Download Great Lakes Worm Watch Our Mission is to

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.
www.greatlakeswormwatch.org
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 (~1/3rd 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 sam
Earthworm Ecological Groups
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.
Illustrated guide to exotic earthworms found in the Great Lakes Region
Books retail for $12.95,
$10.00 each for 10 or more books
You can download order forms from our website:
http://www.greatlakeswormwatch.org/educator/book.html
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.
Impacts of Exotic Earthworms
Forest plant cover
before earthworm invasion
Forest plant cover
after earthworm invasion
Sugar maple forests before earthworm invasion (left) usually have high diversity of native
understory plants and tree seedlings with total understory plant cover of 75-100%. 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%.
Forest plant diversity
before earthworm invasion
Forest plant diversity
after earthworm invasion
In earthworm-free hardwood forests of the Great Lakes region (left), the understory plant communi
Forest soil profile
before earthworm invasion
Forest soil profile
after earthworm invasion
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.