1

The Natural Inquirer • Volume 8, Number 1

Moving Spore-adically

page 7

And Then There 

Were Nun

page 18

Shoot! 

Foiled Again!

page 35

Goll-ly! Don’t Take 

a Knapweed!

page 58

Volume 8, Number 1 • Invasive Species Edition 

Tag, 

You’re It!

page 44

Hurry Up 

and Wait

page 51

Knocked Out 

by Trout

page 26

Invasive Species

Edition
Natural Inquirer

Barbara McDonald

USDA Forest Service

Research and Development

Athens, GA

Jessica Nickelsen

USDA Forest Service

Research and Development

Athens, GA

USDA Forest Service 

scientists highlighted 

in the journal:

Cathryn Greenberg

Robert Haack

Melody Keena

Kathleen Matthews

Kevin McKelvey

Yvette Ortega

Dean Pearson

Therese Poland

Karen Pope

Haiganoush Preisler

David Williams

Other scientists 

highlighted in the journal:

Stephen Burke

Jennifer Davidson

Peter De Groot 

Kristen Falk

Ronald Knapp

Lindsay Moody

Reginald Nott

Heather Patterson

David Wakarchuk

Produced by:

USDA Forest Service

Washington, DC

Dale Bosworth

USDA Forest Service, Chief

Research and Development

Ann Bartuska, Deputy Chief

Resource Use Research Staff

Sam Foster, Director

State and Private Forestry

Jim Hubbard, Deputy Chief

Conservation Education Staff

Safi ya Samman, Director

Iris Velez, Symbols Program 

Manager

Sue Cummings, Program 

Analyst

Vegetative Management & 

Protection Research Staff

Mary Ellen Dix

Terry Shaw

Forest Health Protection Staff

Kerry Britton

Michelle Andrews

Natural Inquirer Staff Assistant

Resource Use Research Staff

USDA Forest Service

Athens, GA

Linda Ries

Conservation Education 

Coordinator

Intermountain Region

USDA Forest Service

Ogden, UT

With thanks to:

Ed Dickerhoof

Resource Use Research Staff

USDA Forest Service

Washington, DC

Tom Grudowski

6th Grade Science Teacher

Oconee County Middle School

Watkinsville, GA

Dan Miller

USDA Forest Service

Southern Research Station

Athens, Georgia

Jeff Magniez

USDA Forest Service

Southern Region

Blairsville, GA

Offi ce of Communication 

USDA Forest Service

Washington, DC

USDA Forest Service

Southern Research Station

Athens, GA

University of Georgia 

Department of Public 

Administration and Policy

Athens, GA

Agriculture in the Classroom

USDA Cooperative State 

Research, Education, and 

Extension Service

Washington, DC

Cradle of Forestry in America 

Interpretative Association

Brevard, NC

Project Learning Tree

Washington, DC

Invasive Species Edition • Volume 8, Number 1 • Winter 2006
1

The Natural Inquirer • Volume 8, Number 1

Editorial Review Board 

Comments about individual 

articles in this edition from 

the Natural Inquirer editorial 

review board:

“I like the glossary!” 

“I think you did a great job, but you 

could make the meaning of dispersal more clear.”

“I think I learned a lot about how 

animals that are accidentally 

brought somewhere can do a lot of 

damage.”

“I learned how important nature 

really is.”

“Very nice pictures.”

“The glossary is a good idea.”

“I wouldn’t put the questions! I 

think this article was full of facts 

and a lot of interesting stuff.”

“That nun [moths] were very dangerous.” (In reference to nun moths 

in article “And Then There Were 

Nun.”)

“Personally I don’t like questions in 

articles that I read. I just like to look 

at the pictures and read without 

‘quizes.’ Every time I thought there 

was something that was needed in 

the article I read a little further and 

there it was! This is an interesting 

and factual magazine!”

“I like the title, it makes you think.” 

(In reference to “Hurry Up and 

Wait” article)

“I like these pictures! Very colorful 

and they go along with what I am 

reading. I can understand more 

w/these.”

“This is very kool!” (In reference 

to picture of quantum sensor in 

“Hurry Up and Wait.”)

“This is very easy reading, but you 

also get a lot out of it! It’s simple but 

to the point.”

“Great fact to know!”

“The pictures are very helpful to 

understand about the meaning of a 

word.”

“I learned that plants need lots of 

sunlight and about Oriental bittersweet.”

“I think this article is very good. 

The article only had about one or 

two words I didn’t understand.”

“It was ok, but you should try to 

make it a little more interesting.”

 “Cool picture! It shows what the 

scientist are doing.”

Natural Inquirer review board.

Natural Inquirer editorial review board hard at work.
2

The Invasive Species Edition

Note to Educators

As a teacher of science, you want 

your students to acquire abilities 

that will enable them to conduct 

scientifi c inquiry, and you want them to gain 

an understanding of the scientifi c inquiry 

process. Scientifi c inquiry can best be taught 

by integrating minds-on and hands-on 

experiences. Over time, such experiences 

encourage students to independently formulate 

and seek answers to questions about the world 

we live in. As an educator, you are constantly 

faced with engaging your students in scientifi c 

inquiry in new and different ways. In an age 

of abundant technology, standard teaching 

strategies can become monotonous to today’s 

learners. The Natural Inquirer provides a fresh 

approach to science and a view of the outside 

world that is larger than the classroom and can 

still be used while in the school setting. 

The Natural Inquirer is a science education 

resource journal to be used with learners 

from grade 5 and up. The Natural Inquirer 

contains articles describing environmental and 

natural resource research conducted by U.S. 

Department of Agriculture (USDA) Forest 

Service scientists and their cooperators. These 

are scientifi c journal articles that have been 

reformatted to meet the needs of middle school 

students. The articles are easy to understand, 

are aesthetically pleasing to the eye, contain 

glossaries, and include hands-on activities. 

The goal of the Natural Inquirer is to stimulate 

critical reading and thinking about scientifi c 

inquiry and investigation while learning about 

ecology, the natural environment, and natural 

resources.

Science Education Standards 

and Evaluations

In the back of the journal, you will fi nd a matrix 

that enables you to identify articles by the 

national science education standards that they 

address. You will also fi nd evaluation forms in 

the back of the journal. Please make copies of 

these evaluation forms and have your students 

complete them after they complete each 

article. Also, please complete the evaluation 

form for teachers. Send the evaluation forms 

to the address listed below. The address is also 

listed at the bottom of the evaluation forms. 

You and your students may also complete the 

evaluation forms online by visiting http://www.

naturalinquirer.usda.gov. 

This journal is created by Environmental 

and Science Education, a science application 

program of the USDA Forest Service. If you 

have any questions or comments, please 

contact:

Dr. Barbara McDonald

USDA Forest Service

320 Green St.

Athens, GA 30602–2044

706–559–4224

babmac@earthlink.net

Educator Resources

Visit the updated Natural Inquirer Web site at

http://www.naturalinquirer.usda.gov/

educators.cfm. From this site, you can read 

and download lesson plans, word games, and 

other resources to help you use the Natural 

Inquirer in your classroom. You can also view 

and download a yearlong lesson plan aimed at 

helping your students learn about the scientifi c 

process.

Visit the Natural Inquirer Web site at 

http://www.naturalinquirer.usda.gov
3

The Natural Inquirer • Volume 8, Number 1

Note to Educators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

About the Natural Inquirer . . . . . . . . . . . . . . . . . . . . . . . 4

Who Are Scientists? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Welcome to the Natural Inquirer 

Invasive Species Edition . . . . . . . . . . . . . . . . . . . . . . . . 5

Features

Moving Spore-adically: 

The Spread of Sudden Oak Death in 

California Forests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

And Then There Were Nun: 

What Trees Could Be Endangered 

by a Nun Moth Invasion . . . . . . . . . . . . . . . . . . . . . . . 18

Knocked Out by Trout: 

The Relationship Between Nonnative Trout 

and Pacifi c Treefrogs . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Shoot! Foiled Again! 

Using Chemicals To Discourage the 

Pine Shoot Beetle . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Tag, You’re It! 

Using Harmonic Radar To Track the 

Flight of Beetles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Hurry Up and Wait: 

Investigating an Unusual Strategy for Invasion . . . . . 51

Goll-ly! Don’t Take a 

Knapweed! 

The Impact of Nonnative Plants and 

Animals on Deer Mice . . . . . . . . . . . . . . . . . . . . . . . . 58

Refl ection Section Answer Guide . . . . . . . . . . . . . . . . 68

Sample Natural Inquirer Lesson Plan . . . . . . . . . . . . . 76

Student Evaluation Form . . . . . . . . . . . . . . . . . . . . . . . . 77

Teacher Evaluation Form . . . . . . . . . . . . . . . . . . . . . . . . 78

Correlation to National Science 

Education Standards . . . . . . . . . . . . . . . . . . . . . . . . . . 79

What Is the USDA Forest Service? . . . . . . . . . . . . . . . 81

What Is Ag in the Classroom?. . . . . . . . . . . . . . . . . . . . 81

Web Site Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 81

The Natural Inquirer is reproduced on recycled paper 

with soy-based inks. Please pass this journal along or 

recycle it when you have fi nished using it.

page 23

page 61

Contents

page 31
4

The Invasive Species Edition

About the Natural Inquirer

Who Are Scientists?

Scientists are people who collect and 

evaluate information about a wide range 

of topics. Some scientists study the 

natural environment. To be a successful 

environmental scientist, you must:

b Be curious—You must be interested in 

learning.

b Be enthusiastic—You must be 

interested in an environmental topic.

b Be careful—You must be accurate in 

everything that you do.

b Be open minded—You must be willing 

to listen to new ideas.

b Question everything—You must think 

about what you read and observe.

Scientists report their research in 

journals, which are special booklets 

that enable scientists to share 

information with one another. This journal, 

the Natural Inquirer, was created so that 

scientists can share their research with you 

and with other middle school students. 

Each article tells you about scientifi c 

research conducted by scientists in the U.S. 

Department of Agriculture (USDA) Forest 

Service. If you want to know more about the 

USDA Forest Service, you can read about 

it on page 81 of this journal, or you can visit 

the Natural Inquirer Web site at http://www.

naturalinquirer.usda.gov. 

All of the research in the Natural Inquirer 

is concerned with nature, such as trees, 

forests, animals, insects, outdoor activities, 

and water. First, you will “meet the scientist” 

who conducted the research. Then you will 

read something special about science and 

about the natural environment. You will also 

read about a specifi c research project. This is 

written in the format that scientists use when 

they publish their research in journals. Then, 

YOU will become the scientist when you 

conduct the FACTivity associated with each 

article. Don’t forget to look at the glossary and 

the special sections highlighted in each article. 

These sections give you extra information. 

At the end of each section of the article, 

you will fi nd a few questions to help you think 

about what you have read. These questions 

are not a test! They should help you to think 

more about the research. Your teacher may 

use these questions in a class discussion.
5

The Natural Inquirer • Volume 8, Number 1

Welcome

to the Invasive Species Edition of the Natural Inquirer!

Do you know what an invasive species

is? If you are thinking of invaders 

from a distant planet, you are close, 

except that these species invade from right 

here on Earth. Invasive species are any 

plant, animal, or organism that is not native

to the ecosystem it is in, and is likely to cause 

harm to the environment, the economy, or 

human health. Although invasive species 

do not come from another planet, they can 

come across oceans from distant countries. 

Invasive species have the potential to cause a 

lot of damage. They have been estimated to 

cost the United States $100 billion each year!

Because invasive species have the potential 

to cause so much harm, the U.S. President in 

1999 signed an Executive Order that created 

a special council to address invasive species. 

The council, which includes people from 13 

departments of the Federal Government, 

created a special plan to address the threat of 

invasive species.

The plan identifi ed four main ways to 

address invasive species:

1. Prevention. Stop invasive species from 

entering the country in the fi rst place.

2. Early identifi cation and rapid response. Look 

for new areas where an invasive species is 

spreading and quickly destroy it before it 

can spread further.

3. Control. When the invasive species 

cannot be destroyed, keep it from 

spreading further.

4. Restoration. Recreate native ecosystems 

whenever possible.

Pronunciation Guide

Accented syllables are in bold.

Glossary:

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

species: (spe sez): Groups of organisms that 

resemble one another in appearance, behavior, 

chemical processes, and genetic structure.

organism: (ôr gä niz um): Any living thing.

native: (nat iv): Naturally occurring in an area.

restoration: (rest or a shun): The act of 

bringing back to an earlier condition.

nonnative (nän na tiv): Not naturally occurring 

in an area.

exotic: (ig zät ik) Strange, different, or foreign.
6 The Invasive Species Edition

Welcome (continued)

Did You Know?

Invasive species are a special type of 

nonnative species. Nonnative species, 

sometimes called alien species or exotics, may 

not be harmful to an ecosystem. They may 

even provide benefi ts to an area. Examples 

include nonnative bushes and fl owers that 

are planted in gardens around homes and 

offi ces. Invasive species are nonnative species 

that cause harm to the environment, the 

economy, or human health. It is important 

to realize that not all nonnative species are 

invasive and harmful.

The introduction of invasive species can 

be on purpose or accidental. Some invasive 

species are introduced for a specifi c purpose, 

such as controlling another invasive species. 

An invasive species that is brought into an 

ecosystem by accident is sometimes called 

a “hitchhiker.” For example, a person hiking 

may accidentally carry an invasive species 

to another area on a hiking boot, or a dog 

might carry an invasive species on its fur! 

Many invasive species are spread to another 

country in the packing material that carries 

the goods being shipped.

For more information on invasive 

species impacts, visit http://www.

invasivespeciesinfo.gov/impacts.shtml.

What you can do—

b Whenever possible, garden with plants 

native to your area.

b Do not transport plants or animals from 

one country to another.

b Learn and share with others about 

invasive species and how they spread.

In this edition of the Natural Inquirer, you 

will learn about several different invasive 

species. You will learn about how these 

invasive species spread and the studies that 

scientists conduct to better understand and 

stop the spread of invasive species. After 

reading the Natural Inquirer’s Invasive Species 

Edition, you will be able to help spread the 

word about what invasive species are and 

how to stop them!
7

The Natural Inquirer • Volume 8, Number 1

Moving 

Sporeadically:

The Spread of Sudden Oak 

Death in California Forests
8 The Invasive Species Edition

Meet the Scientists

Ms. Patterson: I have really enjoyed all the hiking 

around I get to do in beautiful State parks. My favorite 

science experience was the time Kristen Falk, another 

scientist in this experiment, got chased by a turkey while 

we were tagging trees for an experiment. I don’t think it 

liked her red pants!

Dr. Davidson: My most exciting moment as a scientist 

came while walking in the forest in the rain, collecting 

bay laurel leaves infected by sudden oak death and 

quickly taking them to the fi eld station for viewing under 

the microscope. There, on the underside of the leaves, 

were hundreds of spore sacs. Some had already released 

spores that were swimming in the fi lm of rainwater 

across the surface of the leaf. In that one moment, I saw 

the power of this invasive, disease-causing organism. Each leaf had thousands of 

swimming spores and there were hundreds of infected leaves on most of the bay 

laurel trees that year. The forest was swarming with spores to be carried in the rain 

onto oak trees. In this photo, I am testing diseased oaks in 

Mexico. Photo by Melissa Morris, University of California, 

Davis.

Ms. Falk: This past winter 

I was collecting data in the 

woods. I was putting data into the computer from a 

weather station. When I’m in the woods, I hear all kinds 

of sounds, sometimes an owl, a hawk, a woodpecker, or 

a squirrel squawking at me to get out of their territory. I 

had the computer all set up, then I heard this distinctly 

different sound. It was not loud, but it gave me an uneasy 

feeling. I looked around for another person or other 

woodland creatures. Nothing. I continued working and 

then I heard the sound again. My ears told me the sound 

was close. I looked around and saw a lot of fallen trees downhill from me. I wondered 

if this large tree in front of me was about to fall. I panicked and didn’t have much time 

to think, so I grabbed my computer and ran uphill. Not a minute later, a 20-foot piece 

of the tree cracked off of the top and crashed to the ground, right where I had been 

working. My heart was racing, but I’m glad that I relied on my senses to get out of 

there when I did! I am the one on the right in this photo.

5

5

5
9

The Natural Inquirer • Volume 8, Number 1

Thinking About 

Science 

When scientists prepare to study 

something, they do as much 

research about the topic as 

possible before designing their 

study. That way, they will be 

more successful at asking the 

right questions and fi nding the 

clearest answers. In this study, 

the scientists studied the organism that 

causes sudden oak death. They found that 

the organism is like a fungus. Therefore, they 

learned everything they could about how fungi 

spread from place to place. By understanding 

how fungi spread from place to place, they 

were able to look for a similar process in the 

organism that causes sudden oak death. 

Thinking About the 

Environment

When homeowners create gardens or do 

landscaping around their homes, 

they often use plants that are not 

native to the area in which they 

live. These nonnative plants are 

often transported from country 

to country, and across the 

country from nursery to nursery. 

When a plant is infected with a disease, 

it is not just the plant that is transported 

from nursery to nursery. Sometimes, these 

plants and diseases escape into the natural 

environment, where they become disruptive 

to the natural ecosystem. You can see that 

although we usually think of plants as not 

Glossary:

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

spore (spor): A tiny cell of a plant or animal that 

can grow into a new plant or animal.

fungus (fung gus): An organism without 

chlorophyll that reproduces by spores. 

Mushrooms, molds, mildews, and toadstools are 

types of fungus. (Plural is fungi, fung gi).

native (nat iv): Naturally occurring in an area. 

nursery (nür sür e): A place where young trees 

or plants are raised for study or for sale.

ecosystem (e ko sis tem): Community of plant 

and animal species interacting with one another 

and with the nonliving environment.

mobile (mo bul): Able to move from location to 

location.

species (spe sez): Groups of organisms that 

resemble one another in appearance, behavior, 

chemical processes, and genetic structure.

canker (kang kür): An open sore.

broadleaf (brôd lef): Flat broad leaves.

habitat (hab uh tat): Environment where a plant 

or animal naturally grows and lives.

being mobile, their reproduction and transport 

by humans allows them to spread from place 

to place. If a plant has a disease, the disease 

can spread as well. 
10 The Invasive Species Edition

Introduction

Sudden oak death is a new disease of trees 

and plants in the United States and Europe. 

Although scientists are not certain, they 

believe the fungus-like organism that causes 

sudden oak death was brought into the United 

States from another country. At fi rst, the 

disease was found only in California (fi gure 1). 

Since that time, nursery plants affected with 

the organism that causes sudden oak death 

have been shipped to other nurseries across 

the United States (fi gure 2). 

Figure 1. California.

Figure 2. The location 

of nurseries across 

the United States that 

received plants from 

California nurseries 

that were infected 

with the organism that 

causes sudden oak 

death.

One way the organism spreads is through 

the sale of infected nursery plants to 

homeowners or to nurseries in other locations. 

When such movement occurs, the organism 

can be spread quickly across long distances. 

Spraying plants with a chemical to kill the 

organism does not always work well enough 

to keep the organism from reappearing and 

spreading.

