last year. He said
that during a normal year, road mortality is a serious problem for animals in
the state.
“We have a lot of wildlife in Rhode
Island and high road density and high traffic volume, so it’s probably a major
contributor to population declines for certain species,” he said. “Amphibians
and reptiles are especially susceptible because of their life history. They
partake in mass migrations seasonally to breed and forage, and they often have
to cross roads to do it.
“They’re also ectotherms, so they
use roadways to bask and warm up. They’re also small and hard for drivers to
see. And some drivers intentionally target them, especially snakes.”
Hallisey had been using a computer
model to predict where and when large roadkill events may occur, based on
environmental conditions — for example, most amphibians migrate at night when
it rains — and the location of roads near wetlands. He then visited those areas
at the appropriate times to see how many survived the crossing and how many
were killed.
The pandemic forced him to reduce
his research effort, but it also raised new questions about whether the
stay-at-home orders would have an effect on the mortality of reptiles and
amphibians.
So he revisited some of the sites he documented last year as having high mortality, visited new sites this year, and plans to survey all the sites again next year to compare the ratio of live animals to dead ones.
So he revisited some of the sites he documented last year as having high mortality, visited new sites this year, and plans to survey all the sites again next year to compare the ratio of live animals to dead ones.
“We were out one night at the end of
April when more than half of the animals we found were alive, which is
unusual,” he said. “I was amazed how quiet the roads were compared to what you
would normally see.”
Although he hasn't yet completed his
study, Hallisey believes there was a noticeable decrease in the number of
amphibians killed by vehicles during the early days of the pandemic, but he
didn't observe a similar decrease in reptile mortality.
“Given how many get killed, even a
slight reduction in traffic can be a good thing for wildlife,” he said. “Even
one less car on the road could save an animal.”
From the perspective of wildlife and
road mortality, the timing of the pandemic couldn’t have been better. The large
majority of reptile and amphibian movement occurs from March through June, the
peak months of the pandemic lockdown. Many mammals and other animals are also
especially active at that time as well.
“For those species that are breeding
and moving around during those months, they definitely benefited from having
fewer vehicles on the road,” Hallisey said.
Rhode Island resident and author
Todd McLeish runs a wildlife blog.