Fields full of sweet clover and bright yellow dandelions may create a beautiful sight in the Lower 48, but in Alaska, many such plants set off alarm bells. These exotics or invasive plants compete with native plants for soil, space, water and light. If they win the battle, ripple effects may include disruption of native plants, shrubs and trees and loss of wildlife habitat and food sources. Residents of Alaska's cities and towns often organize to walk along roadways and uproot exotic plants. Maps show that many interlopers follow the state's Railbelt running from Seward to Anchorage, through the Mat-su Valley and up to Fairbanks.
The National Park Service's Alaska Exotic Plant Management Team inventoried nearly 8,300 acres of National Park Service land from 2003-2008 and found 98 invasive species. While Arctic parklands revealed no non-native species, parks in Southeast Alaska, including Sitka and Wrangell-St. Elias, each had at least one exotic species infesting more than two-thirds of the area studied. The NPS found that not only parks in Southeast but those on the state's limited road system unsurprisingly had more exotic species and greater distributions than more remote parks and those farther north.
Species raising the greatest concerns include Japanese knotweed, reed canarygrass, bird vetch, yellow toadflax and perennial sowthistle, as well as Canadian thistle and meadow hawkweed. The NPS treated nearly 85 acres with mechanical or manual eradication, with success in removing stands of oxeye daisy, common burdock, bird vetch and hairy cat's ear.
Sitka National Historical Park
The team inventoried 25 acres in a historical park near this Southeast city and found the most prevalent invasive species to be creeping buttercup, European mountain ash, the common dandelion, white clover and common plantain.
Kenai Fjords National Park
The team also visited 58 acres of this national park with its massive icefield lying west and south of Seward and found dandelions, plaintains, three types of clover (yellow, white and alsike), as well as yellow toadflax, foxtail barley and oxeye daisy.
Denali National Park
An inventory of 845 acres of this remote wilderness in the shadow of Mount McKinley found 37 invasive species, including dandelions, narrowleaf hawksbeard, plantain, white sweetclover and pineapple weed.
Lake Clark National Park
The most common invasive species in this fishing paradise southwest of Anchorage include pineapple weed, common lambsquarters, dandelions, plantain and chickweed.