Thursday, 29 October 2020

UMISC 2020 Pathways to Success

Image of UMISC 2020 logo

Next week, November 2 – 6, 2020, groups from across the upper midwest will meet online for their biennial invasive species conference, UMISC 2020. Because of the COVID-19 pandemic, this conference will be a virtual event. One of the principle sponsors is the Invasive Plant Association of Wisconsin (IPAW). This group includes academic researchers, DNR invasive species experts, land managers, and private landowners who share the latest information.

I will be attending this year and will bring you updates on presentations each day. In following weeks, I will follow up with selected presenters to get additional insights for property owners.

The UMISC 2020 covers both land and water borne invaders. My posts will focus on land based species. Check out the UMISC 2020 program to see a listing of the conference events.

Included this year are tracks for terrestrial and aquatic species, as well as a track specifically focused on forest health. In addition, there in an interdisciplinary track that covers topics like public outreach. Special event sessions this year including several by the Woody Invasives of the Great Lakes (WIGL) Collaborative. WIGL is funded by the U.S. Environmental Protection Agency through the Great Lakes Restoration Initiative (GLRI) program.

If you want to attend, there is still time to register for the conference. Cost is $95 for regular attendees, $75 for IPAW members (as well as member of other sponsor organizations), and $55 for students.

Stay tuned and pass on any questions by using the comments section at the bottom of each post.

August 2020

Wednesday, 12 August 2020

Kiss Your Ash Trees Goodby

Image or ash trees whose crowns are partially and fully defoliated by Emerald Ash Borer.

Nobody wants the crown layer of their woodland to look like this.

Wisconsin’s woodlands are changing. Emerald Ash Borer (EAB) is causing the greatest die-off of trees in the state since Dutch elm disease arrived in the 1960s. If you have ash trees on your property, you must learn to recognize EAB damage and quickly take action. In Wisconsin, that means black, green or white ash. Time is not your friend; indecision will remove any options. The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) has a website that shows where EAB is prevalent.

First, cruise your timber. Early detection is your best and only defense. Check out the Wisconsin DNR for website for woodlot owners. Treatment must be made to individual trees and completed before 1/3 if the crown is lost.


One of the best ways to identify emerald ash borer damage is through the “D” shaped holes emerging insects leave in the bark. Unfortunately, these holes are approximately 3/16 inch in diameter and may first appear rather high in the tree. The cream colored larvae living under the bark can be 1½ inches long. These are exit holes for the larvae that are emerging to morph into adults.

Most landowners will first spot the infestation by observing leaf loss in the crown. This crown thinning can easily be overlooked or written off as storm damage. By the time the damage is obvious, it is probably too late.

Image of green ash tree with significant bark blonding

Outer layers of bark begin to fall off an ash as EAB larvae eat their way through the sapwood.

Bark blonding takes place when the bark of an infested tree shards to shed the outer layer of its bark. The tree is essentially dead at this point. Blonding occurs because the sapwood below the bark is dead and outer layers of bark are drying out and stuffing off. 

Image of debarked ash trunk with EAB tunnels

Peal away the bark of an infested ash tree and you will find tunnels in the sapwood created by the EAB lava.

The EAB lays it eggs under the bark. When the eggs hatch, they spend two years developing in the cambium layer of the ash tree. They eat the sapwood, burrowing tunnels are they feed. The tunnels interrupt nutrient flow. Eventually, limbs and even the trunk die as tunnels completely cut the supply of sugars and water.

What’s Next?

If tree you want to save is less than 47″ around at chest height, you may be able to treat it yourself. You can apply a liquid soil drench homeowner product for about $20-35/year. An arborist should treat larger trees or those with special circumstances. Their treatments involve directly injecting trees under the bark. Those treatments typically cost several hundred dollars and must be repeated every 2-3 years.

Recent research suggests that EAB density moves through a forest like a wave (Sadof, 2017). Chemical treatment is most effective when begun early and should be continued for approximately ten years after initial infestation. At that point most neighboring trees have already died and the great mass of EAB have moved on to greener pastures (forests).

The cost or removing dead ash trees start at $1,000 and more, depending on size and location. Your only choice, if you have too many trees to treat, may be to conduct a timber harvest.

More Informaiton

The Emerald Ash Borer Information Network has the latest information about he pest and how to control it.


Sadof, Clifford S., Hughes, Gabriel P., Witte, Adam R., Peterson, Donnie J., and Ginzel, Matthew D. Tools for Staging and Managing Emerald Ash Borer in the Urban Forest, Arborculture & Urban Forestry, 43(1): 15-26. 2017.



November 2018

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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October 2018

Wednesday, 10 October 2018

Patagonia to Hustisford

If you are looking for that special winter getaway, Chile might be just the ticket. The Route of Parks trail spans across 1,740 miles from Puerto Montt all the way to Cape Horn.

