Exotic Species

Spraying exotic species.

Refuge personnel identify and manage exotic and invasive species using a variety of techniques.

  • Background

    Invasive species threaten ecosystems worldwide because of their ability to alter natural communities, patterns, and processes. Many invasive species are non-native (also referred to as exotic, non-indigenous, or alien species) and have been introduced by humans or in association with human activities. At Seney National Wildlife Refuge, many non-native plants and pathogens have been identified, and many more occur in the eastern Upper Peninsula. These species present a future threat of colonization at Seney National Wildlife Refuge.

    In a recent survey of National Wildlife Refuge managers and biologists, the majority agreed that invasive species were among the most important drivers of landscape change (Magness et al. 2012). Management should therefore strive to assess the threat invasive species have on native ecosystems and habitat structure and function and (for those species that constitute the greatest threats) an active management and monitoring program should ensue. Efficient and effective management of invasive species requires an integrated (adaptive management) approach including: 1) threat evaluation, 2) prevention, 3) treatment, and 4) evaluation and monitoring. The following Integrated Pest Management Plan (IPMP) provides guidance for the management of invasive species at Seney National Wildlife Refuge, with the goal of conserving and restoring native communities for the benefit of native wildlife species and their habitats and the public that enjoys them. The Seney National Wildlife Refuge Comprehensive Conservation Plan (CCP, 2009) and Habitat Management Plan (HMP, 2013) laid out the background, land management goals and objectives, and assessment of historical and current conditions. This plans builds on the strategies in the Habitat Management Plan for invasive species (see the Seney National Wildlife Refuge Habitat Management Plan for more background).

  • Species of Concern

    Numerous invasive species are known to be currently present at Seney National Wildlife Refuge (Table 1). In addition, many species occur in the surrounding landscape that present a potential threat for invasion and should be targets for prevention and detection (e.g., garlic mustard). Communication with conservation partners (including two Cooperative Weed Management Areas) should continue so as to inform management decisions. Nonetheless, management priority is based on current and potential threats to native ecosystems; many non-native plants at Seney National Wildlife Refuge are roadside species that do not threaten native ecosystems and pose relatively little threat of becoming invasive. Of high priority for management at Seney National Wildlife Refuge are glossy buckthorn, reed canary grass, purple loosestrife (not known to be currently present at Seney, but is on a Kirtland’s Warbler Wildlife Management Area tract in nw Clare Co.), leafy spurge, garlic mustard (not known to be currently present), multiflora rose, Tartarian honesuckle, non-native common reed or phragmites, forget-me-not, and beech bark disease complex. Priority for management at the Whitefish Point Unit of Seney National Wildlife Refuge is spotted knapweed.

  • List of Exotic Species

    Table 1: Known non-native plant and animal species of concern, management priority, and current status at Seney National Wildlife Refuge. For a list of other species found in the eastern Upper Peninsula, the user should contact colleagues in the Central and Eastern Upper Peninsula Cooperative Weed Management Areas.


