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Transcontinental Phragmites

Grade Level: 6-8

Subject: Social Studies

Time Frame: One to Two 40-45 minute periods (depending on teacher's use of extension activities and other options within the lesson plan)

Lesson Overview:

In this lesson, students will explore the spread of non-native Phragmites  across the Atlantic Ocean, from Europe to America and then across the American subcontinent and will review some of the factors that may have mediated this process.  In so doing, the students will review the geography of the lower 48 US States, and relate the expansion of this plant to the movement of humans within the US over the same period.

NJ-New Jersey Core Curriculum Content Standards

STANDARD 6.1 (Social Studies Skills) All students will utilize historical thinking, problem solving, and research skills to maximize their understanding of civics, history, geography, and economics.

·  Analyze how events are related over time.

·  Use critical thinking skills to interpret events, recognize bias, point of view, and context.

·  Analyze data in order to see persons and events in context.

·  Examine current issues, events, or themes and relate them to past events.

·  Formulate questions based on information needs.

·  Summarize information in written, graphic, and oral formats.

STANDARD 6.4 (United States and New Jersey History) All students will demonstrate knowledge of United States and New Jersey history in order to understand life and events in the past and how they relate to the present and future.

C. Many Worlds Meet

2.        Trace the major land and water routes of the explorers.

STANDARD 6.6 (Geography) All students will apply knowledge of spatial relationships and other geographic skills to understand human behavior in relation to the physical and cultural environment.

A. The World in Spatial Terms

1.        Distinguish among the distinct characteristics of maps, globes, graphs, charts, diagrams, and other geographical representations, and the utility of each in solving problems.

2.        Translate maps into appropriate spatial graphics to display geographical information.

5.        Use geographic tools and technologies to pose and answer questions about spatial distributions and patterns on Earth.

6.        Distinguish among the major map types, including physical, political, topographic, and demographic.

7.        Explain the distribution of major human and physical features at country and global scales.

B. Places and Regions

7. Describe the types of regions and the influence and effects of region labels including:

o        Formal regions: states

E. Environment and Society

1.        Discuss the environmental impacts or intended and unintended consequences of major technological changes (e.g., autos and fossil fuels, nuclear power and nuclear waste).

2.        Analyze the impact of various human activities and social policies on the natural environment… 

Materials Required:


Computers with internet access (optional)


PowerPoint (ppt format;   pdf format)


Student worksheets with maps and other materials  (word format;  pdf format)


Variety of Different Color Markers


In completing this lesson students will:

bulletDiscuss the locations of some of the early human settlements on the US Eastern seaboard and explain why these locations might correspond with the first recorded specimens of an invasive species of European Origin
bulletExplain the link between human movements and the movement of invasive species across North Americae
bulletDescribe the consequences of the spread of the invasive strain of Phragmites  for the native strains of the same plant that were present before the European strain spread into their habitats
bulletReview locations of the lower 48 States as students map the relationship between the spread of Phragmites  and the locations of the major roads and railway lines within the US.

Sequence Instruction

1.  Arrival.  Teacher will show students the map showing the first known locations of the invasive subspecies (haplotype) of Phragmites  (below).

 The three locations shown in the map (from Saltonstall 2002) are:

bulletNew Haven, CT (Site of one of the earliest European settlements, (founded in 1638) and an excellent port.
bulletCamden, NJ (opposite side of the Delaware river to Philadelphia another early European stronghold and port city)
bulletChesapeake Beach, MD (near mouth of Chesapeake Bay site of many early settlements, including Washington DC and Baltimore).

Teacher will ask students:

  1. Why might the invasive Phragmites  strain have been first seen in these locations?

Answer:  Because it too came from Europe and almost certainly  "hitchhiked"  to America with the early Europeans, and many of the early settlements were on the Eastern Seaboard of the US between MD and MA... which is  exactly where we see these plants first become established

  1. How do you think it got there? 

Viable suggestions include the idea that it came in accidentally with  the settlers.  In fact it  most likely was introduced in "dry ballast". When cargo ships don’t have a full cargo they are too buoyant and roll dangerously in the waves, so they must be weighted down to travel safely.  Today this is done with water pumped into special "ballast tanks"  and this ballast water is a major source of invasive species in marine ecosystems, but before there was liquid ballast, dry ballast such as sand, soil or rocks was loaded onto ships when they needed to sail somewhere to pick up cargo. It is possible though that the species was brought in on purpose (Europeans were familiar with the plant and used it for a number of purposes, including thatch-  they may have wanted to have wanted to grow the plant in America for the same purposes, since the local variant wasn’t strong (sturdy) enough, nor did it grow as tall or densely, to use for this purpose).   

Part 2.  Establishment and Early Spread:    After the invasive Phragmites  was introduced to North America it started to spread.  The figure above (also from Saltonstall 2002) documents the spread of the species from New Haven, CT.  The red dots again represent the invasive strain of the species.  The green triangles represent the strain of the species that is native to this part of North America.  Teacher will ask the students to interpret the diagrams above.  What were the consequences of the invasion for the native haplotypes of the species?

If desired, teachers may want to make the obvious analogy here between the arrival of the Phragmites  and its consequences and the arrival of the European strain or haplotype of the human species and its consequences for the races of humans native to this part of North America.  Many of  the reasons for this are similar:  the European haplotype was a superior competitor which was more aggressive about taking and holding land once it was invaded.  European races of humans also tended to develop higher population densities and to change the environments that they invaded in ways that made those habitats less suitable for a wide variety of other native plants and animals. 

