Federal Noxious Weeds of Significance to Alaska
What is a Federal Noxious Weed?
Federal noxious weeds are plants that the U.S. Secretary of Agriculture has identified as needing regulatory action to prevent their introduction and spread within the United States. These Federal Noxious Weeds are prohibited from movement in interstate and foreign commerce without a permit. If found the Secretary of Agriculture has the authority to seize and destroy products, and establish quarantines to prevent the spread of these weeds.
The Secretary of Agriculture’s authority to seize and destroy products, and establish quarantines to prevent the spread of weeds was established through the Federal Noxious Weed Act of 1974 that “provides for control and management of nonindigenous weeds that injure or have the potential to injure the interests of agriculture or commerce, and the public health” (http://www.thecre.com/fedlaw/legal2/fedweed.htm). The act defines noxious weed as “any living stage (including seeds and reproductive parts) of a parasitic or other plant of a kind which is of foreign origin, is new to or not widely prevalent in the U.S., and can directly or indirectly injure crops, other useful plants, livestock, poultry or other interest of agriculture, including irrigation, navigation, fish and wildlife resources, or the public health” (http://www.thecre.com/fedlaw/legal2/fedweed.htm).
The act requires federal agencies to address undesirable plants that are present on federal lands, through development and funding of management programs. Agencies are instructed to establish cooperative agreements with state agencies to complete these management plans, and the agencies are instructed to coordinate programs for control, research, and educational efforts with noxious weeds.
How do we determine which Federal Noxious Weeds are significant to Alaska?
The process of determining if a weed is of concern starts with the Federal Weed Risk Assessment: “a science-based evaluation of the potential of a plant species to establish, spread, and cause harm in the United States” (Information 3/31/17). Specific guidelines are established for conducting a weed risk assessment. Once completed, weed risk assessments are made available online through the USDA APHIS website.
Since the U.S. has many different climates, not all federal noxious weeds are able to grow in all regions of the U.S.. To determine which species are able to grow in Alaska, the Alaska Center For Conservation Science performs climate screening. The climate screening determines the relative similarity of climate in areas a weed is known to grow with three ecogeographic regions of Alaska. These ecogeographic regions include Pacific Maritime, Interior Boreal, and Arctic-Alpine (Figure 1). If the species is already present in one of those ecogeographic regions of Alaska, it is presumed suitable. If the species is not present, than suitability is determined by comparing similarity to of climatic conditions of areas the species is present worldwide with the climatic conditions of representative areas of the three ecogeographic regions using the CLIMEX climate matching program (CLIMEX 1999). The climate similarity must be at least 40% to identify the species as having potential to occur in the ecogeographic region.
Black represents the Pacific Maritime, white represents the Interior-Boreal, and hatched represents the Arctic-Alpine ecogeographic regions of Alaska. The dashed grey line represents the Alaska-Canada border. Image taken from http://accs.uaa.alaska.edu/files/invasive-species/Publications/2011/Invasiveness_Ranking_of_50_Non-Native_Plant_Species_Alaska.pdf.