Thursday, 15 November 2018

Why Are Invasives So Bad?

photo of Phragmites also called common reed grass.

Phragmites creates stands so dense that wildlife cannot move though it.

For the past year, I have been fielding questions about conservation, biology and invasive species on the forum Quora. It gives me a chance to hear the questions and concerns that people have and give back to the community. Questions I think Conservation Digest readers might be interested in have found their way into the FAQ section of this website.

This question appeared last week. Below is my response. After reading it, I hope you see what motivated me to create the website and write this blog.

Invasive garlic mustard, honeysuckle and buckthorn have all but wiped out spring wildflowers from the woodlands of southern Wisconsin. Japanese knotweed crowds out everything along stream banks where it becomes established. Wild parsnip causes serious chemical burns when the sap gets onto the skin. Cattails take over wetlands reducing open water for waterfowl and displacing the native sedge, reeds and wetland wildflowers. Phragmites (common reed) creates such dense stands that waterfowl cannot use the wetland.

Those four sentences capture a small portion of the problems caused by invasive plants that plague natural areas in Wisconsin. They only begin to scratch the surface of the issues created by invasive species.

Check out our new webpage About Invasive Species to learn more about the problem and how to prevent new invaders from getting a foothold in Wisconsin.

Tuesday, 13 November 2018

About Invasive Species

photo of Phragmites also called common reed grass.

Phragmites creates stands so dense that wildlife cannot move though it.

It can be really confusing when people talk about invasive species. What exactly are they and why should I care? These questions are especially important for landowners because invasive plants, and to a lesser extent invasive animals, can cause real and lasting damage. Because many of them have been around for years, a property owner may not even know they these unwanted guests or why they pose a problem.

Picture of common buckthorn leaves

Common buckthorn branch. Photo credit: University of Georgia.

Problem Plants

Invasive garlic mustard, honeysuckle and buckthorn have all but wiped out spring wildflowers from the woodlands of southern Wisconsin. Japanese knotweed crowds out everything along stream banks where it becomes established. Wild parsnip causes serious chemical burns when the sap gets onto the skin. Cattails take over wetlands reducing open water for waterfowl and displacing the native sedge, reeds and wetland wildflowers. Phragmites (common reed) creates such dense stands that waterfowl cannot use the wetland.

Those four sentences capture a small portion of the problems caused by invasive plants that plague natural areas in Wisconsin. They only begin to scratch the surface of the issues created by invasive species.

Staying with plants for a moment, think about how many millions of dollars farmers and ranchers spend every year controlling weeds. They pass along those costs to us in the price of our food. Pesticide drift causes both economic and health threats to farm workers and neighbors. Chemical residues are a problem for consumers.

Picture of zebra mussels.

Zebra mussels colony. Photo credit: USDA

Not Just Weeds

Moving past invasive plants, Zebra mussels cause millions of dollars of damage to power plant systems while reducing the electricity they can generate. Those same invasive mollusks consume the available food for native insects and shell fish causing the base of the food chain to collapse. The lakes they invade turn into water deserts.

Those who grew up in Wisconsin before 1975 will remember the curse of alewife. They are a small invasive fish whose populations exploded in the 1960s. Alewife consumed all the small fish and insects that form the bottom of the food chain. That effectively destroyed the commercial lake trout fishery in Lake Michigan. Fish biologists fought over how to control them and settled on introducing Coho salmon to the great lakes. While coho reduced the alewife and created a new game fishery, native lake trout stocks have not recovered as hoped.

Emerald ash borer (EAB) is an invasive beetle that is destroying  Wisconsin’s green ash trees. Homeowners, public works departments and park managers planted millions of green ash trees over the past half century. That makes them one of the most popular trees on the urban Wisconsin landscape. Whole neighborhoods to lost their terrace trees to EAB. Many parks have gaping holes in their shade canopies.

