Tag: invasive species

Eco-Cows Munch on Invasive Plants

  • Researchers are finding that Scottish Highland Cattle, such as these Rockhill Red Cows, have an appetite for many types of invasive plants. Photo courtesy of Marv & Ann Rockhill.

Cattle that love to eat thorny shrubs and nasty weeds are proving they can clean up areas infested with invasive plant species. The Great Lakes Radio Consortium’s Mary Jo Wagner has this report:

Transcript

Cattle that love to eat thorny shrubs and nasty weeds are proving they can clean up areas infested with invasive plant species. The Great Lakes Radio Consortium’s Mary Jo Wagner reports.


For years, land managers have been trying to find better ways to control particularly troublesome plants. Invasive species such as multi-flora rose, prickly ash and wild parsnip used to be held in check by natural fires, or grazing by bison and elk. But ever since wildfires have been mostly controlled, and elk and bison populations have plummeted, many invasive species in the Great Lakes region have been growing out of control. So researchers have been looking for other ways to fight these invaders. At the University of Wisconsin, researchers have been testing Scottish Highland cattle on some fields containing invasive species. Consultant Martha Rosemeyer says the preliminary results look promising…


“One of the things we’ve found out by following the cattle is they really like wild parsnip when it’s young. Out of a field of grass they’ll identify and hone in on the wild parsnip and eat the whole patch of it.”


One of two farms testing the cattle’s weed eating potential is owned by Peter Rathbun. He says on one of the test plots, the parsnip was so high and thick, biologists wouldn’t go in to take samples.


“I was a little concerned, well are the cows going to go in and eat it and get sick, but they went in and ate it and they loved it.”


Rathbun has various weed and brush problems or “junk” as he calls it on 120 acres, including prickly ash, hawthorn, gooseberries and other plants that produce large thickets. He was one of the first farmers in Wisconsin to start raising the highland cattle several years ago and now has around forty animals eating weeds on half his farm. His goal is to return some o the land to its original oak savannah status. So far on his fifteen test plots with and without cattle, the results of grazing Scottish cattle are positive.


“It’s so wonderfully obvious what’s happening because here’s three strands of electric fence. On one side you can walk right through the woods…its no problem – you can see everything there. On the other side it’s dense, you don’t even want to think about walking through it. And this is only after 2 rotations.”


Rotating means moving groups of up to nine cattle around on once-acre test plots. The cattle spend two or three days on select plots each month throughout the summer. Martha Rosemeyer says researchers were interested in the breed of cattle because in Europe, they’re referred to as “eco-cows.” That’s because of their unique ability to eat plants that have inch-long thorns.


“They’ve got really tough tongues – they wrap them around these and pull – so they pull these things up like prickly ash leaves off and aren’t really bothered by thorns. They actually like thorns to rub and scratch…they’ll lean on things and scratch and they’ll break them and change the vegetation in that way too.”


Peter Rathbun says it didn’t take long for his cattle to tackle a patch of prickly ash after the gate into one test plot was opened.


“They ran over to it and started eating the actual bush. And I loved to see the reaction of some of the graduate students who’ve been working on this for a very long time. In their heart of hearts they really had some doubts whether the animals were really going to like to eat the junk.”


Once results are in by the summer of 2003, consultant Martha Rosemeyer says researchers may have a better idea of how effective the cattle will be at permanent eradication of unwanted plants.


“Certainly if you knock down a plant by taking off it’s above ground vegetation a number of times, it weakens the plant and it eventually will die. That’s what we’re hoping will happen but we’re not sure we need to test this and see the results…it’s speculation at this point.”


By comparison, Rosemeyer says on Department of Natural Resources land, a few test pilots were grazed and burned earlier this year to compare the weed control with the Highland cattle. It turned out that combination was too destructive and the burning was discontinued.


Meanwhile, not only do these animals eat through the bad stuff, but they also provide great hamburgers. Rathbun sells the meat as a low fat, very tasty source of protein.
For the Great Lakes Radio Consortium, I’m Mary Jo Wagner.

