Getting into the weeds with our land stewards along the Sandy River.
In early August, a crew of Columbia Land Trust stewards led by Natural Area Manager Jen Zarnoch visited a conservation site along Oregon’s Sandy River on the lookout for weeds. The site, located near the town of Welches, was of particular interest for two reasons:
1. It is in good ecological condition. In fact, the area is home to a rare plant community, a unique assemblage of flora, which in this case includes black cottonwood, red alder, and salmonberry, growing along the riverside. Recently, the Washington Department of Natural Resources Natural Heritage Program conducted an Ecological Integrity Assessment (think of a report card for plant system health) on the site and determined that it was in good condition. The site is home to thriving native species without an overabundance of competing weed species.
2. This conserved area was the site of a salmon habitat restoration project led by our partners, Sandy River Watershed Council, in 2016. During these kinds of projects, it’s common for construction equipment and human activity to disturb the seedbed in the soil. This, in turn, can stimulate the growth and spread of plants, including any weed species that happen to be present, Scotch broom (Cytisus scoparius) being a prime example in riverside landscapes.
We knew there were areas of significant disturbance during restoration and that we had new weed infestations in these areas, but we didn’t have a good sense of the breadth or extent of these weeds. We also wanted to test our assumption of the generally good ecological condition of the rest of the site and be proactive in addressing any weed problems before they spread.
Stewardship Assistant Sanoe Keliinoi and Monitoring Assistant Jeffrey Lee joined Zarnoch in conducting a weed map survey with the goal of understanding conditions on the ground and then coming up with a plan to manage any threats to the overall condition of the property. The crew came upon some unique species and signs of wildlife, including Monotropa uniflora, also known as ghost plant, and a beaver lodge.
After perusing the forest understory and identifying some expected plants species, Lee happened upon something he didn’t recognize—a cluster of plants with towers of yellow flowers jutted out above its neighbors. The three stewards gathered around a photo of the plant and ventured some guesses before referencing combination of plant ID books, Oregon and Washington wildflower apps, and weed apps.
Based on the flowers, size, and plant structure, they started wondering if they might have something sinister on their hands: A Class A noxious weed known as garden yellow loosestrife (Lysimachia vulgaris).
The Oregon Department of Agriculture assigns different classifications to noxious weeds to help various land managers control the spread of weeds that can have harmful ecological and economic impacts. In particular, Class A plants are either not currently found in Oregon, or are found in such small quantities that they can likely still be contained or eradicated.
While coming across a new noxious weed species on a conserved property is never ideal, finding a Class A species in relatively small occurrence would mean that we could catch the problem early, before a few plants turn into an out-of-control population.
Lee took some photos of the specimen and turned to an increasingly valuable tool for plant identification and community science, the iNaturalist app on his phone. Zarnoch also posted the photo to oregoninvasiveshotline.org. After a little discussion with an associate who maps weeds with Portland State University, Lee concluded that the species is most likely a less alarming look-alike plant known as dotted loosestrife (Lysimachia punctata).* Though less concerning, the species is still a rhizomatous weed, meaning it sprouts through underground plant stems and can spread quickly.
While the plant turned out not be a Class A noxious weed, the discovery validates the importance of weed mapping surveys, annual monitoring, and all of the other on-the-ground stewardship efforts that our team undertakes day in and day out across thousands of acres of conserved lands. While technological advancements and increased collaboration are certainly making our stewardship efforts more efficient and effective, there’s still no substitute for having dedicated, knowledgeable people out on the land. Instead of simply acquiring a landscape and moving on to the next project, the Land Trust looks at the long arc of the landscape. We conserve land with the intention of caring for it to the best of our ability, with the help of dedicated partners and volunteers, leaving the place in the same or better shape than we found it.
Looking forward, our stewardship team will return to the Sandy River site soon to complete their survey, develop a weed management plan, and see if perhaps a volunteer day for pulling weeds might be in order. Stay tuned!
*An important note about plant identification: It can be very tricky! Even seasoned botanists can be stumped on a regular basis when it comes to coming up with a definitive ID. Many plants have look-alike species and subtle variations between species. Zarnoch notes that when identifying a plant, it’s best to have a sample in hand rather than just a photo. It’s helpful to be able to look at a plant from all angles. It’s also ideal to use a plant identification key, which follows a sequence of identifying characteristics to systematically arrive at a plant species. We are fairly certain that the plant we found is dotted loosestrife based on the variety of resources and expert input referenced above. That said, we will be returning to the site soon to collect samples and sure up the identification.