11 invasive species to watch out for in Michigan

The Michigan Department of Natural Resources has a list of invasive species in the state that residents should be aware of and report if spotted.

The Michigan DNR says: Species that are not native and also have the potential to harm human health or to harm natural, agricultural or silvicultural resources can be listed as prohibited or restricted by the State of Michigan. If a species is prohibited or restricted, it is unlawful to possess, introduce, import, sell or offer that species for sale as a live organism, except under certain circumstances.

Here are 11 Michigan invasive species to keep an eye out for:

Eurasian Collared Dove

Identification:

  • Mostly gray with white upper body
  • Black collar on the back of its neck
  • Slender black bill
  • Deep red iris of the eye
  • Broad, squared tail with black base
  • Dark red legs and feet

Habitat: Collared doves live on farmlands, open country, and wood edges in suburban and urban areas. They appear to thrive in areas with a combination of open ground and trees.

Diet: Diet consists mostly of seed and cereal grain. Some berries, plant material, and invertebrates are also consumed.

Native Range: Asia, Europe, and Northern Africa

U.S. Distribution: Established in much of the United States except the northeastern states

Local Concern: Populations spread rapidly and compete with native species. Eurasian collared doves are considered a pest in agricultural areas, especially in areas that grow grains. This species can carry West Nile Virus.

Potential Means of Introduction: Dispersal of young individuals over long distances

Emerald Ash Borer

Identification:

  • Bright, metallic green with purple abdominal segments under its wing covers
  • Length of adult beetle is approximately ½ inch
  • Can fit on the head of a penny
  • Larva are worm-like
  • Create D-shaped exit hole in the tree

Habitat: Urban, suburban, and rural forests

Diet: Adults feed on the foliage of ash trees, while the larvae tunnel and feed on the underside of the bark and cut off the transportation of nutrients and water to the tree.

Related: Officials nab seeds infested with invasive Khapra beetles at Detroit Metro Airport

Native Range: Eastern Russia, Japan, Northern China, and Korea

Local Concern: Since the first discovery in Michigan in 2002, this invasive beetle has killed tens of millions of ash trees in Michigan, both in forests and in neighborhoods. Adults typically only fly about ½ mile. On their own, this species doesn’t spread very far. The real concern with spread is the relocation of infested firewood to non-infested areas. Don’t move firewood!

Means of Introduction: The emerald ash borer most likely arrived in the United States via solid wood packing materials arriving from Asia.

Feral Swine

Identification:

  • Most often brown or black and appear hairy
  • Piglets are lighter in color and often have stripes
  • Long, straight, narrow snout relative to domestic pigs
  • Straight tail with a tuft at the end

Habitat: Commonly found in rural areas, but are adapting to suburban areas. Feral swine are land mammals that use water and dig wallows to regulate body temperature.

Native Range: Europe and Asia

Diet: Feral swine are opportunistic omnivores; they eat what they can when they can. Dietary items include crops, bird and reptile eggs, fawns and young of domestic livestock, tree seeds and seedlings, nuts, roots, and tubers.

Local Concern: Feral swine can be aggressive toward humans and can transmit several serious diseases. Feeding habits put feral swine in direct competition for resources with deer, bear, turkey, squirrel, and waterfowl. Additionally, swine use their sharp tusks to root for food and wallow in the dirt. These two activities destroy crops and native vegetation, negatively affect water quality, and can cause erosion.

Means of Introduction: Intentional release, escape from domestication

Other Names: Eurasian boar, Russian boar, wild boar, wild hog, razorback

Red Swamp Crayfish

Identification:

  • Dark red color with bright red raised spots, look like small lobsters
  • Elongated claws and bony exoskeleton
  • Elongated head with a triangular rostrum
  • 2.2 inches – 4.7 inches in length

Habitat: Red swamp crayfish live in a variety of permanent freshwater habitats. Crayfish are crustaceans that burrow deep into the substrate of their habitat and create large mounds of sand and soil called chimneys with a relatively large hole in the center.

Diet: Crayfish feed heavily on snails, fish, amphibians, and plants.

Related: Invasive red swamp crayfish found in two locations in Michigan

Native Range: Mississippi river drainage and Gulf coast

U.S. Distribution (outside of native range): Established populations in California, Delaware, Maryland, Ohio, Oregon, South Carolina, Utah, Virginia, Washington, and Wisconsin. Introduced but not established in Alaska, Hawaii, Idaho, Illinois, Indiana, Nevada, and New York.

