Summary
In this exercise, students will learn the definition of invasive species. They will choose a specific aquatic invasive species, investigate its distribution, life history, reasons it is considered invasive,
the effects it has on a given ecosystem, and possible solutions of
management practices to control the species or its impacts. They
will create an "unwanted" poster that engages local citizens and
helps them understand the importance of controlling the organism.
Materials
Background for Teachers
Purpose
To understand the properties of invasive species and learn more
about aquatic invasive species and their effect on aquatic ecosystems.
Through creation of an "unwanted" poster, students will also
learn how to present technical information and messages to the
public.
Background
Invasive species are non-native (or alien) to the ecosystem under consideration whose introduction causes or is likely to cause
economic or environmental harm or harm to human health. Not all
non-native species are invasive, since many non-native species are
not able to spread or reproduce in natural habitats.
Invasive species may prey upon, displace or otherwise harm
native species. They may also alter ecosystem processes,
transport disease, or cause illnesses in animals and humans.
Invasives can affect the commercial, agricultural, aquacultural, or
recreational activities dependent on such waters, resulting in severe
economic impacts. Control of invasives can be extremely difficult
once they are established.
Many natural barriers exist which help isolate species and prevent
their introduction into new regions. Invasive species must
overcome barriers in the environment that would otherwise prevent
their spread. These barriers are:
- Geographical barriers such as a mountain range, ocean orriver
that prevents easy movement from one area to another
and separates different habitats.
- Survival and establishment barriers are environmental features
that prevent an introduced species from thriving. These
mightinclude soil moisture or pH for plant species, water temperature
or salinity for aquatic species. 117
- Dispersal and spread barriers are natural or constructed blockades
such as a wall of vegetation on land or a barrier of electricity
in water. These are made to prevent rapid dispersal and spread
from the site of establishment.
Human activities are often the culprit in introducing and
perpetuating the spread of invasive species. Here are some examples
of human activities which have served as pathways for spreading
invasive species:
For more information on aquatic invasive species please call the
Division of Wildlife Resources at (801) 538-4700, email
larrydalton@utah.gov, or see:
Instructional Procedures
Classroom Activity:
Part 1
- Define the term aquatic invasive species. Aquatic invasive species
are water-associated non-native species that threaten the diversity
or abundance of native species. Talk about why invasive species
are a threat to native species in a given ecosystem.
- Give students examples of invasive species. Examples can be
found in the Resource pages of this lesson.
- Ask the students if they can think of any local examples of aquatic
invasive species. Ask them if they can think of any possible
ways those invasive species were introduced to an ecosystem. Be
sure to inform them of the human activities which often introduce
aquatic invasive species to an ecosystem.
Part 2
- Explain to the students that they will be researching and presenting
on a specific aquatic invasive species within Utah.
- Separate the students into small groups of three or four. Assign
each group a specific aquatic invasive species that is affecting the
state. A list of aquatic invasive species in Utah can be found in
the Resource section of this lesson.
- Have students use the Internet to research their assigned invasive
species. From their research, students will fill out the accompanying
worksheet found in the Resources section of this lesson. Be
sure they list the reference.
- Each group will then make a creative, informative poster of their
invasive species using the information from their research worksheet
(see the Resource section of this lesson for an example).
This can be done on the computer or with art supplies.
- After the posters are completed, each group will use their posters
as a visual in a presentation on their aquatic invasive species.
Additionally, the posters can be displayed within the school or
community in order to educate others on aquatic invasive species
within Utah.
Field Activity:
- As with any field trip, exercise appropriate
safety precautions. See Appendix
B in this manual for more information
on safety in the field.
- This is an excellent opportunity to teach
the students the responsibility of field
work and even recreation. Use Best
Management Practices (BMP) discussed
in the further discussion questions.
- Take a field trip to a local, safe, accessible water body. It could be
a river, pond, lake, reservoir, or stream.
- Hold a discussion about
invasive species. Perhaps
start by asking the
students what activities
take place at the field trip
location. Then focus on
how these activities may
facilitate the spread of
invasive species if the
proper precautions are not taken.
- Have the students look at pictures of different invasive species
located within Utah. Talk about the environments where these
species live. Ask the students which of the species they know are
located, or have potential to be located, within the field trip location.
- As the students how they think the invasives species could have
gotten there.
- Have the students sample the water body for using the sampling
equipment. It is likely that the students will not find an invasive
species; however, this is an opportunity to train them to use
BMPs in their fieldwork.
Further Discussion:
- What are the characteristics of an environment that is
vulnerable to invasive species?
- A lack of biotic constraints, such as natural predators or disease,
which the invading organism had in its native environment.
Natural predators help control populations of their prey. Since an
invasive species often has no natural predator in its non-native
environment, its population rapidly increases. With a large population,
it is easy for an invasive species to output native species.
- Vacant niches that can be exploited by invasive species. A niche
is the relational position of a species within an ecosystem, or how
a species responds to its environment, resources, and predators
in order to survive and reproduce. When conditions of a niche
change and its inhabitant leaves or becomes vulnerable, it is easy
for a new species to take over that niche. A disturbance by fire,
construction, agriculture, etc., prior to the invasion. These ecological
disturbances cause a disruption in an ecosystem's natural
function and structure. A disrupted ecosystem is vulnerable to an
invasive species' establishment.
- A disturbance by fire, construction, agriculture, etc., prior to the
invasion. These ecological disturbances cause a disruption in an
ecosystem's natural function and structure. A disrupted ecosystem
is vulnerable to an invasive species' establishment.
