Observation by Mike Brubaker:
On a hike to McKinley Lake, some twenty miles east of Cordova, we were amazed to see European black slugs (some as big as sharpies) all along the trail. There were so many, we stopped counting. The devil's club and other broad-leafed plants were, in some areas, covered with slugs; entire plants reduced to stems and collapsed. I have also heard they feed on skunk cabbage. How are they getting to these remote trails and how much damage are they causing to the plants and ecosystem?
Interestingly, on the adjoining Pipeline Lake Trail, we saw no sign of slugs at all, all the way down to the road. We noticed that there is no vehicle parking at the Pipeline Lake trailhead. However, back at McKinley Lake where we parked (just 1/8 mile down the road), the trailhead was teeming with slugs. Are vehicles a mode of transmission for Arion ater? I put the question to Jason Perkins of Perkins Auto Repair in Cordova: "Do you ever see slugs on vehicles?" He said yes, that slugs are common under the vehicles. In fact, when he puts vehicles on the lift overnight, there will commonly be slime strands hanging from under the vehicle to the floor! He mentioned the range of efforts that have been tried in Cordova over the years to control and remove the slugs. However they are spreading, the fact is that they are everywhere!! We filled up a gallon bucket in minutes along Eyak Lake.
Jacquelyn Schade with Alaska Department of Natural Resources writes:
The Cooperative Agriculture Pest Survey Program is performing a mollusk survey this year and next year. A colleague and I will be surveying the Fairbanks, Anchorage, and Mat-Su areas this year and will survey the Kenai Peninsula and Kodiak areas next year. Currently, there are no management efforts in place to control the black slugs in Cordova. However, the US Forest Service is in the process of creating an Invasive Slug Action Plan for the Chugach National Forest. The Invasive Slug Action Plan began in response to the black slugs invading Cordova and surrounding areas.
Comments from LEO Editors:
Due to concerns over the spread of black slugs and other species, LEO Network has established a new project entitled "Invasive Slugs." The project is attached and LEO Members are invited to post local observations and participate in a state survey to collect samples for slugs in their areas. See the project for more information.
Resources:
Alaska Department of Fish & Game (ADF&G) – The European Black Slug is documented in the Non-Native and Invasive Animals of Alaska Report by the ADF&G as being a non-native species.
ADF&G has provided guidelines for invasive species control and prevention. These include inspecting everything that could be a "carrier of insects, plant seeds or fragments, whole or pieces of animals that can reproduce asexually, and even pathogens. Inspect and thoroughly clean whatever has come into contact with the infected landscape or waterway: shoes, clothing, pet fur, fishing boots and gear, and vessels or vehicles of any kind. For example, be sure to thoroughly clean the tires and undercarriage of cars, trucks, all-terrain vehicles, and cargo vehicles, as well as boat hulls, holding tanks, ballast tanks, anchors, and lines."
Cooperative Agricultural Pest Survey (CAPS) – What is CAPS? To confirm the presence or absence of plant pests, provide a distribution profile of plant pests in the U.S., and early detection & rapid response to exotic pest infestations. Source: Alaska Department of Natural Resources
Observations From Members