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You are here: Home / Manager's Tool Kit / Early Detection and Rapid Response / The Early Detectives / The Nature Conservancy, MD/DC: Weed Watchers
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Early Detection and Rapid Response

The Early Detectives: How to Use Volunteers Against Invasive Species, Case Studies of Volunteer Early Detection Programs in the U.S.

The Nature Conservancy, MD/DC: Weed Watchers

Contacts: Meredith Malone, Deborah Barber; The Nature Conservancy, Maryland-District of Columbia Chapter
E-mail: dbarber@TNC.org, mmalone@TNC.org
Phone: (920) 391-4610
Weed Watcher Busters Program


This program began during the year 2000, and uses approximately 30 volunteers to monitor sensitive areas within 13 nature preserves of 100 to 3,000 acres, with about one volunteer for 100-200 acres. Volunteers make 3-6 site monitoring visits during each growing season. Initially, volunteers search for a "hit-list" of 13 weedy invasive species.

Some observers predicted that volunteers could only be successful at simple, repetitive tasks and minor responsibilities. "We've shown staff and partners what incredible things the right volunteers can do. You can set a volunteer loose on a preserve and have them give appropriate and correct identifications of our 13 target species, even when we have 700 species on some preserves." The directors characterized their volunteers as alert, caring, environmentally-aware citizens.

Perhaps the program's biggest success so far was that a volunteer detected an infestation of several hundred square feet of Japanese stiltgrass (Microstegium vimineum: a low-light, fast-growing streamside invasive) in a cedar swamp in the Plum Creek preserve. "We went out there and pulled and pulled and pulled," for two growing seasons. Native plants are now reclaiming the site. "It was a good example of how important it is to find infestations early."

Motivating Volunteers

"It's really tempting to wait until you get something totally figured out before you take any action." But Meredith and Deborah recommend getting started early with pilot programs, and learning along the way. This approach requires the organizers to remain responsive and open to volunteer feedback. But being responsive is also a way to recognize and support volunteers and motivate them after their training.

Volunteers told the organizers they wanted a manual that would be easy to carry around in the field. The present manual includes search methods, descriptions of the target species with pictures, and navigation techniques in a loose-leaf binder, all of which may not be necessary for a field visit. Because some volunteers found the binder cumbersome, the organizers suggested only bringing what was essential from the notebook into the field, perhaps on a clipboard. They also offered a lightweight handbook of regional invasive species with color photos and identification (Plant Invaders of Mid-Atlantic Natural Areas, by USFWS and NPS).

ED (Weed Watcher) volunteers will often also volunteer for the Weed Busters program, which actually follows through with control and eradication. "The actual work of doing treatment gives people a sense of accomplishment. But I also like to update all of the Weed Watchers on the control work we have done in response to their reports. That makes them realize how important their work really is and what has become of it." This avoids having them feel that all their work has gone into a black hole.

Recruitment and Training

Two volunteers are in their 30s, and most in the mid -50s and many are retired and have more leisure time to spend out in the woods. But younger people can do this if they want to on weekends.

Many recruits are found via the Web site, and others designed to match volunteers with opportunities, such as volunteermatch.org and idealist.org. Organizers of new programs should consider using these sites to recruit their volunteers.

"Anyone with an interest in invasive species can be a good Weed Watcher volunteer, but people who already have a great interest in plants in general and know how to identify plants are especially helpful." Native plant societies and garden clubs are particularly good sources of qualified, interested volunteers, because they often have some experience in identifying plants. Deborah and Meredith would have sought more of these people, if they had it to do over. Volunteers without this background can certainly work out well, however, but the organizers found that extra time was needed to train them for careful identifications. It helps if the volunteers can bring back specimens to the organizers to verify plant identifications.

Volunteers are asked to make a three-year commitment. Promising volunteers are those who love to be out on the land and do not have to be reminded when to do the work. The best are not overwhelmed by the 13-item "hit list" of target species and ask for more. One volunteer discovered an invasion an aquatic weed that no one in the Conservancy chapter had ever seen and could not identify. She watched its growth habit, and did independent research until she figured out that it was Japanese spiderwort, a problem in adjacent states. "She was the early warning system par excellence!"

"Weed busters," who pull the weeds, however, perform fine if they can just walk and talk. No special training. New recruits who are not needed but seem promising are given some training and a tour to keep their interest when needed later.

"It's tempting to have Weed Watchers at a whole lot of sites, because it doesn't require that much support, but we have to remember that we can only control a certain number of these infestations, so it gets to be more information than we have the capacity to do anything about." Treatment is a bottleneck.

Training is informal, and lasts about two days. A PowerPoint presentation teaches the reporting methodology, identification, and navigational skills. Samples of the target species are shown, then the group goes to a local area with a lot of weeds for practice in identifying the target species. The organizers give a quiz, which helps spot teaching and learning weaknesses that can be addressed.

During the second day of training, the organizers assess the level of interest of each volunteer, then schedule a visit to the preserve they will monitor. ED volunteers are assigned sites as close as possible to where they live.

Training is better in one central place with as many volunteers as possible, rather than in ones or twos, several times, for efficient use of time. But one or two visits to sites must be done with each volunteer, to work on identification and navigational skills. Interns are especially valuable and highly recommended for this important but time-consuming training. "If you don't have time to do that, things may not work so well." If the area is unmarked and untrailed, detailed initial site visits and orientation are even more essential.

The organizers have begun training volunteers to recognize invasive exotic tree insect infestations and other changes on the land, too. "We want to protect our species also, good volunteers can help with this." They can foresee the day when invasive animal species are added to the watch lists.

Technical Work

The target list was developed by polling Natural Heritage scientists in Maryland about which species represent the major threats for nature preserves. The list does not often include suburban weeds, because they are not (yet) threats on the countryside where the preserves are. The lists are tailored for the region where the preserve is.

The criteria they used for prioritizing target species include:

1. The extent of the species (is it off of the preserve), and the size of the plant population (smaller is better-easier to control)
2. The potential impacts of the species - e.g., a patch of invasive reeds in a sensitive wetland area would be higher priority than if it were along roadside
3. The value of the habitat where the infestation is - e.g., how close the invasive is to endangered species or fragile ecosystems
4. How hard to control and how many resources you have to throw at the problem.


The organizers note that for some species, detection has been so successful that it has outstripped the volunteers' capacity for control and eradication. If it is not a direct threat to rare species, "We are probably just going to live with it." Keeping ED volunteers motivated under those conditions can be tricky: we will be able to respond to some of your detections, but not all of them. It can make people feel not very useful. They have to be told that in the beginning, that it is still important to know that the infestation is there, and growing or diminishing, and may be taken care of later.

Relocating an infestation is made difficult if the volunteer is not totally familiar with the preserve and did not identify the location well and cannot come along to help find it. Pink tape flag on a nearby tree works, bearing written directions, with landmarks noted. Reports are simple maps on a piece of paper, though some volunteers have been recording the data with electronic mapping software. GPS units could easily take care of this in the future.

The program has resulted in the prevention of a lot of potential weed infestations..."It does take some time and support to keep everything going and if it was not paying off then we would not be spending time on it."

Quick Facts

Staffing: one full-time volunteer manager for 500 volunteers, of whom 30 work in the early detection program, plus part of another staffer's time.

Location: Maryland

Report prepared by: Steve Nash

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Last Modified: Apr 13, 2017
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