Alaskans rely on our abundant natural resources for food, culture, fun and work. But our natural resources are increasingly threatened by invasive species. Defined as non-native species that can cause economic or environmental harm or harm to human, animal, or plant health, invasive species can cause significant economic losses and are considered the second greatest threat to biodiversity after habitat loss worldwide.
Gov. Dunleavy proclaimed June 11-17 as Alaska Invasive Species Awareness Week to celebrate the work that is being done to keep Alaska wild and free of invasive species.
The most problematic invasive species move from human-disturbed areas — yards, cities, industrial sites, roadways, etc. — into pristine areas where they crowd out native species and disrupt ecosystem processes. We are facing a biological wildfire of spreading invasive species, but we can still protect our treasured natural areas and resources if we respond decisively, as we would to a wildfire.
In Anchorage and other communities, we are seeing expanding pockets of natural forests that have become 100% infested with invasive chokecherry, also called mayday or European bird cherry. This happens when the invasive tree crowds out all native trees, shrubs, berries, and grasses. Chokecherry can poison moose and its monocultures along salmon streams may lead to reduced food availability for juvenile salmon. The invasive plants orange hawkweed and creeping thistle are allelopathic, meaning they release chemicals into the soil that prevent other plants from growing, allowing them to completely take over.
The process of invasive species control is just like wildfire management. First, we seek prevention. If that fails, we aim for early detection and rapid response, followed by containment, and finally to extinguish the invasive species. The framework that Alaska state, federal, and conservation groups use for responding to invasive species is Integrated Pest Management, or IPM. IPM starts with prevention — stopping the introduction of new invasive species and taking steps to avoid spreading existing invasive species to natural areas. Every Alaskan has a role to play here! The next IPM tools are manual and mechanical controls, which includes hand-pulling, mowing, tarping and burying. These important tools can work on a small scale, such as a residential yard, but are not effective or realistic for hard-to-control invasive species threatening Alaska-sized natural areas. For example, cutting chokecherry trees or hand-pulling orange hawkweed causes them to grow back thicker. When other tactics will not work, we are left with herbicides, which are an essential tool for conservation managers to protect natural areas from harmful invasive plant species.
In recent years, misinformation has spread among the public about the use of herbicides to control invasive species. When used properly, herbicides are a low-risk and effective tool for invasive plant management. They must be carefully and thoughtfully applied to avoid damage to non-target species and to protect the health and safety of the user, the public and the environment. Alaska resource managers conduct invasive plant control like a surgeon with a scalpel, using all the tools in the IPM toolbox. This includes directly applying herbicides to target invasive plants so the native plants and ecosystems can recover. For objective, science-based information about pesticide safety, the public can contact the National Pesticide Information Center at Oregon State University.
Invasive species are a biological wildfire that threaten to severely damage the natural resources that Alaskans cherish and rely upon. Alaska is about a half-century behind the lower 48 states when it comes to the rate of invasive plant incursion, and the time to act is now. It is important to balance the serious threats posed by invasive species with careful use of herbicide controls. When prevention fails, Alaska resource managers need all the tools available to respond effectively to invasions.
For more information about invasive species and how you can help, visit www.alaskainvasives.org
Tim Stallard is an invasive species manager and consultant with Alien Species Control, LLC and Chair of the interagency Anchorage Cooperative Invasive Species Management Area. Danielle Verna is Chair of the Alaska Invasive Species Partnership. Gino Graziano is an Invasive Plant Educator with the UAF Cooperative Extension Service. Anne Billman is an ecologist and volunteer Secretary of the Board of Supervisors, Anchorage Soil and Water Conservation District.
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