There’s
Life
in Those
Dead Logs!
I
A collaborative partnership
teaches students about
decomposers, biodiversity,
and ecological restoration.
By Devin Biggs,Todd Miller,
and Dee Hall
36
Science and Children
f asked to describe the natural features of forests,
students might start out by mentioning familiar plants
and animals such as trees, mammals, birds, and flowers. Dead trees are not likely to make that list. Although it is unspectacular in appearance, dead wood
is one of the most ecologically important resources
in forests. Fallen logs, dead standing trees, stumps, and even
cavities in live trees fulfill a wide range of roles. Prominent
among these is that they provide habitat for many organisms,
especially insects.
Fourth-grade students at Fox Prairie Elementary School in
Stoughton, Wisconsin, discovered this firsthand when they
and their teacher participated in a unique collaboration. An
environmental education outreach specialist from nearby University of Wisconsin–Madison Arboretum partnered the class,
which had been studying ecological restoration topics, with a
graduate student from UW–Madison who was studying the insects of oak savannas, a highly endangered native ecosystem.
Together, the three educators led students on a six-week exploration of the biology and conservation of dead wood-inhabiting
insects. The collaborative project, which included three educatorled group discussion sessions and five hands-on periods where
students collected and recorded insect data in the classroom, was
conducted two years in a row and culminated the second year with
Collecting Dead Wood
a scientific presentation by the students at a statewide
ecological restoration student conference.
We hope this experience inspires you to create your
own collaboration.
A Perfect Match
Before starting this project, the fourth-grade students
had been studying ecological restoration and had recently planted an oak savanna on school grounds. The
graduate student was working on a project investigating
the effects of cattle grazing on oak savannas, in particular the responses of insects to the experimental manipulations. Farmers and others will be able to use the results
of the study to protect and restore oak savanna on their
properties. For an overview of the project findings, see
Internet Resources.
The collaboration began when the student came to
the arboretum to explore ways of developing outreach
for the grazing/oak savanna project. After a couple of
meetings to review what the students had been studying and make a plan for the class activities, we created
an introductory PowerPoint slide presentation that
covered relevant topics, such as biodiversity, ecological restoration, habitats, and oak savannas (see glossary on p. 40). The slideshow also covered saproxylic
(sap-row-ZY-lick) insects, or insects that live in dead
wood (see “About the Saproxylics” on p. 38 for more
information).
As part of our introductory discussion session, we
emphasized the relevance of the students’ research.
Human activities directly affect the habitat of this important and interesting group of animals. By gaining
better understandings of their requirements, people
might be able to manage ecosystems in ways that will
protect biodiversity and prevent species from becoming endangered or extinct.
The method described in this article is an excellent way to
determine the habitat needs of insect species. It is important to keep in mind, however, that it will unavoidably alter
some habitat. Specific kinds of dead wood or other insect
habitats should not be depleted in areas where they might
be scarce. For this study, we submitted a written description of the proposed study to the UW–Madison Arboretum
and received a collection permit.
Check with your State Department of Natural Resources
for more information on obtaining permits in your area.
Then we talked about possible investigations with
dead logs that students could address with a classroom experiment—What kinds of insects would we
find in each log? How many insects would be in each
log? Using the questions on the “Science Investigation Sheet” (Figure 1), the teacher helped students
refine their predictions:
1. We will find different species of saproxylic insects
in different types of dead wood habitat.
2. We will find more species of insects in the older,
more decomposed wood than in the younger, less
decomposed wood.
Figure 1.
Science investigation sheet questions.
What question needs to be answered?
What do you think will happen?
How will you answer your question?
What did you observe?
What is the general answer to your question?
April/May 2006 37
Collecting the Insects
relative age. Our log samples were either in decay class
2 (relatively young, with bark, lacking small twigs) or
decay class 4 (relatively old, lacking bark and small
limbs). On the surface, these samples just appeared to
be dead wood, but he explained that the two types of
dead wood were distinct habitat types within the larger
ecosystem of oak savanna. How would we determine
what was inside?
Our next step was to number the pieces of dead
wood and put them into rearing containers to hold the
Now that students were ready to begin their investigations, the graduate student brought in dead wood
samples collected from an oak savanna. (See “Collecting Dead Wood,” p. 37, for more information on
collecting wood samples.)
To distinguish between types of dead wood, he
explained wood decay class, a concept used in forest
ecology in which dead wood is classified based on its
About the Saproxylics
Figure 2.