The organism can also spread from plant to 

plant. When the organism that causes sudden 

oak death infects a plant, it is hard to stop its 

spread to other plants and trees. Although the 

organism damages but does not kill all the tree 

species that it infects, it does kill some of them. 

In this study, the scientists wanted to learn how 

the organism that causes sudden oak death is 

spread from tree to tree within a forest. 

N

Relative Risk

 High

Moderate

Low

Refl ection Section

b What is the problem the scientists wanted to 

study?

b Which type of tree would you guess is most 

often killed by the organism that causes sudden 

oak death?
11

The Natural Inquirer • Volume 8, Number 1

Figure 3. Canker 

on an oak tree 

caused by the 

sudden oak death 

organism. Photo by 

Matteo Garbelotto.

Figure 4a. The 

sudden oak death 

organism causes 

the death of leaf 

tips in bay laurels. 

Photo by Jeff Hall.

Figure 4b. The sudden oak death organism 

causes the death of needles on coast 

redwoods. Photo by Jeff Hall.

Figure 4c. The sudden oak death organism 

causes the stem to wilt on Douglas fi r. Photo 

by Jenny Davidson.

Figure 4d. The 

sudden oak 

death organism 

causes the 

leaves to be 

scorched on 

bigleaf maple. 

Photo by Daniel 

Huberli.

What is sudden oak death?

Sudden oak death is a deadly disease 

affecting four oak species in 

California and Oregon. It is caused by 

a fungus-like organism that produces cankers

on the bark of oak trees. These cankers 

look like they are bleeding (fi gure 3). The 

sudden oak death organism also infects 13 

other species of trees in California, including 

California bay laurel, coast redwood, Douglas 

fi r, and bigleaf maple (fi gures 4a–4d). 

Although sudden oak death does not kill 

all the trees that it infects, the infection of 

any tree adds to the problem. When a tree 

is infected with the organism that causes 

sudden oak death, the infection enables the 

disease to continue to spread. 
12

The Invasive Species Edition

Method

The scientists thought the organism that 

causes sudden oak death spreads in a manner 

similar to fungi (fi gure 5). This similarity 

includes the production of spores (fi gure 6). 

The scientists wanted to learn how the 

organism’s spores move from tree to tree 

throughout a forest. The forest they studied 

contained both evergreen trees and broadleaf

trees. The scientists knew that spores of fungi 

are often transported by wind and water and 

through soil. Within a forest, sources of water 

include rain and streams. Soil containing spores 

can be washed into streams or splashed onto 

the leaves of new plants. 

Production of

resting spores

Production 

of infective 

spores

Infection

Survival

Transmission

Movement

Figure 5. The cycle of reproduction of the 

sudden oak death organism.

Figure 6. Spores from the organism that causes 

sudden oak death. Photo by David Rizzo.

The scientists studied an area of land 

covering 166 hectares in California. Within 

this area of land, 17 percent of the coast live 

oak and 82 percent of the bay laurel were 

affected by the organism that causes sudden 

oak death. Sudden oak death can kill as much 

as 20 percent of the coast live oaks it infects 

in a given area (see fi gure 3 in the “Introduction” section). 

Bay laurel trees are not killed by sudden 

oak death disease, but the disease still causes 

problems for the tree. The bay laurel tree’s 

ability to photosynthesize is reduced and 

more leaves are lost from the tree. This loss 

is signifi cant because bay laurel trees provide 

needed habitat and food for wildlife. Even 

though bay laurel trees are not killed by sudden 

oak death, the organism produces millions of 

spores while it is on the leaves. These spores 

may be spread to oaks, which can be killed by 

the organism that causes sudden oak death. 

The scientists placed 30 traps to catch 

rainwater across the area of land (fi gure 7). 

They placed the traps throughout the area 

and collected rainwater over 2.5 years. During 

the rainy season, they collected the rainwater 

every 10 days. During the summer, when there 

were few rainstorms, they collected rainwater 

after each rain. The scientists fi ltered the 

rainwater using a very fi ne fi lter. This fi lter was 

small enough to trap the spores. The scientists 

performed tests to make sure the spores were 

the ones that cause sudden oak death. In this 

Brain Crunches

b Look at figures 4a–4d. Which are evergreen 

trees and which are broadleaf trees?

Number Crunches

b How many acres are equal to 166 hectares? 

Multiply 166 by 2.47 to find out.
13

The Natural Inquirer • Volume 8, Number 1

Study Area

Area outside

of forest–

not forested

Forest outside

of study area

Sites where

screen bags

were placed

in the stream

=

Stream

1 Kilometer

way, the scientists were able to estimate how 

many spores would be released from infected 

trees during a rainstorm.

To determine how far the spores travel 

while it is raining, the scientists put buckets in 

a meadow at the edge of the forest. Bay laurel 

trees affected by sudden oak death disease 

were growing at the edge of the meadow. 

During a rain, the scientists assumed some 

spores would travel away from the bay laurel 

trees, using windblown raindrops as their 

vehicles. The scientists placed buckets 0 

meters, 5 meters, and 10 meters away from 

the trees in the meadow (fi gure 8). They 

collected the rainwater and fi ltered it in the 

same way they fi ltered the rainwater collected 

from the traps. 

The scientists also studied how far spores 

could travel down a stream. The scientists 

Figure 7. Rainwater traps made out of a vinyl 

sheet were stretched over a frame and folded 

over to make a funnel. A 1-gallon jar placed at 

the end of the funnel collected the rainwater.

Figure 8. The buckets placed in a meadow 

near the forest edge. Photo by David Rizzo.

Number Crunches

b How many feet is zero meters? Five meters? 

Ten meters? Multiply the number of meters by 

3.280 to find out. Figure 9. Locations where the trapped leaves 

were placed in the stream.

placed leaves into a screen bag at three 

locations. They put the bags of leaves in the 

stream and tied them so they could not fl oat 

away. If spores were present in the water, 

the trapped leaves would become infected. 

The fi rst location was still in the study area. 

The second location was outside the study 

area but still in the forest where infected trees 

were growing. The leaves placed at the third 

location were 1 kilometer outside the forest 

(fi gure 9). 
14

The Invasive Species Edition

Finally, the scientists wanted to know 

whether spores could be transported on 

people’s shoes. For this part of the study, the 

scientists had the help of students like you. 

Fifteen students hiked a trail in the study 

area. They hiked on 3 different days, with 

fi ve students hiking each day. The scientists 

repeated this experiment at two different 

times. The distance the students hiked was 

2.4 kilometers. At the end of the students’ 

hike, the scientists scraped the soil from the 

students’ shoes into 15 separate bowls. The 

scientists tested the soil in each bowl for the 

presence of spores. They then counted the 

number of students who had transported 

spores on their shoes.

Findings

The scientists found spores in the rain traps 

placed throughout the forest during the rainy 

season but not during the summer. At the 

beginning of the rainy season, the scientists 

found fewer spores than at the end of the 

season. The scientists found that the number 

of spores caught in the traps, however, varied 

from place to place and from year to year.

The scientists found that the farther away 

from the forest edge the buckets were placed, 

the fewer spores were trapped (fi gure 10). 

The scientists found that the leaves fl oating 

in the stream within the study area became 

infected with the sudden oak death organism. 

During the rainy season, they also found 

that spores were present in the stream at 

both other locations, including the location 

1 kilometer downstream from the forest. 

During the dry season, the stream dried out in 

the forest, and the scientists did not fi nd any 

spores downstream during that time.

Figure 10. Percentage of times buckets were 

found with spores in the rainwater.

Percent

50

0 5 10

40

30

20

10

0

Distance from edge of forest in meters

Number Crunches

b How many miles did the students hike? Multiply 

the number of kilometers by .621 to find out.

b How many total students were involved in the 

experiment?

Refl ection Section

b What would the scientists learn by comparing 

the number of spores found after a rain in 

buckets placed in increasing distances from 

infected bay laurel trees?

b What is the difference between the spores found 

in the rainwater traps and in the buckets?

b What would the scientists learn from floating 

leaves in the stream?

b What would the scientists learn from the 

students’ hike?

Number Crunches

b How many miles is 1 kilometer? Multiply the 

number of kilometers by .621 to find out.
15

The Natural Inquirer • Volume 8, Number 1

Of the 30 students who hiked 2.4 

kilometers, 12 of them picked up spores in the 

soil on their shoes. Forty-seven percent of the 

fi rst 15 students’ shoes and 33 percent of the 

second 15 students’ shoes had spores in the soil 

that had clung to their shoes.

This study showed how far the organism 

can travel through rain, streamwater, and 

soil. In particular, the organism can travel 

long distances down streams and on the 

shoes of hikers. Think about the possibility of 

transmitting the organism that causes sudden 

oak death across the country from nursery 

to nursery. If what happened in California 

could happen in other States, think about 

what might happen if the organism spread into 

forests across the United States. Look again at 

fi gure 2 in the “Introduction” section. Could 

sudden oak death get started in your State or 

in a State near you? The organism that causes 

sudden oak death is a new invasive species and 

not much is known about it outside California. 

Because it can kill oak trees, this is a disease to 

which we should pay attention. ■

Refl ection Section

b Basing your answer on the findings, would you 

say that sudden oak death can be transported 

by water? Why or why not?

b Basing your response on the findings, would 

you say that people can transport the spores 

that cause sudden oak death? Why or why not?

b Basing your answer on the findings, under 

what weather conditions would you say the 

transportation of spores is more likely to occur?

Discussion

The fi ndings in this study are similar to 

research done on similar organisms. In other 

words, the organism that causes sudden oak 

death disease is transported from tree to 

tree in a manner similar to other fungus-like 

organisms. The presence of this organism is 

signifi cant because when it is transported to 

new oak trees, it can cause the death of those 

trees. The scientists found that this organism 

is most likely transported from bay laurel trees, 

where the spores infect the tree but do not 

kill it. 

Refl ection Section

b Do oak trees live in your area? What do you think 

would happen if sudden oak death began to kill 

those trees?

b Do you think research should be done on sudden 

oak death outside California? Why or why not?

From: Davidson, J.M.; Wickland, A.C.; Patterson, H.A.; 

Falk, K.R.; Rizzo, D.M. 2005. Transmission of Phytophthora 

ramorum in mixed-evergreen forest in California. 

Phytopathology. 95(5): 587–596.
16 The Invasive Species Edition

Sudden oak death Web resources: 

http://www.suddenoakdeath.org

http://www.na.fs.fed.us/sod/

American chestnut information from S.L. Anagnostakis 

(e-mail: Sandra.Anagnostakis@po.state.ct.us) and 

http://munic.state.ct.us/BURLINGTON/chestnuttree.htm.

FACTivity

In this FACTivity, you will learn about the 

American chestnut tree and compare its 

story to the threat of sudden oak death 

disease. 

The American chestnut was a large 

tree that grew across the Eastern United 

States to the Ohio Valley. American 

chestnut trees could grow so large that 

their trunks sometimes reached 5 feet 

across. The American chestnut was a 

common tree. Its nuts, which were tasty 

and nutritious, were used by both wildlife 

and people. People especially liked to eat 

roasted chestnuts. (Do you remember the 

holiday song, “Chestnuts Roasting on an 

Open Fire”?) The wood from American 

chestnuts was used for furniture and to 

build framing for barns. The trees were so 

numerous that their white blooms often 

made the forests look like they were snow 

capped. 

In 1904, a fungus-like organism was 

brought to the United States. No one 

knows exactly how the organism came 

to the United States. Some think it may 

have come on nonnative chestnut trees 

imported from Asia. This organism enters 

the bark of American chestnut trees 

and kills everything above the place of 

entry. Thus, although the chestnut trees 

are not killed by the organism, they are 

reduced to nothing more than shrub-like 

sprouts. Within 50 years, all large American 

chestnut trees were gone. 

Today, scientists think they will be able to 

bring the chestnut tree back. Even if they 

are able to do so, it will take years for the 

trees to grow. Scientists are not sure how 

the native forest will adapt to this new type 

of large chestnut tree.

In this research article, you read about 

the threat of sudden oak death disease. It 

may seem hard to believe that our Nation’s 

big, strong oak trees could be in danger 
17

The Natural Inquirer • Volume 8, Number 1

because of a fungus-like organism. The 

American chestnut story shows that the 

threat of sudden oak death could be a 

disaster. It could change the look and 

ecology of our Nation’s forests, parks, 

schoolyards, and backyards.

In this FACTivity, you will ride a time 

machine into the future. Imagine you are 

an adult with children the age that you are 

now. Since the time you were their age, the 

organism that causes sudden oak death has 

spread across the United States and killed 

all the oaks. You and your children are now 

living in a world without oak trees. Your 

children have asked you what the forests 

and parks were like when oak trees were 

alive. They want to know if you climbed 

oak trees, if you played under them, and 

what they looked like. 

Write a story for your children about 

living with oak trees. If you have a favorite 

oak tree, you can write about that tree. 

You could tell about climbing an oak tree 

or building a tree house, or you could 

write about that one big oak tree standing 

alone in the park. You may include 

drawings with your story. 

After completing your story, share your 

story with your classmates. You may post 

your stories and drawings on a display. As 

a class, discuss what benefits of oak trees 

were identified in the stories. How might 

your lives be different if oak trees did not 

exist? Basing your response on the class 

discussion, do you think it is important to 

guard against the spread of the organism 

that causes sudden oak death disease? 

Why or why not?

Extension: Students who want an extra 

challenge could do research to learn 

more about recent efforts to bring the 

American chestnut back to American 

forests.

If you are a Project Learning Treetrained educator, you may use PLT Pre 

K–8th Activity Guide #77, “Trees in 

Trouble,” as an additional activity resource. 

This activity teaches how to read signs 

and symptoms of stressed trees.
And Then There 

Were Nun:

Trees That Could 

Be Endangered by a 

Nun Moth Invasion

18 The Invasive Species Edition
19

The Natural Inquirer • Volume 8, Number 1

Meet the Scientist

Dr. Keena: My favorite science 

experience is when the mysteries of 

insect biology or behavior are ultimately 

unraveled at the end of a study.

5

Glossary:

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

nonnative (nän na tiv): Not naturally occurring 

in an area.

species (spe sez): Groups of organisms that 

resemble one another in appearance, behavior, 

chemical processes, and genetic structure.

larva (lär vuh): Wormlike feeding form that 

hatches from the egg of many insects. Larvae 

(lär ve) is the plural. 

organism (ôr gä niz um): Any living thing.

ancestor (an ses tür): An early kind of animal 

from which later kinds have developed.

characteristic (ker ik tür is tik): The special 

character or trait of some person or thing.

habitat (hab uh tat): Environment where a plant 

or animal naturally grows and lives.

conifer (kä na für): A type of evergreen tree 

(pine, fi r, spruce) that has cones.

broadleaf (brôd lef): Flat broad leaves.

crevice (kre vis): A narrow opening caused by a 

crack or a split.

incubate (ing kyu bat): To keep something warm 

and protected so it will hatch.

pupa (pu pa): Intermediate stage of insect 

growth between larva and adult. Pupae (pu pe) 

is the plural.

native (na tiv): Naturally occurring in an area.

foliage (fo le uj): The leaves of a tree or plant.

economic (e ko nom ik): Having to do with 

managing money and resources in a home, 

business, or government.

Thinking About 

Science

In today’s world, we often think about 

our Nation’s security. There are 

many different types of threats to 

our Nation, including biological 

threats from nonnative animal and 

plant species. In this research, 

the scientist studied a species of 

moth that has not yet been found 

in the United States. In Europe and Asia, this 

moth has done much damage to trees. The 

scientist wanted to know what tree species 

in the United States would be damaged if the 

moth were to come into the country. 

To do her study, the scientist brought the 

moth eggs to the United States. When she 

did her experiments, she had to be certain the 

eggs, larvae, or moths did not escape into the 

natural environment. When scientists work 

with dangerous organisms, they must use 

extreme care to make sure their experiments 

are totally secure. 
20 The Invasive Species Edition

way invasive species move from country to 

country. If the nun moth eggs or larvae were 

to come into the United States, they might 

find trees that are favorable to their growth. 

This situation could threaten the health of 

those trees and the forests they grow in.

We hope the nun moth will never invade the 

United States. If it does, however, it would be 

helpful to know which tree species would be 

most at risk. The scientist in this study wanted 

to discover which trees in the United States 

would be the preferred habitat of nun moths.

Thinking About the 

Environment

Over a period of hundreds or thousands of 

years, organisms adapt to survive in 

their environment. Often, similar 

species living in different areas 

have adapted from a common 

ancestor. They may share many 

characteristics, but because 

they have adapted to different 

environments, they may also have different 

characteristics. 

In this study, the scientist examined the 

preferred reproductive habitat of a certain 

type of moth. In Europe and Asia, this moth 

prefers to lay her eggs in particular tree 

species. When the eggs are laid and the larvae 

hatch, the larvae eat the leaves as they grow 

and develop. Eating the leaves damages the 

tree and may even kill it. The scientist wanted 

to know which tree species in the United 

States would be the preferred reproductive 

habitat for this moth, if it were to invade.

Introduction

The nun moth is a major pest of conifers and 

an occasional pest of broadleaf trees in Europe 

and Asia (figure 1). If the moth were to come 

to the United States, it might be a pest in the 

United States as well. So far, the nun moth has 

not been found in the United States. Insects 

like moths can be transported from country 

to country in or on the containers or vehicles 

that hold the goods that countries trade. For 

example, you might notice that your shoes 

were made in another country. Your shoes 

might have been shipped with hundreds of 

shoes in wooden crates when they were sent 

from that country to the United States. 

The nun moth lays her eggs in the crevices

of tree bark (figure 2). Think about what 

might happen if just one nun moth laid her 

eggs in the crevices of wooden crates that 

were shipped to another country. This is one 

Figure 1. Nun moths.

Figure 2. Nun moth eggs in the crevices of 

tree bark.
21

The Natural Inquirer • Volume 8, Number 1

Figure 3. Eastern Europe.

Method

The scientist used eggs that came from 

Eastern Europe (fi gure 3). She incubated the 

eggs (fi gure 4), which caused them to hatch 

into larvae (fi gure 5). She divided the larvae 

into two groups. The scientist observed the 

fi rst group of larvae for the fi rst 14 days of 

their development. She observed the second 

group of larvae through their development 

into pupae. 

Refl ection Section

b In your own words, state the question 

the scientist wanted to answer.

b What is the advantage of knowing in advance 

which tree species might be the preferred 

habitat of the nun moth?

b The scientist did this study in the Northeastern 

United States. Do you think she studied the 

moths inside or outside a laboratory? Explain 

your answer. Figure 4. Nun moth eggs being incubated in 

a mesh packet. You can see the mesh packet 

and eggs inside the petri dish.

Figure 5. The life cycle of the nun moth. The 

eggs are shown in fi gure 2. Here, you can 

see the larva (5a), pupa (5b), and adult nun 

moth (5c).

