According to the results of a global research project, conducted by the University of Konstanz and posted in December 2021, “super-invader” plants are a huge problem and greatly reduce biodiversity.
What even is biodiversity? What do the results mean? How does this even happen? Here’s what you need to know about these invasive plants that spread like wildfire.
What exactly are ‘invasive’ plants?
Coming from all around the world, invasive plant species cause harm to the environment, the economy, and/or to human health through rapid overpopulation. Most invasive plants come from other continents and countries, but few are native to other regions of the United States.
The extremely harmful side effects of invasive plants
- a reduction in native biodiversity which adds to climate change, pollution, and more (I encourage you to self-educate on the importance of biodiversity here)
- alteration of disturbance regimes
- habitat degradation and loss (the loss of native fish, wildlife and tree species)
- loss of habitat for dependent and native species (including wildlife)
- changes in biogeochemical cycling
- the loss of recreational opportunities and income
- crop damage and diseases in humans and livestock
What makes these plants invasive?
Here are some characteristics of invasive plants, through both their properties and how they are distributed over large distances.
- Can produce large quantities of seed
- For example, each garlic mustard plant produces hundreds of thousands of seeds–which is a great abundance
- Seeds are often distributed by birds, wind, or humans which allows them to travel significant distances
- Many produce chemicals that make it difficult for other plants to grow nearby (ex: garlic mustard plant)
- Some plants arrive accidentally in air or water cargo
- Tourism: travelers from one country to another actually commonly spreads things such as insect pests or weed seeds across
- Produce seeds and leaves that germinate and ‘leaf out’ way early in the spring. As an example, the Norway maple‘s seeds can be 6 inches tall before the plant sprouts, and buckthorns keep their leaves into November, long after native plants have lost theirs.
- This results in the plant’s leaves being kept late into fall, allowing them to photosynthesize earlier and later than native plants
Looking deeper into this on a molecular level…
Looking at the basic science of plants is helpful to understand why this earlier photosynthesis is so important. Plants use sunlight, water, and carbon dioxide to create sugars and oxygen in energy form in the process called photosynthesis. Plants contain chloroplasts that perform this process, which is comprised of light-dependent reactions and the Calvin Cycle (light-independent reactions).
The goal of the light-dependent reactions of photosynthesis is to collect energy from the sun and break down water molecules to produce energy-storing molecules ATP and NADPH. These are then used in the Calvin Cycle to turn carbon dioxide from the air into sugar, providing food for plants.
Plants with high photosynthetic rates will grow and reproduce earlier than their native counterparts, often out-competing them and leaving little space for them to thrive. They then can spread really fast due to their other properties listed above.
Why should we care?
Following habitat destruction, invasive species are the second leading cause of biodiversity loss around the world, contributing to climate change and pollution. Forty-two percent of threatened and endangered plants and animals in the United States are directly harmed by the presence of invasive organisms. That’s basically half! Governments around the globe spend billions of dollars each year to control the harm caused by these plants. Yikes.
What can we do?
Here’s what you can do to prevent the super-spread of invasive plants:
- Learn how to identify these plants and educate your friends about them.
- Don’t pick, gather, or bring home wildflowers that you can’t identify.
- Check for weeds and seeds from shoes and clothing after a hike. Also, check your pet’s fur for them! Remove anything that you find before arriving home.
- Try to keep your car off of weed-infested roads and trails.
- Be on the lookout for seeds while camping and coming back from vacation!
- Try to join a plant-removal project! Shown below is the happy result of an invasive species removal project completed by The Southeastern States District Office.
Dr. Mark van Kleunen, Professor of Ecology in the Department of Biology at the University of Konstanz and senior author of the research project’s publication, brings up the most important point: “Unless more effective protective measures are taken to counter the ongoing spread and naturalization of alien plants in the future, they will continue to destroy the uniqueness of our ecosystems — making the world a less diverse place.”