In this edition of Turtle Talk, we'll be discussing invasive plant species and what you can do in your own backyard to manage them successfully! If you are looking for the children's edition--please check out the "Back Yard Invasives for Kids!' for related activities and more outdoor fun at the link below!
https://turtletalkrbnc.blogspot.com/2020/04/back-yard-invasives-for-kids.html
Invasive species can be a real nuisance if not consistently managed--their ability to spread, push out native plants, and the fact that, for the most part, they don't support area wildlife make invasive plants hazardous to everyone's health! In short, they kill the diversity of an ecosystem, which destroys its resilience--its ability to 'bounce back' after a threat has wreaked havoc on it--and diminishes its capacity to provide ecosystem services!
Lately, I've been getting a lot of questions from neighbors trying to identify and manage invasives on their properties. Unfortunately, ignorance of the ecology of a forest ecosystem and the inability to identify and properly manage invasives will do a lot more damage long-term. So here's a run-down of the top three invasive species you're libel to see in our neck of the woods and what you can do about it. Get ready to roll up your sleeves--I guarantee they're going to put up a fight and this isn't going to be easy!
Before we get too in-depth, let's take a look at some terms that commonly describe both animal and plant species around the world.
Native-This species can be found either locally or regionally (including whole continents) and is firmly apart of the ecosystem in some way or another. It is important that these species remain in the ecosystem as they supports a link in the food web and, again, provide ecosystem services (pollination, water filtration, etc.) in some capacity.
Endemic-In addition to being native to the area/region/continent, it cannot be found anywhere else in the world. Typically this is a very specialized species that it is designed to live within the confines of the habitat's physical characteristics such as climate, amount of annual precipitation, elevation, and latitude (amount of sunlight). Furthermore, it most likely plays an equally specialized role in supporting the ecosystem.
Naturalized-This describes an introduced species or migrant who was able to establish itself within the ecosystem without placing pressures on other organisms and actually adds to the support and diversity of the ecosystem.
Invasive-These organisms, like naturalized species, were either introduced to or migrated to the current ecosystem in which they can be found. Unlike naturalized species, these species stress other organisms within the ecosystem and can be either generalists (surviving on several different food resources) or specialists that feed on only one species, such as the Emerald Ash Borer. Invasive species can have a small effect on an ecosystem or completely dismantle it by unraveling a delicate food chain or completely eliminating a link altogether.
As the climate continues to change, we are seeing a north-easterly migration by many different plant and animal species. This invasion of new species can make distinguishing a species from something that will merely naturalize itself into the environment from a species that will really pose a significant risk and damage the ecosystem--very, very difficult. For the most part, the species naturally migrating out of their native habitat are doing so because their native ecosystem is no longer suitable to support it. In short, they are migrants looking for a better life in a more suitable habitat!
Enemy #1: Garlic Mustard
While the leaves of this plant might be tasty on salads, don't be fooled--this species can spread like fire over a habitat! The tricky thing about this particular invasive plant is that it has developed ways around herbivory (or plant predation)--remember, if you're treating this plant, that's like preying on it so you might not be successful the first time around! Garlic mustard rears its ugly head in early April where it appears to be a small plant growing low to the ground. It has a shortened two-year life cycle where first-season plants do not seed but rather store energy from the sun in order to seed during their second year! This plant likes disturbed soils and shade, which is why it is often found in wooded habitats. One of the difficulties in identifying invasives (or any organism for that matter) is that they look different as they mature. Additionally, they can look a lot like native species causing accidental takes to be more frequent. This is also true of garlic mustard--while it may appear small at first, it can grow to be 2-4 feet tall, produce small white flowers in its second year followed by seed pods that break open and spread seeds via wind and water.
Unfortunately, this plant is guilty of pushing out native plants and pumping antifungals into the soil, thus destroying the fungal connections between plants and trees within the habitat. While spraying weed-killer can be an effective way of treating an area of first-year plants, it can also have a devastating affect on the soil and native plants as well. Additionally, if the plant has already flowered and gone to seed, it's really too late to spot treat with spray. I've also seen folks take a trimmer (or weed-wacker) to a grove of first- and second-year plants. While that might improve the aesthetics of the forest, this is a very short-term disruption to the plant's maturity and it will just regenerate leaves within a few weeks.
