Great Lakes Worm Watch Our Mission is to: Increase scientific literacy and public understanding of the role of exotic species in ecosystems change. Provide the tools and resources for citizens to actively contribute in documenting the distributions of exotic earthworms and their impacts across the region. Train educators and other community leaders to help build understanding of the methods and results of scientific research about exotic earthworms and forest ecosystems ecology.

Earthworm Sampling & Identification You can sample earthworms using a liquid mustard solution that irritates the earthworm’s skin. They come to the surface where you can collect them for identification! The recipe is 40 grams (~1/3 rd cup) of ground yellow mustard powder to 4 liters (~1 gallon) of water. One jug of solution will sample an area 35 cm x 35 cm (~1 square foot). To learn how to sample earthworms using a mustard solution, and other earthworm sampling methods, visiting our website. The feeding and burrowing behaviors of different earthworm species affects the impacts they have on ecosystems. The Ecological Group of different earthworm species can be identified by their color and size, when you have adult earthworms. The swollen band on an earthworm, called the clitellum, tells you it is an adult earthworm! You can find out more and download this guide to earthworm ecological groups from our website. Earthworm Ecological Groups Illustrated guide to exotic earthworms found in the Great Lakes Region Above are some examples of the exquisite photographic and line illustrations included in the key. All the details of earthworm anatomy used for identification. A dichotomous key will lead you to the identification of 16 species, which are further illustrated in their own detailed species description. Books retail for $12.95, $10.00 each for 10 or more books You can download order forms from our website:

Impacts of Exotic Earthworms Sugar maple forests before earthworm invasion (left) usually have high diversity of native understory plants and tree seedlings with total understory plant cover of %. However, after earthworm invasion (right) these forests often experience dramatic declines in plant species diversity and tree seedling regeneration with total understory plant cover below 25%. Before earthworm invasion (left), the forest floor, composed of slowly decomposing leaves & twigs, can be very thick. Plants have most of their roots in the forest floor because nutrient cycling occurs there. After earthworm invasion (right), the forest floor can be rapidly eliminated as earthworms consume it and mixed it into the mineral soil below. The result is a thick layer of black “topsoil”. Native forest plants and tree seedlings often do poorly in these altered soil conditions because the soil is more compacted and nutrient availability declines as a result if increased erosion and leaching losses. In earthworm-free hardwood forests of the Great Lakes region (left), the understory plant community is typically composed of a diverse array of wildflowers, ferns, orchids and tree seedlings. However, after earthworm invasion (right), many sites have more exposed bare soil than plants, with only a few remaining plant species. After multiple decades of earthworm invasion, forest understories can become dominated by exotic plant species Forest soil profile before earthworm invasion Forest plant diversity before earthworm invasion Forest soil profile after earthworm invasion Forest plant diversity after earthworm invasion Forest plant cover before earthworm invasion Forest plant cover after earthworm invasion