The saproxylics include representatives of many different
insect orders and the group is incredibly species-rich. In
terms of species diversity, saproxylics in order Coleoptera
(beetles) are estimated to outnumber all land-dwelling
animals with backbones by at least two to one.
Saproxylics fulfill crucial roles in forests. Along with fungi
and microorganisms, they decompose dead wood and return its nutrients to the soil. Saproxylics serve as food for
other forest animals and many of them, including hoverflies,
longhorn beetles, and solitary bees, also pollinate flowers.
Despite their contribution to global biodiversity and their
ecological importance, saproxylics have been studied much
less than many other types of organisms. In some European
countries, however, ecologists have conducted in-depth
studies on saproxylic insects. The sharp declines that they
have measured in the species diversity of these animals are
correlated with the clearing of forests and other kinds of
environmental change. The same processes are happening
in North America and other regions, but scientists working
in those forests are only beginning to document changes in
saproxylic insect diversity in such areas.
Data collection sheet.
Name of Species: Swirly Big Boy
To name your insect species:
• Make up a descriptive name.
• Use the same name as a species in the reference
collection if you are sure that your species is the same.
• Write this name above and on one line of the
weekly data sheet.
Physical description:
Size:
____ Small (< 8 mm)
_x__ Medium (between 8 and 14 mm)
____ Large (> 14 mm)
Shape of body:
____ Slender
_x__ Medium
____ Stocky
Colors: (Describe where the colors are)
The insect is mostly black. It has swirly black lines
on its wings.
Beetles, such as Upis ceramboides, are
common saproxylic insects.
PHOTOGRAPH COURTESY OF THE AUTHORS
Draw the insect in this space:
38
Science and Children
logs while the insects emerged over
several weeks. These devices were
5 G plastic pails, painted black to
make them lightproof. A 1 in hole
in the side of each pail—connected
to a 12 oz clear plastic beverage
bottle—allowed the penetration of
some light. Insects emerging from
the dead wood oriented toward
the light, exited the pails, and were
captured in bottles. For a detailed
description of how to construct the
insect rearing container, see Internet Resources.
Because the dead wood was collected in late winter, insects that
were present as adults became active in the warm classroom environment and quickly emerged into the
collection bottles. Other insects—
present as eggs, larvae, pupae, or
nymphs—continued their development, just as they would have
with the onset of warm, springtime
weather. These animals appeared in
the bottles as adults over the course
of the next six weeks.
Figure 3.
Data compilation.
Sorting the Specimens
Once a week, for about a month
and a half, the teacher emptied the
collection bottles into glass baby
food jars half-filled with a 80% isopropyl alcohol/20% water mixture.
See the Materials Data Safety Sheet
(MSDS) for isopropyl alcohol for
handling and first-aid instructions (see Internet Resources). Do not store flammable alcohol in the classroom and
keep it away from heat sources such
as lights. The insects poured right
out of the collection bottles and
were quickly killed by the alcohol.
The entire procedure took about 20
minutes each week.
In class, students worked in
groups of four or five to sort through the “catches,”
which were placed in petri dishes by the teacher. Students used paintbrushes and forceps to handle the
insects and carefully examined each specimen with
hand lenses. They recorded characteristics of the insects’ physical appearances (size, shape, color) on a
data collection sheet (Figure 2).
The students made up a creative descriptive name
for each new kind of insect that they found and then the
teacher placed one example of each species into its own
bottle, which was labeled with the number of the wood
sample it came from. These steps required about 20
minutes. The students were always enthusiastic to sort
the samples and assign names to the insect species.
April/May 2006 39
Interpreting Data
Figure 4.
After the students had
completed a month and a
Data summary.
half of data collection, the
graduate student returned
to the school for a second
visit to collect the materials
and supplies, including the
specimens and student data
sheets. Reviewing the insect
specimens and data sheets,
he produced a compilation
(Figure 3, p. 39) based on
type of dead wood, species, and insect order. The
students had filled out the
data sheets accurately—the
information on the sheet
coincided with the insect
samples—so he found it easy
to do this step.
The data summary (Figure
4) suggested several relationships. The decay class 4 dead
wood had twice as many
species as the decay class
2 dead wood. Five species
were found in more than one sample. None, however,
occurred in both wood decay classes. With the summarized data in hand, the graduate student and the
outreach specialist returned to the school once again
for a final classroom discussion.