The emerald ash borer is also wiping out the native black ash, which Native American tribes in Wisconsin call basket wood. Ho Chunk woven wood baskets are purchased by collectors around the world. The loss of black ash means an important cultural and economic resource disappears from the state.

Long History

Invasive species are nothing new. Farmers introduced sheep to northern Wisconsin during World War II. Sheep brought with them a liver fluke that nearly wiped out the white tailed deer population in those counties. Dutch elm disease swept through Wisconsin in the 1960s doing away with a large percentage of our native elm trees. Recently, the pest has returned to attack many of those trees it missed the first time, as well as their offspring.

As long as people get on planes and ships, moving around the world and bringing living stuff with them, the threat for bad things happening will be there. Sometimes invaders are introduced on purpose because the they pose is not understood. Other times pest species sneak in as weed seed in grain, or insect eggs in pallets.

Picture of Asian longhorn beetle on human finger.

Asian longhorn beetle. Photo credit: USDA

Solutions Are Simple But Difficult

There is a way to stop them from becoming a serious problem. The key is early detection and eradication. In 1998, Asian longhorn beetles were discovered on the north side of Chicago. This is a pest that kills maples and other trees in genus Acer. The black and white beetle spreads with amazing speed. The beetles were traced back to pallets that arrived from China that were delivered to a local hardware distributor. Local officials jumped into action and in what was seen by some as over reaction, cut down 1,500 in northeastern Illinois. This quick response stopped the invasion in its tracks, so that by 2003 there were no new infestations.

Be Part of the Solution

You can help. Check out the Wisconsin DNR invasive species website and learn how you can identify them. Report suspicious plants or pests to the DNR using their reporting website. Citizen science is becoming popular in the state. The Wisconsin Early Detection Network is a program of the UW Extension Weed Science program. It encourages landowners to actively get involved in locating and reporting new invaders. The DNR will eradicate prohibited species preventing major problems.

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2017

October 2017

Saturday, 28 October 2017

Bring in the Hit Squad

Picture of young garlic mustard plants.

Young garlic mustard plants are especially easy to treat in the late fall or early spring when native plants are dormant. [Conservation Media, llc]

Are you struggling with tough invasive like garlic mustard and reed canary grass? This is a great time to put a serious hurt on these super species. It is also among the most economical times to get your revenge.

By now, native plants have gone dormant. The landscape should by and large be brown and tan. For landowners, who are battling any number of exotic weed species, the remaining green is a bitter reminder of their problem.

Fortunately, this green also represents a unique opportunity. Since native plants are safely sleeping beneath the soil, landowners are free to use non-selective herbicides that would otherwise harm beneficial plants. Chief among these is glyphosate, which is cheap and highly effective.

Those living plants that are sprayed now will either be killed outright or severely weakened so that they are unable to survive the stress of winter. By contrast, application made in spring or summer might stress but not kill something like reed canary grass, which could substantially recover before the arrival of winter.

Glyphosate is short lived, breaking down in the soil in just a couple weeks. This means that wildflowers and native grasses that emerge in the spring will be unaffected by fall spraying.

I still avoid broadcast spraying in most situations because it is wasteful. Spot spraying is way easier when your green target weeds stand out so well. This tactic is especially useful in situations where weeds are scattered among more rate native plants I want to protect.

Depending on weather, this window can be short. Snow and hard freezes will force even hearty weeds into dormancy. Herbicides tend to be more readily taken up on warm sunny fall days. 

Herbicide needs to be part of an integrated weed management approach that includes management tools like controlled fire, cover crops and mowing. As always, follow label directions to minimize the amount of chemical used while making sure it will do its job.

April 2017

Friday, 14 April 2017

Bag ‘Em Danno

Garlic mustard can be pulled or cut, as well. Plants need to be bagged and removed as they produce allopathic chemicals that will continue to suppress native plants if the dead garlic mustard is left not he ground. The other reason for bagging and removing garlic mustard is that plants that have flowered will use their remaining nutrients to produce mature seed even after the plant is pulled.