Sparked by the recent donation of 408,000 hectares of private conservation land by Tompkins Conservation, the Chilean government announced that it will convert 2 million hectares of conservation reserve land into national park land. Combined with the Tomkins donation and existing national park property, the new Patagonian Route of Parks trail stitches together a network of national parks that occupy around 11.5 million hectares.

Douglas and Kristine Tompkins made their fortune in outdoor apparel, founding both North Face and Esprit. They created Tomkins Conservation and began buying up land for conservation in the 1990s. Tomkins Conservation made the donation last year, following the accidental death of Douglas Tomkins kayaking the Patagonia in 2015. 

While I do not usually post about outdoor recreation, this story is different. The Patagonian Route of Parks not only created a trail for hikers and backpackers, but a vital corridor for wildlife.

Meanwhile back in Wisconsin

Fragmentation is second only to habitat loss as threats to rare plants and animals. In Wisconsin, this plays out as small prairie remnants nestled along old town road right-of-ways, railroad corridors and the forgotten corners of early graveyards. Minute micro habitats where a tiny number of native plants, as well as the insects and animals that depend on them, hang onto a tenuous existence.

An increasing number of private landowners are deciding to manage part of all of their land for conservation. Small restored prairies are showing up in areas where once they dominated the landscape. Woodland owners are investing great effort to thin over-mature woodlands and clear invasive shrubs that a generation ago chocked out grasses and wildflowers.


Staying connected

While the work and money these landowners are plowing back into their land is vital to conserve and protect Wisconsin, those efforts cannot by themselves same many of the species that are heading for a quite death. These islands of habitat need to be connected.

Take for example the whirled milkweed. This tiny member of the milkweeds, grows barely a foot tall. It spreads through rhizomes into patches thirty feet or more across. However, whirled milkweed does not self-pollinate. That means that pollen from stems in the same clone must be transported to flowers on a different clone in order to pollinate those flowers and produce seed.

As farms and the equipment got bigger, fences were removed. Less productive land was also worked up for cultivation. This reduced that places where the Whirled milkweed could grow.It also isolated the few remaining populations that had been hanging on. These plants can live for thirty years of more. However, without cross pollination, the few remaining plants will eventually die without producing seed for new generations.

The solution to the problem is obvious, we need to connect fragmented islands of habitat. These do not need government to set aside vast expanses of public land to make that happen. As private landowners, we can work together to protect our natural heritage. Working together, neighbor to neighbor, we can make a difference.

Maintaining our outdoor traditions means ensuring we have a strong habitat where wildlife can survive long-term. This is called resilience, which comes from keeping as many pieces of the puzzle as we can.

Better together

So what can you do? None of us are billionaires who can purchase hundreds of thousands of acres. We can, however, walk next door and talk to with the folks who live around us. That marsh stretching a half mile south across the next two properties is more valuable for waterfowl if you work with your neighbors.

Together, we cans share equipment, labor and knowledge to increase the impact our conservation work has. This is especially important when taking on tough invasive species like buckthorn, garlic mustard or phragmites. Increasing waterfowl production will  be much easier if you can get those two neighbors upstream to work with you.

Restoring and maintaining the natural heritage of our state is too big for individual landowners to fix. Government cannot maintain the land it owns, so they can only be very limited partners. Neighbor-to-neighbor, is the only way we get back the quail and ruffed grouse. Working with neighbors is the only way to ensure our woodland remain clear of buckthorn and garlic mustard. A shared vision is the best way to return waterfowl production to that marsh seemingly lost to cattail and phragmites.

It takes time to make these things happen, but there is no time like right now to go for a walk with your neighbor.

Friday, 05 October 2018

Are there biological control success stories for invasive plants?

Yes, the invasive perennial purple loosestrife (Lythrum salicaria) was the scourge of midwestern wetlands for twenty years. Marshlands turned a pinkish purple every summer and fall because virtually all competition was eliminated.

Researchers chose Galerucella beetles because they knew Galerucella feed on loosestrife in Asian and Europe where it grows naturally. Local school children and non-profit organizations set up beetle rearing projects; releasing the natural loosestrife predator to feed and lay eggs on the exotic invader.

Note that biological control is not eradication. Wetlands rebounded because the number of beetles rise and fall with those of the loosestrife. Because of the Galerucella beetle, purple loosestrife is now just another member of the wetland community and no longer the big bad bully pushing everything else out of its way.

The reason why the Galerucella beetle is a rare success story is that biological controls must be thoroughly vetted prior to introduction. Scientists must ensure that the beetles are effective, but even more critical, that they do not cause other unintended consequences. Researchers exposed Galerucella beetles to pretty much every native plant they were likely to encounter in the their new home, but safely in isolated greenhouses. Researchers made sure the beetles would not harm native plants.

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June 2018

Thursday, 28 June 2018

How long does it take for an invasive species to destroy an ecosystem?

