Forested seep wetlands dominated by skunk cabbage (Symplocarpus foetidus) occur frequently in the Canoe Creek watershed of the Upper Iowa River, but this type of wetland has not been described systematically in the upper Midwest. The goal of this study is to document the herbaceous plant flora of five seeps. Although individual seeps are small (200-500 m2), they provide habitat for a high number of plant species. Five seeps with total area less than 0.2 ha supported more than 120 native vascular herbaceous taxa, 20 of which have a coefficient of conservatism (C-value) of 7 or higher and 23 that are obligate wetland species. Several species that were common in these habitats 100 years ago appear to have been locally extirpated or have become uncommon in the region, including Gentianopsis crinita, Cirsium muticum, Eupatorium altissimum, Chelone glabra, and Micranthes pensylvanica. Today, these plant communities are threatened by invasive plant species, high levels of deer herbivory, and destruction by human activities. We hope that by documenting their current species composition we can inspire protection of these wetlands and provide a baseline for monitoring future changes.
Coefficient of conservatism rankings for the flora of Montana.