- Areas that are located near potential sources of invasive species
are more likely to be invaded. Since people transport many nonnative
species, urban areas and their surroundings typically have
more invasive species than remote areas.
New species often find their way into new ecosystems, but not all become
nuisance species. In order for a non-native species to become an
invasive species, it must harm and negatively impact its new environment.
This harm must outweigh any beneficial impact.
- What can be done to control aquatic invasive species?
- Mechanical Control removes an invasive species by hand or with
a machine. The process is often very labor intensive and needs
multiple efforts. In Utah Lake, the Common Carp is being removed
through boats, large nets, and hand labor to capture and remove
about five million pounds of fish annually over a six year period.
Trapping, electricity, trawling, or bait ing may also be used.
- Chemical Control uses chemical applications to control invasive
species. The chemical Rotenone is often used to treat water bodies
infested with invasive fish species. However, chemicals like Rotenone,
such as pesticides, herbicides, or other piscicides, are often
not target-specific and can harm water resources as well as other
plants and animals besides invasive species.
- Biological Control involves the release of a new species in the
environment to control an invasive species. A biological control
agent, the Saltcedar Leaf beetle Diorhabda elongate, has been
released in nine western states including Utah in order to control
122 tamarisk populations.
- There are specific procedures to protect against introduction
of aquatic invasives:
- Assume every water body is contaminated and that boats and
equiment should always be considered contaminated
- Eliminate water from all equipment before transporting
anywhere
- Remove all visible mud, plants, and fish/animals
- Keep one set of equipment for use only on infested waters
- Decontaminate equipment following each use, whenever
possible, by cleaning and drying anything that came in contact
with the water
- Keep boat and equipment clean between trips and let dry for as
long as possible
- Do not release or put plants, fish or animals into a body of
water unless they came out of that body of water
- Report the finding of an aquatic invasive species to the Utah
Division of Wildlife Resources at 801-538-4700
- Why are the definitions of invasive species sometimes unclear?
Some non-native species are considered harmful, and therefore,
invasive by some sectors of our society while others consider
them beneficial. This discontinuity is reflective of the different
value systems operating in our free society, and contributes
to the complexity of defining the term invasive species. (Invasive Species Definition Clarification and Guidance White Paper (pdf))
- How do aquatic invasive species affect water quality?
Aquatic invasive species affect water quality through small
changes in the ecosystem. These small changes have a significant,
negative impact over time. One example of this is the Common
Carp. This is a fish which feeds by browsing through underwater
vegetation. This feeding uproots plants which muddies the water
and destroys the food and cover needed by other fish. Another
example of this is the Water Hyacinth. This is a plant which blocks
light for photosynthesis, which greatly reduces oxygen levels in the
water. This reduction in oxygen in turn reduces other underwater
life such as fish and other plants, thus depleting biological diversity
which alters an ecosystem's animal community.
(For more information, see:Impacts)
- What are a few impacts of aquatic invasive species? How
will invasive species affect water resources and what are the
associated effects?
Invasive aquatic plants and animals destroy habitats in coastal
waterways and interrupt the flow of water in inland desert
irrigation canals. They clog storm canals leading to the flooding of
homes and displace native species in our nation's wetlands.
Furthermore, they compete with native species for resources, often
leading to a decline in the population of native species. One
example of this is seen in the competition between the native
Cutthroat Trout and the nonnative Brown Trout in many rivers
within Utah. Both are competing for the same food source, which is
causing a decline in the native Cutthroat Trout population.
- Invasive species have a place in their native habitat. When
introduced to a new habitat, they are only doing what every
other organism does: taking advantage of opportunities to
survive and perpetuate their species. How does this viewpoint
affect human responsibility for invasive species control?
Most invasive insects, marine invertebrates, and microorganisms
are accidentally introduced. For this reason, most countries have
many restrictions and regulations in place detailing how imported
and exported products will be monitored.
- What can you do to prevent the spread of invasive species?
- Inspect your boat and equipment (e.g., waders, ect). Remove
any plants or animals.
- Drain water from the motor, livewell, bilge, or transom well.
- Never release or transport live aquatic species from one water
body into another.
- Never dump aquariam plants or pets out in lakes or streams.
- What are our future management, policy, and societal needs
to lessen or adapt to the effects of invasive species as they alter
aquatic ecosystems?
"The best way to limit impacts of nonnative species is to prevent
them from invading and becoming established in a new area. If this
fails, eradication may still be possible, but generally only if the
species is identified and treated quickly. Once
established, efforts to restrict spread to uninfested areas can limit
further damage. Controlling population sizes in heavily invaded
areas can also reduce deleterious effects, but is unlikely to lead to
eradication. Last, maintaining healthy natural communities, either
by limiting human disturbance, or restoring of previously impacted
areas, can limit opportunities for exotics to take hold."
(Invasion (pdf))
Extensions
- Write to a government agency or political leader with concerns and recommendations
for aquatic invasive species.
- Have students create an outreach campaign for the community based on their
posters of the aquatic invasive species. This can include tips and suggestions for the prevention of introduction and spreading of aquatic invasive species.
- Have a guest speaker from an agency implementing invasive species action
plans or with knowledge and experience on invasive species come speak to the
class.
Bibliography
Lesson plan authors: Andree Walker and Nancy Mesner (Utah State University Water Quality Extension)
This curriculum was made possible through funding from the Environmental Protection
Agency, the United States Department of Agriculture, Cooperative State Research,
Education, and Extension Service, the Utah Division of Wildlife Resources, and Utah
State University Extension.
Additional resources can be found on the USU Stream Side Science 9th Grade Curriculum web page.