Lesson Plan Title: Invasive Plant Species

Lesson Plan Title: Invasive Plant Species

Grade Level:5-8

Concept / Topic To Teach: Effects of invasive plants on the ecosystem

Specific Objectives:

Students will identify invasive plant species in a given boundary
Students will discuss the effects of invasive plant species on the land and water
Students will explain how invasive plant species spread
Students will use a GPS device to mark waypoints for where invasive plants were located

Required Materials: Scavenger hunt check list, laminated invasive species identification and information cards, pencils, clipboards

Anticipatory Set (Lead-In): Students will need background knowledge on invasive plant species. Go over the following information before beginning lesson.

Background:

For most people, weeds are just a minor nuisance in their gardens and lawns. However, exotic or invasive weeds are more than a minor problem. Already infesting 70 million acres in the United States (about the size of Nevada), invasive weeds continue to expand their range by 4,600 acres a day - on public lands alone! Why is this a problem?

Exoticweed species are those that originate in other countries. Many exotic weed species exist in North America. The natural checks and balances that keep these species under control in the environment in which they evolved are not present in our country. Once they have been introduced, exotic species out-compete nativeplants by stealing the moisture, nutrients, and sunlight that native plants use. Areas in which the soil and plant communities have been disturbed are the most vulnerable to invasion by exotic species. From an ecological viewpoint, invasive weeds are a pioneer species. Natural plant communities are altered when native species are eliminated. These alterations are often a detriment to many other organisms, including humans. These invasive weeds are responsible for threatening 2/3 of endangered species. In addition, they make land more susceptible to wild fires. Weeds are a costly problem for rangelands and crops.

Most invasive species are native plants of Europe or Asia. Some of these invasive species were introduced to North America by accident or unintentionally; some were introduced intentionally. Some unintentionally introduced species entered the continent as seeds hidden in bags of wheat or other grains. Other seeds were hidden in the hay or grass used to feed animals during the long ocean voyage to this country. Some arrived as hitchhikers in the fur of domestic animals that settlers brought to the New World. Others arrived as hitchhikers in the clothing and bedding of the settlers themselves. Seeds were often hidden in the soil used for the ship’s ballast. Examples of species that were accidentally introducedinclude spotted knapweed and leafy spurge. Spotted knapweed probably entered our country in the late 1800s, hidden in alfalfa seed from Eastern Europe. Leafy spurge probably entered America in the early 1800s in Massachusetts. Species that were intentionally introduced include horticultural and food plants. Three extremely invasive horticultural species are Melaleuca, Eucalyptus, and Cytisus (scotch broom).

Weeds can travel in as many different ways as people can, and then some, since seeds are small. Weeds can spread their seeds by wind, water, wildlife, livestock, machinery, automobiles, boats, and people.

Why invasive species succeed

Invasive species possess highly effective adaptationsthat enable them to out-compete native plantsafter they have been introduced into an area, especiallyin disturbed areas or environments. Manmadedisturbances include building roads, homes,shopping centers, schools, and playgrounds. Farming,gardening, and landscaping can also disturbplant and soil communities. Natural disturbancesinclude eroded stream banks, volcanic deposits,flood plains, and burned areas.Some invasive weeds have developed characteristicsthat give them an advantage over native plants.These characteristics enable weeds to out-competenative plants. All weeds have not developed allcharacteristics; however, all weeds are opportunistic,and weeds have a broad tolerance to a widerange of climate and soil conditions.

Reproductive advantages

The seeds of many weed species can germinate in a variety of environments. Weeds often grow and produce seeds rapidly, and weeds continue to produce seeds as long as the growing season permits.Consequently, weeds produce a large number of seeds. For example, a single purple loosestrife plantmight produce millions of seeds in a single summer. Seeds from invasive plants can often survive for many years, have a high rate of germination, have high seedling survival rates, and possess highly effective adaptations for dispersal. Russian thistle is an example of one weed that has developed effective adaptations for dispersal. This weed has brittle stems and a round shape. These characteristics help scatter the Russian thistle’s seeds as it tumbles.Many weeds have the ability to self-fertilize and cross-fertilize. Many unspecialized visitors or the wind often pollinate weed flowers. Many weeds are annuals that complete their life cycles quickly. Some weeds can readily propagate without producing seeds. Perennial weed species, such as Canada thistle, are often capable of vigorous vegetative reproduction. Canada thistle can regenerate from a root piece less than one-half inch long. Vegetative reproductive structures often survive through the winter.

