Invasive Plant Task Force - James River Park System

Cooper Island Study Area

Cooper Island Study Area Map

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Study area summary

The Cooper Island study area includes approximately 9.8 acres of park land and was divided into three smaller management units. The lead organization for the baseline study of this park section was the James River Outdoor Coalition. The task force field team identified a total of 13 invasive plant species across all management units, including:

  • 8 species ranked with high invasiveness;
  • 4 species ranked with medium invasiveness; and,
  • 1 species ranked with low invasiveness.

Of the three management units for the Cooper Island study area, the results Management Unit 1 and 2 were fairly similar in that each unit had 50 to 75 percent cover (Cover Class 4) of invasive plants. This data reflects dominant populations of mimosa, Amur honeysuckle, hydrilla (Hydrilla verticillata), and Oriental bittersweet that range from 25 to 75 percent cover. Unlike Management Unit 2, Management Unit 1 also had a small abundance of winter creeper and Japanese hop (Humulus japonica). While DCR-DNH rank these plants with medium invasiveness, the plants are known to grow profusely in the local floodplain, and should be eradicated before further infestation occurs in and around this study area.

Management Unit 2 had a slightly lower abundance of invasive plants, but at 20 to 50 percent cover (Cover Class 3), still dense enough to be considered a dominant component of the overall plant community. Tree-of-heaven, mimosa, and princesstree (Paulownia tomentosa) were each found at nearly 20 percent cover, and frequently along edge habitats. While no invasive shrubs were recorded in Management Unit 2, the understory was noted with Asiatic dayflower (Commelina communis) and lady’s thumb (Persicaria longiseta), as well as hydrilla submerged in the waters of the James River shoreline.

The native plant community within Cooper Island is similar to that found in other floodplain sections of the JRPS. The tree canopy is often formed by trees such as green ash, red maple, various oaks (Quercus spp.), and tulip tree. Understory composition often consists of saplings and small shrubs such as ironwood, paw paw, spicebush, and bladdernut, as well as an herbaceous stratum of wild rye (Elymus spp.), blackberry, pokeweed, Virginia creeper, wingstem, and boneset. Native vines typically include occasional stems of muscadine, greenbrier, trumpet creeper, and poison ivy.

ยป Phase One Baseline Study Data Summary (PDF)

Updates from the study area

None at this time.