Do you remember reading those “Highlights” magazines when you were in the dentist office or waiting for your mom at the dr? There was one recurring column called “Goofus and Gallant” about brothers who behaved very differently, Goofus was always turning over chairs or breaking plates while Gallant was helping his mother arrange tables for the tea party or something like that. I thought of that cartoon when I read THIS.

Muskrats are key to Poplar Island restoration

In the Chesapeake Bay, the muskrat is a valuable partner in an ambitious project to restore a remote island under siege. It’s helping turn sediment scooped from Baltimore shipping channels into healthy salt marsh habitat.

The same silt that clogs a port can rebuild an island. Since the mid-1990s, barges have carried the dredged material down the bay to the Paul S. Sarbanes Ecosystem Restoration Project at Poplar Island, where it’s used to recreate the island. The U.S. Fish and Wildlife Service partners with USACE and MDOT MPA on the ambitious undertaking.

Although perhaps less intentional than their well-known cousins, muskrats also shape their surroundings. While beaver dams flood the landscape, killing trees and creating freshwater marshes, muskrats eat their way through salt marshes, helping other wildlife and strengthening the habitat.

Did you get that? Muskrats save salt marshes and beavers kill trees! No really! I’m totally sure that that Fish and Wildlife and MDOT know exactly what they’re talking about and understand about the beavers that live in salt marshes and affect those channels.

“They engineer the ecosystem just as beavers do,” said McGowan. An animal with brown fur and a long, hairless tail gnaws on a plant held in its front paws, with water and a large rock in the background.

No.

No they really don’t.

They build trails. I grant you by swimming around looking for food. And they eat plants you would like to get out of the way. But they do not do what beavers do. We could sit down and count every animal that uses their habitat and it wouldn’t come close to the list we create at a beaver pond.

They create habitat like thieves generate the economy.

Muskrats eat marsh grasses, such as smooth cordgrass and marsh hay, and the roots of shrubs like high-tide bush. They consume one-third their weight every day, opening areas of dense vegetation, keeping troublesome plants from taking over, spreading nutrients, and aerating the soil.

Perhaps most important to restoration, muskrat trails — called leads — move water throughout the salt marsh. Marsh plants are adapted to the coming and going of the tide, and they can’t survive constant flooding.

“Water gathers in areas where sediment has settled,” said McGowan. “Muskrat leads drain interior pools and keep vegetation from standing in water for long periods.”

That’s nice. Isn’t that nice? And I’m sure there’s no beaver living in brackish water that helps them with this onerous task.

Leads also let marsh birds like ducks and rails travel more easily and save energy. Small fish and invertebrates can reach ponds in the marsh’s interior.

And so, it turns out, can turtles. Researchers from Ohio University recorded as many as 1,500 diamondback terrapin hatchlings in one year on Poplar Island.

Smaller rodents like shrews and voles find shelter in the huts, and turtles climb on top to bask in the sun. Raptors such as short-eared owls and northern harriers rest atop the houses, where they scan the marsh for their next meals. Mallards and Canada geese sometimes build nests on the mounds.

“A great variety of wildlife uses these biological highways,” said McGowan. In addition, muskrat huts, which are three- to four-feet high, add what biologists call microtopography to the marsh. On Poplar Island, muskrats build their mounded homes from salt meadow hay and salt marsh cordgrass.

Oh pulleeze. Before you go one step further proclaiming the ecosystem services of the muskrat I would like to see proof that you know for CERTAIN there are no beavers helping them out. Good lord.

You can, however, have too much of a good thing, and muskrats are no exception. As the population grows, so too do the odds of disease, starvation, and conflict over territories. At a certain point, they start to harm the very habitat they — and so many others — depend upon.

With no mammalian predators to keep them in check, muskrat populations on Poplar Island tend to be cyclical — numbers increase for a few years, stressing the habitat, then crash due to disease. To reduce habitat damage, biologists manage the animals.

Well it’s nice to know that even little muskrats deserve killing sometimes, I mean it’s only fair. Man is so important we have to kill things regularly to keep the machinery running smoothly. Didn’t you know?

“To keep the system in balance, the model allows for muskrats to remove no more than four percent of the plant biomass,” said McGowan. “The model calculates the carrying capacity of the marsh and, if the muskrat population exceeds it, tells us how many need to be culled.”

Service staff remove the extra muskrats through trapping. It’s not necessary every year, and the numbers are usually low.

That’s right. Because I’m sure a booming muskrat population wouldn’t get snapped up by hawks or eagles or even otters if they’re in the way. Good thing you found something else to trap.

Thanks to one hungry rodent, some creative state and federal agencies, and an unlimited supply of sediment, Poplar Island is once more a destination for migratory birds and people alike. It also protects Maryland’s eastern shore from westerly waves. Its recipe for successful remote island restoration is being cooked up worldwide.

Isn’t that special?