New Ballast Treatment on Display

The state of Michigan is trying a new approach to stop the spread of foreign aquatic species in the Great Lakes – using a new system to clean ships’ ballast water. The Great Lakes Radio Consortium’s Quinn Klinefelter has more:

Transcript

The state of Michigan is trying a new approach to stop the spread of foreign aquatic species in the Great Lakes – using a new system to clean ship’s ballast water. The Great Lakes Radio Consortium’s Quinn Klinefelter has more.


A generator deep in the bowels of the Canadian freighter “Federal Yukon” spits copper ion particles at a cargo hold filled with ballast water. The particles poison any creatures living in the water…a second process cleanses the ballast before it’s drained into the Detroit River. It’s a test designed to find – and hopefully eliminate – any species carried in the water that is NOT native to the Great Lakes. Michigan Lt. Governor Dick Posthumous warned the threat from foreign species like zebra mussels is very real.


“Like an uninvited house guest…they come in uninvited…they eat all your food…and then they leave the house all messed-up.”


Posthumous says the Great Lakes Governor’s Association will meet with Canadian leaders this fall in Chicago to try and find ways to prevent the spread of foreign aquatic species. For the Great Lakes Radio Consortium, I’m Quinn Klinefelter.

U.S. Responds to Year-Old I.J.C. Report

After taking more than a year to consider the matter, the U.S. has now responded to a report that said a new sense of urgency is needed to restore and protect the Great Lakes. The report was issued by a binational commission overseeing U.S. and Canadian cooperation on lakes issues. The Great Lakes Radio Consortium’s Lester Graham reports:

Transcript

After taking more than a year to consider the matter, the U.S. has now responded to a report that said a new sense of urgency is needed to restore and protect the Great Lakes. The report was issued by a bi-national commission, overseeing U.S. and Canadian cooperation on lakes issues. The Great Lakes Radio Consortium’s Lester Graham reports.

The International Joint Commission monitors whether the two countries are complying with a water quality agreement, when its reports were released in July of last year. The commission warned that every delay in restoring the health of the lakes carried a steep price. Despite that urgency, the U.S. response to the report was delayed, in part because of the change in administrations in the White House. Mark Elster is an analyst with the U.S. EPA’s Great Lakes National Program Office. He sums up the U.S. response to the I.J.C. report this way.

“I would say we generally agree with most of their recommendations.”

Yet, the U.S. response says it is unable to clean up contamination and stop invasive species quite as quickly as the I.J.C. calls for, and Elster notes the U.S. has to coordinate many of its plans with Canada.

“So, for those bi-national type recommendations, we’ll be in contact with our Canadian colleagues to see if we’re in agreement in the tenor of our responses.”

The Canadian response, similar to the U.S. response, also took a year to be issued. For the Great Lakes Radio Consortium, this is Lester Graham.

Tackling an Invasive Beetle

Foresters think they might be on the verge of eradicating a pest that destroys trees. The Great Lakes Radio Consortium’s Lester Graham reports:

Transcript

Foresters think they might be on the verge of eradicating a pest that destroys trees. The Great Lakes Radio Consortium’s Lester Graham reports.


The Asian long horned beetle attacks maples and elms. The bug first appeared in 1996, after wood crates infested with the beetle were shipped to New York from China. A second infestation appeared in the Chicago area in 1998. Stan Smith is a manager of the tree nursery program for the Illinois Department of Agriculture. He says the Asian long horned beetle might be under control around Chicago.


“Our population, we feel, is small enough that it might be getting to the point where it might not be able to reproduce very well. Hopefully within four to five years we’ll have everything pretty well cleaned up. At least that’s what we think can happen.”


The beetle is more widespread in New York, but fortunately the insect can’t fly very far. That means it can’t spread quickly, giving foresters a better chance at eliminating the pest.