    Glossy buckthornHighWidespread in Unit 1; scattered in Unit 2-3; management priority since 2003 with numerous successes/lessons learned; research has shown efficacy of treatments using 2.5% a.i. Rodeo
    Reed canary grass  HighOne main patch in Unit 1; no past management activities known
    Purple loosestrifeHighAbsent?; has shown up periodically in Unit 1 and has been extirpated using 2.5% a.i. Rodeo, status elsewhere not known, but populations are found off Manistique River Rd. to the south and on South Manistique Lake. Also a Kirtland’s Warbler Wildlife Management Area parcel in Clare Co. has been managed for this species: T20N-R5W S. 5 SE1/4
    Leafy spurgeHighSporadic populations in Units 1 and 2; sporadic management in the past using 2.5% a.i. Rodeo
    Garlic mustardHighAbsent?
    Non-native phragmitesHighSamples taken from Units 1-3 only show some small non-native patches in Unit 1; sporadic management in the past using 2.5% a.i. Rodeo has extirpated this phenotype?
    Multiflora roseMediumSporadic populations in Units 1-3; sporadic management using 2.5% a.i. Rodeo in the past with some success; plants do not seem to be thriving
    Spotted knapweedMediumWidespread throughout Unit 1-3 wherever roads exists and at Diversion Farm; does not thrive anywhere where it needs to compete for sunlight (e.g., in dense vegetation, in forests); primary management is to allow surrounding vegetation to grow and mowing (2.5% a.i. Rodeo used in dunes at Whitefish Point Unit where this species is a priority)
    Tartarian honeysuckleMediumSporadic populations in Units 1-3; at the Headquarters, Visitor Center, and along some edges of farm fields; sporadic management in the past with some success using 2.5% a.i. Rodeo; plants do not seem to be thriving
    Forget-me-notMediumChicago Farm field and Conlon Field roads only?; treatments using 2.5% a.i. Rodeo started in 2011
    Silvery cinquefoilLowPresent, unknown distribution and abundance
    TimothyLowPresent, unknown distribution and abundance
    Live-foreverLowPresent, unknown distribution and abundance
    Japanese barberryLowPresent, unknown distribution and abundance
    St. John’s wortLowPresent, unknown distribution and abundance
    Canada thistleLowPresent, unknown distribution and abundance
    Musk mallowLowPresent, unknown distribution and abundance
    Yellow sweet cloverLowPresent, unknown distribution and abundance
    Smooth bromeLowPresent, unknown distribution and abundance
    Butter-and-eggsLowPresent, unknown distribution and abundance
    Orchard grassLowPresent, unknown distribution and abundance
    Kentucky blue-grassLowPresent, unknown distribution and abundance
    CatnipLowPresent, unknown distribution and abundance
    Shepherd's purseLowPresent, unknown distribution and abundance
    RyegrassLowPresent, unknown distribution and abundance
    Queen Anne's laceLowPresent, unknown distribution and abundance
    Ox-eye daisyLowPresent, unknown distribution and abundance
    Tall buttercupLowPresent, unknown distribution and abundance
    Bladder campionLowPresent, unknown distribution and abundance
    Bird's foot trefoilLowPresent, unknown distribution and abundance
    Orange hawkweedLowPresent, unknown distribution and abundance
    Heal-allLowPresent, unknown distribution and abundance
    Yellow goat's-beardLowPresent, unknown distribution and abundance
    Field Sow-thistleLowPresent, unknown distribution and abundance
    PlantainLowPresent, unknown distribution and abundance
    Beech scaleHighBeech scale (a non-native insect) is part of the Beech Bark Disease Complex, with fungi causing mortality; scale and the complex is found in all northern hardwood stands in Units 1-4; no management known to reduce extent of the scale; forest enhancement efforts used to mitigate the effect
    European earthwormsMediumNo management actions, but reducing acreage in farm fields may help suppress populations and reducing the movement of soils may slow further spread
    Rusty crayfishLowFound in the Driggs River and seems well established in Pine Creek; no known effective management strategies exist
    Sea lampreyPriorityFound in most streams, managed by Marquette Office
    Emerald ash borerLowUnknown, minimal ash found within the Refuge with some found at Chicago Farm area.


  • Glossy Buckthorn

    Glossy Buckthorn

    Glossy buckthorn (Frangula alnus) is a small tree invading many Midwestern wetlands. It is native to Europe and Asia, and can be identified by its glossy dark green leaves and gray bark (Voss 1985). The U.S. Forest Service considers glossy buckthorn a “Category One” invasive species because it is highly invasive, invades natural habitats, and replaces native species. Where glossy buckthorn becomes established, it out-competes natural vegetation (e.g., Alnus, Betula, Prunus, Viburnum, and Salix species), can become a monoculture, and can alter ecosystem patterns and processes. When cut it resprouts vigorously from the stump. Previous studies have indicated that invasions of glossy buckthorn along wetland areas have resulted in decreased plant species diversity and altered hydrology (Devine 1999), with negative implications for wildlife habitat. Active management of glossy buckthorn is critical to minimize the spread of this species to other wetland areas, and to rehabilitate those areas presently impacted.

  • Reed Canary Grass

    Reed Canary Grass

    Reed canary grass (Phalaris arundinacea) is a perennial, cool-season grass that grows to 3-6 ft. It has single flowers that bloom in dense clusters form May to August, and are initially green and purple, turning tan as they ripen. While native North American genotypes likely exist, the Eurasian genotype has been widely introduced for hay and forage and can become an aggressive invader (HNF 2005e). Due its aggressive nature, hardiness, and rapid growth, reed canary grass can replace native wetland and wet prairie species. It grows best in disturbed areas and on wet soils and spreads by seed or rhizome. Rapid growth occurs in early spring, seeds ripen and shatter in late June, and growth declines by mid-August.

  • Purple Loosestrife

    Purple Loosestrife

    Purple loosestrife (Lythrum salicaria) is an herbaceous perennial with showy purple flowers. It was first introduced in the early 1800s. It invades wetland habitats and moist roadsides. Invaded wetlands often lose 50% of native plant biomass, particularly endangered, threatened, or declining plant species, and in extreme cases native plants can be completely outcompeted (Van Driesche 2002). It is associated with disturbance and can be transported by water, wind, animals, and humans.

  • Leafy Spurge

    Leafy Spurge

    Leafy spurge (Euphorbia esula) is a perennial herb with small, greenish-yellow flowers. Native to Europe and Asia, it was brought to the United States in the late 1890s in impure seed. It is most aggressive in dry soils, but can survive in moist soils as well. It invades fields, grasslands, roadsides, and woodlands. It displaces native vegetation and can produce plant toxins that prevent the growth of other plants. The stems and leaves contain a latex that is toxic to most grazing mammals and can irritate the skin of animals and humans if touched.

