As I wind down the season this last week of September, my time working on the stewardship crew these past months sure seems to have flown by. Although this is not my first season in a position on a field crew, I’ve still learned a ton of new and insightful information relating to land management, ecosystem restoration, and Michigan’s natural features. The majority of the work I performed was helping to control invasive species populations throughout Oakland Township’s parks. While in our day to day tasks, it can be hard to look at the big picture of invasive species management and how to assess long-term goals. Though reflecting on our work and talking with the director of Oakland County’s Cooperative Invasive Species Management Area, I hope to do just that.

What Makes a Plant “Invasive”?

Working throughout the season, I have seen firsthand the devastation that certain plants have caused in our parks. How is it that we label these havoc-wreaking species as “invasive”, and what makes them so detrimental? An invasive species can be defined as a non-native species (plant, animal, disease, etc.) with the ability to “invade” or “take over” an ecosystem in a way cause s a negative impact on the environment, human health, or the economy. In most cases, an invasive species’ introduction into an area is brought on by human activity, such as the purposeful or accidental transportation of the species from one part of the world to another. In their native ranges, these species have evolved to serve an important role in their ecosystems, and are kept in check by natural competitors. However, the same species can have catastrophic effects when transplanted to new environments that haven’t had thousands to millions of years to adapt to its presence. Because of this, they are able to outcompete native species and drive an overall biodiversity loss. For example, Oriental bittersweet is an ornamental plant brought over from Eastern Asia that has the capability to spread rampantly throughout our forests. Its vining growth habit leads it to grow around trees or shrubs and eventually strangle them to death, or cover a massive amount of area on the forest floor. Oriental bittersweet and other invasive plants disrupt an area’s native food web which limits resources critical for native birds, bees, butterflies, and other animals. These effects also work to destroy habitat for native wildlife.

A Changing Climate Creates New Challenges

Our earth is experiencing changes at an abnormally high rate as time progresses. Climate change news is always prevalent, but has had significant media attention especially recently as the Intergovernmental Panel on Climate Change published its report highlighting the devastating consequences of our changing planet. I was curious to see how exactly increasing global temperatures and more extreme weather events would affect the prevalence of invasive plant species. In short, I found that longer summer growth seasons will allow for more vegetative growth of invaders, and overall warming will shift individual species ranges northward over generations.

I noticed firsthand this spring that there was the absence of water in a lot of areas that should have been seasonally wet, such as vernal pools and the Paint Creek Heritage Area – Wet Prairie. Although anecdotal, this observation may tie into the fact that we had less snowfall this past winter due to drier and warmer than average conditions. Fluctuations in temperature and precipitation are commonplace year to year, but climate change will make them more common and extreme. So, what does this mean for invasive species? Based on what I’ve learned about wet prairies this year, this habitat type relies on periodic wetness to help keep its native species dominant and drown out unwelcomed guests. However, certain invasive plants like purple loosestrife and narrow-leaf cattail may not be bothered, and in some cases may even thrive.

How the Oakland County CISMA is Helping

Since management of invasive species requires cooperation on a local scale, organizations known as Cooperative Invasive Species Management Areas (CISMAs) are often established with the goal of uniting relevant agencies in their efforts to control unwanted species. I was interested in learning more about what kinds of problems climate change introduces for managing invasive species in my local area, so I got in touch with Erica Clites, Director of the Oakland County CISMA. I asked her questions regarding the nature of her work and what the CISMA is doing to prepare for changing climate variables.

What is the role of the Oakland County CISMA in combating invasive species?

The Oakland County CISMA mainly acts as the main information base regarding invasive species in the area. Expertise about species identification and management are offered to both partner organizations and the public. In addition to education, the CISMA is also involved in direct surveying and management of invasive species. Their efforts are often concerned with long-term management, which comes in the form of partnerships with organizations like the Oakland County road commission. Working with the road commission allows them to help manage the spread of invaders like Phragmites australis, a persistent weed that often grows in roadside ditches.

What does a changing climate mean for invasive species management in Oakland County?

I asked Erica about how she anticipates climate change will affect her work with the CISMA. Managing invasives is just as much about working in the present as it is looking towards the future. By being aware of the general trend of warmer global temperatures and increased intensity of weather events, Erica can anticipate how certain species will act and which ones to watch out for.

With higher average winter temperatures, more species will be able to live in Michigan than previously. Until recently, certain invasives have been prevented from becoming established here due to their inability to survive our cold winters. Water lettuce and water hyacinth are two non-native aquatic plants that fall under this category. Both species are legal for sale in the water garden trade, with the pretense that they should not be released into the environment. Unfortunately, these plants do eventually end up outside of their intended area, as is often the case with ornamental species. With the threat of warmer winters, water lettuce and water hyacinth have the potential to become invasive if left unchecked. The Oakland County CISMA is aware of the threat of these plants and other potential invasives and works towards removing what they can find as a preventative measure.

Temperature changes often shift the ranges of species over time, and invasive plants are no exception. According to Erica, certain species that are known to be established in the southern US are at risk of moving northward in response to increasing global temperatures. The CISMA remains vigilant and watches for certain species that are predicted to move northward in the future. The Michigan Invasive Species Watchlist is a great resource for those wanting to know which species may be moving into your neighborhood. Species that are expected to move up to Michigan from southward latitudes can be found on this list.

Climate change will create more variable conditions in weather patterns and increase stressors such as drought and extreme heat. I had initially thought that these changes would somewhat even the score since they affect both native and nonnative plant species. However, I was disappointed to learn that invasive species are often more flexible and better equipped to handle these changes than native plants are. Invasive plants are able to successfully populate an area because of their ability to tolerate a wider range of conditions, and this includes weather and climate. Think about an open field that has been turned into a neighborhood. Most species will not be able to tolerate such a dramatic change in their environment, but tenacious plants like dandelions will still pop up through cracks in the pavement.

How You Can Help

My goal in writing this blog post was not to instill you with a feeling of impending doom, but to ignite your motivation to help deal with the threat of invasive species. Fortunately, there are plenty of ways to help for those interested. The Oakland County CISMA’s website has plenty of resources available for identification and management of several of the most common and pervasive species in the county. Their YouTube channel and Facebook page have a lot of useful information as well.

I asked Erica what she would recommend for those wanting to be part of the invasive species mitigation solution, and she recommended a number of options:

• Go out into your yard or a local park and use a smartphone application to learn what plants are around you, and which ones are invasive or native (I recommend iNaturalist and the Midwest Invasive Species Information Network app)
• Attend a volunteer invasive species removal workday with the Oakland County CISMA or one of their partners (you can also sign up to attend one of the Oakland Township Parks’ stewardship workdays here!)
• Attend MSU Extension’s Master Gardner Program or Conservation Stewards Program