URI scientists investigate distribution of muskrats, beavers, otters in Rhode Island
Traveling
via kayak, John Crockett will search for evidence of muskrats, beavers and
river otters in waterways of southwestern Rhode Island this winter before
expanding his search to other areas of the state in the coming years.
“The
main goal of the study is to get a good sense of the distribution of each
species across the state,” said Crockett, a native of Fort Collins, Colorado,
who is collaborating on the study with URI Assistant Professor Brian Gerber.
“To do that, we’re conducting an occupancy analysis, which means we’re going
out looking for signs of tracks, scat, chewed sticks, lodges and sightings of
the animals.”
All
three species have been the target of trappers in Rhode Island for many years –
though the state legislature banned the trapping of river otters in the 1970s –
and most of what state wildlife officials know about the animals is derived
from trapping data. But since trapping has been decreasing in popularity in
recent years, less and less data about the animals is being collected.
“We want to make sure we have a good assessment of where these mammals are found,” said Gerber. “It’s been 10 or 15 years since anyone has spent much time looking for them, and we want to see if we find any changes in their distribution since those earlier surveys.”
Muskrats
are in decline across much of their range in the United States, according to
Crockett, and now they are difficult to find. The decrease in trapping activity
has made it difficult to tell whether the animals are in decline in Rhode
Island or if the lack of trapping just makes it appear to be so.
Since
river otters have not been trapped for 50 years, very little is known about
their distribution and population in the state. “Ever since the ‘70s, we’ve
been mostly in the dark about where they are and how many there might be,”
Crocket said.
Beavers
are believed to have recovered well after being extirpated from the area due to
unregulated trapping and forest clearing in the 1800s. “Now they are creating
conflicts with their dams causing flooding in some places,” Gerber said. “We’d
like to be able to identify the habitat features where beavers are doing well
and those areas where they are likely to cause conflict. To do that, we need
distribution data.”
Crockett
expects to conduct his surveys from December through March for the next three
years, as well as periodic summer surveys. He eventually hopes to be able to
estimate the probability that any of the three species will be found in a given
habitat.
“Part
of what we’re doing is trying to relate their distribution to changes in land
use,” he said. “We have pretty good data on how these wetlands have shifted
over time, so hopefully we can find some hint of an answer about why these
animals’ populations are changing.”
The
URI scientists are working closely on the project with wildlife biologists at
the Rhode Island Department of Environmental Management so the data can be used
to help prioritize habitat for protection and inform management decisions on
trapping limits.
This
is one of two research projects Gerber is leading that focus on learning more
about Rhode Island’s mid-sized predators. The other is investigating the
distribution and movement patterns of fishers in the state.