  • Garlic Mustard

    Garlic Mustard

    Garlic mustard (Alliaria petiolata) is a biennial herb with heart-shaped, coarsely toothed leaves, white flowers, and seeds in slender pods. Native to northern Europe, it was first documented in the United States in 1868. It is now widely distributed across the eastern and central United States, invading woodlands, roadsides, and urban areas. It is promoted by disturbances, and where established, can dominate eliminating native vegetation.

  • Common Reed

    Common Reed

    Common reed (Phragmites australis) is tall wetland grass. Some genotypes are native, but the aggressive invaders are those of non-native origin. It is found in wetlands as well as along the edges of ponds, lakes, and streams, and along roadsides in drainage ditches. It is a strong competitor and often crowds out other plants. The rapid expansion of populations may be associated with disturbance or environmental stress.

  • Mulitflora Rose

    Multiflora Rose

    Multiflora rose (Rosa multiflora) is a perennial shrub from the rose family. Native to eastern Asia, it was introduced for use as a living fence and for wildlife food and cover. It is identified by its arching canes and clusters of flowers ranging in color from white to pink. It can invade woodlands, fields, roadsides, and some wetland habitats. As it grows, it crowds out native plants and can create an impenetrable wall. It is commonly associated with disturbed areas, but due to its tolerance for a variety of conditions, as well as its production of up to a million seeds per year, it spreads easily.

  • Spotted Knapweed

    Spotted Knapweed

    Spotted knapweed (Centaurea maculosa) is a perennial herb native to Eastern Europe. It invades grasslands, woodlands, roadsides, and open sites. It is most competitive in dry sunny sites. Spotted knapweed blooms in July and August and produces seed shortly after.  In addition, it produces an allelopathic compound that reduces the growth of other surrounding plants, facilitating its ability to crowd out native plants and create monotypic stands. Grazing animals will not eat it, but will instead feed on the native plants reducing their presence further. It has also been found to degrade soil over time by removing much of the moisture and nutrients.

  • Tartarian Honeysuckle

    Tartarian Honeysuckle

    Tartarian honeysuckle (Lonicera tatarica) is a deciduous shrub identified by its egg-shaped leaves, white to pink flowers, and presence of a hollow stem. Native to Eurasia, it was first collected in the Midwest in the 1890s. It can be found in woodlands, open areas, and roadsides. Some species can also be found in wetland habitats. Honeysuckle competes with native plants by decreasing light, moisture, and nutrient availability. It can release a toxic chemical that prevents other plant growth.

  • Forget-me-not


    Forget-me-not (Myosotis spp., right) is a perennial herb with small blue flowers with yellow centers.  It is a common invader of roadsides and forest openings; however it can also establish within intact forests.  It can become dominant and spread rapidly, decreasing native plant abundance and diversity.  Seeds are easily carried by vehicles, humans, and animals, expanding its current distribution.

  • Beech Bark Disease

    Beech bark disease (BBD) is a serious threat to the American beech tree and northern hardwood forests. This disease is caused by an interaction of the exotic sap-feeding beech scale insect (Cryptococcus fagi) and at least three species of Nectria fungi. Beech scale was first introduced to North America from Europe sometime around 1890. By the 1930s, the scale was found in Maine and the Maritime Provinces of eastern Canada. Other areas of New England and New York were found to have the scale in their forests by the 1960s. By 1975, the scale was in northeastern Pennsylvania. Presently, it is also found in West Virginia, Virginia, North Carolina, Tennessee, Ohio, Ontario, and Michigan. Although the disease has likely been in Michigan for quite some time, it was not until 2000-2001 that beech bark disease was reported in nine counties in Michigan’s northern Lower Peninsula and the Upper Peninsula counties of Luce, Chippewa, Alger, and Delta.  Beech bark disease can cause reduced leaf size, discolored foliage, dieback, reduced tree growth, reduced mast, and tree mortality.

  • European Earthworms

    European earthworms (family Lumbricidae) were likely introduced with the arrival of early European settlers, and have since been spread widely for use in agriculture and composting. They are now invading natural areas in the northern Great Lakes previously devoid of native earthworms (Shartell et al. 2012). Their presence in forested landscapes has been linked to detrimental changes in understory plant biodiversity, community composition, forest floors and soils, and ecosystem processes, deterring restoration and preservation efforts. Studies in similar forest ecosystems elsewhere in the Lake States have suggested that exotic earthworms may have numerous deleterious effects on northern hardwood communities, including ground-nesting songbirds (Loss and Blair 2011). No methods for removal of earthworms exist thus far, however prevention of introduction and spread is essential to maintaining earthworm free conditions in forests currently lacking earthworms.