Finland

Russia

Belarus

Ukraine

Sweden

Poland

Georgia

Syria Iraq

Turkey

Italy

Greece

Germany

Czech

Republic

Black Sea

Baltic Sea

Adriatic Sea

Bosnia and Herzego- vina

Serbia

and

Montenegro

Croatia

Albania

Former Yugoslav

Republic of Macedonia

Slovenia

Moldova

Estonia

Latvia

Lithuania

Austria

Romania

Bulgaria

Slovakia

Hungary

B C

A
22

The Invasive Species Edition

Within each of the two large groups, the 

scientist further separated the larvae into 

groups of 30. She allowed each group of 30 

to feed on one particular tree species. The 

scientist used 26 tree species that are native

to the United States and 8 tree species 

native to Europe or Asia. The larvae that 

were observed until they became pupae 

were allowed to feed on trees native to the 

United States. They also were allowed to 

feed on their two favorite European trees for 

comparison.

For each group of 30 larvae, the scientist 

used a container to hold the larvae. She placed 

the foliage from one tree species into a cup 

with water, and then placed the cup with the 

foliage in a container with the larvae. She 

covered each container with clear plastic to 

allow light to enter (fi gures 6a and 6b). 

Because the foliage needed to remain fresh, 

the scientist periodically placed new foliage 

in the containers. Each time she changed the 

foliage, the scientist removed all contents 

of the container. She counted the number 

of live and dead larvae and recorded her 

observations. She also observed and recorded 

what species of foliage the larvae were eating. 

When the scientist put fresh foliage into the 

container, she placed the remaining live larvae 

back into the container with the fresh foliage. 

At the end of 14 days, the scientist removed 

the fi rst group of larvae from its containers. 

For each container, the scientist counted the 

number of larvae still alive and calculated the 

percentage that had survived 14 days. 

Figures 6a and 6b. Containers that held 

larvae and foliage. There were 34 different 

containers, each with a different species of 

foliage and 30 larvae.

A B

Number Crunches

b How was the percentage of surviving larvae 

calculated?

Remember that larvae from the second 

large group were allowed to develop into 

pupae. For this group, the scientist counted 

and recorded any pupae that had developed 

from larvae and then removed them from the 

container. Removing the pupae left only larvae 

in each container. The scientist removed the 

pupae each time she changed the foliage. She 

continued to do this until all the larvae should 

have developed into pupae, which was a total 

of 70 days. She then counted and recorded 

the number of larvae that did not develop 

into pupae. From this number she was able 

to calculate the overall percentage of larvae 

becoming pupae in each container. 

Number Crunches

b How did the scientist calculate the percentage of 

larvae that had become pupae?

Refl ection Section

b What did this experiment enable the

 scientist to discover?

b When the scientist placed fresh foliage in each 

container, do you think she used the same 

species of foliage that she had removed from 

that container? Why or why not?

b Why do you think the scientist wanted to 

discover what percentage of larvae became 

pupae?
23

The Natural Inquirer • Volume 8, Number 1

Findings

The scientist compared the percentages 

of surviving larvae and pupae for each of the 

34 types of foliage. Basing her calculations 

on this comparison, she rated each of the 

tree species as being suitable, intermediate in 

suitability, or poor in suitability for nun moth 

development. For species rated suitable, few 

additional larvae died after living for 14 days. 

The larvae ate the foliage of every conifer 

species. For most of the conifer species, the 

larvae preferred to eat the young foliage that 

had just emerged. Foliage that had grown in 

previous years was not eaten by most of the 

larvae until they had reached an older stage of 

development (fi gure 7).

The results were mixed for the broadleaf 

species. Some of the broadleaf species were 

not eaten at all. The larvae did not want to 

eat the small young reddish leaves of the white 

oak tree, but when the young leaves turned 

green, the larvae devoured them (fi gures 

8a and 8b). The larvae also ate the foliage 

of gray birch, American beech, black oak, 

northern red oak, and California white oak. 

They also ate the fl owers of wild cherry trees.

Figure 7. The larvae ate the young needles of 

the Norway spruce fi rst. You can see they did 

not eat the older needles.

Figure 8a. The newly unfolded reddish leaves 

of the white oak were not eaten by the larvae.

Figure 8b. After the reddish white oak leaves 

turned green, they became a favorite meal of 

nun moth larvae.

Refl ection Section

b What species of trees do nun moth larvae prefer 

to eat?

b Do you think these findings are good news or 

bad news for people worried about the invasion 

of nun moths into the United States? Why?
24

The Invasive Species Edition

Discussion

If the nun moth were to invade the United 

States, it could cause a lot of problems 

for trees, forests, and people. The forests 

most likely to be affected are those in 

the Northwestern United States, the 

upper Midwestern United States, and the 

Northeastern United States. Many of the 

tree species preferred by nun moth larvae are 

economically important, and their damage or 

loss could affect people working in the forest 

industry. ■

Refl ection Section

b Trees are important to people in forest 

industries, such as those using trees for wood 

products. Many industries that depend on 

forests might need the trees alive and healthy. 

What other forest-dependent industries could 

be affected by a nun moth invasion?

b In addition to economic problems, what other 

kind of problems might be created by the 

damage or loss of a large number of trees in a 

forest?

b What is one way we can protect trees in the 

United States from a possible nun moth 

invasion?

From: Keena, M.A. 2003. Survival and development of 

Lymantria monacha (Lepidoptera: Lymantriidae) on North 

American and introduced Eurasian tree species. Journal of 

Economic Entomology. 96(1): 43–52.

Doing Research on Dangerous Insect Pests

Scientists at the U.S. Department of 

Agriculture (USDA) Forest Service 

use a secure laboratory to conduct 

research with insect pests such as the nun 

moth. The building is locked and has an 

alarm system. When scientists enter the 

building, they must change into special suits 

that they wear only inside the laboratory. 

The laboratory has no windows, and the 

exhaust system has very fi ne mesh through 

which no insect can escape. 

Within the laboratory, scientists handle 

all insects inside safety cabinets, which 

further prevents escape. These cabinets 

also protect the scientists from the insects. 

After the scientists fi nish the experiments, 

they kill all insects and sterilize their remains 

before putting them into special bags. Later, 

specialists will burn these bags, passing 

the exhaust through fi lters. This special 

laboratory enables USDA Forest Service 

scientists to learn about insect pests without 

endangering people or the environment.
25

The Natural Inquirer • Volume 8, Number 1

FACTivity

In this FACTivity, you will use the 

fi ndings from this study to draw a 

conclusion about the possible danger 

from a nun moth invasion. You will answer 

the following question:

Could nun moths damage trees growing 

in your area? 

You will use the following method to 

answer this question:

1. Reread the “Findings” section of this 

article. Make a list of the types of 

trees nun moths like to eat. 

2. Consult a guidebook to learn which 

trees can be found in your area. You 

can fi nd books in the library or you 

can fi nd this information on the Web. 

Usually, guidebooks will present the 

trees that grow in a large area, such 

as the Southeastern United States, 

or the Great Lakes area. Using the 

list you made in #1, identify which 

trees, if any, are growing in your area 

that the nun moth may want to eat. 

Do not forget that, according to this 

article, the nun moth likes all conifer 

trees.

3. Make a list of the trees growing in 

your area that a nun moth might like 

to eat.

4. Basing your conclusion on the list 

you made in #3, what would you 

conclude about the potential impact 

of the nun moth if it were to invade 

in your area? 

5. Hold a class discussion about the 

potential impact of the nun moth 

in your area. Basing your thoughts 

on this discussion, do you think it 

is important to protect the United 

States from a possible nun moth 

invasion? Why or why not?

Activity extension:

Make an inventory of the trees growing 

in your schoolyard. If the nun moth were 

to invade in your schoolyard, what kind 

of effect would it have? How would your 

schoolyard look different? 

If you are a Project Learning Treetrained educator, you may use PLT Pre 

K–8th Activity Guide #40, “Then and 

Now,” and Activity Guide #3, “Peppermint 

Beetle,” as additional activity resources. 

These activities teach what happens when 

a nonnative species is introduced and 

how insects use their sense of smell to 

fi nd food and mates.
The Relationship Between 

Nonnative Trout and 

Pacifi c Tree Frogs

Knocked 

Out by 

Trout:

26 The Invasive Species Edition
27

The Natural Inquirer • Volume 8, Number 1

Meet the Scientists

Ms. Pope: My favorite 

science experience 

was learning about 

the different strategies 

animals use to survive 

in their natural 

environment. For 

example, mountain 

yellow-legged frogs 

survive the long, cold 

winter in the high Sierra 

Nevada mountains by 

fi nding pockets of water 

under the ice and breathing through their 

skin—for up to 9 months at a time.

Dr. Matthews: My favorite science 

experience was seeing the results of 

our research used in new management

programs that led to increased amphibian 

populations.

Dr. Preisler: 

My favorite 

science 

experience is 

talking with 

scientists about 

a new data set!!!! 

For a statistician 

(stat uh stish

un), happiness 

is a new data 

set! Statisticians 

are people who collect and arrange facts 

that are presented in numeric form. This 

photograph was taken in the Canadian 

Rockies.

Dr. Knapp: My favorite 

science experience is 

spending my summers 

in the mountains, 

counting frogs, catching 

bugs, and enjoying the 

most beautiful “offi ce” 

in the world. This 

photograph was taken 

in the Sierra Nevada 

mountains, where this 

research was done.

5

5

5

5
28 The Invasive Species Edition

fl uctuation (fl uk choo a shun): The act of 

continually changing or wavering.

species (spe sez): Groups of organisms that 

resemble one another in appearance, behavior, 

chemical processes, and genetic structure.

publicly (pub lik le): By the government, on 

behalf of all citizens.

Federal (fed ür ul): A union of States having a 

central government. A reference to this central 

government.

metamorphosis (met uh môr fuh sis): The 

process of change in the form of some animals 

from an immature stage to an adult stage.

equation (e kwa zhun): A written statement that 

indicates the equality of two expressions.

altitude (al tuh tud): Height; especially, the height 

above sea level.

Glossary:

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

management (man ij ment): Decisions and 

actions taken to achieve specifi c purposes.

population (päp yoo la shun): The whole 

number of individuals of the same type 

occupying an area.

data (dat uh): Facts or fi gures studied to make a 

conclusion.

biological (bi o loj uh kul): Having to do with 

plants and animals.

germination (jür mi na shun): The act of 

sprouting or beginning to grow.

nonnative (nän na tiv): Not naturally occurring in 

an area.

natural resource (na cha rôl re sôrs): A supply 

of something in nature that takes care of a 

human need, such as oil.

variable (ver e uh bul): Thing that can vary in 

number or amount.

native (na tiv): Naturally occurring in an area.

ecosystem (e ko sis tem): Community of plant 

and animal species interacting with one another 

and with the nonliving environment.

component (käm po nent): Any of the main 

parts of a whole.

Thinking About 

Science

Although all biological scientists collect data, 

they know the differences between 

a study done in a laboratory and 

one done in the natural world. 

One difference has to do with 

the concept of control. When 

scientists want to discover the 

effect something has had on 

something else, they try to control the things 

that can vary, except for the things that they 

want to observe. This is much easier to do 

in a laboratory than in the natural world. In 

a laboratory, for example, if a scientist wants 

to discover the best temperature for seed 

germination, she can control the amount of 

heat reaching different seeds and compare 

their growth. 

In the natural world, this kind of control is 

diffi cult to create. In this study, the scientists 

found an unusual situation in the natural 

world that enabled them to study the effect 

of nonnative trout on a tree frog population. 

In this study, you will learn how past and 

current natural resource management action 

controlled one of the most important variables, 

providing an opportunity for the scientists 

to study the relationship between nonnative 

trout and tree frogs.
29

The Natural Inquirer • Volume 8, Number 1

Introduction

This study was conducted in the Sierra 

Nevada mountains of California (figure 1). 

Many small and large lakes are found in these 

mountains (figure 2). Historically, no fish lived 

in the lakes and frogs were abundant in the 

areas around the lakes. 

Much of the Sierra Nevada mountains 

is publicly owned. The mountain range 

is managed by two Federal Government 

agencies, the U.S. Department of Agriculture 

(USDA) Forest Service and the U.S. 

Department of the Interior National Park 

Thinking About the 

Environment

In a native ecosystem, the living components

have adapted together over time. 

This usually results in a stable 

ecosystem, meaning that within 

certain limits of fluctuation

and possible continuous but 

slow change over time, the 

components remain about the 

same. This stability is threatened when a 

natural or human-created disruption occurs 

within the ecosystem. A natural disruption 

is something such as a hurricane, flood, or 

volcano. Human-created disturbances include 

things such as cutting down all the trees, 

mining, and building roads and buildings. 

Another way that humans have created 

disturbances within stable ecosystems is by 

introducing nonnative species into these native 

ecosystems. When a nonnative species is 

introduced into a stable native ecosystem, the 

relationships that have defined that ecosystem 

change. Often, the nonnative species has 

a negative effect on the native ecosystem. 

In this study, the scientists wanted to know 

how the population of Pacific tree frogs was 

affected by the introduction of nonnative trout 

into lakes that had historically had no fish living 

in them.

Service. You can read about the USDA Forest 

Service on page 81, by visiting the Natural 

Inquirer Web site (http://naturalinquirer.

usda.gov), or by visiting http://fs.fed.us. 

The National Park Service manages the 

Figure 2. A lake found within the Sierra 

Nevada mountains.

Figure 1. Location of the study sites in 

California.

California

N

Location of John Muir

Wilderness and Kings

Canyon National Park ★
30 The Invasive Species Edition

N John Muir

Wilderness

No stocking

Currently

stocked

Kings Canyon

National Park

5 0 5 10

Kilometers

In earlier studies, scientists found a 

relationship between nonnative trout 

populations and a particular frog population. 

The scientists found that when nonnative 

trout are present, the population of mountain 

yellow-legged frogs begins to decline (figure 5).

This change occurs because trout eat frog 

eggs, which the frogs lay in the water.

The scientists were interested in discovering 

whether the Pacific tree frog population might 

also be affected by the presence of nonnative 

trout, similar to the way these trout had 

affected the mountain yellow-legged frog 

population. The scientists wanted to compare 

the populations of Pacific tree frogs with the 

populations of nonnative trout in JMW and 

KCNP (figure 6).

Nation’s national parks, including Yellowstone, 

Yosemite, and Great Smoky Mountains 

National Parks. You can learn more about the 

National Park Service by visiting http://nps.

gov. 

This study took place in an area the USDA 

Forest Service manages in the southern Sierra 

Nevada mountains. This area is called the 

John Muir Wilderness, or JMW. You can read 

about wilderness by visiting the Natural Inquirer

Web site and checking out the Wilderness 

Benefits Edition, or by visiting http://

wilderness.net. In the 1950s, the California 

Department of Fish and Game began stocking 

the fishless lakes with nonnative trout to 

provide fish for fishermen. This practice has 

continued to this day (figure 3).

The National Park Service manages an 

area immediately south of the JMW called 

the Kings Canyon National Park, or KCNP 

(figure 4). In 1977, the National Park Service 

began to phase out stocking the lakes within 

KCNP with nonnative trout. By 2000, fewer 

lakes in KCNP than in JMW had trout living in 

them. In the lakes with trout, scientists found 

almost half the number of trout living in 

KCNP than in JMW. 

Figure 3. Stocking the lakes with fish dropped 

from a plane.

Figure 4. The location of JMW and KCNP in 

the Sierra Nevada mountains.
31

The Natural Inquirer • Volume 8, Number 1

Method

In a laboratory, scientists can control most 

of the variables. When a change occurs or a 

difference is found, the scientists can be fairly 

sure what caused the change. In this study, 

the lakes in JMW and KCNP were almost 

identical. They had been historically fi shless 

and are located very close to each other. 

The ecosystems of these lakes and the areas 

surrounding these lakes are very similar. 

One difference is that the areas are 

managed by different Federal agencies. Before 

1977, both agencies allowed the California 

Department of Fish and Game to stock the 

lakes with nonnative trout. Since 1977, the 

lakes in KCNP have not been stocked with 

nonnative trout and the lakes in JMW have 

continued to be stocked. You can see that this 

difference in management would be a good 

situation for scientists wanting to discover 

whether the number of nonnative trout can 

make a difference in the ecosystem of an area.

The scientists studied 669 lakes in JMW 

and 1,059 lakes in KCNP. The scientists 

walked the shoreline of each lake, recording 

the number of Pacifi c tree frogs that they 

saw (fi gure 7). The scientists recorded the 

existence of adult frogs, frog larvae, and frogs 

that had recently undergone metamorphosis 

Figure 7. Sometimes it was diffi cult for the 

scientists to walk the shoreline and record the 

number of tree frogs that they saw.

Figure 5. Mountain yellow-legged frog.

Figure 6. Pacifi c tree frog.

Refl ection Section

b Basing your response on the information 

presented in the “Introduction,” state in your 

own words what the scientists expected to find 

out about the population of Pacific tree frogs in 

JMW compared with KCNP. Then, give the reason 

for your statement. 

b You read about the concept of experimental 

control in “Thinking About Science.” (If you need 

a reminder, reread that section.) Which variable 

did natural resource management control, 

enabling the scientists to study the effect of 

nonnative trout on Pacific tree frog populations?
32 The Invasive Species Edition

1 2

4 3

5

(fi gure 8). The scientists also recorded the 

presence or absence of nonnative trout in 

each lake. 

The scientists used an equation to learn 

the relationship between the presence of 

nonnative trout and the population of Pacifi c 

tree frogs. They entered the equation and 

their data into a computer. For each lake in 

JMW and KCNP, they entered the number 

of Pacifi c tree frogs found, as well as whether 

nonnative trout were present. The computer 

program was designed to tell them whether 

the tree frog population was about equal in 

each of the lakes, after considering the lake’s 

size, altitude, and other considerations. The 

scientists did not include the presence of 

nonnative trout in the fi rst calculations. 

If the population of tree frogs was about 

equal after considering things such as size 

and altitude, the scientists could conclude 

that the presence of nonnative trout does 

not make a difference in the population of 

Pacifi c tree frogs. If the population of tree 

Figure 8. Frog metamorphosis.

frogs was not equal, the scientists looked at 

whether nonnative trout had been found in 

the lakes where the tree frog populations 

were not equal.

Findings

The scientists found that 7 percent of 

lakes in JMW contained Pacifi c tree frogs, 

compared with 27 percent of lakes in KCNP. 

The percentage of the total water surface 

area containing tree frogs was almost 20 times 

higher in KCNP than in JMW. The lakes 

having the fewest nonnative trout were in 

the southern end of JMW and the northern 

and central sections of KCNP. The highest 

percentage of nonnative trout was found 

in lakes in the northern end of JMW. The 

scientists found this area to have the lowest 

percentage of lakes with tree frog populations. 

The scientists considered all of the 

conditions that might affect the number of 

tree frogs present in a lake, such as its size 

and depth, and how much silt was in the lake. 

After taking these conditions into account, the 

scientists found that lakes with no trout were 

almost four times more likely to have tree 

frogs than lakes with trout.

