BULLFROG: Widespread Consequences

While native to the Central and Eastern US, bullfrogs are an invasive species in Montana.
Bullfrogs are voracious predators of our native wildlife. They can carry the chytrid fungus that
affects frogs and amphibians and contribute to the dwindling population of native frogs. A
bullfrog removal project is underway in western Montana.

EASTERN HEATH SNAIL: Accelerating Impacts

A small land-dwelling snail that feeds on a wide range of crops and will climb vegetation and
fenceposts to escape high ground temperatures. It can contaminate hay and crops, clog harvest
and processing equipment, and transmit plant and animal diseases. While most agricultural and
plant-pests are insects or pathogens/diseases, this mollusk pest highlights the need for
additional taxa to be considered for national plant pest priorities. This snail is found in Cascade

EMERALD ASH BORER*: Preventable

This beetle threatens ash trees in Montana’s urban communities, shelterbelts, and woody draws.
The larvae feed on tissue underneath the bark, killing the tree. Emerald ash borer is one of many
tree-killing beetles that can travel long distances in firewood. Preventing the transport of
firewood from out of state into Montana can slow the spread of this and other tree pests.
Emerald ash borer has infested 35 eastern states but was recently discovered in Oregon.

FERAL SWINE: Preventable

This species will impact agriculture producers through damage to crops, predation on livestock,
and as a vector to spread diseases. Their destructive behaviors affect wildlife, habitat, and water
resources. Feral swine are rampant in southern US states with no chance of eradication and
Canadian populations continue to expand unchecked. Stopping the intentional movement of
feral swine and responding to sightings are measures that keep this species out of Montana.

FLOWERING RUSH: Accelerating Impacts 

Invasive aquatic plants degrade aquatic habitats, impede water-based recreation and obstruct
irrigation canals. Flowering rush has infested Flathead Lake and downstream to the Clark Fork
River. Preventing the spread of invasive aquatic plants through cleaning watercraft and
preventing aquarium and ornamental pond releases is an important part of protecting
Montana’s waters.

RUSH SKELETONWEED: Accelerating Impacts

A deep-rooted perennial noxious weed that is very drought resistant and can easily spread from
rangeland to cropland. Impacts in rangeland include loss of forage and biodiversity. In croplands
like cereal grains and potatoes, rush skeletonweed can reduce production, quality, and hamper
harvest machinery with sticky latex sap. Rush skeletonweed is very difficult to identify in the
field and management can be laborious. It is found mostly in western Montana.

SALT CEDAR: Accelerating Impacts

This tall woody shrub establishes in riparian areas and replaces large stands of native
cottonwood and willows, reduces wildlife access, increases soil salinity, and has the potential to
take up significant amounts of water through a deep tap root. Saltcedar is a drought tolerant
species that spreads easily by wildlife and water. When it develops dense stands, it can alter
stream channels and floodplains. Saltcedar is found along the Missouri and Yellowstone rivers
and tributaries.

ZEBRA MUSSELS: Preventable

Invasive mussels can have major impacts on Montana’s waters. They disrupt the food chain and
impact recreational boating and fishing. Mussels can cause significant damage to infrastructure
by clogging pipes used for hydropower, irrigation, and water treatment plants. Zebra mussels are
established in the Dakotas and other eastern states. Preventing the spread of invasive mussels
by cleaning watercraft and equipment is a top regional priority.

VENTENATA: Accelerating Impacts

A noxious winter annual grass which can impact Montana’s native landscapes and degrade
rangelands, pastures, and crops by decreasing agricultural production and increasing the risk of
soil erosion. Ventenata has little to no forage value and its diminutive stature makes it difficult to
identify. Ventenata is found from northwestern through southcentral and southeastern Montana.