Foreign Wasp Flying Westward

A foreign wasp from Europe has made its way to several Great Lakes states this summer. The European Paper Wasp was first detected on the Eastern seaboard in 1980. But as the Great Lakes Radio Consortium’s Gina Carrier reports, it’s now being sighted in greater numbers in the Midwest:

Transcript

A foreign wasp from Europe has made its way to several Great Lakes states this summer. The European Paper Wasp was first detected on the Eastern seaboard in 1980. Now it is being sited in greater numbers in the Midwest. The Great Lakes Radio Consortium’s Gina Carrier reports.


The European Paper Wasp looks very similar to our native yellow jacket. But it’s not as aggressive and can actually help Midwest gardeners because it likes to feed on certain pesky caterpillars. Tom Ellis is an entomologist at Michigan State University. He says the European paper wasp can be found in central and southeastern Michigan, Indiana, and Ohio and the Chicago area.


“The things that it became accustom to and fed on the eastern seaboard are pretty much similar if not the same to what we have in Michigan and throughout the Great Lakes states certainly.”


He says it’s unknown whether the wasp will continue to move westward. There’s no effort to stop its spread because Ellis says the wasp isn’t destroying crops or foliage. For the Great Lakes Radio Consortium, I’m Gina Carrier.

Native Lake Species Fighting Back

  • Alewives washed up on Lake Michigan shores after the invaders' populations exploded, then crashed. Researchers have a difficult time predicting how invasive species will affect the balance of nature in the Great Lakes.

Ever since the Great Lakes were opened to shipping, exotic species of aquatic animals have invaded the lakes. Nearly always it’s been bad news for the region’s native fish and wildlife. The Great Lakes Radio Consortium’s Lester Graham reports on the latest effects of the invaders:

Transcript

Ever since the Great Lakes were opened to shipping, exotic species of aquatic animals have invaded the lakes. Nearly always it’s been bad news for the region’s native fish and wildlife. The Great Lakes Radio Consortium’s Lester Graham reports on the latest effects of the invaders.


Some of the exotic species that have caused major problems in the Great
Lakes have been around since the 1940’s and ’50s. For example, the sea lamprey found its way into the lakes through manmade channels. It’s a parasite that attacks lake trout and other large game fish. It devastated the lake trout fisheries. Only recently have efforts gotten the lamprey under control. It’s still out there, but it’s not decimating the lake trout population as it once was.


More recently, a big concern has been the zebra mussel. It hitchhiked its way to the Great Lakes in the ballast water of cargo ships. In the last couple of decades the zebra mussel has caused major changes in all the lakes except for Superior where it seems limited to the shallow and warmer bays.


David Jude is a researcher with the University of Michigan’s Center for
Great Lakes and Aquatic Sciences. He says the huge numbers of zebra mussels siphon through lake water like a giant network of filters. There are so many of them that water in the lakes is actually clearer.


“I think people tend to hear about the water clarity increases. ‘Ah, the water’s clearer,’ you know, ‘That’s great!’ But it’s not great, because there’s a lot of things going on in the water column.”


Things such as, algae converting the sun’s energy into more phytoplankton.
Small fish and tiny invertebrate animals called zooplankton eat the phytoplankton and then they become food for fish. But, the zebra mussels filter out a lot of the phytoplankton, stealing food from the native zooplankton.


David Jude says a couple of other invaders are also causing havoc at the base of the food chain in the Great Lakes. Instead of eating just the green phytoplankton, zooplankton invaders from the Black and Caspian Seas also eat their North American cousins.


“These are predators. And they feed on the zooplankton, our native zooplankton that is out there already. So, not only do we have the impact of zebra mussels removing algae which is a food for these zooplankton, now we’ve got two predators that have been introduced and both of those will eat zooplankton which would have been food for fish to eat.”


Besides the zooplankton floating around in the water column, a major food source for fish is in the sediment at the bottom of the lakes, and it’s disappearing. James Kitchell is with the University of Wisconsin – Madison. He says many different kinds of fish depend on a little creature called diaporeia, which have become scarce in many areas.


