To effectively combat exotic plant invasions, land managers need assistance identifying the location and extent of invasive species. Resources are rarely available to conduct detailed monitoring of invasive species presence. Engaging the public in ecological research poses a unique opportunity to communicate the seriousness of environmental problems and to assist in management. We hypothesized that volunteers from the general public who enjoy long-distance hiking 1) could be trained to monitor presence and abundance of commonly seen invasive plants, and 2) their involvement in scientific data collection would espouse changes in their attitudes or knowledge about science or the environment.

We recruited 126 volunteers in collaboration with a regional hiking organization over a three-year period. Volunteers were given a one-day training session on plant identification in the classroom and the field and in data-gathering protocols. Two-mile sections of hiking trails were sampled by teams of 2 hikers, at 0.1 mile intervals. Volunteers collected data on location and abundance of the target species. 'Validators' highly trained in plant identification then collected the same data along 25-50% of the volunteer data points, and it was compared with the volunteer data to assess accuracy.

Results/Conclusions

Accuracy was higher for collected specimens than for species observed in the field. For 67% of teams, all specimens were accurately identified. When points without invasives were excluded, volunteers correctly identified the target species in 51% of trail points, and in 33% they correctly characterized the abundance. However, in 43% of trail points, they reported the presence of a species when it was not actually there. In 54% of trail points they failed to observe the presence of particular species. Accuracy of individual teams ranged from 100% to 0%. Volunteers were more successful in correctly noting absence of invasives and in identifying commonly occurring species (Berberis thunbergii, Microstegium vimineum). Accuracy declined with increasing invasion. Volunteers struggled to correctly identify an invasive species in the field context indicating that with minimal training they may be most effective in sparsely vegetated areas. We also found that participation in our project resulted in significant learning gains in content knowledge and issue awareness. Gains in scientific process and epistemology were more limited. In conclusion, volunteers can contribute scientifically valid data about invasive plant distribution, and their experiences can be a viable means to communicate to the public about environmental issues.