Folks who live in southeastern Wisconsin can participate in 2017 Garlic Mustard Pull-A-thon. Sponsored by the Southeastern Wisconsin Invasive Species Consortium, Inc. (SEWISC), it is an annual fundraiser event, that encourages youth and adults throughout southeastern Wisconsin to protect their woodlands by pulling this invasive plant.  The goal this year is to pull 10,000 pounds and raise essential funds for the fight against invasive species!

Head to the Wisconsin DNR website for more information about controlling garlic mustard.

Monday, 10 April 2017

Fired Up Over Garlic Mustard

Photograph by: Paul Bolstad, University of Minnesota, Bugwood.org

My favorite method to control garlic mustard is with prescribed fire. Not only does it kill the weeds and their seed in the soil, it stimulates fire adapted native plant seeds to germinate. Not only will the fire control garlic mustard, but it suppresses the invasive shrubs that have degraded so much of our woodlands in Wisconsin.

photograph by Mark Horn, Conservation Media LLC

Unfortunately, you must have a trained and well equipped which most private landowners find too difficult to find or expensive to afford. Garlic mustard also often grows in areas that lack enough ground fuel to carry fire through the weed patches.

While it may be too late to arrange a controlled burn this spring, now is a great time to begin planning for next year. The Wisconsin Prescribe Fire Council is a good place to start

Head to the Wisconsin DNR website for more information about controlling garlic mustard.

Tuesday, 04 April 2017

Torch ‘Em

 

picture of propane weed torch

Propane weed torch shown here without pressure its pressure regulator.

For those who refuse to use herbicide to kill garlic mustard and other invasive plants, there is the weed torch. It uses propane flame to kill young garlic mustard plants. Early spring is also a good time for this method as desirable plants are less likely to be burned.

The cost of a torch rig is around $200.00, which is quite a bit of money considering its limited usefulness. The torch assembly is also difficult to transport.

Some people strap the bottle to a backpack frame, but I am not comfortable with that arrangement. Others use a two wheel cart that can be difficult to navigate of narrow trails and steep slopes.

Head to the Wisconsin DNR website for more information about controlling garlic mustard.

Monday, 03 April 2017

Ready, Set, Spray

This week is your chance to Roundup garlic mustard before spring wildflowers start to appear. This invasive plant from Europe forms dense mats in woodlands and along edges that poison the soil crowd out spring wildflowers.

Early spring is a great time of year to get ahead of this serious invasive pest. Plants are small and more easily killed by herbicide. Native plants are still dormant and will be for a couple more weeks.

Roundup (glyphosate) is a non-selective herbicide which means that any plant that gets sprayed will die or be seriously injured. It breaks down in sunlight and the soil within two weeks. This means spring wildflowers that sprout in late April and early may will not be hurt.

To be fully effective, glyphosate must spend enough time on the leaves to be absorbed. Make sure that leaves are dry and that there is no rain forecast for twelve hours after spraying. This gives the herbicide time to get transported from the leaves down into the roots where it does kills the plant.

Follow label directions, typically a 3-5% solution depending the formulation of glyphosate. In this case more is not better; it simply wastes money. Leaves will only absorb so much and the rest breaks down in the soil as the plant dies. Likewise, only spray leaves to the point of runoff; again the rest is wasted money.

As always, there may be some desirable plants nearby that have already sprouted or are likely to appear in the coming days, so only spray areas where garlic mustard is actively growing.

New garlic mustard plants may sprout later in the season, but since it is a biennial they will not bloom or set seed until next year.

My favorite method to control garlic mustard is with prescribed fire. Not only does it kill the weeds and their seed in the soil, it stimulates fire adapted native plant seeds to germinate. Unfortunately, you must have a trained and well equipped which most private landowners find too difficult to find or expensive to afford. Garlic mustard also often grows in areas that lack enough ground fuel to carry fire through the weed patches.

Head to the Wisconsin DNR website for more information about controlling garlic mustard.