Refl ection Section

b Why did the scientists not include the presence 

of nonnative trout in their first calculations? 

b Basing your thoughts on previous scientific 

findings about the presence of nonnative trout 

and the population of mountain yellow-legged 

frogs, do you think the scientists found a 

difference in the populations of Pacific tree frogs 

in JMW and KCNP? Why or why not?
33

The Natural Inquirer • Volume 8, Number 1

Discussion

Previous research had shown a relationship 

between the presence of nonnative trout and 

a large reduction in other frog populations 

in the Sierra Nevada mountains. Because 

Pacifi c tree frogs are more widespread than 

mountain yellow-legged frogs, the scientists do 

not believe that nonnative trout will threaten 

the population of Pacifi c tree frogs. They do, 

however, believe that in high mountain areas 

where nonnative trout are present, the tree 

frog population will be reduced. 

Refl ection Section

b Why do you think the scientists 

considered things such as the size and depth 

of the lakes and how much silt was in them?

b After reading the “Findings” section above, 

would you conclude that the presence of 

nonnative trout had an effect on the number 

of tree frogs in a lake? Why or why not?

Refl ection Section

b Garter snakes are a source of food for skunks 

found in the Sierra Nevada mountains. Basing 

your thoughts on what you know about food 

webs and the results of this research, do you 

think it is likely or unlikely that continued 

stocking of nonnative trout could affect the 

population of skunks in the Sierra Nevada 

mountains? Why?

The scientists have also studied how the 

reduction in the tree frog population might 

affect the population of garter snakes in the 

high Sierras. Pacifi c tree frogs and other 

amphibians are a main source of food for 

these garter snakes. The scientists found 

that the continued stocking of high mountain 

lakes in the Sierra Nevada mountains with 

nonnative trout impacted garter snake 

populations as well. ■

From: Matthews, K.R.; Pope, K.L.; Preisler, H.K.; Knapp, R.A. 

2001. Effects of nonnative trout on Pacifi c tree frogs (Hyla 

regilla) in the Sierra Nevada. Copeia. (4): 1130–1137.
34 The Invasive Species Edition

FACTivity

In this FACTivity, you will explore 

whether it is in society’s interest to stock 

the Sierra Nevada lakes with fi sh or to 

stop stocking the lakes. You will use the 

following method:

1. Divide the class into fi ve groups. 

Group 1 will consist of three 

students. The remaining students 

will be divided into four equal-sized 

groups. Two of those groups will 

be arguing in favor of continued 

stocking of the lakes with trout. The 

remaining two groups will be arguing 

in favor of stopping the stocking of 

fi sh. 

2. Using the Internet and other sources, 

research the topic of stocking high 

mountain lakes with trout. Use 

search words such as:

 Sierra Nevada fi sh stocking

 Nonnative trout

 Sierra Nevada fi shing

 Mountain yellow-legged frog

3. Prepare a list of reasons for and 

against fi sh stocking in the Sierra 

Nevada lakes. Depending on 

which side of the argument you 

will take, you will want to highlight 

your position. It is important to 

understand the other position as 

well, so do research on both sides 

of the argument. You may want to 

If you are a Project Learning Treetrained educator, you may use PLT 

Pre K–8th Activity Guide #33, “Forest 

Consequences” or Pre K-8 Activity Guide 

#45, “Web of Life,” as additional activity 

prepare visual aids to support your 

position. Each group should meet 

to decide on its approach to the 

debate. You may appoint one or 

two spokespersons to represent the 

group. The group of three students 

should be excused from doing this 

research.

4. The group of three students will 

function as a citizen advisory 

committee to the governor. While 

the other students are doing their 

research, this group will decide how 

they will make their decision about 

stocking. Will they vote? Will they 

insist on unanimous agreement? 

After listening to the arguments for 

and against stocking, the advisory 

committee will meet privately and 

discuss the issue. Then, the three 

students will make a decision about 

stocking and explain to the class why 

they made their decision.

5. Following the advisory committee’s 

decision, hold a class discussion 

to review the entire exercise. How 

did the four groups feel about the 

advisory committee’s decision? Did 

they feel that their position was fairly 

considered? Do all groups feel that 

the best interests of society have 

been served? Why or why not?

resources. These activities teach how 

different types of land management affect 

ecosystems and introduce how nonnative 

species change the web of life.
35

The Natural Inquirer • Volume 8, Number 1

Shoot! 

Foiled Again!

Using Chemicals 

To Discourage 

the Pine Shoot 

Beetle
36 The Invasive Species Edition

Meet the Scientists

Dr. De Groot: My favorite science 

experience is working outdoors to set 

up and run my experiments so that I can 

discover new facts about trees and forest 

insects.

Dr. Poland: My favorite research 

experience was working in China. The 

experience was so different from the United 

States. Many local farmers and children came 

to help us. The area had very poor farmland 

with trees planted to protect the area from 

wind. The children were so eager to help 

us. They collected beetles for us and stored 

them in wire bicycle baskets.

Dr. Burke: In the 1980s, I created a special 

chemical in a chemistry lab. This was a powerful 

pheromone that is a very strong attractant 

for a particular species of beetle. This beetle 

causes severe damage to logs that will be cut 

into lumber. Tiny amounts of the pheromone 

that I made were formulated into lures, and the 

lures were placed in funnel traps similar to the 

one you see in this photo. One month later, we 

inspected the traps, which we had placed at 

lumber mills. Many traps contained more than 

25,000 beetles and virtually no other insects. 

At one mill, we caught over 12 million beetles in 

1 year. Here was science in action! It was truly 

amazing that the chemical, made in the sterile environment of a laboratory, could cause 

such a strong effect in the fi eld. This photo was taken in China, where I was studying 

the pine shoot beetle. I am the person on the left.

5

5

5
37

The Natural Inquirer • Volume 8, Number 1

 Dr. Wakarchuk:

One of my most 

exciting moments as 

a chemist occurred 

when we took the 

fi rst pheromone 

lures into the fi eld 

during a beetle fl ight. 

It had taken several 

months of work in 

the laboratory to 

create the beetle 

pheromones out of chemicals. When we 

brought the lures out, the tiny beetles were 

landing on our clothing and bouncing off 

our heads. Chemistry really came alive 

when I realized that our clothing had small 

amounts of pheromone on it, and that the 

beetles were strongly attracted to this small 

amount of pheromone. It was very satisfying 

to know that all the chemistry work was 

done right and that the beetles weren’t able 

to distinguish people contaminated with

synthetic pheromone from their normal host 

(a freshly killed tree infested with beetles). 

In this photo, I am holding a multifunnel trap 

that is often used to trap bark beetles. A 

multifunnel trap was used in this research, 

as you will learn.

Dr. Nott:

My favorite 

science 

experience had 

to be meeting 

Dr. Roberta 

Bondar who 

worked at the 

Great Lakes 

Forestry Centre 

when she 

was a student 

attending 

university. Dr. 

Roberta Bondar 

was the second Canadian and the fi rst 

Canadian woman to go into space 

aboard the space shuttle Discovery. 

Shortly after her historic fl ight, she visited 

our Centre to give a fi rsthand account of 

her experience. It was awesome!! Here 

is a photo of me setting up one of the 

traps for the pine shoot beetle. The pine 

shoot beetle emerges very early in the 

spring so our traps had to be installed 

while snow was still covering the ground 

(and me).

Dr. Haack: My favorite science experience 

happened in ancient history (1975–1978) when 

I was working as a forester in the Peace Corps 

in Guatemala in Central America. There was a 

massive outbreak of pine-infesting bark beetles 

that killed millions of pine trees in Guatemala. 

It was that experience that made me want to 

study forest insects, and so after returning to the 

United States in 1978, I went to graduate school 

at the University of Wisconsin to study forest

entomology.

5

5

5
38 The Invasive Species Edition

larva (lär vuh): Wormlike feeding form that 

hatches from the egg of many insects.

pupa (pu pa): Intermediate stage of insect 

growth between larva and adult. Pupae (pu pe) 

is the plural.

emit (e mit): To throw out or eject.

population (päp yoo la shun): The whole 

number of individuals of the same type 

occupying an area.

broadleaf (brôd lef): Flat broad leaves.

control (kän trol): Something used for 

comparison when checking the results 

of an experiment.

average (av rij): The usual kind or amount. 

The number obtained by dividing the sum 

of two or more quantities by the number 

of quantities added.

Glossary:

 vuh): Wormlike feeding form that 

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

pheromone (fair uh mon): A chemical given 

off by certain animals to attract mates, mark 

trails, etc. 

species (spe sez): Groups of organisms that 

resemble one another in appearance, behavior, 

chemical processes, and genetic structure.

synthetic (sin theh tik): Made by putting 

together chemicals rather than using natural 

products.

entomology (en to mul o je): The study 

of insects.

disperse (di spürs): To scatter or spread in 

all directions. 

habitat (hab uh tat): Environment where a plant 

or animal naturally grows and lives.

ecosystem (e ko sis tem): Community of plant 

and animal species interacting with one another 

and with the nonliving environment.

native (nat iv): Naturally occurring in an area.

invasive (in va siv): Tending to spread or 

infringe upon.

resource (re sôrs): Something that takes care 

of a need.

phloem (fl o em): Tissue that transports nutrients 

from the leaves to the rest of the plant.

Thinking About 

Science

Science is a process of discovery that helps 

society by answering questions. 

The questions involve a specifi c 

problem that, when solved, will 

improve something that society 

values. Let’s take this research 

as an example. Society places a 

value on healthy pine trees for a 

number of reasons. In this study, the scientists 

studied pine trees that people were going 

to use during the winter holiday season to 

decorate their homes. 

When an insect attacks and damages or kills 

a large number of holiday pine trees, society 

considers this a problem. Fewer holiday trees 

might mean higher prices for the people who 

want to buy them. Trees damaged by insects 

might also be less attractive. The problem can 

be stated as a question, such as “What can 

be done to prevent an insect from attacking 

pine trees?” Scientists can ask many different 

questions that stem from the same problem. 

In your own words, develop another question 

that scientists could ask, based on the problem 

of insects attacking pine trees.
39

The Natural Inquirer • Volume 8, Number 1

N

Introduction

In a healthy ecosystem, plants and animals 

have adapted together to keep the whole 

system healthy. Healthy ecosystems are 

usually made up of native plants and animals. 

When a nonnative plant or animal invades 

a native ecosystem, the ecosystem can 

be damaged. A nonnative plant or animal, 

called an invasive species, causes damage by 

reproducing so much that it uses too many 

native resources.

The pine shoot beetle (figure 1) is an 

invasive species in the Great Lakes region of 

the United States (figure 2). The pine shoot 

beetle was brought to the United States from 

Europe, Asia, and northern Africa. This 

beetle damages or kills pine trees by using the 

Thinking About the 

Environment

You know that plants have fragrances. 

Think about the fragrances of 

flowers and newly mown grass. 

Scientists call these fragrances 

volatiles (vol uh tilz). They 

are released when a chemical 

inside the plant is exposed to 

air. When exposed to air, the 

chemical evaporates, which causes it to be 

dispersed in the air. Many plants have volatiles 

that humans cannot smell. Insects, however, 

can smell many of these volatiles. Most insects 

smell volatiles using special cells on the surface 

of their antennae. The volatile attracts the 

insects to the plant. They can then use the 

plant for food, as a place to lay their eggs, or 

as habitat. Name one example of an insect 

that uses its antennae to find food.

In this research, the scientists were 

interested in finding out how to prevent a 

particular insect from being attracted to pine 

trees. In this case, when the insect smells the 

volatile and finds the pine tree, its use of the 

tree damages the tree and can even kill it.

Figure 3. The phloem of a tree.

Figure 1. Pine shoot beetle.

Figure 2. The Great Lakes region of the 

United States.

trees for reproduction and feeding. Female 

adult beetles bore a hole into the bark of a pine 

tree along the roots, where they breed with 

a single male. The females then bore into the 

phloem of the tree, where they lay their eggs 

(figure 3). When each egg hatches into a larva, 

the larva further tunnels in the phloem, where 

it becomes a pupa. When the pupa becomes 

Outer Bark

Phloem: Moves the sugars 

produced by photosynthesis 

in the leaves to the cambium, 

to the roots, and for storage 

in the wood

Cambium (produces 

new xylem and phloem)

Heartwood

(central support 

of the tree)

Sapwood

(xylem tissue)
40 The Invasive Species Edition

Ontario, Canada N

★= Study sites

Michigan,

United States

Lake Superior

Lake Huron

Lake Ontario

Lake Erie

Lake Michigan

Wisconsin,

United States

★

★

Figure 4. A young pine shoot beetle feeding 

on a pine shoot.

Method

The scientists conducted two identical 

experiments. One was done in southern 

Ontario, Canada, and the other in southern 

Michigan (fi gure 5). They conducted the 

an adult, it emerges from the tree. These 

young adult beetles then feed on the healthy 

shoots of the pine tree (fi gure 4). As you can 

imagine, when many beetles reproduce in one 

tree, the tree can be damaged or killed.

As you read in “Thinking About the 

Environment,” insects are attracted to plants 

such as trees by smelling their volatiles. Think 

about what might happen if too many pine 

shoot beetles are attracted to a particular pine 

tree. Soon, the tree would have too many 

beetles, and the additional beetles’ needs 

for breeding and eating could not be met. 

Something interesting occurs to keep this 

situation from happening. The beetles emit a 

special type of pheromone that other beetles 

detect. This chemical, called a verbenone 

(vür buh non), tells other beetles that the area 

is overcrowded. As more beetles attack a tree, 

the rising amount of verbenone discourages 

other beetles from using that tree.

Unfortunately, verbenone does not 

discourage other beetles until so many beetles 

are present that the tree is damaged or killed. 

The rising amount of verbenone protects 

the beetle population, but it does not protect 

the tree. The scientists in this study wanted 

to fi nd out if chemicals such as verbenone 

could be used to keep pine shoot beetles from 

attacking trees in the fi rst place. They also 

wanted to know if other volatiles, such as 

those from broadleaf trees, would discourage 

pine shoot beetles from attacking pine trees. 

The scientists thought the use of broadleaf 

volatiles might fool the beetles into thinking 

the pine trees were not really pine trees, but 

broadleaf trees.

Refl ection Section

b Explain in your own words how verbenone 

protects the beetle population but not the 

pine trees. 

b In your own words, ask one question the 

scientists wanted to answer.

Figure 5. The study sites were in southern 

Ontario and southern Michigan. Photo courtesy of Steve Passoa, USDA Animal and Plant Health Inspection 

Service, http://www.forestryimages.org.
41

The Natural Inquirer • Volume 8, Number 1

The scientists repeated the placement of 

the 12 traps in 10 separate areas of each of the 

two pine plantations. 

experiments in holiday tree plantations of 

Scots pine. In these plantations, trees are 

planted in rows and pruned into the popular 

cone shape. You can see some of the trees 

in Dr. Nott’s photo at the beginning of this 

article. The scientists used traps to catch the 

pine shoot beetles. (See the scientists’ photos 

at the beginning of this article.) They baited 

all but one trap with Scots pine volatiles and 

also included other chemicals on some traps to 

discourage the beetles (fi gure 6).

Figure 6. Traps were set containing a 

combination of volatiles and other chemicals.

Trap 

number

Traps 

1–3

Traps 

4–6

Traps 

7–9

Traps 

10–12

Chemicals in 

each trap

No chemicals

Scots pine volatiles. 

The Scots pine 

volatiles should 

attract the beetles.

Scots pine volatiles 

plus broadleaf 

volatiles. The Scots 

pine volatiles 

should attract the 

beetles, and the 

broadleaf volatiles 

should discourage 

the beetles.

Scots pine volatiles 

plus broadleaf 

volatiles plus 

verbenone. 

The addition of 

verbenone, when 

compared with 

traps 7–9, will 

tell the scientists 

whether verbenone 

further detracts 

beetles.

Purpose of trap

Control

To attract beetles. 

This is a test to 

fi nd out whether 

the Scots pine 

volatiles attract 

the beetles.

To attract and 

discourage 

beetles. This 

is a test to fi nd 

out whether the 

broadleaf volatiles 

discourage 

beetles.

To attract and 

discourage 

beetles. This 

is a test to fi nd 

out whether the 

verbenone adds 

to the broadleaf 

volatiles.

Number Crunches

b How many total traps were set on each pine 

plantation? How many traps were set overall?

The scientists collected the beetles from 

the traps twice each week for almost 6 weeks. 

They identifi ed the sex of each beetle and 

counted the number of beetles according to 

its sex. The scientists then compared the 

number of beetles collected in each trap.

Refl ection Section

b Explain in your own words what the scientists 

might learn from each of the four sets of traps 

(from figure 6).

b Why do you think the scientists repeated the 

experiment 10 times on each plantation?

Findings 

The results of the experiment are shown in 

table 1.

As you can see, there were differences 

in the average number of beetles captured 

in Michigan and in Ontario. The pattern for 

each set of traps, however, is similar. In both 

Michigan and Ontario, the number of beetles 

being trapped was much higher when the 

Scots pine volatile was used than when it 

was not used. (Compare the fi rst and second 

set of traps for each place.) Regardless of 

the chemicals used, the average number of 

beetles trapped was much lower than when 

no chemicals except the volatiles were used. 

(Compare the second set of traps in each 

place with the third and fourth sets.) When 
42

The Invasive Species Edition

Traps Average number 

of male pine shoot 

beetles captured

Average number of 

female pine shoot 

beetles captured

Table 1. The average number of beetles caught in each set of traps.

the scientists compared the third and fourth 

set of traps, they found that the addition of 

verbenone made only a small difference in the 

average number of beetles trapped.

Michigan: No chemicals 1 1

Michigan: Scots pine volatiles 77 91

Michigan: Scots pine volatiles plus 25 24

broadleaf volatiles 

Michigan: Scots pine volatiles plus broadleaf 21 18

volatiles plus verbenone

Ontario: No chemicals 0 0

Ontario: Scots pine volatiles 22 21

Ontario: Scots pine volatiles plus broadleaf volatiles 7 8

Ontario: Scots pine volatiles plus broadleaf 5 6

volatiles plus verbenone

Discussion

The scientists found that pine shoot beetles 

can be discouraged from entering a trap that 

contains a combination of broadleaf volatiles 

and verbenone. The scientists suggest that 

Refl ection Section

b Look at table 1. Would you say the Scots 

pine volatiles attracted pine shoot beetles to the 

traps? Why or why not?

b If you were one of the scientists, what would you 

tell people who manage holiday tree plantations 

about the use of chemicals to discourage pine 

shoot beetle damage?

Refl ection Section

b Why do you think the broadleaf volatiles 

discourage the pine shoot beetle from attack?

b Do you think these findings are important to 

people who grow holiday pine trees for sale 

during the winter holiday season? Why or why 

not?

From: Poland, T.M.; De Groot, P.; Burke, S.; Wakarchuk, 

D.; Haack, R.A.; Nott, R. 2004. Semiochemical disruption 

of the pine shoot beetle, Tomicus piniperda (Coleoptera: 

Scolytidae). Environmental Entomology. 33(2).

the number of pine shoot beetle attacks on 

trees can be reduced by placing these chemical 

traps around the edges of holiday pine tree 

plantations and throughout the plantations. ■
43

The Natural Inquirer • Volume 8, Number 1

FACTivity

A beetle’s sense of smell is 

tremendous. The beetle uses smell to 

attract him to something or repel him 

from something. In this FACTivity, we want 

you to think about what scents you really 

like and what scents you really do not 

like. First, make copies of the Scent Chart, 

then take about 5 minutes to list some 

scents that you like and some scents that 

you do not like. Think about why you like 

the scent or why you do not like the scent. 