The short answer is it depends. It depends on the invasive species; how quickly it reproduces, how many offspring it produces, how many ways it has to spread itself, and what tools it has to overwhelm native species. It also depends the environment it is invading; how large is the ecosystem being invaded, how well suited it is to the invading species, as well as the relative strength of native species defenses. Above all, it depends on how soon the invader is identified and effective counter measures are taken to control the invader.

Invasive species often go undetected for long periods, sometimes decades, until they form monocultures that totally transform a landscape. When this happens eradication becomes impossible and control becomes the only viable strategy.

Even really tough invasive species can be controlled and even eradicated if they detected early and effective steps are quickly taken.

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April 2018

Saturday, 14 April 2018

What are the negative things about Invasive species?

Living things (plants, animals, fungi, etc) evolved in communities. Plants turn sunlight and CO2 into sugars and starches that form the base of the food chain for all the other living things around them. Very slowly, those species that were best adapted to fit into their niche in the community survived and thrived. A type of equilibrium exists that changes slowly as the community itself changes.

Invasive species are really bad because they can seriously disrupt the existing plant and animal communities, often changing the character of their adopted ecosystem. Native species suffer, diversity is lost and the now out of balance community can become subject to damage from soil erosion and other maladies associated with a sick environment.

When species are dropped into a community where they did not evolve, some die off immediately because they cannot survive. Other species fit in more or less nicely, eating and being eaten by others; finding and inhabiting that new niche.

Some species, when introduced, into a new community are able to exploit the new home in ways that their new neighbors cannot. One example well known in the upper Midwest is garlic mustard. This plant sprouts from the ground in late February or March, just as soon as the snow melts. It continues growing through the warm months and into early winter, only going dormant in the deepest of the cold months. It also produces a tremendous amount of viable seed. Finally, its roots put out a chemical that inhibits other seeds from sprouting. Most of the micro organisms, insects and animals that would eat it in its native Europe do not exist here, so it has few natural enemies.

Hope that was helpful. Let me know if you have specific questions or need additional information.

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Can invasive species drive the extinction of indigenous species?

Absolute extinction is not the only danger, serious disruption to an ecosystem occurs much more often than the obliteration of a single species.

When I finished college in 1983, I left Wisconsin and headed out to build a career in other parts of the county. The woodlands were notable for their lovely displays of spring wildflowers like trout lilies, dogtooth violets, jack-in-the-pulpet and lady slipper orchids. Upon my return in 1997, I found that nearly every woodland in southern Wisconsin was ringed by dense stands of honeysuckle bushes, buckthorn and biennial called garlic mustard. These three plants had completely changed the character of the woodland environment across an entire region. Woodlands chocked by these invasive plants saw almost no sunlight getting to the soil. Slopes and small ravines lost tremendous amounts of topsoil, eroded because the native plant community had been replaced by a small number of plants, none of which was good holding or building the soil.

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What is the difference between invasive, alien, and exotic species?

Most alien (plant) species are well behaved. European settlers brought oats, wheat, barley, many varieties of turf grass; your name it they brought it to America. Think of boxwood, lilacs, tulips and apples. These are all alien species and stay put pretty well where they are planted.

Certain native (plant) species can become invasive under the right circumstances. Sumac is a good example. It is native to North America but when it moves into disturbed ground its rhizomes spread quickly and it forms dense thickets. Many of the brambles, like black cap raspberries, push out native prairie grasses and wildflowers if they are not controlled by fire or herbicide.

Soil type, moisture and temperature can influence whether a species (alien or native) is invasive. Japanese knotweed is incredibly invasive in the UK and the Pacific Northwest but be less aggressive in places where cold winters and drier soils limits its rate of spread.

Finally, microbes can limit the reproduction and spread of plants. Native plants evolved with their surroundings and so are eaten by and have some level of defense against predation by the microbes in their neighborhood. Alien plants may be ignored by microbes in their new surroundings and so gain a competitive advantage over native plants.

Now let’s talk animals. All animals need food, water and shelter. Like plants, animals can be alien or native; invasive or well behaved. The success of an animal is limited either by environmental constraints (food, water & shelter) or predation by microbes and other animals. For every animal native to its environment, there are other animals that use it as food. Even top predators have predators.

Alien animals may find that they have few if any animals around them that see them as food. The New Zealand Mud Snail has been found in fresh water streams in southern Wisconsin. It thrives on the nutrient loaded surface water runoff from farm fields. None of the fish in those streams know how to eat the snail or they find it unpalatable. Regardless, with no natural predators, this new arrival is causing havoc in its new home.

The real problem with invasive species is that they upset the natural balance in an ecosystem resulting in lower lower diversity of species, lowering of native populations, and disruption of multiple food chains. It is often these disturbances more than their relative success that cause the most damage to the environment. It can take generations or centuries for their new neighbors to evolve predators and disease organisms that bring the new invader into ecological check.

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