  • Objective

    Seney National Wildlife Refuge's Habitat Management Plan presents the following objective for invasive species management:
    “By 2020, reduce the area infested with target invasive plant species by 50% from the documented 2007 level and eliminate new infestations of these and other highly invasive species as they occur.”

    Figure 1. Initial mapping of glossy buckthorn in 1999 indicated that the infestation was densely concentrated around the Headquarters and Visitor Center (Petrella et al. 1999).   

    This objective was set based on what then was known to be the current distribution and abundance of invasive plants (Figure 1). Since then, more surveys (some systematic, see Figure 2, and some not systemic) have been conducted to document the current range and distribution of species. And other studies and surveys too have been used to find where invasive plants (or non-native species, Shartell et al. 2012) may be found. For instance, in the forest rapid ecological assessment of Corace et al. (2011) virtually no invasive plants were recorded in any forest plots (112 plots), nor were any recorded in the work of Bork et al. (2013) or Cohen and Slaughter (2007). All told, the combination of evidence suggest that our current knowledge of the invasive plant community at Seney National Wildlife Refuge should be considered fair to good (see Figure 3, below).

    Consequently, we suggest that the measure of success for management could be found in the efficacy of treatments (e.g., Nagel et al. 2008; Corace et al. 2008; DiAllesandro 2012) and the amount of effort needed to treat sites repeatedly. For instance, since 2002 the effort to treat dikes of Unit 1 pools (including the Wildlife Drive and the Fishing Loop) has been reduced substantially as a result of the efficacy of treatments.

  • History of Management

    Glossy Buckthorn

    At Seney National Wildlife Refuge, glossy buckthorn is the main invasive plant species managed. Glossy buckthorn has invaded both anthropogenic and native wetland habitats, and is assumed to have similar negative effects as shown in similar wetlands in Michigan including lower soil pH, fewer vegetative hummocks, less light availability, lower plant coefficient of conservation, less total plant cover, and lower graminoid dominance (Fiedler and Landis 2012). 

    Glossy buckthorn was first mapped at the refuge in 1999, at which time it was noted that the infestation was densely concentrated around the refuge Headquarters and Visitor Center (Petrella et al. 1999; Figure 1, above). Treatment of glossy buckthorn began in 2001 and has occurred regularly since that time, focusing on Unit 1 where most infestations still occur. Highest densities of glossy buckthorn exist in the northeast portion of Unit 1 and decrease moving south and west into the refuge. Mapping of glossy buckthorn in 2007 within pools of Unit 1 shows this pattern of occurrence density (Figure 2).

    Figure 2. The 2007 distribution of glossy buckthorn on islands within Unit 1. The pattern of density follows that within Unit 1 overall, namely that higher densities are found to the north and lower densities to the south.

    Initial treatment of glossy buckthorn consisted of cutting and stump application of 20% a.i. glyphosate, as well as spraying 5% a.i. glyphosate on seedlings and smaller stems. Nagel et al. (2008) studied the efficacy of different management methods on reducing the amount and distribution of glossy buckthorn at the Refuge. Stump application of 20% a.i. glyphosate alone proved ineffective one year after treatment, with no difference in sprout density between this concentration of herbicide applied by sponge application, scorching with the flame of a propane torch, or untreated controls. Additional low-volume broadcast application of 5% a.i. glyphosate to resprouts the following year significantly reduced sprout density as compared to scorching and controls, with no difference between scorch treatments and the controls. 

    Low-volume spraying of the herbicide to extirpate seedlings reduced the number of stems by 96% and 91% one and two years following treatment. There was no difference in seedling density between scorching treatments and the controls. Follow-up work by Corace et al. (2008) and DiAllesandro (2012) showed that 2.5% a.i. Rodeo or Garlon were also effective and suggested that using both herbicides may reduce the potential of herbicide tolerance while still dealing with problems of efficacy noted by others (e.g., Dornbos and Pruim 2012)