Local Concern: Red swamp crayfish compete aggressively with native crayfish species for food and habitat. Feeding behavior reduces the amount of available habitat for amphibians, invertebrates, and juvenile fish. Burrowing and foraging behavior can also lead to summer cyanobacteria blooms and eutrophic conditions.

Other Names: Louisiana crayfish/crawfish

Potential Means of Introduction: Aquaculture/aquarium trade, classroom/laboratory release, live bait dumping, small chance of introduction through fish stocking events

Native look-alikes and how you can tell them apart from red swamp crayfish:

  • Devil crawfish: mostly tan body with red highlights around head, body, and claws
  • White river crayfish: color may vary from tan to rusty red color, no bright red bumps

Girdled Snail

Identification:

  • Shell is triangular or pyramid shaped
  • Shell size is about 6-7 mm high and 10-14 mm wide
  • Shells tend to be brown to yellow with a white band on the widest part
  • 5-6 whorls
  • Aperture (opening) of the shell is oval

Diet: Girdled snails feed on a variety of plant materials.

Habitat: Girdled snails are often found to aggregate in large numbers in gardens and on hedges.

Native Range: Mediterranean

Local Concern: Due to this species’ tendency to aggregate in large numbers and its herbivorous habits, girdled snails pose a threat to native plant communities.

Gypsy Moth

Identification:

  • Gypsy moth caterpillars emerge from tan, fuzzy egg masses in April and feed on leaves through late June.  
  • Caterpillars are hairy, with a yellow and black head and 5 pairs of blue spots, followed by 6 pairs of red spots.
  • Mature caterpillars are 1.5 to 2 inches in length.
  • Leaf debris and small, round frass found under trees are indications of gypsy moth infestation.
  • Male moths’ wings have a wavy pattern of brown to dark-brown and span 1.5 inches.
  • Female moths are larger than males and do not fly.  Wings are white to cream with wavy black markings.

Habitat:  Most often feeds on the leaves of oak and aspen but can also be found on hundreds of other plant species.

Native Range: Europe and Asia

Related: Gypsy moth outbreak poses risk to Michigan trees

U.S. Distribution: Northeastern U.S. west to Minnesota

Local Concern: Gypsy moth caterpillars defoliate trees, leaving trees vulnerable to diseases and other pests, which may lead to tree mortality.  During large outbreaks, debris and frass from feeding caterpillars can be disruptive to outdoor activities.

Pathways of Spread: Though female moths do not fly, small caterpillars can be blown by the wind to other trees.  Gypsy moth egg masses and pupae can be unknowingly transported on firewood, vehicles and recreational gear.  

Common Buckthorn

Identification:

  • Deciduous small tree or shrub – can reach 25 feet tall
  • Leaves are dark- green, oval and slightly toothed
  • In spring, small, yellow-green, 4-petaled flowers grow in clusters of 2-6 at the base of leaves
  • Small, purple to black fruits ripen in the fall
  • Twigs often have a single, sharp thorn at their tip
  • Distinctive orange inner bark

Habitat: Common buckthorn can be found in disturbed and undisturbed areas including roadsides, pastures, old fields and woodlots. 

Native Range: Europe and Asia

U. S. Distribution:  East Coast and Midwest, also in limited areas of California and Oregon.

Local Concern: This invasive plant spreads quickly through seeds distributed by birds and wildlife and crowds out native shrubs and understory plants. It is a host for alfalfa mosaic virus and crown fungus, and may be a possible host for the soybean aphid.

Black Swallow-wort

Identification:

  • An herbaceous, perennial vine growing up to 7 feet in length
  • Leaves are shiny dark-green and oval to heart-shaped with a pointed tip
  • Small, star-shaped flowers are dark purple with 5-petals and grow in clusters of 6-10 blooms
  • Seed pods are milkweed-like and full of flat, brown seeds covered in fine, white hairs

Habitat: Black swallow-wort vines thrive in both shade and sun and are found in disturbed areas along roadsides, pastures, old fields and gardens as well as alvar and along fens.

Native Range: Southwestern and Northern Europe

U.S. Distribution:  From the Atlantic coast to the Midwest and as far south as Kentucky and Missouri. Also present in Quebec and Ontario.

