Evaluation of Restoration Efforts
in the Tryon Creek Watershed
Portland State University Senior Capstone Project
A group of Portland State University students have spent the last two months visiting previous restoration sites in the Tryon Creek Watershed. The students visited each site and took account of the amount of native versus invasive species of current plants, and the general success rates of past re-plantings. The focus was to help the Tryon Creek Watershed Council be aware of which sites are still in need of eradication of invasive plant species that are preventing native species from thriving.
What’s the big deal about invasives?
Invasive species are a threat to biodiversity and water quality.
- Non-natives can spread from the confines of a private yard or garden on shoes, in the wind, or by animals.
- When they enter a foreign ecosystem, they compete with the existing native species for resources. Invasive species are often more adaptable than native species, and grow rampantly without animal predators in the area that are unable to digest the introduced plant.
- The result is that the invasives eventually become one of the main species in the ecosystem, decreasing biodiversity
- As a result, this promotes soil erosion because lack of plants suited to hold back water banks and slow water absorption leads to more sediment in the waters. The warmer, cloudier water makes it very difficult fish to spawn or for bacteria to maintain a balanced water quality
- Without a broad range of different species of plants, animals, insects, etc. living in an ecosystem, the entire ecosystem can collapse.
Not all non-natives are created equal
The non-native plants that compete for resources such as sunlight and water are the ones that pose a threat to beneficial native species. The following are some common invasive species the Portland State University students documented. Some have easily mistakable native “look alikes,” which are also listed, along with the main ways to differentiate between the native and invasive types:
Other invasives are much more obvious to identify as they possess characteristics unlike other plant-life in the area such as:
Why does all of this matter?
Volunteering at parks and public green spaces is a practical way for all of us to give back to our world, which we are a big part of! It can also foster a deeper connection with nature and provide us all an opportunity for reflection about how everything we do has an impact on ecology. Restoration projects are important to the health and balance of ecosystems, thereby benefitting all of the life forms that occupy it.
What can you do to help?
Volunteer! Tryon Creek Watershed Council coordinates great volunteer opportunities for people who live in and outside of the Tryon Creek Watershed. Volunteers do on-the-ground work of removing invasives and planting new natives.
Do you live on a property bordering a creek or stream in the Tryon Creek Watershed? The Tryon Creek Watershed Council works with private landowners to survey land for invasive plant species, canopy cover, soil erosion, and other factors that contribute to a health of a streamside ecosystem. Volunteer teams are sometimes available to help restore the area by removing invasive species, planting native species, and cataloging the site for further assessment.