    Other Species of Concern

    Included in the 1999 assessment of invasive plants at Seney NWR was spotted knapweed, multiflora rose, tartarian honeysuckle, leafy spurge, purple loosestrife, and reed canary grass (Petrella et al. 1999). Spotted knapweed was found to exist along most roads within the Refuge and within Walsh and Diversion Farms (Petrella et al. 1999). Management for this species has been to allow surrounding vegetation to grow, thereby shading out current populations or treatment by mowing along roadsides. Refuge annual narratives indicate that both multiflora rose and tartarian honeysuckle were planted in Unit 1 between 1937-1943 along ditches, roadsides, and dikes and as habitat and food for wildlife. Scattered plants can be found at locations in Units 1-3, and since 2004 have been treated with use of herbicide application (2.5-5.0% a.i. Rodeo). Multiple year treatments have been necessary in some cases, however herbicide application has been successful. Leafy spurge was found to occur at two isolated locations on the refuge in 1999, the J-I Spillway and on Marsh Creek Road south of T-2 West pool (Petrella et al. 1999). Other infestations have since been identified, typically associated with bridges or other structures where introduction may have occurred through contaminated fill. Known populations have been treated with herbicide (2.5-5.0% a.i. Rodeo) with unknown success. Small populations of purple loosestrife on lands adjacent to Seney NWR have been identified and a few plants have shown up on the Refuge in the past. These have been treated successfully with herbicide application (2.5-5.0% a.i. Rodeo) to prevent further spread. Reed canary grass was identified at the refuge in one location between J-1 and G-1 pools (Petrella et al. 1999). No treatment has been applied. In the past, non-native phragmites has been identified in Unit 1 and treated successfully using herbicide application (2.5-5.0% a.i. Rodeo). Recently it was determined that most phragmites present at the refuge are native genotypes (Corace and DiAllesandro 2011), however a non-native population was identified at C-1 Pool and treated with 2.5% a.i. Rodeo. Other non-native populations have been identified at Harbor Island NWR and (likely) Michigan Islands NWR. Forget-me-not was identified at Chicago Farm and Conlon Farm and treated beginning in 2011 using herbicide (2.5% a.i. Rodeo), with some success.

  • Current Conditions

    Current known extent of invasion across the Refuge is mapped for forget-me-not, glossy buckthorn, leafy spurge, multiflora rose, and reed canary grass, as well as for purple loosestrife occurring outside of the refuge boundary (Figure 3, below). Most of the invasive species of priority are found in Unit 1 where the hydrology is most altered and the most developed land (pools, roads, buildings) and vehicle traffic exist. Refuge forests, however, are almost completely devoid of invasive plants (Corace et al. 2011), but hardwood forests do have issues with non-native pathogens and animals (Shartell et al. 2012). In Units 2-4, invasive species are relatively uncommon (Cohen and Slaughter 2007; Bork et al. 2013). Nonetheless, more invasive species are expected to arrive in the future. For example, garlic mustard has not been identified at Seney National Wildlife Refuge, but known populations exist in the surrounding area such as at Pictured Rocks National Lakeshore located north of Seney National Wildlife Refuge. Although invasive animals are less of a problem at Seney National Wildlife Refuge, recent studies have documented the distribution, abundance, and potential effects of non-native earthworms within forests at the refuge (Shartell 2012; Shartell et al. 2012). Population sizes are relatively small, although some severely impacted stands exist, particularly where agriculture is adjacent such as at Conlon Farm. In addition, beech scale is found in all northern hardwood stands in Units 1-4. 

    Figure 3. (see text for more detail). Locations are based on surveys, treatment data, and miscellaneous observations and other published and unpublished documents. Some species (e.g. leafy spurge, multiflora rose, purple loosestrife) are scattered within indicated areas, rather than covering the full area. Tartarian honeysuckle, not shown, occurs in isolated small patches at the Headquarters, Visitor Center, and along some edges of farm fields (i.e., Conlon, Smith, Sub-Headquarters). Also not shown is a patch of leafy spurge near the C-3 Pool gate, I-J Spillway, and along Robinson Rd. near the gravel piles at Sub-Headquarters. Finally, recent evidence suggests that glossy buckthorn can be more accurately thought to be ~1/4 mi further west and is found from Pine Creek Rd., then east. Shapefiles of these data were given to the Midwest Invasive Species Network (MISN). Mixed colors mean that more than one invasive plant is found in that location. 

  • Prevention

    To prevent the introduction and further spread of invasive species, vehicle and equipment cleaning will be a priority. All vehicles entering the refuge (non-public access) during the growing season will be required to be cleaned both outside and inside. Vehicle and other equipment cleaning will be required for all Special Use Permits. Current washdown procedures are as follows:


    Vehicle Washdown Guidelines July 2012


    Limiting the establishment of invasive plants is a priority for refuge management per the 2009 Comprehensive Conservation Plan. Roads and vehicles are major factors in the spread of invasive plants. Access behind locked gates is deemed a privilege and usually requires a Special Use Permit. Through inventory data and exchanges with other colleagues, the refuge is generally aware of those invasive plants found at the refuge and on nearby lands.

    The following are guidelines for the washdown of all vehicles using refuge roads other than the Wildlife Drive and the Fishing Loop (Unit 1). The goal of these guidelines is to reduce the likelihood of invasive plants becoming established at the refuge; our objectives include removing seeds and soils from vehicles before they enter the refuge. In most instances, these guidelines will be a part of a Special Use Permit or an addendum to the same. Oversight for making sure all heavy equipment coming to the refuge is clean is the responsibility of the program associated with that heavy equipment.