Other Advantages

Some weed species have extra long roots, which enable them to easily access water and minerals. The root of a leafy spurge plant can exceed 17 feet. It is difficult to remove long-rooted weeds by pulling or digging. Creeping vegetative structures, such as roots and stems, enable the weed to spread to new sources of water and nutrients. Buds on reproductive structures, such as root nodes on Russian knapweed, can produce a new plant. Some weeds, such as witchweed, dodder, and mistletoe, are parasitic. Parasitic plants derive nutrients directly from host plants at the expense of the host plant. Some weeds inhibit the growth of their competitors by exuding chemicals that poison the soil. These chemicals prevent the normal growth of other plants. This phenomenon is known as allelopathy. Examples of plants that limit crops through allelopathy include quackgrass, giant foxtail, large crabgrass, johnsongrass, and common sunflower.

Step-By-Step Procedures:

Invasive Species Game:

Explain to students that Wyoming and this site in particular, has invasive species present that could cause future problems if not kept in check or eliminated. Play the following game to help students visualize the effects of invasive plant species on the land.
Designate a playing area by placing cones at edges/corners of the playing field. (30' x 60' area works well for 20 students.)
Scatter playing chips throughout the area (each different colored chip represents a different need for a plant or animal to survive. (White = Shelter/Space, Red = Food/Minerals, Blue = Water)
Be sure to provide enough chips so each player may collect one chip of each color during the first round in order to survive.
Round One: All players will be native to the specific area. Everyone will line up along the edges of the playing field at the start of each round. At the sound of the whistle, players will enter the playing field, collect one of the three different colored chips and return to the edge of the playing field. After all of the students have returned to the sideline, they return to the playing field and collect another chip of a different color. Once again, they go to the sideline, returning a third time for the third colored chip.
After a player has collected all three colored chips, he or she moves to the sidelines to wait for the signal to end the round. All players should survive the first round.
Round Two: This round will be played the same as Round One, but will now include non-native species. Two players wearing colored armbands represent a non-native species. The non-native species are more aggressive and will be allowed to collect two chips per trip into the playing field. The non-native will also be allowed to return to the playing field as often as they are able but must collect three different colors in order to survive. The native species will be considered a survivor if he or she collects three different colored chips as they had done in Round One.
Sound the whistle to end Round 2. Identify the survivors. Evaluate by comparing population size and impact the non-native had on the natives.
Round Three: Native species that did not survive Round Two become non-native for this round. Give each new non-native an armband. Continue to play Round Three just like Round Two.
At the end of Round Three, most, if not all, of the native population should not survive. Evaluate as in Round Two.
After Round Three, discuss with your students what they observed as they were playing the game. As a class, have them begin to figure out how and why those students who played as the initial non-native species were not only able to survive, but to actually take over the entire playing field.

Scavenger Hunt:

Explain to students that using invasive species identification cards and GPS systems, they will be going on a scavenger hunt to see how many Wyoming invasive species they can locate in a given boundary of land (this will be dependent on age of students and teacher preference). Boundary should include area bordering the Tongue River.
Divide students into groups of three or four. Each group should have a set of laminated identification cards, a GPS device (provided by the school), a scavenger hunt check list, and a pencil.
Groups will set out to try to find as many invasive species as they can. When they find a species, they should read the information on the back of the identification card. Then, they should use the GPS device to get a waypoint for where they located the species and record this waypoint on the scavenger hunt check list. Groups should be aware that they might not find all the invasive species on the checklist.
Reconvene as a class and discuss which invasive species the groups found and where they were located. For an extension, have students map these waypoints and discuss patterns they see.

Closure (Reflect Anticipatory Set):

Have students answer and discuss the following questions.

Which invasive plant species did you find in the boundary? Were some species more prominent than others?
Which invasive plant species did you find along the river? How does this affect soil and water quality?
How do these invasive plant species spread?
What effects do invasive plant species have in your community?
How can you help control the spread of invasive plant species?

Assessment Based On Objectives:Scavenger hunt check-list and closure discussion questions.

Locate as many of the following invasive plant species as you can. Use your GPS to record the waypoint of each species that you find.

Plant Species / Waypoint
Black Henbane
Bull Thistle
Canada Thistle
Cheatgrass
Dalmatian Toadflax
Dyer’s Wood
Houndstongue
Leafy Spurge
Muck Thistle
Russian Olive
Salt Cedar
Spotted Knapweed
Whitetop (Hoary Cress)

Black Henbane

Interesting Facts

Has been used as a medicinal plant since the Middle Ages
Been used as a beer flavoring many years ago
All parts of the plant are poisonous to animals and humans
Has a foul odor and has been called “stinking nightshade”

Description

Black Henbane (Hyoscyamusniger) is covered with greasy hairs and has a thick, fleshy taproot.

