Supplemental Lesson - Threats to the Forest and other Ohio Ecosystems
Skills:
Researching and processing information
Overview
Forests have long been threatened by a variety of different agents. Natural events such
as drought, ice storms, tornadoes, fire events, etc. can destroy forests but more and
more we hear about invasive species threatening our forests and other ecosystems.
What is an invasive species?
Invasive species also referred to as exotic species, nonnative, or alien species are
defined as not native to the ecosystem; and whose introduction does or is likely to
cause economic or environmental harm or harm to human health. Invasive species
including its seeds, eggs, spores, or other biological material capable of propagating
that species, are all considered invasive.
Invasive species is a common topic in Ohio.
Understanding an Ecosystem
An ecosystem includes all of the living things (plants, animals) in a given area,
interacting with each other, and also with their non-living environments (weather, earth,
sun, soil, climate, atmosphere).
In an ecosystem, each organism has its' own role to play but each one (plant and
animal) depends on one another for their survival.
Consider a backyard or a school yard. In it, you may find all sorts of living things, from
microorganisms, to insects and plants. These may depend on non-living things like
water, nutrients in the soil, sunlight, and temperature.
Anytime an invasive species, or nonnative species, is introduced into an ecosystem, it
can potentially upset the natural balance (or diversity) of things living in that ecosystem.
Sometimes invasive species can cause great harm to that ecosystem because it can
distort the natural balance enough that it forces the delicate balance of the ecosystem to
change and thus force of the interaction between the orgainismis to change as well.
For more information on ecosystems, check out Youth Scientist - Unit 1, Why Trees
Matter at [http://u.osu.edu/youthscientist].
Ohio Example of an Interupted Ecosystem - Great Lakes Region
(http://www.invadingspecies.com/invaders/fish/round-goby/)
The round goby is a small, bottom-dwelling invasive fish. Native to the Black and
Caspian seas in eastern Europe, it was first found in North America in 1990 in the St.
Clair River north of Windsor, Ontario. Researchers believe the fish was brought to North
America in the ballast water of ships from Europe. In less than a decade the round goby
has successfully spread through all five Great Lakes and has begun to invade inland
waters. In some areas the fish has reached densities of more than 100 fish per square
meter.
Round goby prefer waters with rocky and sandy bottoms. They feed aggressively on
insects and other small organisms found on lake and river bottoms. Adult round goby
eat large quantities of zebra and quagga mussels, and occasionally small fish and fish
eggs. Their aggressive eating habits and ability to spawn several times each season
have helped them multiply and spread quickly
Impacts of Round Goby
The round goby's aggressive habits and rapid spread have had serious impacts on
native species.
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The fish compete with and prey on native bottom-dwelling fish such as mottled
sculpin (Cottus bairdii) and logperch (Percina caprodes). Round goby also
threaten several species at risk in the Great Lakes Basin, including the northern
madtom (Noturus stigmosus), the eastern sand darter (Ammocrypta pellucida),
and several species of freshwater mussels.
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Round goby have reduced populations of sport fish by eating their eggs and
young and competing for food sources.
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Researchers believe the round goby is linked to outbreaks of botulism type E in
Great Lakes fish and fish-eating birds. The disease is caused by a toxin that may
be passed from zebra mussels, to goby, to birds, resulting in large die-offs of fish
and birds.
The Hemlock Wooly Adelgid
Hemlock Woolly Adelgid (pronounced ə-DEL-jəd) (Adelges tsugae) is an introduced
pest from Asia that is a threat to Eastern Hemlock (Tsuga canadensis) and Carolina
Hemlock (Tsuga caroliniana) in eastern North America. White cottony sacs found at the
base of the needles are good evidence of the Hemlock Woolly Adelgid (HWA).
This small (less than 1/16”) insect sucks sap from young twigs, which retards or
prevents tree growth and causes needles to discolor and drop prematurely. This
severely affects plant health; defoliation and tree death can occur within 4 to 10 years of
infestation.
In 2012, HWA was discovered at Shade River State Forest in Meigs County near the
Ohio River. This infestation is along the leading edge front as HWA moves across the
eastern United States. Management for HWA in this area has included a combination of
tree removals and chemical treatments since its discovery. Future plans for the Shade
River infestation include continued removals and treatments as well as biological
control.
In late winter 2013, a single woolly mass was detected by Ohio Department of
Agriculture nursery inspectors on a hemlock tree at Cantwell Cliffs in Hocking Hills State
Park. Since that discovery, the Ohio Department of Natural Resources has partnered
with OSU Extension, Ohio Department of Agriculture, and others to address this
potentially devastating threat. Eastern hemlocks dominate the vegetation in and around
the beautiful sandstone gorges of the Hocking Hills; loss of hemlocks in the region
would seriously impact the tourism industry in the region.