    1. Any vehicle that has been off of paved roads in the eastern U.P. counties of Alger, Delta, Schoolcraft, Luce, Mackinac, and Chippewa or any vehicle coming from anywhere else is expected to be thoroughtly washed (inside and out) prior to arrival at Seney.

    2. If the above is not practical, a washdown facility has been established directly adjacent to fuel tanks at the shop area. A small shed attached to the backside of the fuel house contains a vacuum, and a water hose is located nearby. This facility is available at any time, day or night.

    3. Vehicles must be sprayed (only) with water on the exterior and have their interior vacuumed before going behind locked gates.

    4. Consideration should be given to thoroughly washing around the vehicle wheel wells and vacuuming the inside floor mats, etc. The engine compartment is NOT to be washed due to oils and other materials that could be freed; the use of any soap is likewise not allowed. The washdown is meant to function as a physical treatment for seed removal.

    5. The entire exterior washdown should take between 15 and 30 minutes and should remove the vast majority of visible soil, etc. The vacuuming should take another 15 minutes or so.

    6. This procedure need not be done daily, but should be done to meet the requirements of #1, above.

    Large refuge equipment (mowers, etc.) should be washed off when moved from Unit 1 (where most infestations exist) to other units.

  • Treatment

    Most active management of invasive species should occur in Units 1-3, with increasing emphasis on reducing the extent of invasive species in Unit 1 and preventing establishment in Units 2-4. Consideration should be made for potential management options in Unit 4 (Wilderness Area) if necessary (see Cohen and Slaughter 2007).

    Management methods include biological (natural enemies, shading), mechanical (pulling, cutting, mowing), chemical (herbicide), and fire (natural or prescribed burning, scorching). When possible, biological or passive management are preferred. For instance, many roadside invasive plants are shade intolerant; allowing neighboring vegetation to grow taller and provide shade can be an effective (and cheap) management strategy. In cases where biological management techniques are not available, chemical, mechanical, and prescribed fire strategies should be used to manage infestations. Proper timing of treatment application is also critical to the success of or management and the protection of non-target species.
    At Seney National Wildlife Refuge, herbicide application is a common treatment method, and the herbicide regularly used (with some efficacy quantified) is Rodeo (chemical name glyphosate). Rodeo is a water soluble, non-selective herbicide that is approved for aquatic environments. Application can be foliar spray, cut stump, or basal bark. In all herbicide applications care should be taken to limit application on non-target vegetation, as well as overspray into water bodies. To limit negative impacts, the lowest effective concentration of herbicide should be used. For example, a test of differing concentrations of glyphosate (Rodeo) in managing glossy buckthorn found that a 1.25% concentration was effective at killing re-sprouts, when commonly concentrations of 5% have been used (Corace et al. 2008). Presently, Seney National Wildlife Refuge staff use a ~2.5% solution of Rodeo (and some 2.5% or Garlon). In addition, herbicide application should not take place in windy or rainy conditions. The following are recommendations for management and appropriate timing for those species of concern at Seney National Wildlife Refuge.

    Glossy Buckthorn

    Current management methods (mainly application of 2.5% a.i. Rodeo or Garlon to foliage) have showed success and should be continued, with most work occurring in the late summer and early fall (late July through September) when the plant is most easily identifiable and treatments are the most successful. In sensitive areas, herbicide application should be done in fall or winter rather, as this further limits non-target injury to surrounding vegetation (HNF 2005a). In addition to the use of Rodeo, recent studies have shown that low concentration Garlon (chemical name triclopyr) can be effective for managing glossy buckthorn seedlings and re-sprouts (DiAllesandro 2012). The use of multiple herbicides may provide benefit if herbicide resistance were to develop in glossy buckthorn (DiAllesandro 2012).

    Reed Canary Grass

    Recommended methods of management for reed canary grass include application of herbicide, mechanical removal by repeated mowing, or burning (HNF 2005e). Use of herbicide should take place in late summer or early fall as this is when the plant is actively transporting nutrients to the roots (HNF 2005e). This timing or an early spring application can also help to limit non-target injury (HNF 2005e). Combining herbicide with mowing or burning treatments may increase success (HNF 2005e).

    Purple Loosestrife

    Because purple loosestrife is rare within and surrounding the Refuge effort should be taken to identify new invasions early. Small populations, when identified, should be spot treated with application of herbicide (2.5% a.i. Rodeo) to prevent further spread (such as the tract in nw Clare Co., Kirtland’s Warbler Wildlife Management Area). Herbicide application is most effective after peak bloom (typically late August, HNF 2005d). Large populations of purple loosestrife are often managed with success using biological control (HNF 2005d), and this method should be considered if purple loosestrife becomes well established at the Refuge.

    Leafy Spurge

    Known populations should be treated with herbicide (2.5% a.i. Rodeo or Garlon) every year and monitored until eradicated. Glyphosate application is most effective during mid-summer (June-July), however the risk for undesired effects on non-target plants is greatest during this time (HNF 2005c). A second application of herbicide is recommended in fall before frost (HNF 2005c).

