In a partnership project between the Hoosier National Forest (NF) and State of Indiana Cooperative Invasives Management (SICIM), portions of the Charles C. Deam Wilderness are being surveyed for the presence and extent of spread for different invasive species.

Eco Logic LLC, an ecological firm out of Bloomington that focuses on restoration, was contracted to map invasives along the 36 miles of trails in the Wilderness, according to a news release from Teena Lugman who is a SICIM board member. A total of 14 different invasive species were found.

In 2023, the group surveyed within 25 feet of either side of the Wilderness trails looking for signs of the invasives. SICIM administered the contract with Eco Logic. For 2024, Eco Logic is currently mapping invasives in an area around Frog Pond Ridge in the Wilderness. The Hoosier plans to apply for more funds in 2025 to continue the mapping to focus on two overly common invasives that are from old homesites: tree-of-heaven and wineberry. The hope is to capture the full extent of these species so they can be primary targets for future control.

Cheryl Coon, economic partnership coordinator for the Hoosier, said the mapping is helping the Forest Service have a more comprehensive idea of how extensive the spread of invasives species are in the Wilderness. With this information, the Forest can develop a strategic management plan on what species they can control and how. The historical human use and disturbance of this area of Indiana has allowed invasives to get a strong toehold in the area, and it will take more work than for most natural areas, to eliminate the non-native invaders.

Forest Service staff have worked with an Indiana University professor and volunteers to hand-pull garlic mustard along a corridor in the Wilderness for more than 15 years.

With limited funding, having these maps will help prioritize where to focus other invasive work in the Wilderness to have the most impact. Coon emphasized that though there are a lot of invasives in the Wilderness, the infestations are not hopeless at this point.

“Good stewardship can make all the difference. We can get the invasives back under control and the native ecosystems will rebound,” Coon said.

Currently, use of herbicides is not authorized in the Wilderness. SICIM’s experience is that proper use of herbicides is a proven and effective tool that can give managers the edge to remove invasives and restore ecosystems.

Control of woody invasives, such as autumn olive and bush honeysuckle, are not feasible without herbicide, Ligman said.

“If the Hoosier National Forest does not consider herbicides for control the invasives will continue to spread from trails and old homesites to more interior portions of the Wilderness and become cost prohibitive to manage, she said.

“The Forest Service would need to do a comprehensive environmental analysis of herbicide use in the Wilderness to look at potential impacts and include public input to any such activity being considered,” Ligman said. 

The results of Eco Logic’s surveys include maps of where the different invasives species were found.

These may be viewed on SICIM’s website at sicim.info/news.

Of the species surveyed for, lesser celandine (Ficara verna) and Siberian squill (Scilla siberica) were not found during the surveys. Another targeted species, garlic mustard (Alliaria petiolata), was found in only four areas.

There were clusters of hundreds of seedlings at these sites historically, but the ongoing work with volunteers has significantly reduced the number of plants and their spread.

Star-of-Bethlehem (Ornithogalum umbellatum) was found widely scattered in three places in the Wilderness.

Poison hemlock (Conium maculatum) is a biennial plant found at the trailheads.

These five spring species covered less than 10% of the Wilderness and don’t yet represent a major threat to the Wilderness but more surveys and initial control efforts are recommended by Eco Logic to keep them in check.

Japanese stiltgrass (Microstegium vimineum) is the most abundant trailside invasive species in the Wilderness. It follows trail corridors and streams. Sericea lespedeza (Lespedeza cuneata) is a legume found in several places in the wilderness, mostly young forests and openings. It is relatively shade-intolerant. Myrtle (Vinca minor) is a groundcover that has escaped in two areas associated with cemeteries.

There were several herbaceous species found but not mapped: Oriental lady’s thumb (Persicaria longiseta) is common along trails but does not seem to be spreading. Beefsteak plant (Perilla frutescens) also was found along trails but did not seem to move beyond the disturbed trail margins. Japanese honeysuckle (Lonicera japonica) is found in scattered locations, often around old settlements.

There also were invasive shrubs.

Multiflora rose (Rosa multiflora) was the most common woody invasive plant in the trail corridor by far. Dense infestations occur in early successional hardwood forests and pine. The rose is likely left from when much of the Wilderness was in pastureland. Autumn olive (Elaeagnus umbellata) is the second most common invasive shrub. Generally found in young woodlands.

Amur honeysuckle (Lonicera maackii) is still rather scarce in this Wilderness with only a few sites where it was found. In much of the Hoosier this invasive shrub is prolific. This shrub has the potential to expand rapidly so is a high priority to control. Wineberry (Rubus phoenicolasius) is a shrub with biennial canes that is becoming well established.

Japanese barberry (Berberis thunbergii) was found in isolated random locations. Burning bush (Euonymus alatus) was only found in three places in the survey. Despite its scarcity, burning bush is considered a major threat. Privet (Ligustrum vulgare) also was only found in three isolated areas.

Tree-of-heaven (Ailanthus altissima) was found in two locations along trails, but it is likely that other colonies will be found around former settlements in the Wilderness as mapping continues. No spotted lanternflies were found in the vicinity of these trees, but they will continue to be surveyed for in the future. Callery pear (Pyrus calleryana) was only noted in a couple places.

This invasive, however, is exploding in nearby Bloomington, so the area should be monitored for more pear that may seed in. Osage orange (Maclurapomifera) is mostly found in one area with a few other scattered specimens noted.

The survey noted which areas were the epicenters of spread for invasives. Observations about the correlations with pine plantings and occurrences of some invasives were made, noting that the previous agricultural land use and settlement of the area that is now the Charles C. Deam Wilderness is likely the reason for so manyinvasives there today. The trail system further provides a conduit for spread for many species whose seeds are easily tracked or moved by hikers and horses.

The partners plan to use the results of these mapping efforts toimprove management of the invasive plant species in the Wilderness.