Current efforts to address HWA in the Hocking Hills and Ohio:
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Region-wide surveys to determine extent of infestation
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Mapping of infested trees
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Develop educational and training opportunities
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Evaluate soil characteristics and research options for the development of a plan
to address HWA at Hocking Hills State Park
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Chemically treat over 500 hemlock trees in the Hocking Hills
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Continued monitoring of treated trees to evaluate effectiveness of treatments
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Annual surveys of hemlock stands to detect new HWA infestations quickly
Future management for HWA in Ohio will include chemical treatments, tree removals,
and biological controls. Biological control in the state has already been initiated, with
field insectaries being started in urban locations in Washington County. L. nigrinus
beetles were collected in spring of 2013 with assistance by OSU Extension and ODA,
and were released in three locations with heavy HWA populations. These release sites
will be supplemented with additional beetles, both L. nigrinus and S. coniferarum, in
future years to increase their populations so that beetles can be collected here for
releases to other areas of the state as needed.
Surveys for new HWA populations are conducted every winter in counties with native
stands of hemlocks. Homeowners with hemlocks in their landscapes or woodlands are
encouraged to regularly inspect their trees for signs of HWA. HWA can be easily
identified from late October through early June as white “woolly” masses on the
underside of hemlock branches. Early detection of HWA provides the best opportunity
to successfully treat the infested trees.
Impacts
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Hemlock Wooly Adelgid and the disintegration of the eastern hemlock
ecosystems http://na.fs.fed.us/fhp/hwa/pubs/hemlock%20adelgid%20management%20DE%2
0Water%20Gap.pdf
Wildlife Habitat Association in Eastern Hemlock -Birds, Smaller Mammals, and
Forest Carnivores http://na.fs.fed.us/fhp/hwa/impacts/wildlife_habitat_associations.pdf
Activity 1.1
Web Of Life
(Adapted from Project Learning Tree - Activity 45 using the Hemlock Wooly
Adelgid/example from Cathy Knoop - Big Brother Big Sisters of Central Ohio)
This activity can be used in a variety of ecosystems. In this example, a Hemlock forest
is used to highlight this specialized ecosystem, thus giving students an idea of how
Hemlock Wooly Adelgid can disrupt a Hemlock Forest.
Items Needed for Activity:
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Hemlock Ecosystem Cards
Ball of Yarn
Resources for Activity (available under Unit 2 resources):
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Ohio Invasive Species List
Web of Life Activity Cards Sheet - Hemlock Ecosystem
HWA Factsheet
Hemlock Heroes Song
What to do:
1. Have students sit on the floor in a circle. Explain to your students that they are
going to look at a Hemlock ecosystem. In this activity, students represent
members of the Hemlock Forest Ecosystem. Remember to explain to your
students that “Eco” means “House”, so they are looking at the Hemlock Forest as
a House or a Home for everything there.
2. Give each student a hemlock ecosystem card and explain to them that they are
taking on the role of a living or nonliving member in the ecosystem.
3. Begin by talking the students through the ecosystem, starting with sandy, acidic
soil. As you describe each member of the ecosystem (note: you can have more
than one of each member) pass the yarn to the next person so that they can be
"connected" to the Web of Life. The string represents the ways they depend on
each other.
4. As the students make these connections, the string forms a visual Web of Life.
After the students have all connected, have the students raise their string 1foot
off the ground and then gently tug on their string to feel that all the members of
the ecosystem are interconnected with each other.
5. Initiate a discussion on invasive species and what they do to disrupt an
ecosystem.
6. Finally, introduce the Hemlock Wooly Adelgid into their "house" to see what
happens. (note this can easily be done by having the students that are hemlock
trees release their string.
7. Questions for discussion:
a. What happens when they remove a link in the Hemlock Forest
ecosystem?
b. Will they be connected with each other?
c. What will happen to the other members of their house?
d. Finally, what are the consequenses of an invasive species invading an
ecosystem?
Tips for Success:
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Have Students sit on floor in a Circle.
Pass the Yarn Ball yourself. Do not have students throw it.
Have them hold their String firmly on floor.
(This way you can walk across the Web as you are passing the yarn ball to
build it.)
Think through the connections you want the students to see. You may need
to direct them. Remember, they do not have all the knowledge you do. Try to
let them figure out connections that make sense.
Raise the string waist high on your count: 1…2…3!
Give direction when and how you want them to GENTLY tug or release their
string.
Be clear and concise with directions.
HAVE FUN!!!!!
Activity 1.2 Invasive Species Investigation Activity
Adapted from Ohio's Why Trees Matter 4-H Book - [ http://estore.osuextension.org/productdetails.cfm?PC=2785 ]
Resources:
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Ohio County Map
Ohio Invasive Species List
What to Do:
1. Using the Ohio County Map (Unit 2 resource section), find and label your county.
Also find and label Toledo, OH, which is where EAB was first discovered in Ohio.
2. To show that ash trees grow everywhere in Ohio, outline or color the entire map
in green.
3. Do an online search for "Ohio EAB infestation map*." Is EAB in your county? If it
is, draw a picture of a green beetle in your county. If it isn't, draw a picture of a
healthy tree.
* A map is available at: http://www.agri.ohio.gov/public_docseab_maps/eab-mapinfestation.pdf
Activity Extension:
1. Check out the invasive species list available under Unit 2 resources. Have
students use the Ohio Map again to map out another invasive species. Have
students find the initial point of infestation, if it impacts a certain host, and what
areas of the State may be impacted by this species.
Appendix (located under Unit 2 resources)
Ohio's Invasive Species List
Web of Life Activity Cards Sheet - Hemlock Ecosystem
HWA Factsheet
Hemlock Heroes Song
Ohio County Map