    Garlic Mustard

    Garlic mustard can be an aggressive invader once established; therefore efforts should be taken to identify populations early. Common habitats that should be monitored include roadsides, disturbed sites, and hardwood forests . Shartell et al. (2011) predicted that the highest risk areas for establishment of garlic mustard were located in the southeast portion of the refuge, particularly in hardwood forests in this area and along Manistique River Road (Figure 4). Early detection efforts for garlic mustard should focus on these areas of high risk. Where found, garlic mustard adults should be pulled by hand, preferably before seed set (typically July) and removed from the site in garbage bags (HNF 2005b). First year rosettes and large dense populations should be treated with herbicide (2.5% a.i. Rodeo or Garlon). Herbicide application should be applied in fall to avoid injury to non-target vegetation (HNF 2005b). Follow-up treatments are necessary each year to ensure exhaustion of the seed bank (HNF 2005b). 

    Figure 4. Predicted risk of garlic mustard establishment at Seney National Wildlife Refuge (Shartell et al. 2011). Detection efforts for new invasions should focus on areas at risk for garlic mustard.

    Common Reed

    When identified, non-native phragmites should be treated using herbicide (2.5% a.i. Rodeo or Garlon) and treated areas should be monitored to ensure eradication. The recently identified non-native population at C Pool should be revisited yearly and retreated when necessary. Herbicide application should take place after plants have formed tassels (typically August to September), as this is when translocation into roots is most active (Marks 1986).

    Multiflora Rose

    Where large individual plants exist surrounding the Headquarters and Visitor Center and elsewhere in Unit 1, cutting and removal is recommended. Smaller roadside infestations (along north end of Driggs River Rd.) can be treated using mowing and herbicide. In other areas, treat with use of herbicide application (2.5% a.i. Rodeo or Garlon) applied when foliage is present (i.e. at A-1 Pool, along Driggs River Road near Diversion Farm, at G-D spillway, and at I-G spillway). Follow-up at past treatment is necessary sites to ensure success.

    Spotted Knapweed

    Where possible, passive management should be used at Seney National Wildlife Refuge. This will allow surrounding vegetation to grow, thus shading out spotted knapweed. At the Whitefish Point Unit, treat with herbicide (2.5% a.i. Rodeo or Garlon) during early August. When present along roadsides, mowing before plants seed (typically in late July and August) is recommended to prevent further spread.

    Tartarian Honeysuckle

    Where large individual plants exist surrounding the Headquarters and Visitor Center and in Unit 1 treat by cutting and revisit with herbicide application if necessary. In other cases herbicide application (2.5% a.i. Rodeo or Garlon) can be used when foliage is present.


    Little research has been done to assess management methods for forget-me-not. Identification and treatment is easiest in early summer (May-June). Small populations can be pulled by hand. Where present along roadsides or within fields mowing can be used for management. Other populations (Chicago Farm Rd.) can be treated with use of herbicide application (2.5% a.i. Rodeo or Garlon).

    Beech Bark Disease

    There is no management known to reduce or remove beech scale, however forest management efforts should be focused to mitigate impacts, such as promoting other species in areas where beech is expected to be lost. It is suggested that beech may show some resistance to beech bark disease (Koch et al. 2011), so unaffected trees should be retained as potential sources of seed.

    European Earthworms

    No known management exists for removing earthworms; however prevention of further spread should be implemented by reducing vehicle and soil movement between sites and restricting the dumping of earthworms when used as fishing bait. Reducing the extent of remnant and existing agricultural fields may help suppress earthworm populations.

  • Invasive Plant Management

    Table 2: Invasive plant management actions by month. A schedule for early detection should also be devised based on plant phenology, but is not done here due to limited staff time and lack of available resources.


    Management Action and Plant Species
    AprilMayJuneJulyAug. Sept.Oct.
    PlanningX     X
    Forget-me-not (spraying) XX    
    Leafy Spurge (spraying) XXX   
    Glossy Buckthorn (spraying)   XXX 
    Multiflora Rose (spraying)   XXX 
    Tartarian Honesuckle (spraying)   XXX 
    Purple Loosestrife (spraying)   XX  
    Spotted Knapweed (herbicide at Whitefish Point)    XX 
    General Roadside Species (mowing)  XX   
    Reporting      X


  • Evaluation and Monitoring

    Currently, the Refuge maintains an Excel dbase that describe the general location of treatments and the amount of herbicide used each day. In 2012 the refuge worked with colleagues in the Midwest to evaluate a related database and changes to what treatment data are recorded occurred (see data form in Appendix). This information is used to create maps of species on the refuge and for the Pesticide Use Proposal (PUP) dbase. 