“It appears to correlate in general with an increases in zebra mussels. So, there’s the prospect that diaporeia is literally starving to death as a consequence of zebra mussels eating the available food, but when you look at the diaporeia, they appear to be healthy. They’re not skinny and look to be starving. So that doesn’t explain it.”


It’s a big concern because a lot of fish that anglers like, such as yellow perch, depend on diaporeia for food.


Besides the zebra mussels and the two zooplankton predators, a fourth invader is causing problems. Populations of the round goby, an ugly, aggressive feeding little fish from Eastern Europe, have exploded in the Great Lakes. The round goby scours the bottom, eating the eggs and larvae of native fish. The University of Michigan’s David Jude says as big of a problem as the invasive fish has been over the last several years. The round goby’s future might soon be curtailed a bit.


“We did SCUBA dives in Lake Erie, for example, we’d turn over rocks. Round gobys would tear out from under the rocks and we’d have small mouth bass following us around and they would ignore the round gobys. They didn’t know how to catch a round goby. But, because there’s so many round gobys now, they had to learn how to eat them or die. So, the predators are definitely learning how to eat round gobys.”


Other native fish are beginning to eat the exotics. The silver chub, which once nearly disappeared from the Great Lakes, is making a bit of a comeback feasting on zebra mussels. With each invader, the lakes ecosystems go through upheaval, and then find a new balance. But make no mistake. It’s a different balance. Nicholas Mandrak is a researcher at Youngstown State University. He says exotic species invading the Great Lakes will mean continued changes, and for people who fish the lakes, not many of the changes will be good.


“You’re not going to be able to catch as many species that you’re used to catching. You know, the native species are going to decline. The walleye are going to decline. So, I think the bottom line is the recreational and commercial fisheries are going to change in a manner that is negative to most people.”


Researchers, though, have learned to be careful about predicting how invasive species will affect the lakes. They’re often surprised by the intricacies of the food web and the ecosystems that support it. Throwing an exotic invader into the mix makes it that much more unpredictable, and it will likely get worse. Mandrak says they’ve been studying how global warming might affect the lakes. One scenario suggests 30 to 40 new exotic species from the South will make their way through manmade canals as temperatures rise. For the biologists, it’s a worrisome concept. For the Great Lakes Radio Consortium, this is Lester Graham.

NATIVE LAKE SPECIES FIGHTING BACK (Short Version)

It appears that fish native to the Great Lakes are beginning to prey on some of the alien species that have invaded the lakes. The Great Lakes Radio Consortium’s Lester Graham reports:

Transcript

It appears that fish native to the Great Lakes are beginning to prey on some of the alien species that have invaded the lakes. The Great Lakes Radio Consortium’s Lester Graham reports.


Aquatic Species from Europe and elsewhere have hitchhiked to the Great Lakes in the ballasts of cargo ships for many years. A lot of them have upset the natural ecosystems of the lakes. Lately, though, some native fish are taking advantage of the invaders. Nicholas Mandrak is a researcher at Youngstown State University. He says a Great Lakes minnow that was once thought to have died out has recently re-emerged.


“And they’re eating zebra mussels. So, it looks like the increase
in silver chub is related to zebra mussels, so we finally found a native
fish that is benefiting from the zebra mussel.”


Other researchers say small mouth bass are beginning to prey on another invasive species, the round goby, which eats the eggs and larvae of fish native to the Great Lakes. The researchers say the benefits don’t outweigh the negative affects on native species. But it evens the score a little. For the Great Lakes Radio Consortium, this is Lester Graham.

Break in the Great Lakes Food Web?

A major link in the food web is disappearing from the Great Lakes. Researchers are concerned that its absence will damage fish populations. The Great Lakes Radio Consortium’s Lester Graham has more:

Park Service Combats Exotic Plants

There’s a silent danger creeping through national parks across the
country. The parks – like many other wild areas – are being invaded by
alien species. Officials say these exotic plants are the most
significant threat to the parks’ natural resources. And now, the
National Park Service is taking action. The Great Lakes Radio
Consortium’s Wendy Nelson reports: