Muskrat populations aren’t doing well anywhere, but why and what can be done about it?
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The good news? The decline in muskrat populations in Pennsylvania and across the Northeast seem to have ended.
The bad news? Their numbers have settled in at a very depressed level.
So says Tom Hardisky, a furbearer biologist with the Pennsylvania Game Commission.
The question is what’s happened and why.
Possible culprits
Unfortunately, answers are few, Hardisky said.
First of all, avian predators are more common, he noted. But there’s no evidence of disease or parasites impacting muskrats, nor any proof environmental contaminants are an issue.
“They are really tolerant of all sorts of bad stuff out there,” Hardisky said.
Second, human predation via trapping has never been an issue and likely isn’t now either, he added.
So what’s that leave?
Habitat conditions, Hardisky said.
And there have definitely been changes there, Hardisky said. An emphasis on flood control is one example.
That’s led to more variability in water levels as dams are used to change creek flows, he said.
That’s bad for muskrats. They need stable water.
“That’s one critical item muskrats need to survive,” Hardisky said.
Likewise, many streams have also been outfitted with riprap banks. That, too, is troublesome.
Muskrats are preyed on by all sorts of other animals, he noted. He said they’re “born to die,” with some studies showing up to 96 percent mortality in given population in any one year.
When stream banks offer no cover, they’re especially vulnerable.
“Muskrat survival is greatly dependent on concealment. Protective cover is very, very important,” Hardisky said.
The future
Is there anything anyone can do to help muskrats?
That’s going to be tough, Haridsky said. He compared them to another species that long ago fell on hard times in Pennsylvania because of changing habitat.
Ring-necked pheasants were once widespread across the state. But in time, their range shrunk, and they’ve never recovered.
“What happened with pheasants is those pockets dwindled down and we’re left with practically nothing,” Hardisky said. “Muskrats seem to be hanging on. But we’re in kind of a pocket situation right now.
“So we have to hang on to what we have and manage those populations.”