    With current funding levels, we suggest that the measure of success could be found in the efficacy of treatments (e.g., Nagel et al. 2008; Corace et al. 2008; DiAllesandro 2012) and the amount of effort needed to treat the same site over multiple years. For instance, since 2002 the effort to treat dikes of Unit 1 pools has been reduced substantially as a result of the efficacy of treatments.

  • Literature Cited and Other References


    Bork, S.P., T.G. Pypker, R.G. Corace III, R.A. Chimner, A.L. Maclean and J.A. Hribjlan. 2013. A case study in large-scale wetland restoration at Seney National Wildlife Refuge, Upper Michigan, USA.American Midland Naturalist 169:286-302.

    Corace, R.G. III, K.P. Leister and B. Brosnan. 2008. Efficacy of different glyphosate concentrations in managing glossy buckthorn (Frangula alnus L.) resprouts at Seney National Wildlife Refuge, Upper Michigan.Ecological Restoration 26:111-112.

    Corace, R.G. III, H.A. Petrillo and L.M. Shartell. 2011. Rapid Ecological Assessment of Forests and Associated Exotic Earthworms in the Laurentian Mixed Forest-Great Lakes Coastal Biological Network, Midwest Region, National Wildlife Refuge System, US Fish & Wildlife Service, Summary Tables and Figures: Seney National Wildlife Refuge. 

    DiAllesandro, A. 2012. An assessment of foliar application of triclopyr of varying concentrations for managing glossy buckthorn (Rhamnus frangula) seedlings and resprouts (Michigan).Ecological Restoration 30:18-19.

    Dornbos, D.L. Jr. and R. Pruim. 2012. Moist soil reduce the effectiveness of glyphosate on cut stumps of buckthorn. Natural Areas Journal 32:240-246.

    Fiedler, A.K. and D.A. Landis. 2012. Biotic and abiotic condition in Michigan prairie fen invaded by glossy buckthorn (Frangula alnus). Natural Areas Journal 32:41-53.

    Hiawatha National Forest. 2005a. Non-Native Invasive Plants Species Invasiveness Rank Form: Common and Glossy Buckthorn (Rhamnus cathartica and Frangula alnus). U.S. Forest Service, Marquette, MI.

    Hiawatha National Forest. 2005b. Non-Native Invasive Plants Species Invasiveness Rank Form: Garlic Mustard (Alliaria petiolata). U.S. Forest Service, Marquette, MI.

    Hiawatha National Forest. 2005c. Non-Native Invasive Plants Species Invasiveness Rank Form: Leafy Spurge (Euphorbia esula). U.S. Forest Service, Marquette, MI.

    Hiawatha National Forest. 2005d. Non-Native Invasive Plants Species Invasiveness Rank Form: Purple Loosestrife (Lythrum salicaria). U.S. Forest Service, Marquette, MI.

    Hiawatha National Forest. 2005e. Non-Native Invasive Plants Species Invasiveness Rank Form: Reed Canary Grass (Phalaris arundinacea L.). U.S. Forest Service, Marquette, MI.

    Koch, J.L., M.E. Mason and D.W. Carey. 2011. A management strategy for beech bark disease: exploiting native resistance. Proceedings of the 22nd U.S. Department of Agriculture Interagency Research Forum on Invasive Species.

    Marks, M. 1986. TNC Element stewardship abstract of Phragmites australis. The Nature Conservancy, Arlington, VA.

    Nagel, L.M., R.G., Corace III and A.J. Storer. 2008. An experimental approach to testing the efficacy of management treatments for glossy buckthorn (Frangula alnus) at Seney National Wildlife Refuge, Upper Michigan.Ecological Restoration 26:136-142. 

    Nowacki, G.J. and M.D. Abrams. 2008. The demise of fire and “mesophication” of forests of the eastern United States. BioScience 58:123-138.

    Petrella, S., N. Shutt and D. McNeill. 1999. Invasive exotic plant inventory. Seney National Wildlife Refuge. Seney, MI.

    Shartell, L.M., L.M. Nagel and A.J. Storer. 2011. Multi-criteria risk model for garlic mustard (Alliaria petiolata) in Michigan’s Upper Peninsula.American Midland Naturalist 165:116-127.

    Shartell, L.M. 2012. Invasion patterns of emerald ash borer and European earthworms in forested ecosystems. Michigan Technological University, Houghton, MI. (Ph.D. Dissertation)

    Shartell, L.M., R.G. Corace III and A.J. Storer. 2012. Exotic earthworm communities within upland deciduous forests of National Wildlife Refuges in the Upper Midwest.Journal of Fish and Wildlife Management 3:332-340.

    Van Driesche, R. 2002. Introduction. In Van Driesche, R. Biological Control of Invasive Plants in the Eastern United States. USDA Forest Service Publication FHTET-2002-04.