Part 3:  Conquering the Continent:  Finally, the teacher will show the students this picture of the distribution of the invasive strain or "haplotype" of Phragmites  in recent years (again from Saltonstall 2002) and will ask the students what they notice i.e. that most are still on the E Coast where the invasive haplotype is now found more or less everywhere.   The students should also note that the plant has moved essentially right across the country.   Clearly plants can’t walk, so how might the plant have moved this far in under 100 years? 

To answer this direct students to the following resource: (if web is not available, copies can be printed out for students).

Once the students have had a chance to review this material, teacher should ask

1.  What NATURAL pathways might have contributed spread this species?

a.       Wind carrying seeds?   

b.      Ocean Circulation

c.       Riverine

Now have the students brainstorm.  Are these likely causes in this case?

Wind carrying seeds?    Seems unlikely since prevailing winds in NA are W to E (teacher may wish to discuss / review why this is) 

Image Source:

Ocean Circulation:  Clearly this is not the mechanism for spread of a species across a continent!

Riverine:  Have the students brainstorm.  Do any major rivers in the US flow in the direction of spread (since things tend to move downstream not upstream)?  Again the answer should be no!

Another possible natural pathway not mentioned in the Fish and Wildlife "Plants on the Move" resource is seeds being carried by wild animals.  Again, though this is possible, it is probably not the most likely solution.

This leaves the other main pathway mentioned in the Fish and Wildlife "Plants on the Move"resource"   Seeds or rhizomes carried by humans.   This is probably the most likely explanation.

Again using the resource provided have the students brainstorm what are some of the pathways


Accidentally moved ship ballast, ship cargo, airplane, truck


(seeds or shoots caught in the wheels of trucks, undercarriages of trains, in materials used as bedding, packing materials etc).


Deliberately planted (introduced as ornamentals) 


Contamination of crop seed with seed of weeds growing in the same area as the source of the seeds


Tourism (intentional carrying of plants home from a trip.  Accidental transport-  seed in shoe, seed on top of camper etc).


Four Main Pathways of Transport









Part 4.  Making the Connections

On the student worksheet are large copies of the map of post 1960 Phragmites  distributions along with of maps of the main branches of the Transcontinental railroad and the main highways across the US.

Teacher will ask the students to work in groups to draw the route of the main railways (especially the main "Union Pacific" line) and highways (we suggest 94, 90, 80 and 70) onto the map of the Phragmites  distributions.  This will require the students to correctly identify the States outlined on the three  maps and to translate the information from the railroad and road maps onto the Phragmites  map.

Image Source:

Image source:  

Once the three maps have been combined into one comprehensive resource the teacher will encourage students to notice the similarities between the major routes of human movement across the continent and the movement of this invasive species. The tendency of roads and railways to serve as pathways for invasive species into new habitats is one big reason for why environmental activists suggest avoiding running roads through previously undeveloped "natural areas" (other reasons include the fact that once the roads are there development in the form of homes, highway support services (restaurants, gas stations etc. tend to follow, and habitat destruction is usually accelerated as a result)


Optional Extension Activit

It is important to note that the trend we’ve seen with Phragmites  is not an isolated case.  Many invasive species tend to be distributed by humans and thus to follow patterns of human navigation / habitat use.  For example, another plant that’s invasive in wetlands is Epilobium hirsutum  (Hairy Willow Herb)

Image source:

The map below shows the pattern of spread of this species in the past 150 years.

Image Source:  Invasive Species in a Changing World By Harold A. Mooney, Richard J. Hobbs, International Council of Scientific Unions Scientific Committee on Problems of the Environment. Published by Island Press, 2000

  1. Using the student worksheets provided, have the students color the boxes (pre-1900) Red.   Then have the students color circles from 1900 - 1930  (0 - 30)  Green, the circles from 1930-50 (30 - 50), Blue and the circles from 1950 - 70 (50 - 70) Pink (or another color that contrasts with the others)
  2. Working in groups, have the students work out from the maps and write down the following information:
    1. What States were invaded before 1900
    2. What new States were invaded between 1900 and 1930
    3. What new States were invaded between 1930 and 1950
    4. What new States were invaded between 1950 and 1970
    5. During which period did the plant’s range expand most rapidly?
    6. In the map below we see the current distribution of this species.  Students should note that a major leap has occurred and the species is now present in Washington and Oregon (as well as a number of Canadian Provinces that we are not considering here).  What are 2 possible explanations for this?

                                                               i.      Jump dispersal across Continent (plane, train, car carried it across the un-colonized States and dropped it off on the West Coast

                                                             ii.      A new introduction of the plant via ship from the ocean, releasing the plant on the West Coast

Teacher may wish to have students think about which of these seems more likely (though there is no right answer).  If desired teacher could ask students if they can think of a way to determine which pathway is more likely.  Assuming kids are watching crime TV some may be able to suggest genetic testing.  If the plants came by a land route, they should (likely) be more closely related to populations from the nearest population.  However, if the coast population is a new introduction, they should be genetically more similar to those in a coastal source region- either on the East Coast of North America, or in the original (European) source region.

Current distribution of the species (

AssessmentStudents should pass in their completed worksheets for assessment.

Closing ActivityStudents will write a paragraph about the way in which invasive species spread and how this knowledge may be used to help prevent, or at least reduce, the spread of invasive species in the future.  If desired, students can then be asked to share one idea from their paragraph with the class / work group before the end of class.


TEACHER FEEDBACK REQUEST:  We are always to working to improve these lesson plans. If you use this lesson plan, we'd love to hear from you with your thoughts, comments and suggestions for future improvements.  Please take the time to fill in our survey at .  Thanks!

© 2009. Louise Wootton

 Although the information in this document has been funded wholly or in part by the United States Environmental Protection Agency under assistance agreement NE97262206  to Georgian Court   University, it has not gone through the Agency's publications review process and, therefore, may not necessarily reflect the views of the Agency and no official endorsement should be inferred.

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