The Maryland Native Plant Society (MNPS) and Sierra Club, in cooperation with Charles County and the State of Maryland, lead stewardship nature walks the first Sunday of each month. At these nature walks Marc Imlay teaches community volunteers about the harms caused by invasive species and instructs them on eradication. For decades, Marc and others in the environmental community have worked hard to have parks by stopping development. Alien species erase what is gained in natural areas with normal ecosystem functions because the land can have 30-50 percent invasive plant coverage. Marc and volunteers at Swann Park go after invasives where they find them and work to decrease the area of invasion. So far the program has been successful and the spread of several invaders has been controlled. Marc believes the most important part of volunteer-based invasive species eradication is showing the volunteers how bad the invasive species problem is and that they can do something about it. Successful results have kept volunteers hard at work at Swann Park, fighting the good fight against invasive species.
Invasive plant control work has been conducted on the 800-acre North Tract of Chapman Forest, and the 200-acre Swann Park where excellent progress has been made in the past three years. Before eradication efforts began, invasive plant monocultures (there had been little overlap of invasives in the park) had covered 20 acres or ten percent of Swan Park. Now only 3.5 percent of the park still has invasive plant coverage. The following is a summary of the eradication results at Swann Park:
English ivy: 0.2 acre eradicated
Periwinkle: 1 acre 98 percent eradicated
Ailanthus: the 2 acres in 5 areas of patches virtually eradicated
Garlic mustard: 5 acres reduced to 4 acres
Stilt grass: 5 acres reduced to 1 acre (controlled)
Beefsteak plant: 2 acres reduced to 0.2 acre (controlled)
Multi flora rose: 2.5 acres, now 1 acre (no seed producing left)
Wineberry: 2 acres now 0.2 acre
Chinese privet: 1 acre reduced to 0.5 acre
In addition, the vertical component (i.e. 1/2) of honeysuckle was removed.
These are the primary non-native species that had been detected as established in Swann Park. Japanese knotweed, Asiatic Bittersweet and Japanese Barberry have been found and scheduled for control this year. A patch of Chinese Day Lily was eradicated.
Battling invasives: A day at Swann Park
A normal stewardship walk begins at 10 am in Swann Park. Volunteers meet Mark and other experts at the Ruth Swann Park parking lot. The first part of the day is filled with instruction. Volunteers are briefed on the invasive species problem and are instructed on the invasive plants to be targeted, methods, park navigation and safety orientation. Volunteers complete a sign-in form and are given the schedule for the day and fact sheets for the targeted invasives. After the introduction and one to two hours of work, there is beach lunch after which volunteering begins, which can last until the late afternoon, but normally finishes around 4 pm.
Training the volunteers involves showing them the plants to be targeted. Distinguishing features of each invasive are pointed out and compared to similar looking native plants. It is normally pretty easy for volunteers to figure out which plants are the invaders after the training session. Pre-surveys are normally performed the day before to plan an appropriate choice of species or site for the size of volunteer group that shows up.
Recruitment and Training
Swann Park and the MSNP recruit volunteers from several sources. Many volunteers are MSNP members. Oftentimes these volunteers bring friends to help out and enjoy a day in the park. Other volunteers come from garden clubs, schools, senior organizations and other environmental groups. MSNP members are active in encouraging neighbors and others in Maryland to join the battle against invasive species.
The most important part of retaining volunteers is keeping their morale up. MSNP reminds volunteers that when they work to clear the 20 acres of invasive plant coverage, they are actually clearing the entire park. In time the invasives would take over most of the native vegetation in the park. Volunteers see their role as being more important when they understand this.
Volunteer-Based Eradication Methods
Flexibility is key for effective eradication. When the soil is wet, it is best to pull weeds. Dry weather is good for removing annuals and killing invasive plants with biodegradable herbicides. Volunteers do most of their clearing manually. State officials have decided that only Park staff members with state certification or a few well-trained registered volunteers under their supervision should use herbicides. For these reasons, the MNPS and Swann Park try to match funds for staff to do the work that volunteers find too difficult or are not certified to do. The Program designers feel that volunteers are most effective in the maintenance of pristine sites.
Volunteer Leader's Reflections
Marc Imlay has been very happy with the achievement of the volunteer early detection and eradication efforts at Swann Park. The program at Swann Park is not a typical early detection program. It is site-based, which means staff and volunteers focus on the land they are protecting rather than the species they protect the land from. Early detection is part of the program rather than its main focus.
While the volunteer-driven eradication efforts at Swann Park have been successful, the biggest hurdle the program faces is funding. This is typical for volunteer based early detection programs. So far volunteers have raised $30,000 to help Swann Park become invasive species free. Program directors are trying to win government grants to supplement the "extensive volunteer work" with contract work. If the program had more funding the Park could reach full invasive plant eradication sooner, and could then begin the easier job of maintaining a pristine site.
The MNPS uses a site-based approach in selecting its target invasives. The site-based approach yields ecosystem preservation because it controls all significant species at the site. Thus, any invasive plant present at a site will be targeted. MNPS communicates a goal to have 100% native plant cover. At Swann Park the targeted species are English ivy, periwinkle, Ailanthus, Garlic mustard, Japanese Stilt grass, Beefsteak plant, Multi flora rose, Wineberry, Chinese privet, and Japanese honeysuckle. These are the only non-native species that had been detected as established in Swann Park. Eradication efforts have significantly reduced the acreage these plants cover.
What Can we Learn From Swann Park
- Maintain Volunteer Morale
- Have volunteers both detect and eradicate. Eradication is empowering and lets volunteers see the good they are doing.
- Try these species specific techniques that have worked for Swann Park
Japanese Stilt Grass: After treating Japanese stilt grass (back-pack spray with roundup) be sure to check the following year for results in May or June, as opposed to August or September, because individual stems will grow to expand into the available space and Japanese stilt grass re-growth from the seed bank will appear to be more extensive than is actually the case.
Wineberry: Over one acre of wineberry was pulled by the roots in very wet soil gently using 4 prong spading forks to first loosen the roots. Almost none came back next year or the following year. As much as thirty percent came back elsewhere with dry soil.
Japanese Honeysuckle: Pull out Japanese honeysuckle by the roots in Winter wherever we see it up in the trees, aim the roots upward and tie them in place. The absence of light energy causes the trailing vines to decline precipitously next year. Thus we control 80% of the honeysuckle with 10% of the effort and minimal soil disturbance (do not pull it out of the trees and watch for native vines (moonseed, trumpet vine, native grape etc.) This method greatly reduces spraying requirements.
Number of Volunteers: Target of 20 for each "stewardship walk."
Operating Budget: Whatever can be raised through donations and grants
Habitats Patrolled: Swann Park and Chapman Forest (Mixed Evergreen and Deciduous Forest
English ivy (Hedera helix)
Periwinkle (Vinca minor)
Ailanthus/ tree of heaven (Ailanthus altissima)
Garlic mustard (Alliaria petiolata)
Japanese stilt grass (Microstegium vimineum)
Beefsteak plant (Perilla frutescens)
Multi flora rose (Rosa multiflora)
Wineberry (Rubus phoenicolasias)
Chinese privet (Lingustrum sinense)
Japanese honeysuckle (Lonicera japonica)
Location: USA, Swann Park, Charles County, Maryland
Report prepared by: Lucas Nagy