Invasive Species

Plants, Birds, Amphibians, and Fish Species
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Exotic/Invasive Plants

Noxious Species of Concern

The most prevalent State-listed noxious weeds occurring on the Refuge's uplands include yellow toadflax, spotted knapweed, orange hawkweed, houndstongue, and Canada thistle.  

Exotic Species of Concern 

  • Reed canarygrass (Phalaris arundinacea) is native to North American and the Pacific Northwest, however, a more aggressive hybrid has been widely used as a forage grass species. Early refuge narratives mention that orchard grass and reed canarygrass were planted for cover on the dikes following wetland restoration. Currently, reed canarygrass is the most abundant invasive plant on the Refuge, forming dense monocultures in seasonally flooded wetlands, wet pastures, and the understory of open canopy riparian forests.  
  • Cattails, while native, can also become invasive. They are very prolific and can quickly dominate a wetland turning it into a monotypic cattail marsh whereby reducing the overall value of the habitat for wildlife.  Control of cattails can be achieved by cutting, crushing, or disking.
  • Eurasian watermilfoil (Myriophyllum spicatum) is an aquatic plant species which displaces native aquatic plant communities.  Watermilfoil can form thick underwater stands of tangled stems and vast mats of vegetation at the water's surface, interfering with water recreation and crowd out native water plants.  

Management Tools

Mowing, hand pulling, prescribed burns, biological control, and herbicides are used to control these invasive plant species.


Introduced Birds

Non-native game birds were introduced in order to allow sportsmen greater hunting opportunities.  The pheasant is a non-native species that was introduced on the Refuge in 1966 by Idaho Department of Fish and Game biologists. The majority of these birds were preyed upon by eagles and coyotes.  Today, ring-necked pheasants can still be found on the Refuge, typically in the grain fields.

Wild turkeys, while native to North America, are not native to Idaho but were transplanted in 1961 by the Idaho Department of Fish and Game.  The Merriam's wild turkey is the species that is distributed throughout the Idaho panhandle and a dozen or so have been observed on the Refuge.

Other non-native bird species occurring on the Refuge include the house sparrow, rock dove, European starling, and the Eurasian collared-dove.

Introduced Amphibians

Bullfrogs (Rana catesbeiana), native to the eastern United States, were introduced to the Pacific Northwest in the 1920s/1930s to be raised as food. Bullfrogs prey upon native amphibians, turtle hatchlings, and even ducklings. Bullfrog presence on the Refuge was first mentioned in the 1970 Annual Narrative Report.  No bullfrog control has been conducted on the Refuge.

Introduced Fish

There are 39 native and 28 introduced fish species in Idaho.  The majority of non-native species that have been introduced into Idaho were for sport, food, bait, and fish forage.  While many introduced species have provided increased angling opportunities they have had a detrimental effect on native stream ecosystems.  Non-native species compete for food and spawning grounds and often prey upon native species.  


Some of the most common non-native species in the Kootenai River drainage include the brook trout (Salvelinus fontinalis), largemouth bass (Micropterus salmonides), yellow perch (Perca flavescens), pumpkinseed (Lepomis gibbosus), black crappie (Pomoxis nigromaculatus), and brown bullhead (Ictalurus nebulosus).  

Facts About Invasive Species

National Invasive Species Awareness Week

February 22-28, 2015