Garlic mustard wages a multi-year war, so if you're serious about getting rid of it (and making your management easier for years to come) the only way to truly control the plant is by pulling, bagging, and dumping it in the trash. They should not be left in the forest as they may root back into the soil and seeds will drop from dried pods. The success of this method comes from not only removing the above-ground parts of the plant, but by also removing the roots of the plant as well. Typically these plants are very easy to pull from the ground by grasping it low at the base of the plant, beneath leaves and any stems, wiggling it a little, and then pulling upward. Many hands make light work--this is where kids come in! They tend to be excellent garlic mustard detectives and, if turned into a contest, great and eager 'pullers'--especially if there's a reward involved. And, yes, I speak from experience here!
The picture above is of a lot line near my house--on the left is a property that has managed its garlic mustard for more than 30 years. The property to the right of the fence line is covered with early first- and second-year garlic mustard plants that have been allowed to grow and establish over several years where management was absent. Obviously, this poses a problem for the property owner on the left as they will see a 'spill over' affect from the neighboring plants making it increasingly more difficult to manage in coming years. (On a side note, if you are actively removing sticks and downed tree limbs from your wooded area--STOP! As these twigs and limbs are broken down by various species of fungi, they return nutrients to the soil and strengthen fungal relationships between soil and plant/tree life, thus combating the effects of garlic mustard!)
Enemy #2 Wanted Dead (not alive!): Multiflora Rose
If you're a hiker that likes to get off the beaten path like I do, then you'll understand the horrors of walking past one of these thorny beasts! While not as prolific as garlic mustard, multiflora rose prefers well-drained soils to spread its 500,000 seeds per year in a multitude of habitat types ranging from open forest to prairies to roadsides. What's worse is these seeds stay viable in the soil for 10-20 years! Unfortunately, as with many invasives, this one was introduced through the garden market as a shrubby fence, to help with soil erosion, and even to provide food and cover for wildlife. This last point is funny because that's also one of its biggest problems--it can grow so thickly that it prohibits wildlife from entering and pushes out native plant life.
It's a short little shrub with an attitude sporting husky thorns to prevent herbivory. However, birds and other animals do eat and distribute its seed-bearing berries, which develop after producing showy little white-to-pale pink flowers. When managing this beauty of a beast, it's best to wear thick gloves. There are several effective ways of managing this invasive--the best being to dig it up, roots and all or it will regenerate its stems. Continuously mowing over the plant for 3-4 years will effectively eliminate the plant as well. Additionally, performing prescribed burns will also work, however, roses may tolerate this management technique and resprout in communities where fire is common on the landscapes (ie: prairies and grasslands).
Enemy #3: Buckthorn
You may be familiar with this nasty invasive--it grows thorns in its early years and develops into a large shrub (or small tree) growing up to 25 feet tall. It takes advantage of the growing season by being the first to leaf out in the spring and the last to lose its leaves, making it relatively easy to identify in early winter. Its small round bluish-black berries look deceptively delicious to hungry birds late in the winter but it packs a dangerous punch causing diarrhea and ultimately weakening birds already struggling to survive harsh winters. This is why there are few birds where large patches of buckthorn have taken over.
Like multiflora rose, it prefers well-drained soils and will establish itself quickly in the same environments. While it is easy to identify female buckthorn by its berries, it can be difficult to correctly ID their male counterparts. Additionally, buckthorn is commonly mistaken for young cherry trees; however, a small cut into the bark will reveal an orangish tint to the cambium wood just inside the bark, whereas cherries will show a reddish color. Unfortunately, this species is highly prolific and, when allowed to spread and establish, can block wildlife routes and sunlight from reaching the forest floor, killing tree seedlings and other plant life. If that wasn't enough, it releases toxic chemical compounds that hinder the growth of nearby plant and tree life, changing the growing conditions of the soil in which it grows, and effectively eliminating any and all competing species.
So how do we get rid of this one? It's number three on the list for a reason--it's one of the most difficult to manage successfully. The cut and treat method applies after identifying the species in early winter and involves cutting it at the base and reapplying a strong stump treatment (with glyphosate) several times. Other techniques involve digging it up, grinding up the stem and roots, or performing prescribed burns to eliminate seedlings. Finally, girdling the larger trees by removing at least six inches of bark in the form of a ring around the trunk will also be effective and can be done anytime throughout the year.
Unfortunately, it's not enough to eliminate these species--we need to immediately plant native species in their place, otherwise invasives will merely see the open space as a vacancy and attempt to fill it! In other words, managing for invasives is a full-time job and involves two phases: extraction/elimination and planting.
So there you have it--the three big baddies of Wisconsin's invasive species! As the climate changes and our population continues to develop land and travel outside of our own ecosystems, more and more invasives will emerge. Only time will tell which species will be a nuisance and which will be accepted in their new homes.
Thank you for reading!
Stay wild and free and healthy as can be!
-CT
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