Exotic and Invasive Species
Exotic species, also known as non-native, are organisms introduced outside their natural range. Lacking natural predators, they can spread quickly and outcompete native species. Invasive plants, animals, and microbes may disrupt ecosystems, harm economies, and threaten public health. Encroachment, on the other hand, refers to native species—often woody plants—rapidly expanding into areas where they were once uncommon. This page highlights examples of invasive and encroaching species already present in the Dakota Prairie Grasslands (DPG), as well as other species identified nearby that could pose future threats.
The Emerald Ash Borer (EAB)
Figure 1. A highly magnified direct head-on image of the Emerald Ash Borer.
The Emerald Ash Borer (EAB) is a destructive wood-boring winged beetle that feeds on and kills ash trees (Figure 1).
Although the EAB has been reported in both North and South Dakota, there are no known sightings in the Dakota Prairie Grasslands; however, it poses a threat to green ash found along rivers, streams, and woody draws across the grasslands. North Dakota is estimated to have about 90 million ash trees, the state's most abundant tree species. South Dakota's green ash population accounts for 21% of its hardwood biomass.
The most common way EAB and other wood pests spread is through the movement of infested firewood, logs, branches, and similar materials. Transporting contaminated wood allows pests to invade new areas and speeds up their spread. To prevent this, don’t move firewood. Instead, purchase firewood from local vendors within 50 miles of where it was cut, or as close as possible to your destination. If you must bring firewood, use only heat-treated, USDA or state-agency-certified wood. When permitted, collect dead and downed wood at your campsite. Never take unused firewood home—burn it all or leave it for others.
Contact the local Ranger District Office for more information or to report an EAB sighting.
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Protect Against EAB
This NDSU Extension video discusses the Emerald Ash Borer (EAB) and its potential impact.
Aquatic Invasive Species (AIS)
Aquatic Invasive Species (AIS) are non-native, water-dependent plants, animals, or pathogens introduced outside their natural range. Without natural predators or competitors in local lakes, rivers, or wetlands, these species spread rapidly, causing environmental damage, reducing biodiversity, and impacting water-based economies.
AIS Animals
Aquatic Invasive Species (AIS) animals may include non-native fish, mollusks, crustaceans, or other organisms introduced to local lakes, rivers, and wetlands (often via human activity) that spread rapidly, outcompete native species, and damage ecosystems and water-based recreation. The photo gallery below features several AIS animals found in or near the DPG ecosystems.
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AIS Plants
Aquatic Invasive Species (AIS) plants are non-native, water-dwelling flora that spread rapidly, causing ecological and economic harm by outcompeting native vegetation in lakes, wetlands, and rivers. The photo gallery below features several AIS plants found in or near the DPG ecosystems.
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Clean, drain, and dry your equipment. Always follow these simple steps to help prevent the spread of aquatic invasive species (AIS).
AIS Preventative Protocols
Follow these steps to help contain AIS:
- Clean: Remove visible plants, mud, and debris from boats, trailers, fishing gear, waders, and motors before leaving the access area.
- Drain: Pull all drain plugs and remove all water from bilge, ballast tanks, bait wells, and live wells while still on land.
- Dry: Allow all equipment to dry completely in the sun for at least 5 days before visiting a new body of water.
Encroaching Trees and Shrubs
Encroachment refers to native species—typically woody plants—rapidly spreading into areas where they were previously rare or absent. In the DPG, woody encroachment happens when native trees and shrubs expand into formerly treeless regions due to changes in ecological conditions. This shift leads to decreased forage, diminished wildlife habitat, and a higher risk of wildfires.
To address woody encroachment, the DPG employs prescribed burning and mechanical removal techniques such as cutting or mowing. These methods help restore native prairies, lower the density of encroaching woody plants, and support healthy grasslands, often through partnerships with local organizations. Examples of encroaching tree and shrub species are shared in the photo gallery below.
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Noxious Weeds
Invasive species threaten the DPG by outcompeting native plants, reducing biodiversity, and degrading habitat for wildlife and livestock. Early detection and proactive management are essential to protect this unique landscape.
North Dakota and South Dakota each have their own regulations for identifying and managing noxious weeds and invasive grasses. Dakota Prairie Grasslands collaborates with both states to support their efforts. The photo gallery below highlights invasive species found in or near the grasslands, along with state-specific resources further below.
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South Dakota Noxious Weeds
Visit the South Dakota University Extension website for information about noxious weeds in South Dakota.
North Dakota Noxious Weeds
Visit the North Dakota Department of Agriculture site for information about noxious weeds in North Dakota.