Pennsylvania Game News - January 2018 - 15

NTO THE 1980s, muskrats appeared to be almost everywhere with highbanked creeks and dams, or emergent marshes.
Minks did not. The few that were taken often came to muskrat trappers
through den-entrance and runway sets.
Today, the prevalence of these furbearers has reversed. It's not something
that can be ferreted out through furbearer harvests reports, which are influenced
strongly by furtaker participation and market trends. But more of us - particularly those who spend time near water - seem to be seeing more minks afield
than before.
It's an increased visibility that wasn't as noticeable, even 10 years ago.
At the same time, muskrats have slipped into a decline like most people over
50 never thought possible. Speculation about their reduced presence varies.
Game Commission furbearer biologist Tom Hardisky is among those who
believe it's tied to changes in habitat caused by significant environmental reform.
The muskrat's decline ties directly to Pennsylvania's and America's varied
programs to keep Commonwealth topsoil and nutrients north of the MasonDixon line and out of the nation's rivers. The effort aimed to increase oxygen
in waters, stabilize banks and improve biodiversity.
But keeping manure out of farm creeks also removed the nutrients that
promoted the vegetative cover and food muskrats need.
"Muskrats died for reasons that parallel the causes of pheasant and bobwhite
quail declines in Pennsylvania," Hardisky said. "In all three scenarios,
significant environmental change had taken place, resulting in the loss
of critical food, cover and shelter.
"Although it's difficult to conclusively prove that any one factor was
responsible for any specific population decline, it's clear these species
responded similarly and seem to have shared basic habitat deficiencies."

VULNERABILITY
Without sufficient cover and escape waters, muskrats became sitting ducks to predators. Not because there were more predators, but because muskrats were more visible.
It was worse when 'rats endured floods and droughts, and were forced to concentrate
in the only remaining viable habitat.
The muskrat's chief predators in Pennsylvania are minks, raccoons and great
horned owls, Hardisky said. They all are opportunists, taking advantage of whatever
comes easiest.
But Hardisky is quick to point out that predators aren't the problem.
"We tend to put the total blame on predators for declines in prey populations,"
noted Hardisky. "However, we need to avoid treating symptoms and focus on
the root causes."
Good habitat is the foundation every muskrat population needs to flourish.
Anything less limits the land's ability to provide muskrats food, shelter and cover,
the glue that holds their populations together.
When habitat suffers, so do muskrats, and their decline isn't always readily
noticeable. That is until their huts aren't constructed on autumn marshes, or when
JANUARY 2018

Pennsylvania Game News - January 2018

Table of Contents for the Digital Edition of Pennsylvania Game News - January 2018