Stems are upright, tough – almost woody - and can be very thick. Plants can grow to 1m or taller and may be branched or unbranched.

Leaves are alternate, large – up to 15 cm wide and 20 cm or more long – and have a heavy, foul scent. Leaf edges are shallowly lobed (variable) and veins are conspicuous.

Flowers are pale yellow with deep purple veins and throats and are borne on spikes. Flowers are hermaphroditic – both male and female organs – and have a strong, unpleasant smell. The flower base forms a 2.5 cm urn-shaped fruit with a thickened lid that pops off at maturity and spills the numerous, tiny, black-brown seeds is primarily by seed production and sprouting from lateral roots to a lesser extent.

Habitat

Black henbane grows in a wide range of soil textures and pH but does require well drained soil. It does not tolerate shade.

Bull Thistle

Interesting Facts

Can grow up to 7 feet tall
Dense infestations of this spiny plant can exclude livestock and wildlife movement
Seeds have a silky down covering allowing windblown dispersal of great distances

Description

Bull thistle is a large spiny forb that can grow 7 feet in height

Stems have spiny wings and grow 1 to 7 feet tall, with many spreading branches, and sometimes a single stem
Leaves are more or less lance-shaped and 3 to 12 inches long, prickly hairy on the top and very hairy underneath
Flowers Bull thistle flower heads are 1.5 to 2 inches in diameter, 1 to 2 inches long, usually solitary, and more or less clustered at the ends of shoots and branches.
Seeds are 5 mm long, with a downy pappus

Habitat

Bull thistle is a very widespread weed that can grow in a wide range of environments but is most troublesome in disturbed areas such as pastures, overgrazed rangelands, recently burned forests and forest clearcuts, and along roads, ditches, and fences. Bull thistle is found on dry and wet soils, but is most common on soils with intermediate moisture.

Canada Thistle

Interesting Facts

Contrary to the name, Canada thistle did not come into the U.S. from our northern neighbor, but rather was introduced in the 17th century from the Mediterranean region and southeast Europe.
Tea made from Canada thistle leaves has been used as a diuretic as well as for treatment of tuberculosis
It is the only thistle with male and female flowers on separate plants
Roots can branch out to 15 ft. wide and deep.
Seeds are winged and are easily dispersed by wind
New plants can develop from small broken pieces of the plant
Disperses a chemical that may inhibit growth of other plants
Seed may remain viable in soil up to 20 years

Description

Canada thistle is an herbaceous perennial in the aster family with erect stems, prickly leaves, and an extensive creeping rootstock.

Stems are branched, often slightly hairy, and ridged
Leaves are lance-shaped, irregularly lobed with spiny, toothed margins and are borne singly and alternately along the stem
Flowers are rose-purple, lavender, or sometimes white flower and occur in rounded, umbrella-shaped clusters
Seeds are tan curved and has a papery covering

Habitat

Canada thistle is found in open areas with a moderate amount of moisture but does poorly on wet soils lacking sufficient oxygen. It can grow on many different soil types but it does not grow well in shade and is rarely found within wooded sites, except in clearings. It is commonly found in abandoned fields or lots, abandoned gravel pits, pastures, right-of-ways, roadsides, railway embankments, lawns, gardens, and agricultural fields. It also invades wet areas with fluctuating water levels such as stream banks or irrigation ditches and sloughs.

Cheatgrass

Interesting Facts

Cheatgrass (downy brome) is a noxious weed that can invade grassland communities and displace native plants; it thrives in disturbed areas.
This weed can produce more than 10,000 plants per square yard and is highly flammable.
Cheatgrass can be controlled mechanically, biologically, chemically, or by applying fire under controlled conditions.

Description

Cheatgrass is an annual—it lives for only one year/growing season and then dies. It reproduces by seed and is termed a winter annual because its seed germinates from fall into winter. The plant reaches maturity in the spring and turns brown and dies with the onset of summer.

The height of cheatgrass ranges from three to 30 inches. It has a crooked seed head and small soft hairs covering the entire body of the plant. Leaves emerge dark green with a hint of purple. As it matures and begins to cure, cheatgrass turns yellow to reddish-brown in color with seed heads ranging from two to six inches long at maturity. These seeds have wedged awns that may be dispersed by wind and water, but most often they are spread by adhering to clothes or to the coat of a wild or domestic animal.

Habitat

Cheatgrass often occurs as a significant component of foothills rangeland vegetation along the eastern front of the Rocky Mountains. While cheatgrass is usually found along roadsides and disturbed sites in the east, it is highly abundant in the west and has invaded disturbed and undisturbed grassland communities to become the dominant species in many lower-elevation areas.