Local Concern: Black swallow-wort grows rapidly and can cover other vegetation. Seeds are carried on the wind or transported by water. Roots are toxic to mammals, including livestock. Plants are toxic to many insect larvae including monarch caterpillars.  

Japanese/Oriental Weatherfish

Identification:

  • Eel-like body that’s brown with greenish grey-brown marbled marking on the dorsal side and pale silver coloration on the ventral side
  • small, narrow mouth with thick and fleshy lips and six barbels
  • Body length may reach 28 centimeters, but averages are smaller
  • Sexually dimorphic, where the female is often longer than the male

Habitat: These fish are often found in shallow, low-gradient waters with muddy or silty substrates. They can survive in oxygen-poor waters and through long droughts by burrowing into soft substrates, owing to the intestine acting as an accessory respiratory organ.

Diet: Oriental weatherfish primarily consume small benthic invertebrates and detritus.

Native Range: Eastern Asia

Related: Invasive bloody red shrimp discovered in Lake Superior

U.S. Distribution: Established in Shiawassee River and lower Michigan, New Jersey, and New York, Alabama, California, Florida, Hawaii, Idaho, Illinois, Louisiana, Indiana, Oregon, and Washington; Has been collected in Tennessee, North Carolina, and Maryland.

Local Concern: Competition for aquatic insects puts native fish populations at risk. There may also be a significant reduction in macroinvertebrate abundance and an increase in turbidity and nitrogen levels of standing water.

Other Names: Japanese weatherfish, dojo, weather loach, Amur weatherfish

Rudd

Identification:

  • Deep and stocky body with green-brown back, brassy yellow sides, and near white belly
  • Lengths can reach 48 cm.
  • Pectoral, pelvic, and anal fins are bright red-orange
  • Dorsal and caudal (tail) fins are red-brown
  • Caudal fin is forked and lower lip is protruding
  • Red spot on iris of the eye

Habitat: Preference is given to stagnant and slow-flowing freshwater with a lot of vegetation, but rudd are adaptable.

Diet: Rudd are omnivorous fish. Their diet consists primarily of fish in the early spring and changes to mostly vegetation in the summer and fall.

Native Range: From Western Europe to the Caspian and Aral Sea basins

Related: Invasive sea lamprey population increases in 2 Great Lakes

U.S. Distribution: Rudd have been introduced to 20 U.S. states and has been used as a bait fish in many of the others.

Local Concern: Although the impacts of introduction are largely unknown, the rudd’s ability to shift its diet as necessary, and its tolerance of eutrophic or polluted waters gives it an advantage over native species. Another ecological impact comes from an increase in nutrients in the water due to the rudd ineffectively processing plant material.

Native look-alikes and how you can tell them apart from a rudd:

  • Golden Shiner: Unscaled ventral keel, yellow-green eyes, yellow-green fins (except in spawning adults)
  • Redfin Shiner: No ventral keel, fins typically clear except in breeding males, small dark spot at anterior base of the dorsal fin

Mute Swan

Identification:

  • Adult mute swans have orange bills
  • A black knob on the top of their bill
  • “S” curve of the neck (trumpeter swans have a “C” curve)
  • A quieter bird (trumpeter swans have a loud “trumpet” call)

Means of Introduction:

Mute swans were introduced to North America in the mid-1800s to decorate parks and estates, and later brought to Michigan in 1919. These captive swans escaped and established a feral population. With their numbers growing quickly, this non-native invasive species is causing conflicts and damage across the state.

Concern: 

One of the world’s most aggressive waterfowl species, especially while nesting and raising their young, mute swans drive out native waterfowl and other wetland wildlife with their hostile behavior. Mute swans will chase native breeding birds from their nests.

Related: How one Michigan township plans to fight 'invasion' of mute swans

A single mute swan can consume four to eight pounds of plants a day. They uproot and destroy these wetland plants that are a main food source for native birds and cover for native fish and invertebrates. Continuous feeding by a flock of mute swans can destroy an entire wetland ecosystem.

These large birds show little fear of people. Each year the DNR receives reports of mute swan attacks on people in boats and on shore.

How to report an invasive species:

Non-Watch List species should be reported using the Midwest Invasive Species Information Network (MISIN) online reporting tool or the MISIN smartphone app. Alternately, these species can be reported to the Cooperative Invasive Species Management Area for your region or your local conservation district.

Check out the full DNR database here.

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