Does the scent remind you of something? 

Or does it make you hungry? Or does it 

make you feel sick? After 5 minutes, share 

your likes and dislikes with the class. See 

if there are any scents that the whole 

class likes or the whole class dislikes. If 

there are such scents, why do you think 

the whole class feels this way about 

them? Also discuss why a sense of smell 

is important for humans and compare 

the use of this sense of smell for humans 

with the beetle’s use of smell. Are there 

similarities? Differences? 

Dislike

Freshly cut grass

Scent Like Why?

Reminds me of 

springtime and 

gardening

Scent Chart

If you are a Project Learning Treetrained educator, you may use PLT Pre 

K–8th Activity Guide #3, “Peppermint 

Beetles,” Activity Guide #22, “Trees 

As Habitats,” and Activity Guide #77, 

✓

“Trees In Trouble,” as additional activity 

resources. These activities show how 

insects use scent for communication, how 

insects use different parts of trees, and 

how trees express stress.
Using Harmonic 

Radar To Track 

the Flight 

of Beetles

Tag, 

You’re 

It!

44

The Invasive Species Edition
45

The Natural Inquirer • Volume 8, Number 1

Meet the Scientist

Dr. Williams: One of my most 

interesting science experiences was 

placing tags on Asian long-horned 

beetles. Because the beetles eat 

through wood in their early life stages, 

they have very strong jaws. It takes 

two people to tie a tag on them, and 

you have to be very careful because 

when they bite they draw blood! In this 

photograph, Mr. Liu is helping me place 

a tag on a beetle.

5

Glossary:

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

entomologist (en to mul o jist): A scientist 

who studies insects.

native (na tiv): Naturally occurring in an area.

nonnative (nän na tiv): Not naturally occurring 

in an area.

habitat (hab uh tat): Environment where a plant 

or animal naturally grows and lives.

import (im port): To bring goods into one 

country from another.

larva (lär vuh): Wormlike feeding form that 

hatches from the egg of many insects.

pupa (pyü puh): Intermediate stage of insect 

growth between larva and adult.

manager (ma ni jür): A skilled person who 

directs or manages something.

average (av rij): The usual kind or amount. 

The number obtained by dividing the sum of 

two or more quantities by the number of 

quantities added.

antenna (an ten uh): A set of wires used to 

send and receive signals.

speculate (spek u lat): To think about or 

make guesses.

habitat (hab uh tat): Environment where a plant 

or animal naturally grows and lives.

of the words “transmitter” and “receiver” 

because the transmitter also receives the 

signal that is refl ected off the tag.) This signal 

enables the scientist to locate the tag and, 

in this case, the insect to which the tag is 

attached. The refl ected signal is the same for 

all tags, so the scientists must also mark the 

insects so that they can identify individuals. In 

this study, the scientist followed the fl ight of a 

beetle native to China. 

Thinking About 

Science

Technology is giving environmental 

scientists new ways to study the 

natural world. For entomologists, 

technology has enabled them to 

track the movements of fl ying 

insects. To track the movement 

of animals larger than insects, 

scientists use a transmitter placed 

on the animal that sends a signal to a receiver. 

For small fl ying insects, these transmitters are 

too heavy because they require a battery. 

Entomologists are now using technology 

called harmonic radar. The scientist attaches 

a small metal tag to an insect. The tag refl ects 

an electronic signal coming from a hand-held 

transceiver. (Transceiver is a combination 
46 The Invasive Species Edition

Introduction

The Asian long-horned beetle is an insect 

pest that was discovered in New York in 1996 

and Chicago in 1998 (fi gure 1). It arrived in 

the United States on wood packing material 

that was being used to import goods from Asia. 

The beetle lays its eggs under the bark of trees. 

As the larva and pupa develop, they use the 

tree for food. These activities can kill the trees. 

Fortunately, the beetle was quickly identifi ed 

and destroyed in New York and Chicago.

Unfortunately, thousands of trees had to 

be removed from New York and Chicago 

to destroy the Asian long-horned beetle. 

Scientists estimate that if the Asian longhorned beetle had been allowed to disperse, it 

might have cost the United States more than 

$600 billion. The United States could have 

lost millions of trees if the Asian long-horned 

beetle had dispersed across the country.

Thinking About the 

Environment

All animals move. Sometimes movement 

results in animals placing more 

distance between themselves 

and other animals. When animal 

movement results in more 

distance between individual 

animals, scientists call this 

dispersal (dis pür sul). For insects, dispersal is 

often the result of short fl ights, usually made 

when an insect is searching for food or new 

breeding sites for laying eggs. When the insect 

is a nonnative pest with eating or breeding 

behavior that can damage or kill plants, it is 

important to understand its dispersal. 

In this study, the scientist traveled to China 

to study the dispersal of an insect pest that 

had recently been found in the United States. 

By observing the insect’s dispersal in its 

native habitat, the scientist was able to better 

understand how its dispersal might occur in 

the United States.

One key to destroying the Asian longhorned beetle is to remove the trees. After 

removal, the trees are cut into small chips and 

then burned. To be successful in removing the 

trees to destroy the beetles, forest managers

must know about how far the insect moves 

every day. As you read in “Thinking About the 

Environment,” fl ying insects fl y in search of 

food or places to lay their eggs. The scientist in 

this study wanted to know about how far an 

Asian long-horned beetle can fl y every day. 

Figure 1. Asian long-horned beetle. This beetle 

has been painted with a number so it can be 

identifi ed for this study. What is this beetle’s 

number?

Refl ection Section

b State in your own words the question 

the scientist wanted to answer through this 

research. 

b If the Asian long-horned beetle were found 

again in the United States, how would forest 

managers use the scientist’s information to help 

them destroy the insects?

b If a different insect pest were found in the 

United States, should forest managers use this 

information about the Asian long-horned beetle 

to tell them how far the insect might fly? Explain.
47

The Natural Inquirer • Volume 8, Number 1

The scientist planned to release Asian longhorned beetles onto the trees and then track 

their dispersal over 16 days. Before releasing 

the beetles, the scientist placed a metal tag on 

each one (fi gure 3). The tag was tied onto 

the beetle with dental fl oss. The tag included 

Method

The scientist traveled to China to study the 

Asian long-horned beetle. The area studied 

was located at latitude 39°23 ́ N. longitude 

117°00 ́ E. The study site was about 80 

kilometers southeast of Beijing (fi gure 2). 

Number Crunches

b How many miles southeast of Beijing was the 

study site? Multiply 80 by .621 to find out.

The scientist conducted his study on a 

row of existing trees. He found a row of 200 

willow trees that were growing along a fourlane highway. Agricultural fi elds were on both 

sides of the highway. The trees covered a 

straight-line area of almost 1,000 meters. The 

average height of the trees was 5.1 meters. 

5

Figure 3. Asian long-horned beetle released 

on a tree. Can you see the two wires that 

served as antennas? Is this the same beetle 

or a different beetle than the one shown in 

fi gure 1? How do you know?

Number Crunches

b To calculate how many feet 1,000 meters are 

equal to, multiply 1,000 by 3.280. 

b What was the average tree height in feet?

N

Beijing

★ 45 degrees

latitude north

120 degrees

longitude east

105 degrees

longitude east

30 degrees

latitude north

90 degrees

longitude east

Figure 2. Map of China with 

lines of latitude and longitude. 

Latitude and longitude are 

imaginary lines drawn over 

the surface of Earth so places 

can be precisely located. 

Latitude lines mark the 

distance north and south from 

the equator. Longitude lines 

mark the distance east and 

west from the prime meridian, 

an imaginary line running 

through Europe and western 

Africa. Examine this map 

to see if you can locate the 

approximate location of this study.
48 The Invasive Species Edition

two small wires that served as antennas. Each 

beetle was also marked with a number so 

it could be identifi ed. If you have not done 

so, read “Thinking About Science” above. 

This section explains that the scientist used a 

technology called harmonic radar to track the 

dispersal of the beetles. 

The scientist placed between 7 and 12 

beetles on the willow tree trunks every day 

for the fi rst 5 days of the study. He released 

55 beetles overall. Almost equal numbers of 

male and female beetles were released. The 

scientist used different willow trees each 

day for releasing the beetles. He recorded 

each beetle’s number and on which tree it 

was released.

The scientist searched for the beetles from 

the 2nd day of the experiment through the 

last day. He used the transceiver to search for 

beetles in the tree canopy (fi gures 4 and 5). 

He also used binoculars and the naked eye 

to search for beetles (fi gure 6). When the 

scientist found a beetle, he recorded its 

number, sex, and location.

To determine how far a beetle traveled, the 

scientist summed the straight-line distance 

measured each time each beetle was identifi ed 

(fi gure 7). Remember that the scientist also 

recorded the sex of each beetle so he could 

compare the movement of males and females.

Figure 5.

Scientist using 

the transceiver.

Figure 4. Tree canopy.

Figure 6.

Scientists 

searching for 

beetles using 

binoculars and 

the transceiver.

Refl ection Section

b Do you think the scientist should have 

done this study in the United States? 

Why or why not?

b What would have happened if the scientist had 

forgotten to paint a number on each beetle?
49

The Natural Inquirer • Volume 8, Number 1

In earlier research, other scientists found 

that females traveled farther than males. In 

this study, a high percentage of female beetles 

did not travel at all. The scientist speculated 

that the female beetles in this study did not 

travel because they were sexually mature and 

ready to lay their eggs. They probably found 

the willow tree that they were released on 

was a suitable habitat for laying their eggs. 

Figure 7. Example of how the 

total distance traveled was 

recorded. The total distance 

traveled by one beetle was the 

sum of the distances between 

the grey diamonds. The 

diamonds represent the place 

where the beetle was found 

each day. As you can see, the 

beetles moved both within and 

between trees.

Findings

Male beetles traveled more than six times 

the distance of female beetles and moved 

twice as fast. Most females did not move 

from the tree on which they were released. 

Overall, the beetles that moved went equally 

in both directions (east or west) from their 

place of release. After they began moving in 

a direction, most beetles continued moving in 

the same direction. Of those that moved, the 

average distance traveled over the 16 days was 

about 22 meters (table 1). 

Number Crunches

b Calculate the number of feet the beetles moved 

by multiplying the distance in meters by 3.280.

scientist in this study speculated on the 

reasons for the different distances. First, 

the daily air temperature during this study 

was extremely high compared with other 

studies. The daily high temperature averaged 

33.6 degrees Celsius. 

Table 1. Average number of meters traveled 

per day by male and female beetles.

Gender

Male Female

Average number of 

meters traveled per day 3.7 1.9

Number Crunches

b To calculate the temperature in Fahrenheit, 

multiply the temperature by 9/5 then add 32.

Refl ection Section

b Why do you think the beetles moved 

only either east or west and did not move north 

or south? (Hint: Reread the second paragraph in 

“Method” above.)

b Do you think this study completely answers the 

question of how far Asian long-horned beetles 

travel? Why or why not?

The fi ndings in this study are different 

from what other scientists had found about 

the dispersal of Asian long-horned beetles. In 

this study, the beetles did not travel as far as 

the distance other scientists had found. The 

Beginning point End point

General direction of beetle movement
50 The Invasive Species Edition

Discussion

The scientist thinks more studies are 

needed to better understand the dispersal of 

Asian long-horned beetles. Although he found 

that most females did not move from the tree 

that they were released on, one of the females 

traveled more than 30 meters in a little more 

than a week’s time. If the female beetles are 

not ready to lay their eggs as they probably 

were in this study, they may travel longer 

distances. As a dangerous pest of American 

trees, even just a few females traveling 30 

meters in a week’s time could pose a threat. ■

Refl ection Section

b In what way could a few female beetles 

traveling 30 meters pose a threat to American 

trees?

b From the results of this study, what might you 

conclude about the dispersal of Asian longhorned beetles?

From Williams, D.W.; Li, G.; Gao, R. 2004. Tracking 

movements of individual Anoplophora glabripennis 

(Coleoptera: Cerambycidae) adults: application of harmonic 

radar. Environmental Entomology. 33(3): 644–649.

FACTivity

In this FACTivity, you will participate in a 

“rapid response” exercise. You will pretend 

you are scientists responding to the news of 

an Asian long-horned beetle invasion in your 

town. The method you will use is as follows:

Students will work in pairs. Each pair 

represents a team of entomologists who 

are studying the Asian long-horned beetle. 

Your team has just been contacted by the 

Department of Homeland Security. A citizen 

has called with a report of an Asian longhorned beetle. After doing some research, 

the Department of Homeland Security has 

traced the beetle to a shipment of goods 

from China. The beetle arrived in a shipping 

crate. It is unknown how many other beetles 

might be loose in your town. All that is known 

is that the shipment of goods from China 

arrived in your community 15 days ago. 

Your team has been asked to help stop 

the spread of the Asian long-horned beetle. 

Using the data from this study, develop a 

plan for stopping the spread of the beetle. To 

refresh your memory, reread the “Thinking 

About the Environment” and “Introduction” 

sections. Also, you may want to review the 

“Findings” and “Discussion” sections. 

Each team should develop a written plan 

for destroying the Asian long-horned beetle. 

You may want to use visual aids as well. Each 

plan should include reasons for each action 

based on information from this article or from 

other sources about the Asian long-horned 

beetle. Each team should present its plan to 

the class.

Following the presentations, hold a class 

discussion about the various plans. How were 

they similar? How were they different? The 

class may want to vote on the best plan for 

destroying the Asian long-horned beetle. 

If you are a Project Learning Tree-trained 

educator, you may use PLT Pre K–8th 

Activity Guide #8, “Forest of S.T. Shrew,” 

and Activity Guide #22, “Trees As Habitats,” 

as additional activity resources. These 

activities guide the study of microhabitats 

and introduce trees as insect habitat.
51

The Natural Inquirer • Volume 8, Number 1

Hurry Up 

and Wait:

Investigating 

an Unusual 

Strategy for 

Invasion
52 The Invasive Species Edition

Thinking About 

Science

When scientists complete their research, 

they communicate the scientifi c 

method they used and their fi ndings 

with other scientists by submitting 

a writeup of their research 

to a scientifi c journal. Other 

scientists evaluate the writeup 

and make suggestions about how 

the scientists can improve the writeup. The 

Meet the Scientists

Ms. Moody:

My favorite science 

experience 

occurred when 

I was teaching 

high school. I 

taught Earth/

environmental 

science and did a 

stream study on our 

campus with each 

class. I loved seeing the students get 

really excited about the bugs we were 

catching and getting into the data we 

were collecting about the health of their 

stream. My students always told me the 

stream study was one of their favorite 

activities of the semester.

 Dr. Greenberg:

My favorite science 

experience is 

learning how animals 

need plants for food 

and habitat and how 

many plants also 

need animals to 

disperse their seeds 

to new places.

5

5

Glossary:

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

habitat (hab uh tat): Environment where 

a plant or animal naturally grows and lives.

disperse (di spürs): To scatter or spread in all 

directions. 

native (na tiv): Naturally occurring in an area.

diversity (duh vür suh te): The quality of being 

different or varied.

ecosystem (e ko sis tem): Community of plant 

and animal species interacting with one another 

and with the nonliving environment.

nonnative (nän na tiv) Not naturally occurring in 

an area.

defecate (def uh kat): To get rid of waste matter 

from the bowels.

resource (re sôrs): Something that takes care 

of a need.

relationship (re la shun ship): When two or more 

things are connected in some fashion.

germination (jür mi na shun): The act of 

sprouting or beginning to grow.

hypothesis (hi paw thuh sis): An unproven 

idea that is accepted for the time being and is 

often tested during a scientifi c study. Plural is 

hypotheses (hi paw thuh ses).

density (den suh ti): The condition of a 

substance having its parts close together.

writeup may be accepted or rejected by the 

journal based on these evaluations.

If your teacher asks you to write a paper 

and then gives you feedback on how your 

paper can be improved, he or she is doing 

something similar to what scientists do. 

There are two major differences, however. 

When your teacher gives you feedback, you 

know who is making the suggestions for 

improvement. When scientists review and 

evaluate the writeups of other scientists, the 
53

The Natural Inquirer • Volume 8, Number 1

Introduction

The Oriental bittersweet is a vine that was 

transported to the United States from Asia 

in 1860. Oriental bittersweet is attractive, 

partly because it produces lots of bright orange 

berries (figure 2). Unfortunately, birds eat 

the berries and then fly away from the plant. 

When the birds defecate, they deposit the 

seeds deep in the forest, often far from where 

the seeds were eaten. Oriental bittersweet 

escaped from gardens and has spread into 

natural areas where it is not native. When the 

vine takes over natural areas, native vegetation 

cannot compete with it for the resources they 

need. These resources include space, water, 

and sunlight (figure 3).

identity of the reviewers is kept secret. This 

method is called a blind review. A blind review 

gives the reviewers more freedom to make 

suggestions. The other difference is that the 

reviewers do not know who wrote the paper 

they are reviewing. What is one advantage of 

keeping the author’s identity a secret?

Thinking About the 

Environment

When plants are introduced into an area 

where they are not native, they 

sometimes reproduce to the point 

of disrupting or destroying the 

native vegetation. When this 

change happens, plant diversity

is reduced and normal ecosystem

processes are changed. Nonnative

plants that damage a native ecosystem are 

called invasive plants. 

Invasive plants have certain characteristics 

that help them invade and take over the native 

ecosystem. For example, they often produce 

lots of seeds that are dispersed far and wide 

by wind or animals. They can also spread 

by underground roots called suckers. In this 

study, the scientists studied a plant with some 

of these traits called the Oriental bittersweet 

(figure 1). Oriental is a term that used to refer 

to areas east of the Mediterranean Sea. The 

region known now as Asia, therefore, used to 

be called the Orient.

Figure 1. Oriental bittersweet. Photo by Henry 

McNab. 

Figure 3. Oriental bittersweet taking over 

resources in an open area within a forest. 

Photo by Henry McNab.

Figure 2. Oriental bittersweet berries.
54 The Invasive Species Edition

(100%)

Full sunlight

70%

sunlight

= Each pot represents 20 containers with seeds

53%

sunlight

37%

sunlight

20%

sunlight

Shadecloth

Oriental bittersweet, like many invasive 

plants, grows well in an area with a lot of 

sunlight. Often, invasive plants cannot grow 

well in a forest. This lack of growth happens 

because the leaves overhead create a shade 

so deep that invasive plants cannot become 

established. Oriental bittersweet is different. 

It seems as if Oriental bittersweet is able to 

become established in deep shade. Then, it 

just sits and waits for an opportunity to grow. 

At some time in the future, something 

might happen in the forest to disturb the 

deep shade. An old tree could fall over on a 

windy day, or a wildland fi re could burn an 

area of forest. When sunlight hits the small 

Oriental bittersweet, it reacts by growing 

and reproducing quickly. Soon, Oriental 

bittersweet has reproduced so much that it has 

grown over the native plants (see fi gure 3).

The scientists in this study wanted to learn 

more about the relationship between different 

amounts of sunlight and the germination and 

growth of Oriental bittersweet. They wanted 

to test the hypothesis that the amount of 

sunlight reaching the ground will affect the 

percentage of seeds that germinate and the 

rate at which the seedlings grow. 

Method

The scientists conducted their experiments 

in a greenhouse (fi gure 4). The scientists 

planted an Oriental bittersweet seed in each 

of 100 identical containers using the same kind 

of potting soil. They divided the 100 containers 

into 5 groups of 20 containers in each group. 

They exposed each of the fi ve groups to 

a different amount of sunlight (fi gure 5). 

Figure 4. The greenhouse where the scientists 

conducted their experiments.

Refl ection Section

b What human actions caused the problem 

we now have with Oriental bittersweet? What 

actions might be taken today to help solve the 

problem?

b If you were the scientist, how would you set 

up an experiment to compare the amount of 

seed germination and growth under different 

amounts of shade and sunlight?

Figure 5. Each group of containers received 

a different percentage of sunlight by covering 

the containers with different densities of 

shadecloth.
55

The Natural Inquirer • Volume 8, Number 1

Figure 6. The scientists used a quantum 

sensor to measure the amount of sunlight 

reaching each group of containers. Here, 

the scientist is pointing to the part of the 

equipment that senses light. The box on the 

ground records and displays the information.

Figure 7. The scientists covered the containers 

with shadecloth that allowed different amounts 

of sunlight to reach the pots. This photograph 

shows another experiment that is similar to the 

study of Oriental bittersweet, except that the 

pots contain oak seedlings.

The scientists controlled the amount of 

sunlight reaching each group of containers 

by using shadecloth. Shadecloth is like a 

screen but is more fl exible. Shadecloth can be 

purchased at different densities. The denser 

the weave of the shadecloth, the less the 

amount of sunlight that can shine through it. 

The scientists used a piece of equipment 

called a quantum sensor (fi gure 6) to 

measure the amount of sunlight reaching 

each group of containers. 

The scientists covered all but the “full 

sunlight” containers with increasing densities 

of shadecloth in the greenhouse (fi gure 7).

The scientists watered and observed the 

containers every day. They recorded the date 

of seed germination. After 100 days, they 

counted the number of leaves and measured 

the lengths of the plant stems and the roots 

in each container. Then they compared the 

germination and growth of the fi ve groups of 

Oriental bittersweet vines.

Refl ection Section

b What is the reason the scientists used 

shadecloth to cover the four groups of 

containers and a quantum sensor to measure 

the amount of sunlight reaching them?

b Why did the scientists count the number of 

leaves and measure the roots and stems of 

each plant?
56 The Invasive Species Edition

Findings

The scientists found no large differences 

among the different groups of containers 

(table 2). About the same percentage 

of seeds germinated in each group, with 

an average of 55 percent of the seeds 

germinating. 

Even though the differences were not very 

great, the scientists found that the plants in 

containers with 100 percent and 70 percent 

sunlight grew a greater number of leaves and 

had longer stems and roots than the plants 

receiving a smaller percentage of sunlight. 

Look at table 2 and see if you can fi nd the one 

exception to this fi nding.

Table 2. No large differences exist among the groups of containers.

Percentage of sunlight 100 70 53 37 20

Number of leaves 19 18 13 16 13

Days until germination 16 15 13 15 14

Stem length in centimeters 8.1 8.2 7.0 8.2 7.5

Root length in centimeters 27.8 27.8 25.6 26.5 25.2

Discussion

This study shows that Oriental bittersweet 

can become established under a wide range 

of sunlight conditions. Even in heavily shaded 

areas, the seeds will germinate and grow. 

Because of this pattern, Oriental bittersweet 

seeds do not need to be transported to a sunlit 

area to reproduce. Once the plants become 

established in a shaded area, they remain alive 

but do not grow very large. By being able to 

wait until something happens to open a shaded 

area to sunlight, Oriental bittersweet has been 

able to survive and spread across most of the 

United States. ■

Refl ection Section

b Basing your answer on what you know about 

plant germination, does it surprise you that 

Oriental bittersweet germinated and grew at 

about the same rate, regardless of the amount of 

sunlight? Why or why not?

b Reread the second paragraph in the 

“Introduction.” What do you think would happen 

to the plants in the five groups if the scientists 

had let the plants grow for another 100 days 

before measuring them?

Refl ection Section

b Do you think Oriental bittersweet could become 

a bigger threat to native forests in the future? 

Why or why not?

From Greenberg, C., H.; Smith, L.M.; Levey, D.J. 2001. Fruit 

fate, seed germination, and growth of an invasive vine—an 

experimental test of ‘sit and wait’ strategy. Biological 

Invasions. 3: 363–372.
57

The Natural Inquirer • Volume 8, Number 1

FACTivity

In this FACTivity, you will examine how 

different amounts of light affect another type of 

seed’s germination. You will compare this seed’s 

germination pattern with the germination pattern of 

Oriental bittersweet. You will answer the following 

question:

How does the amount of light affect the 

germination of lima bean seeds compared with the 

amount of light affecting the germination of Oriental 

bittersweet seeds? 

You will use the following method to answer this 

question:

 1. Get 16 pieces of screening, like the screening 

you might fi nd on a screen door. Each piece 

should be about 4 inches square.

 2. Get 12 lima beans from a seed store. Put 

potting soil in 12 plastic cups and then plant 

seeds about 3/4ths of an inch to 1 inch below 

the surface of the soil. Water the soil until it is 

moist. Number each cup from 1 to 12.

 3. Place cups 1–4 in direct sunlight. They will 

receive 100 percent sunlight.

 4. Cover cups 5–8 with one layer of screening. 

Cover cups 9–12 with four layers of screening. 

Cups 5–8 will receive 50 percent sunlight, and 

cups 9–12 will receive 10 percent sunlight.

 5. Place cups 5–12 near the cups in 

direct sunlight.

 6. Note that the screening will provide different 

amounts of shade for the cups. 

 7. Water the seeds every day and replace the 

coverings. Count the number of days until 

each seed germinates. Use the chart below to 

record your data.

 8. After all the seeds have germinated, look for a 

pattern in the germination of the seeds. Is the 

pattern similar to or different from the pattern 

of Oriental bittersweet germination (from table 

2 in the “Findings” section)? How is it similar or 

different? Now answer the question posed at 

the beginning of this FACTivity.

 9. Continue to water the seeds for 2 weeks 

and record their progress. At the end of 2 

weeks, measure and record the length of 

the stems. Compare your fi ndings with the 

fi ndings in table 2. How are your fi ndings 

similar or different?

10. Basing your conclusion on the fi ndings in the 

study of Oriental bittersweet, what might you 

conclude about the ability of lima bean seeds 

to survive in the same manner as Oriental 

bittersweet? What would you need to do to be 

certain of your conclusion?

Alternative Method 

of Seed Germination

Use three 9- by 11-inch trays. Place four to fi ve 

moist (not soaked) paper towels on the bottom 

of each tray. Place 10–12 lima bean seeds on the 

paper towels in each tray. Cover the trays with 

plastic wrap and place them in direct sunlight. 

Cover one of the trays with a double layer of 

screening and another with four layers of screening. 

Keep the paper towels moist. Observe and record 

the germination of the seeds using a chart similar to 

the one shown below. This method of germination 

will enable students to see the seeds germinate. 

Days until 

germination

Cups

Cup 1

Full

sun

Cup 2

Full

sun

Cup 3

Full

sun

Cup 4

Full

sun

Cup 5

Med.

shade

Cup 6

Med.

shade

Cup 7

Med.

shade

Cup 8

Med.

shade

Cup 9

Most 

shade

Cup 10

Most 

shade

Cup 11

Most 

shade

Cup 12

Most 

shade

If you are a Project Learning Tree-trained 

educator, you may use PLT Pre K–8th Activity 

Guide #27, “Every Tree For Itself,” and Activity 

Guide #41, “How Plants Grow,” as additional 

activity resources. These activities teach plant 

growth requirements and competition for 

resources, and they investigate various conditions 

for plant growth.
The Impact of Nonnative 

Plants and Animals 

on Deer Mice

Goll-ly! 

Don’t Take a 

Knapweed!

58 The Invasive Species Edition
59

The Natural Inquirer • Volume 8, Number 1

Meet the Scientists

Dr. Pearson: My favorite science experience is when I can 

prove a scientifi c hypothesis. I work in a special scientifi c area 

called community ecology. Community ecology addresses 

the relationships of different kinds of communities within an 

ecosystem, such as plant communities and communities of 

animals. You have to examine many things at once, and these 

examinations make the research very complex. When you 

make a hypothesis about what is happening in a complex 

system and through careful experimentation are able to show 

that your hypothesis is correct, it is very satisfying. In this 

photograph, I am holding a Lynx kitten.

Dr. Ortega: I grew up in southern California in a big city. 

My fi rst biology job took me all the way to the wilds of Alaska. 

That convinced me that I was on the right career path. On 

the fi rst day of work, our boat was approaching a rugged 

shore in Princess Bay where we were to set up our bird 

banding station. We noticed a fi gure on the beach. As we got 

closer, we realized that it was a brown bear, standing on its 

back legs! It did not seem afraid of us or our boat and, in fact, 

was letting us know whose beach it was! We got the picture 

and turned around. But we returned to that beach in Princess 

Bay all summer long to band birds, never again seeing the 

bear, but always paying our respects to her by calling out, 

“Hey Princess!”

Dr. McKelvey: My favorite science experience was not 

in the outdoors, but while sitting at a computer. I had just 

fi nished building a map-based computer model of how 

spotted owls move across the land. The model could draw 

land areas of different sizes and shapes. I was surprised 

to see that large areas of irregularly shaped land behaved 

like networks of smaller areas. Shape was as important 

as size to providing good habitat for the spotted owl. As I 

pondered this fi nding, I realized that many scientists were 

dismissing the importance of the size and shape of land 

areas for wildlife habitat. This realization has shaped my 

career as a scientist. Here is a picture of me handling a 

1-year-old wolverine. I was placing radio collars on 

wolverines to track them as they moved across the land.

5

5

5
60 The Invasive Species Edition

native (na tiv): Naturally occurring in an area.

mammal (ma mul): Any warm-blooded animal 

with a backbone and glands to produce milk for 

feeding their young.

larva (lär vuh): Wormlike feeding form that 

hatches from the egg of many insects. Larvae 

(lär ve) is the plural.

arid (air id): Dry.

prey (pra): An animal hunted for food by 

another animal.

livestock (liv stawk): Animals kept or raised on 

farms or on rangelands.

population (päp yoo la shun): The whole 

number of individuals of the same type 

occupying an area.

Glossary:

tiv): Naturally occurring in an area.

a as in ape

ä as in car

e as in me

i as in ice

o as in go

ô as in for

u as in use

ü as in fur

oo as in tool

ng as in sing

Pronunciation Guide

Accented syllables are in bold.

hypothesis (hi paw thuh sis): An unproven 

idea that is accepted for the time being and is 

often tested during a scientifi c study. Plural is 

hypotheses (hi paw thuh ses).

ecology (e kä luh je): The study of the 

interactions of living things with one another and 

with their environment.

relationship (re la shun ship): When two or more 

things are connected in some fashion.

ecosystem (e ko sis tem): Community of plant 

and animal species interacting with one another 

and with the nonliving environment.

habitat (hab uh tat): Environment where a plant 

or animal naturally grows and lives.

invasive (in va siv): Tending to spread or 

infringe on.

species (spe sez): Groups of organisms that 

resemble one another in appearance, behavior, 

chemical processes, and genetic structure.

nonnative (nän na tiv): Not naturally occurring in 

an area.

larval (lär väl): Relating to the wormlike feeding 

form that hatches from the egg of many insects 

or animals that changes form when it becomes 

an adult.

Thinking About 

Science

In environmental science, scientists see 

no end to the problems they could 

study. Scientists often identify 

new problems to study from 

the fi ndings of earlier research. 

When research is done, more 

questions always emerge at the 

end of a study. Scientists spend 

a lot of time reading and thinking about the 

results of previous research. They may also 

observe on their own what is happening. They 

then think about what information is missing. 

Often, scientists compare what they know 

with what is missing to develop hypotheses or 

predictions. This method of comparison is one 

way that science progresses.

In this study, previous research had 

discovered information about the relationship 

between an invasive plant species and nonnative 

insects that might help to control it. Part of 

the insect’s life cycle includes a larval stage. 

The scientists observed that a native mammal

enjoyed eating these insect larvae. The 

scientists wondered if the substitution of the 

mammal’s usual food with a nonnative food 

might affect the ecology of the whole area.
61

The Natural Inquirer • Volume 8, Number 1

Introduction

One risk to a native ecosystem is an 

invasion of nonnative plants or animals. In the 

Western United States, spotted knapweed is 

one of the most widely found nonnative plants 

(figures 3a and 3b). Spotted knapweed was 

brought to the United States from Eastern 

Europe in the early 1900s. When spotted 

knapweed spreads into an area, it takes over 

and native plants cannot compete with it. This 

change reduces the amount of food available 

to animals that eat the native plants, such as 

livestock and other hoofed animals.

To control the spread of spotted knapweed, 

two types of gall flies have been released into 

Figure 2. Deer mouse being measured during 

this study.

Thinking About the 

Environment

An ecosystem is a community of plants 

and animals that interact with each 

other and with the nonliving 

environment. An ecosystem is 

not a specific size area. It can 

be any size one wishes to study. 

For the purposes of research, 

scientists often define an 

ecosystem by the plant or animal communities 

that live in a particular area. In this research, 

the scientists were interested in the ecosystem 

defined as an arid grassland (figure 1). 

One animal living within this arid grassland 

ecosystem is the deer mouse (figure 2). In an 

arid grassland ecosystem, deer mice usually 

breed and raise their young in the summer 

when food is most easily found. Deer mice eat 

a lot of different foods, including fruits, small 

nuts, insects, and spiders. Deer mice are prey

for a wide variety of other animals, including 

snakes and owls. During the day, deer mice 

hide under rocks, in burrows, and use the 

thick grasses for protection. Using the deer 

mouse as an example, you can see that in an 

ecosystem many different plants and animals 

interact with and depend on each other.

Figure 1. Arid grassland with bluebunch 

wheatgrass and balsamroot. Figures 3a and 3b. Spotted knapweed.
62 The Invasive Species Edition

native foods. The scientists thought that this 

preference could cause a problem for the 

ecosystem overall. 

Gall fl y larvae are available to deer mice 

from September through May of every year. 

They become unavailable in the summer 

when the adult gall fl ies emerge. This change 

means that deer mice, which usually do not 

reproduce in the winter when native food is 

scarce, might be reproducing into the winter 

months because gall fl y larvae are available to 

eat. More importantly, the scientists thought 

that the availability of gall fl y larvae in the 

winter might help more mice to survive the 

cold winters. 

Usually, deer mice reproduce during the 

summer when native foods are available. 

Because knapweed overtakes native plants, 

native foods are less available to the deer mice. 

You can see that the presence of spotted 

knapweed and gall fl ies are changing the 

habits of deer mice. Because gall fl y larvae 

are available to eat throughout the winter, 

the population of deer mice might be growing 

beyond its normal size. 

The scientists wanted to study the effect 

of spotted knapweed and gall fl ies on the 

population of deer mice in arid grassland 

ecosystems. They predicted that they would 

fi nd an overall increase in the population of 

deer mice within these ecosystems.

 

areas with spotted knapweed (fi gure 4). Gall 

fl ies lay their eggs on the fl owerhead of the 

spotted knapweed. When the eggs hatch and 

become larvae, the larvae burrow into the 

fl owerhead to feed on the plant (fi gure 5). 

This feeding destroys the developing seeds 

and helps control the reproduction of spotted 

knapweed.

Unfortunately, these gall fl ies are not native 

to the arid grassland ecosystem. The scientists 

in this study observed that deer mice prefer 

eating gall fl y larvae more than they prefer 

Figure 4. Gall fl y.

Figure 5. 

Cross-section 

of a spotted 

knapweed 

fl owerhead 

showing a gall 

fl y larva (on 

the right).

Refl ection Section

b In your own words, state how spotted 

knapweed and gall flies have changed some 

things for deer mice living in the arid grassland 

in this study.

b What question did the scientists want 

to answer?
63

The Natural Inquirer • Volume 8, Number 1

N

★

★

Method

The scientists selected two large areas to 

study in the Lolo National Forest in Montana 

(fi gure 6). The large areas were similar in 

many ways, except that one had mostly 

native plants and the other had been invaded 

by spotted knapweed. In the area with 

knapweed, gall fl ies had been released and 

were living throughout the area. Within the 

two large areas, the scientists selected four 

smaller areas. Then within each of those four 

areas, they identifi ed four even smaller sites 

to study. 

Figure 6. The location of the Lolo National 

Forest in Montana.

Number Crunches

b How many total sites did the scientists study? 

b How many total areas with spotted knapweed 

did they study?

The scientists trapped deer mice using live 

traps at each of the 32 study areas (fi gure 7). 

Live traps enable scientists to trap animals 

unharmed and then release them back into 

the environment. They baited the traps with 

peanut butter and oats. The scientists checked 

each trap two times every morning for 4 days. 

Figure 7. A live trap in the knapweed.

When a mouse was trapped, the scientists 

weighed it and recorded its sex. They gave 

each mouse a different number and placed an 

ear tag on it. The scientists then released the 

mouse back into the environment.

The scientists repeated the trapping and 

recording of mice for 3 years. They trapped 

mice for 4 days each in May (spring), July 

(summer), and September (fall) of each year. 

The scientists then counted the number of 

different individual mice trapped at each site 

in each of the seasons. They compared the 

number of mice trapped in the spring with 

the number trapped the previous fall. The 

difference between the two numbers would 

give them an estimate of the number of mice 

that had lived throughout the winter.

Refl ection Section

b Why did the scientists select two large areas 

to study—one ecosystem with nonnative 

knapweed and the other a native ecosystem 

without knapweed?

b Why was each deer mouse given a different 

number?

b Why did the scientists collect information 

over 3 years?
64 The Invasive Species Edition

Findings

Throughout the 3 years, the scientists 

checked the traps 21,760 times. They trapped 

583 individual deer mice. If they counted the 

deer mice they trapped more than once, in 

total they trapped deer mice 913 times.

Number of deer mice per site

5

1999 2000 2001

4

3

2

1

0

Knapweed sites

Native sites

Number of deer mice per site

5

6

7

Spring Summer Fall

4

3

2

1

0

5

6

7

4

3

2

1

0

5

6

7

4

3

2

1

0

19 9 9 2 0 0 0 2 0 0 1

Knapweed sites

Native sites

Number Crunches

b What percentage of deer mice were trapped 

more than once? (Hint: Divide 583 by 913 then 

subtract that number from 100.)

b What percentage of the time did the scientists 

trap deer mice? (Hint: Divide 913 by 21,760.)

In all 3 years, the scientists trapped more 

deer mice in the knapweed sites than in the 

native grassland sites (fi gure 8). 

In 1999 and 2000, the number of deer 

mice was larger in every season, except 

for the summer of 2000 (fi gure 9). Look 

closely at fi gure 9. Do you see a difference 

between 1999, 2000, and 2001? The 2001 

numbers show a large decline in the number 

of mice found at knapweed sites. This decline 

probably happened because of the drought 

that occurred over the spring and summer of 

that year. Because the number of knapweed 

plants decreased, the scientists expect that the 

number of gall fl ies was reduced as well.

The scientists found that in the sites with 

knapweed plants, 80 percent of the spring 

population of deer mice trapped were adults. 

This fi nding told the scientists that the winter 

availability of gall fl y larvae helped to keep deer 

mouse adults alive over the winter months.

Figure 8. The average number of deer mice 

trapped per site.

Figure 9. The average number of deer mice 

trapped per site by season of the year.
65

The Natural Inquirer • Volume 8, Number 1

Refl ection Section

b Reread the last paragraph in the 

“Introduction” section. Was the scientists’ 

prediction correct? What is the evidence?

b During the summer when gall fly larvae are 

not available, the population of deer mice 

living in areas with spotted knapweed eats 

more native seeds and insects than it normally 

would eat simply because the total number 

of individuals is higher. How might an overall 

increase in the number of deer mice affect the 

native seeds and insects?

b Do you think the introduction of invasive 

species can upset the ecology of any area? 

Using this study as an example, explain 

your answer.

Discussion

In this study, the invasive plant species 

knapweed was supposed to be controlled 

by the nonnative gall fl y. Unfortunately, the 

knapweed population is still getting larger. 

In addition to not solving the knapweed 

problem, the introduction of gall fl ies has 

affected the population of other animals in the 

ecosystem. ■

From: Ortega, Y.K.; Pearson, D.E.; McKelvey, K.S. 2004. 

Effects of biological control agents and exotic plant invasion 

on deer mouse populations. Ecological Applications. 14(1): 

241–253.

Refl ection Section

b Basing your response on the findings 

and implications of this study, what would you 

conclude about using nonnative species to 

control invasive ones?

b Purple loostrife is an invasive plant. Scientists 

recently found that Galerucella beetles, native 

to Europe and Asia, help control purple loostrife 

by eating its leaves. How does this information 

change your answer to the question above?
66 The Invasive Species Edition

FACTivity

In this FACTivity, you will compare different 

ways of displaying research fi ndings. You 

will answer the following questions in this 

FACTivity:

1. Which of two methods of displaying 

results is easier for you to understand? 

2. Can the use of pie charts, rather than 

tables, help you better understand the 

results of an experiment? 

You will use the following method to 

answer these questions:

1. Look at fi gures 8 and 9 in the article. 

You will be using these fi gures to create 

bar charts (also called histograms).

2. Create four bar charts using the 

information from fi gures 8 and 9. See 

the example below, taken from fi gure 8.

3. Compare your bar charts with the 

fi gures shown in this article. Hold a 

class discussion about the different 

forms. Are the bar charts easier to 

read? More diffi cult? Discuss how 

the same information can be shown 

in different forms. Can you think of 

any other ways to display this same 

information? Answer the fi rst question of 

this FACTivity.

4. Examine the table on page 67.

5. After looking at the table, can you 

determine any patterns in the number 

of deer mice trapped by age class and 

season? If so, what are the patterns?

6. Complete the table by adding up the 

numbers in each of the two columns 

marked “Knapweed” and “Native” for 

each season. Total knapweed trappings 

in the spring is done as an example.

7. Using the total number as the 

denominator, determine the percentage 

of each age class for each season. For 

example, in the spring for knapweed 

trappings, the total of 106, 19, and 8 is 

133. This number has been placed in the 

table for you. The denominator, therefore, 

is 133, and the numerators are 106, 

19, and 8. To calculate the percentage 

represented by 106, divide 106 by 133. 

The answer is .796, or .80. You can see 

that .80 has been placed in the column 

next to 106. The other percentages 

have also been calculated for spring 

knapweed trappings. Fill in the shaded 

areas of the table with your calculations, 

like the example for knapweed trappings 

in the spring.

8. Create six pie charts based on the 

calculated percentages. Label each of 

your pie charts. See the example on 

page 67. This pie chart shows the 

information for spring knapweed 

trappings. To create the pie charts, you 

can use a computer program, such as 

Excel, or you can use a protractor. 

Number of mice per site

7

6

5

Spring

Knapweed Native Knapweed Native Knapweed Native

Summer Fall

4

3

2

1

0
67

The Natural Inquirer • Volume 8, Number 1

Percentage

Spring

 Adult

 Pre-adult

 Juvenile

Total

Summer

 Adult

 Pre-adult

 Juvenile

Total

Fall

 Adult

 Pre-adult

 Juvenile

Total

Season and age class Knapweed Native

Number of deer mice trapped in knapweed and native grasslands by age class and season, 

1999–2001.

Percentage

106

 19

 8

133

 83

26

 12

 81

 40

 25

 .80

 .14

 .06

1.00

 51

 7

3

 

45

19

 15

 44

 39

 19

10. Hold a class discussion about whether 

the pie charts helped you understand 

the findings of this research. What 

are the advantages of using charts 

and graphs over tables? What are 

the disadvantages? Reread the first 

paragraph of this FACTivity. What is the 

answer to question #2?

9. After you complete and label your pie 

charts, revisit the question asked in 

#5, above. This time, use the pie charts 

rather than the table to describe the 

patterns. 

Juveniles

Pre-adults Adults 6%

14%

80%

Deer Mice Trapping During Spring, 

Knapweed, 1999-2001

If you are a Project Learning Treetrained educator, you may use PLT Forest 

Ecology Secondary Module #4, “Home 

Sweet Home,” Pre K–8th Activity Guide 

#45, “Web of Life,” and Activity Guide 

#43, “Seeds Will Travel,” as additional 

activity resources. These activities 

introduce how nonnative insect control 

affects the web of life and how seed 

dispersal varies.
68 The Invasive Species Edition

The following section provides a guide to possible answers to the refl ection questions found in 

each section of the articles. Refl ection Sections 

are meant to stimulate critical thinking about the 

article, not to test knowledge. Use the answers 

below as a guide to stimulate critical thinking and 

discussion in your classroom.

 Refl ection Section Possible Answers

oak death if spores were in the stream. This 

part of the experiment would tell the scientists 

if spores were in the stream within the forest 

and, if so, if the spores could survive in the 

water 1 kilometer downstream of the forest.

• What would the scientists learn from the 

students’ hike? The scientists would learn 

whether spores from infected trees would get 

in the soil and then onto the students’ shoes. 

They would learn whether the spores would 

remain on the shoes after a 2.4-kilometer 

walk. This fi nding would tell the scientists 

whether hikers can transport sudden oak 

death if they walk through a forest with 

infected trees.

Findings

• Basing your answer on the fi ndings, 

would you say sudden oak death can be 

transported by water? Why or why not? 

Yes. The evidence indicates that the spores 

that cause sudden oak death are transported 

by rainwater and down streams.

• Basing your response on the fi ndings, 

would you say that people can transport 

the spores that cause sudden oak death? 

Why or why not? Yes. The student hiking 

experiment showed that spores are in the soil 

and can be transported after the soil gets onto 

hikers’ shoes.

• Basing your answer on the fi ndings, 

under what weather conditions would 

you say the transportation of spores 

is more likely to occur? During the rainy 

season, or when it rains.

Discussion

• Do oak trees live in your area? What do 

you think would happen if sudden oak 

death began to kill those trees? These 

questions are for individuals and each 

Moving Spore-adically

Introduction

• What is the problem the scientists 

wanted to study? The problem is that 

sudden oak death, a disease that can damage 

or kill trees, is spread from tree to tree within 

a forest. The scientists wanted to know how 

sudden oak death is spread from tree to tree in 

order to try to stop it. 

• Which type of tree would you guess is 

most often killed by the organism that 

causes sudden oak death? Oak.

Method

• What would the scientists learn 

by comparing the number of spores 

found after a rain in buckets placed in 

increasing distances from infected bay 

laurel trees? They would learn about how 

far the spores travel from affected trees across 

open spaces during a rain.

• What is the difference between the 

spores found in the rainwater traps and 

in the buckets? The rainwater traps would 

tell the scientists how many spores can travel 

from infected trees in the forest through rain 

to the ground. The bucket traps would tell 

the scientists how far spores can travel from 

infected trees across open spaces during a rain.

• What would the scientists learn from 

fl oating leaves in the stream? The fl oating 

leaves would become infected with sudden 
69

The Natural Inquirer • Volume 8, Number 1

student should come up with his or her own 

ideas. Some potential answers include: 

(1) Animals that use oak trees for food and 

habitat would no longer have a place to live, 

(2) the beauty of oak trees, including what 

they contribute to the area, would be lost, 

and (3) the ecology of forests with a lot of oak 

trees would be changed.

• Do you think research should be done 

on sudden oak death outside California? 

Why or why not? Yes. Because sudden 

oak death can kill oak trees and is easily 

transported from tree to tree in California, 

it would be best to know how it might be 

transported in areas outside California and 

which trees might be affected. 

And Then There Were Nun

Introduction

•In your own words, state the question the 

scientist wanted to answer. Which tree 

species in the United States are most likely to 

be the preferred habitat of the nun moth?

• What is the advantage of knowing in 

advance which tree species might be the 

preferred habitat of the nun moth? If the 

nun moth were found in the United States, 

people would already know which tree species 

the moths prefer as habitat. People could stop 

the spread of the nun moth by cutting down 

those trees within the area where the moths 

were found, or by otherwise controlling the 

moths before they spread. 

• The scientist did this study in the 

Northeastern United States. Do you 

think she studied the moths inside or 

outside a laboratory? Explain your 

answer. The scientist had to do her study 

inside a laboratory because she did not want 

any eggs, larvae, or moths to escape into the 

outside environment.

Method

• What did this experiment enable the 

scientist to discover? The scientist 

discovered which species of foliage kept larvae 

alive and which species of foliage supported 

the development of larvae into pupae. 

• When the scientist placed fresh foliage 

in each container, do you think she used 

the same species of foliage that she had 

removed from that container? Why or 

why not? Yes. If she used foliage from a 

different tree species, she would have no way 

of knowing which species of foliage supported 

the larvae’s development.

• Why do you think the scientist wanted 

to discover what percentage of larvae 

became pupae? If the scientist had stopped 

the entire experiment at 14 days, she might 

have overestimated the percentage of healthy 

larvae. Some larvae may have lived but might 

never have become pupae.

Findings

• What species of trees do nun moth larvae 

prefer to eat? Most conifer species and many 

oak species appear to be preferred by nun 

moth larvae.

• Do you think these findings are good news 

or bad news for people worried about the 

invasion of nun moths into the United 

States? Why? These findings would be bad 

news for people worried about a possible 

nun moth invasion because nun moth larvae 

appear to survive on a wide variety of tree 

species that are found in the United States.

Discussion

• Trees are important to people in forest 

industries, such as those using trees for 

wood products. Many industries that 

depend on forests might need the trees 

alive and healthy. What other forestdependent industries could be affected 

by a nun moth invasion? You may need to 
70 The Invasive Species Edition

encourage your students to think outside the 

box. One forest industry that encompasses 

many different businesses is the tourism 

industry. If many trees are damaged or die 

from a nun moth invasion, people may not 

want to visit the forest for recreational 

activities such as hiking, bird watching, 

camping, and boating. This lack of visitors 

could affect businesses such as hotels, stores, 

restaurants, and recreation guides. Your 

students may think of other industries that 

could be affected.

•In addition to economic problems, what 

other kind of problems might be created 

by the damage or loss of a large number 

of trees in a forest? It would cause a lot of 

environmental damage, which could include 

the loss of habitat for animals, increased 

erosion that results in loss of soil and in water 

siltation, and a loss of tree diversity.

• What is one way we can protect trees 

in the United States from a possible nun 

moth invasion? Your students may come up 

with a variety of suggestions. Some obvious 

ones include: (1) Carefully inspect wooden 

packing crates for nun moth larvae before 

allowing them into United States ports, and 

(2) teach people how to identify nun moths so 

that if they do come into the United States, 

they can be dealt with before they spread.

Knocked Out by Trout

Introduction

• Basing your response on the information 

presented in the “Introduction,” state 

in your own words what the scientists 

expected to find out about the population 

of Pacific tree frogs in JMW compared 

with KCNP. Then, give the reason for 

your statement. Your students may state 

it differently, but in essence, they should 

state that the scientists expected that the 

population of Pacific tree frogs would be lower 

in JMW than in KCNP. The reason for this 

expected answer is the higher population 

of nonnative trout found in JMW compared 

with KCNP.

• You read about the concept of 

experimental control in “Thinking 

About Science.” (If you need a reminder, 

reread that section.) Which variable did 

natural resource management control, 

enabling the scientists to study the effect 

of nonnative trout on Pacific tree frog 

populations? The number of nonnative trout 

living in the lakes in JMW and KCNP was 

controlled by the natural resource managers.

Method

• Why did the scientists not include the 

presence of nonnative trout in their first 

calculations? If the number of tree frogs was 

about the same between JMW and KCNP, 

then the number of nonnative trout did not 

affect the population of tree frogs, and the 

scientists would have no reason to count their 

presence or absence.

• Basing your thoughts on previous scientific 

findings about the presence of nonnative 

trout and the population of mountain 

yellow-legged frogs, do you think the 

scientists found a difference in the 

populations of Pacific tree frogs in JMW 

and KCNP? Why or why not? Yes. One 

would expect to find a difference based on 

the previous research. The previous research 

indicated that when nonnative trout are 

present, the population of frogs is lower than in 

areas where nonnative trout are not present.

Findings

• Why do you think the scientists 

considered things such as the size and 

depth of the lakes and how much silt 

was in them? The scientists considered that 

these other things could also influence the 

presence and number of tree frogs in a lake. 

If they did not consider these things, they 

would not know for sure whether the number 
71

The Natural Inquirer • Volume 8, Number 1

of tree frogs in a lake was due to the lake’s 

characteristics or whether it was due to the 

presence and number of nonnative trout.

• After reading the “Findings” section 

above, would you conclude that the 

presence of nonnative trout had an effect 

on the number of tree frogs in a lake? 

Why or why not? Yes. The evidence shows 

that after considering the characteristics of the 

lakes, the presence and number of nonnative 

trout had the strongest relationship with a 

lower number of tree frogs. 

Discussion

• Garter snakes are a source of food for 

skunks found in the Sierra Nevada 

mountains. Basing your thoughts on 

what you know about food webs and the 

results of this research, do you think it is 

likely or unlikely that continued stocking 

of nonnative trout could affect the 

population of skunks in the Sierra Nevada 

mountains? Why? It seems likely that a 

reduction in an animal population’s food source 

would affect its numbers. If fewer tree frogs are 

available as food and the population of garter 

snakes is therefore reduced, it seems likely 

that the population of skunks could be affected 

as well. Your students might have different 

explanations, such as the skunks finding a new 

food source. Above all, the students should be 

able to support their answers.

Shoot! Foiled Again!

Introduction

• Explain in your own words how 

verbenone protects the beetle population 

but not the pine trees. The verbenone 

is emitted from individual beetles as they 

reproduce, eat, and grow. When a large 

number of beetles is on a tree, the combined 

amount of verbenone tells other beetles 

that many beetles are already present. This 

message discourages more beetles from 

attacking the tree and, therefore, encourages 

them to find new trees. The number of beetles 

present at this point is already high enough to 

damage or kill the tree. 

•In your own words, ask one question 

the scientists wanted to answer. (1) Can 

verbenone be used to discourage pine shoot 

beetles from attacking pine trees? (2) Can 

other volatiles, such as those from broadleaf 

trees, be used to discourage pine shoot beetles 

from attacking pine trees? Your students may 

state these questions a little differently.

Method

• Explain in your own words what the 

scientists might learn from each of the 

four sets of traps (from figure 6). The first 

set of traps is a control. With no chemicals, 

it provided a way to equally compare each of 

the other traps. The second set contained the 

chemical that attracts pine shoot beetles to 

Scots pine. This set of traps told the scientists 

how many beetles would be attracted in the 

absence of any repelling chemical. The third 

set of traps contained the attractant and the 

broadleaf chemicals that might discourage 

beetles. This set of traps, when compared 

with the second set, told the scientists how 

many beetles might be discouraged from 

Scots pine trees when using chemicals from 

broadleaf trees. The fourth set of traps 

contained the attractant, the broadleaf 

chemicals for discouraging beetles, and the 

verbenone, which should also discourage 

beetles. This set of traps, when compared 

with the third set, told the scientists how 

many more beetles might be discouraged 

from Scots pine trees with the addition of 

verbenone to the broadleaf chemicals.

• Why do you think the scientists repeated 

the experiment 10 times on each 

plantation? The more traps that could be 

set and compared, the more confidence the 
72

The Invasive Species Edition

scientists could have in their results. If the 

traps set in different areas of the plantation 

showed different results, then the scientists 

might suspect that something more than the 

chemicals was affecting the behavior of the 

beetles. If the results were similar across all 

experiments, then the scientists could assume 

that the beetles’ behavior was the result of the 

different chemicals in the traps. 

Findings

• Look at table 1. Would you say the Scots 

pine volatiles attracted pine shoot beetles 

to the traps? Why or why not? Yes. The 

average number of beetles caught was much 

higher than in the control, which contained no 

attractant.

•If you were one of the scientists, what 

would you tell people who manage 

holiday tree plantations about the use 

of chemicals to discourage pine shoot 

beetle damage? I would tell them they 

can discourage the pine shoot beetle by 

using broadleaf volatiles or a combination of 

broadleaf volatiles and verbenones.

Discussion

• Why do you think the broadleaf volatiles 

discourage the pine shoot beetle from 

attack? Because the broadleaf volatiles smell 

like a broadleaf tree to the beetle. Broadleaf 

trees are not the preferred habitat of the 

beetle. The beetle is fooled into thinking the 

tree is a broadleaf, not a pine.

• Do you think these findings are important 

to people who grow holiday pine trees for 

sale during the winter holiday season? 

Why or why not? Yes. If the pine shoot 

beetle damages or kills too many holiday trees, 

the trees will not be available for sale. If the 

people who grow these trees cannot sell them, 

they will lose money.

Tag, You’re It!

Introduction

• State in your own words the question 

the scientist wanted to answer through 

this research. About how far do Asian longhorned beetles fly in a day’s time? 

•If the Asian long-horned beetle were 

found again in the United States, how 

would forest managers use the scientist’s 

information to help them destroy the 

insects? They could determine approximately 

how far and how fast the insects would 

disperse. This information would help them 

determine how large an area they would need 

from which to remove and burn the trees.

•If a different insect pest were found in the 

United States, should forest managers use 

this information about the Asian longhorned beetle to tell them how far the 

insect might fly? Explain. If the insect pest 

were similar to the Asian long-horned beetle, 

the information learned in this study could be 

used as a guide, if no other information were 

available. Different insect species behave 

differently, however, and it could be disastrous 

to use information learned about one insect 

and apply it to the behavior of another.

Method

• Do you think the scientist should have 

done this study in the United States? 

Why or why not? No. The Asian longhorned beetle is an insect pest in the United 

States. It might be disastrous to do this study 

in the United States. Beetles would likely 

escape from the study area and destroy trees. 

• What would have happened if the 

scientist had forgotten to paint a number 

on each beetle? The scientist would have 

no idea how far each beetle had dispersed, 

because he would have no way of knowing 

which beetle was which.
73

The Natural Inquirer • Volume 8, Number 1

Findings

• Why do you think the beetles moved 

only either east or west and did not move 

north or south? (Hint: Reread the second 

paragraph in the “Method” section.) The 

study site was a row of willow trees growing 

along a highway with agricultural land on 

either side. Therefore, the beetles were most 

likely to fly from tree to tree, which were lined 

up east to west.

• Do you think this study completely 

answers the question of how far Asian 

long-horned beetles travel? Why or 

why not? The study does not completely 

answer the question because its findings 

were different from other findings. It gives a 

clue about the relationship between distance 

traveled and air temperature. It also provides a 

clue as to the relationship between the sexual 

maturity of females and whether and how far 

they will travel.

Discussion

•In what way could a few female beetles 

traveling 30 meters pose a threat to 

American trees? If the females laid eggs, 

those eggs could hatch and the population of 

Asian long-horned beetles would increase. 

To control the beetle population, forest 

managers might have to cut down hundreds or 

thousands of trees.

• From the results of this study, what might 

you conclude about the dispersal of Asian 

long-horned beetles? You might conclude 

that higher air temperatures slow the dispersal 

of beetles. You might also conclude that after 

a beetle begins to move, he will most likely 

continue to move in the same direction. You 

might also conclude that female beetles that 

are ready to lay eggs will be less likely to travel 

than female beetles that are not yet ready to 

lay eggs.

Hurry Up and Wait

Introduction

• What human actions caused the problem 

we now have with Oriental bittersweet? 

What actions might be taken today to 

help solve the problem? On the surface, the 

answer would be that we imported Oriental 

bittersweet as an ornamental plant, and this 

action certainly started the problem. You can 

challenge your students, however, to consider 

other actions that have expanded the current 

problem. Other actions include gardeners 

being careless with the plant and allowing it 

to escape from gardens. They also include 

using the plants for indoor arrangements, then 

discarding the plants outdoors along with 

their seeds. Actions that might help solve the 

problem include educating people about the 

danger posed by Oriental bittersweet and 

helping people identify the plant. People could 

also learn how to remove or destroy the plant 

when they find it.

•If you were the scientist, how would you 

set up an experiment to compare the 

amount of seed germination and growth 

under different amounts of shade and 

sunlight? You could take the seeds and plant 

them in containers. Then you could place 

them under different amounts of sunlight and 

shade and compare their germination and 

growth. You can ask your students to be as 

specific as possible as they think about how 

they would do this experiment.

Method

• What is the reason the scientists used 

shadecloth to cover the four groups of 

containers and a quantum sensor to 

measure the amount of sunlight reaching 

them? By using shadecloth, the scientists 

could control the amount of sunlight reaching 

the containers. By using the quantum sensor, 
74

The Invasive Species Edition

they could know exactly what percentage of 

sunlight was reaching each group of containers.

• Why did the scientists count the number 

of leaves and measure the roots and stems 

of each plant? The scientists needed a way 

to compare the growth rate of the plants. By 

counting and measuring, the scientists could 

compare the plants’ growth. Counting and 

measuring provided a way to compare the 

plants without introducing personal opinion or 

evaluation into the process. 

Findings

• Basing your answer on what you know 

about plant germination, does it surprise 

you that Oriental bittersweet germinated 

and grew at about the same rate, 

regardless of the amount of sunlight? 

Why or why not? Students should know 

that most plants will germinate better either 

in more sunlight or in less sunlight, depending 

on the unique needs of the plant. It is unusual 

for a plant to germinate and grow almost 

equally regardless of the amount of sunlight 

it receives. Students should be able to back 

up their answers with their own evidence 

or knowledge.

• Reread the second paragraph in the 

“Introduction.” What do you think 

would happen to the plants in the 

five groups if the scientists had let the 

plants grow for another 100 days before 

measuring them? The Oriental bittersweet 

plants growing in 100 percent and 70 percent 

sunlight should grow much faster and have 

more leaves than the plants in the more 

shaded conditions. 

Discussion 

• Do you think Oriental bittersweet could 

become a bigger threat to native forests 

in the future? Why or why not? Oriental 

bittersweet will likely become a bigger threat 

in the future. The reasons are that it can 

germinate and grow in shaded conditions, 

and it can sit and wait until an area is open to 

sunlight before it grows quickly and further 

reproduces. Regardless of the answers your 

students give, they should be able to back up 

their answers with observations, knowledge, 

or logic.

Goll-ly! Don’t Take a Knapweed!

Introduction

•In your own words, state how spotted 

knapweed and gall flies have changed 

some things for deer mice living in the 

arid grassland in this study. The spotted 

knapweed has reproduced so much that 

native grasses and other native plants are 

overtaken and choked out. The addition of 

gall flies has caused the feeding cycle of deer 

mice to change. They now can eat as much 

as they want from September to May. Then 

in the summer, their food source is reduced. 

This situation is the opposite of their natural 

cycle. This change may also be causing the 

population of deer mice to increase because 

of the wide availability of food for much of 

the year.

• What question did the scientists want 

to answer? Is the population of deer mice 

higher in areas where spotted knapweed has 

overtaken native plants and gall flies have been 

released to control it?

Method

• Why did the scientists select two large 

areas to study—one ecosystem with 

nonnative knapweed and the other a 

native ecosystem without knapweed? 

The question the scientists wanted to answer 

required them to compare a native ecosystem 

with a grassland area that had been overtaken 

by nonnative knapweed.

• Why was each deer mouse given a 

different number? Each deer mouse was 
75

The Natural Inquirer • Volume 8, Number 1

given a different number so the scientists 

could tell if they had trapped the same mouse 

twice. Also, when recording the weight and 

sex of each mouse, the number helped to 

identify it as an individual. 

• Why did the scientists collect information 

over 3 years? The only way the scientists 

could compare fall and spring populations was 

to collect information over more than 1 year. In 

addition, the more times and the more different 

conditions under which the scientists were able 

to compare the numbers of mice, the more 

confidence they could have in their findings.

Findings

• Reread the last paragraph in the 

“Introduction” section. Was the 

scientists’ prediction correct? What is 

the evidence? Yes, the scientists’ prediction 

of a larger population of deer mice in spotted 

knapweed sites was correct. The evidence is 

shown in figures 8 and 9, which indicates that, 

overall, larger numbers of deer mice were in 

spotted knapweed sites.

• During the summer when gall fly larvae 

are not available, the population of 

deer mice living in areas with spotted 

knapweed eats more native seeds and 

insects than it normally would eat simply 

because the total number of individuals is 

higher. How might an overall increase in 

the number of deer mice affect the native 

seeds and insects? As predators of insects 

and seed eaters, an increase in the number of 

deer mice, along with a decrease in other food, 

would cause the number of insects and seeds 

to be reduced.

• Do you think the introduction of invasive 

species can upset the ecology of any 

area? Using this study as an example, 

explain your answer. Yes. In this study two 

nonnative species have been introduced. The 

introduction of these two species has caused 

a change in the number of deer mice, which 

ultimately will have an impact on other plants 

and animals in the ecosystem.

Discussion

• Basing your response on the findings and 

implications of this study, what would 

you conclude about using nonnative 

species to control invasive ones? You 

might conclude that before using nonnative 

species to control invasive species, you should 

give careful thought to the problem and do 

research to predict and protect against any 

harmful results that might happen to other 

plants and animals in the ecosystem.

• Purple loostrife is an invasive plant. 

Scientists recently found that Galerucella 

beetles, native to Europe and Asia, help 

control purple loostrife by eating its 

leaves. How does this information change 

your answer to the question above? If 

you concluded that nonnative species should 

not be used to control invasive species, this 

information will help you see that, in some 

cases, using nonnative species may be the best 

approach to controlling invasive species.
76 The Invasive Species Edition

Invasive Species Lesson Plan

Subjects Covered

• Science: Life science and environmental science

• Reading: Comprehension

• Writing: Summarization

Science Skills

• Comparing, recording, analyzing, classifying

Science Education Standards Addressed

• Science as Inquiry

• Regulation and Behavior

• Population and Ecosystems

• Diversity and Adaptation of Organisms

Objectives

• Students will be able to describe the difference 

between a nonnative and an invasive species.

• Students will be able to read and explain 

research about invasive species using the 

Natural Inquirer.

• Students will be able to identify a specifi c 

problem with invasive species using the 

Natural Inquirer.

• Students will be able to explain the fi ndings 

and implications from a scientifi c study using 

the Natural Inquirer.

• Students will be able to compare and contrast 

different types of invasive species.

• Students will be able to explain why invasive 

species may be harmful to an ecosystem.

Estimated Time for Lesson

• Two class periods

Materials

• Invasive Species Edition of the Natural 

Inquirer journal

• Notebook

• Pencils

Procedures

1. Begin the lesson by engaging students in a 

brief discussion about nonnative and invasive 

species and the reasons why invasive species 

may be harmful to an ecosystem.

2. Divide the class into groups of three or four 

and assign each group a Natural Inquirer

article to read. 

3. As the groups read their article, have them 

take notes about the article. They should at 

least answer the following questions:

a. What is the name of the invasive species?

b. What type of organism is the invasive 

species (animal, plant, etc.)?

c. Why is the invasive species a problem?

d. What problem did the scientists study?

e. What are the fi ndings from the study?

f. What are the implications of the study?

4. After students have fi nished reading and 

taking notes on their article, ask each group to 

present the information to the class.

Assessment

After students have presented their information 

to the class, ask students to compare and contrast 

the different invasive species that they heard about 

during the presentations. Note: You may want to 

encourage students to take notes while listening 

to other groups’ presentations. Have students also 

discuss questions such as: How can students help 

control the spread of invasive species? Teachers 

may also want to assess students by collecting the 

notes from the groups and by considering class 

discussion and presentations. 

Modifi cations

For students who want an extra challenge after 

fi nishing this activity, ask the student to research 

an invasive species in the area where the student 

lives and prepare a report for the class on the 

invasive species and how it can be controlled. 

For students who have diffi culty reading or writing, 

try pairing them with a reading buddy. In addition, 

it may be helpful for students to create a word 

wall of science vocabulary words for the journal 

before they begin reading the article. To create 

the word wall, ask students to use the glossary at 

the beginning of each article and create word and 

defi nition cards to put on the wall. Students may 

want to include drawings that represent the word 

to help them remember the word. 
77

The Natural Inquirer • Volume 8, Number 1

PLEASE COPY THIS FORM BEFORE COMPLETING!

STUDENTS—Tell Us What You Think About The Natural Inquirer

1. The article I read was entitled: _____________________________________________________

Circle the answer that best describes how you feel about the article you just read.

2. The article was: Easy to understand Hard to understand Very hard to understand

3. The article was: Very interesting to read Somewhat interesting to read 

 Not interesting to read

4. Did you learn something from reading the article? Yes No

5. Did you try to answer the Reflection Questions? Yes No Some of them

 If you read and tried to answer any of the Reflection Questions, did they help you to think 

about the article? Yes No

6. Would you like to read another article? Yes No

7. How old are you? 9 10 11 12 13 Other age: 

8. What grade are you in? 4th 5th 6th 7th 8th 9th 

9. Are you a girl or a boy? Girl Boy

Now write in your answer: 

10. What did you learn from reading the article? _________________________________________

_______________________________________________________________________________________

_________________________________________________________________________________________

_________________________________________________________________________________________ 

11. What is your favorite subject in school? _____________________________________________ 

Along with your class or by yourself, please send this form to:

Dr. Barbara McDonald • Forest Service • 320 Green St. • Athens, GA 30602-2044

Thank You!

77

The Natural Inquirer • Volume 8, Number 1
78 The Invasive Species Edition

For each article that you read, please answer the 

following:

Name of Article:_____________________________

 

1. Would this article help you meet any of the required statewide science curriculum standards?

 Yes No

2. How close to the appropriate reading and comprehension level for your students is this article 

written?

 Very close Somewhat close Not close

3. If the article is somewhat close or not close to 

the appropriate reading and comprehension 

level, is it: 

 Too hard Too easy

4. Would or did you use this article in your classroom as an educational resource?

 Yes No

Why or why not? ______________________________

_____________________________________________

_____________________________________________

5. Please rate the article sections on a scale of 

1 to 5. The number 1 means the section was 

not useful at all. The number 5 means the section was very useful.

 Not useful Very useful

FACTivity 1 2 3 4 5

Glossary 1 2 3 4 5

Introduction 1 2 3 4 5

Methods 1 2 3 4 5

Results 1 2 3 4 5

Graphs, figures, photos 1 2 3 4 5

Reflection Questions 1 2 3 4 5

For any of the sections you rated with either a 

1 or a 2 in question 5, please indicate why the 

section was not useful or how it can be improved:

FACTivity_____________________________________ 

Glossary_____________________________________

Introduction __________________________________

Methods ____________________________________

Results _____________________________________

Graphs, figures, photos _______________________

Reflection Questions __________________________

6. Was the “Note to Educators” useful to you?

 Yes No Somewhat

7. What grade(s) do you teach? ________________

8. What subject(s) do you teach? _______________

9. Other comments or suggestions: _____________

_____________________________________________

_____________________________________________

_____________________________________________

 

 

Please send this evaluation, along with your 

students’ evaluations, to 

Dr. Barbara McDonald

Forest Service

320 Green St.

Athens, GA 30602-2044

Thank you! Your evaluations will help us to 

continually improve The Natural Inquirer.

P L E A S E C O P Y T H I S F O R M B E F O R E C O M P L E T I N G .

The Natural Inquirer

Teacher’s Evaluation

78 The Invasive Species Edition
79

The Natural Inquirer • Volume 8, Number 1

National Science Education Standards for Invasive Species 

Edition of the Natural Inquirer Moving Spore-adically! And Then There Were Nun Knocked Out by Trout

Shoot! Foiled Again!Tag, You’re It!Hurry Up and Wait

Goll-ly! Don’t Take a Knapweed!

Science as Inquiry 

Abilities Necessary To Do Scientifi c Inquiry

Understandings About Scientifi c Inquiry

Life Science 

Reproduction and Heredity 

Regulation and Behavior 

Populations and Ecosystems

Diversity and Adaptations of Organisms 

Science and Technology

Understanding About Science and Technology

Science in Personal and Social Perspectives 

Risks and Benefi ts

Science & Technology in Society

History and Nature of Science 

History of Science 

Science as a Human Endeavor

Nature of Science

National Research Council, Content Standards, Grades 5-8.
80 The Invasive Species Edition

Student’s Notes
81

The Natural Inquirer • Volume 8, Number 1

What Is the USDA 

Forest Service?

The Forest Service is a part of the U.S. 

Department of Agriculture (USDA). It is 

made up of thousands of people who care for 

the Nation’s forest land. The USDA Forest 

Service manages more than 150 national 

forests and almost 20 national grasslands. 

These are large areas of trees, streams, and 

grasslands. National forests are similar in some 

ways to national parks. Both are public lands, 

meaning they are owned by the public and 

managed for the public’s use and benefit. Both 

national forests and national parks provide 

clean water, homes for the animals that live 

in the wild, and places for people to do fun 

things in the outdoors. National forests also 

provide resources for people to use, such as 

trees for lumber, minerals, and plants used 

for medicines. Some people in the USDA 

Forest Service are scientists, whose work is 

presented in the journal. USDA Forest Service 

scientists work to solve problems and provide 

new information about natural resources so 

we can make sure our natural environment is 

healthy—now and into the future. 

What Is Ag in the 

Classroom?

Agriculture in the Classroom is a grassroots 

program coordinated by the USDA’s 

Cooperative State Research, Education, 

and Extension Service (CSREES). The 

goal of Agriculture in the Classroom is to 

help students and teachers gain a greater 

awareness of the role of agriculture in the 

economy and in society. The program is 

carried out in each State, according to State 

needs and interests. People involved at the 

State level represent farm organizations, 

agricultural businesses, education, and 

government. The mission of the CSREES 

is to advance knowledge for agriculture, the 

environment, human health and well-being, 

and communities. The CSREES provides 

leadership to identify, develop, and manage 

programs to support university-based and 

other institutional research, education, 

and extension.

USDA Forest Service

http://www.fs.fed.us

The Natural Inquirer

http://www.naturalinquirer.usda.gov

Conservation Education

http://na.fs.fed.us/spfo/ce/index.cfm

Cooperative State Research, Education, and 

Extension Service 

http://www.csrees.usda.gov

USDA Kid’s Page

http://www.usda.gov/news/usdakids/

Agriculture in the Classroom

http://www.agclassroom.org

NatureWatch

http://www.fs.fed.us/outdoors/naturewatch/

Woodsy Owl:

http://www.fs.fed.us/spf/woodsy

Smokey Bear:

http://www.smokeybear.com

Project Learning Tree

http://www.plt.org/

National Forests by Map:

http://www.fs.fed.us/recreation/map/finder.shtml

National Forests by State:

http://www.fs.fed.us/recreation/map/state_list.shtml

Visit These Web Sites for More Information
Natural Inquirer editorial review board members.

FS-837

Winter 2006

United States 

Department 

of Agriculture

Forest Service

USDA Forest Service Invasive Species 

Information and Management

http://www.fs.fed.us/foresthealth/programs/

invasive_species_mgmt.shtml

Invasive Species: A Gateway to Federal and 

State Invasive Species Programs

http://www.invasivespeciesinfo.gov/

Invasive and Exotic Species

http://www.invasive.org/

Animal and Plant Health Inspection Service’s 

Invasive Species Page

http://www.aphis.usda.gov/oa/invasive/invasive.html

Invasive Species Forecasting System

http://bp.gsfc.nasa.gov/

The Invasive Species Initiative—The Nature 

Conservancy

http://tncweeds.ucdavis.edu/index.html

Visit These Web Sites for More Information About Invasive Species

The U.S. Department of Agriculture (USDA) prohibits discrimination in all 

its programs and activities on the basis of race, color, national origin, age, 

disability, and where applicable, sex, marital status, familial status, parental 

status, religion, sexual orientation, genetic information, political beliefs, 

reprisal, or because all or part of an individual’s income is derived from any 

public assistance program. (Not all prohibited bases apply to all programs.) 

Persons with disabilities who require alternative means for communication 

of program information (Braille, large print, audiotape, etc.) should contact 

USDA’s TARGET Center at (202) 720–2600 (voice and TDD). To file a 

complaint of discrimination, write to USDA, Director, Office of Civil Rights, 

1400 Independence Avenue, S.W., Washington, D.C. 20250–9410, or call 

(800) 795–3272 (voice) or (202) 720–6382 (TDD). USDA is an equal 

opportunity provider and employer.

Photo courtesy of Steve Passoa, USDA Animal and Plant Health Inspection Service, http://www.forestryimages.org.