The graduate student wrote the data summary on
the chalkboard and used the information, along with
a few guiding questions, to help students interpret
the experiment’s outcomes. The students were able
to conclude that even though the decay class 2 wood
had fewer species than the decay class 4 wood, and
might seem less important for conservation of biodiversity, its species were totally different. Many
organisms have specific requirements, so the loss of
any type of habitat, even a certain kind of dead wood,
might lead to species extinctions.
Such insights can be applied to the ecology and management of larger areas—such as prairies, oak savannas,
and forests—and indicate the importance of providing
a range of habitats for wild plants and animals.
Glossary
Biodiversity - the diversity of living things
Ecological restoration - the practice of restoring the function and biodiversity of altered or damaged ecosystems
Habitat - the place where an animal, plant, or other organism lives
Insect life cycles - a term that refers to the changes in form that insects experience as they mature
Insect order - a classification grouping within class Insecta; examples include Coleoptera (beetles),
Hymenoptera (ants, bees, and wasps), and Diptera (flies)
Oak savanna - an ecosystem that has scattered oak trees and a ground layer with many species of
grasses, flowers, and other plants
Saproxylic insects - insects that live in any kind of dead wood; most eat either wood, fungi, or other
saproxylic insects
Wood decay class - a classification system, based on relative ages of pieces, used to describe dead wood
in forests
40
Science and Children
Authentic Assessment
The culminating experience came in May 2003,
when students who participated in the dead log experiment the second year presented their findings at
“Restoring Wisconsin’s Biodiversity,” the first-ever
K–12 student research conference on ecological
restoration hosted by The Earth Partnership for
Schools at the University of Wisconsin–Madison
Arboretum. About 100 students from eight local
schools attended the event.
In their presentation, the students provided an
overview of their research methods and explained
the ways in which their data supported their predictions. They also explained how their findings related
to their school’s ecological restoration projects,
such as planting oak savanna, thus demonstrating
the importance of restoring and protecting insect
habitats. The clarity and strength of the conference
presentation demonstrated that the students had
solid masteries of scientific concepts and implications. The students’ presentation was a real-life
application of their knowledge and skills—an authentic assessment.
Learning Realized
The dead log study truly embodied the best of
inquiry-based learning in the classroom. Students
integrated knowledge and information from a range
of disciplines; strengthened cooperative skills by
taking turns recording data, sharing equipment, and
agreeing on names for the species that they found;
and drew associations between their experimental
results, their own study of Wisconsin natural resource conservation, and real research being conducted on the same topics.
Connecting to the Standards
This article relates to the following National Science
Education Standards (NRC 1996):
Content Standards
Grades K–4
Standard A: Science as Inquiry
• Abilities necessary to do scientific inquiry
Standard C: Life Science
• Characteristics of organisms
• Life cycles of organisms
• Organisms and environments
Standard F: Science in Personal and
Social Perspectives
• Changes in environments
Educator collaboration was
key to the success of the project, starting with the outreach
specialist’s match between the
oak savanna project outreach ac- Keywords: Insects
tivities and a fourth-grade class www.scilinks.org
Enter code: SC040603
that had been studying related
topics. The classroom teacher helped students grasp
concepts and to draw conclusions. The graduate
student’s conceptual and material support were key
to setting up the experiment.
Our experience revealed a great potential in the pairing of science teaching with current scientific research.
This inquiry-based, collaborative model worked well
for teaching biodiversity conservation, but it should
succeed in many other areas of science teaching. ■
Devin Biggs ([email protected]) is a
graduate student in the Gaylord Nelson Institute for
Environmental Studies at the University of Wisconsin–Madison, in Madison, Wisconsin. Todd Miller
([email protected]) is Research Outreach
Specialist for the Earth Partnership for Schools at
the University of Wisconsin–Madison Arboretum.
Dee Hall ([email protected]) is a
fourth-grade teacher at Fox Prairie Elementary School
in Stoughton, Wisconsin.
Resources
Borror, D.J. 1998. A field guide to insects. Boston, MA:
Houghton Mifflin.
Jeran, C. 1999. Exploring experimental design. Science and
Children 36(4): 24–27.
National Research Council (NRC). 1996. National science education standards. Washington, DC: National
Academy Press.
Quinones, C., et al. 2005. Planting the spirit of inquiry. Science
and Children 42(7): 32–35.
Internet
Eastern Forests and Biodiversity
www.biodiversityproject.org/EF%20Kit/
messagekit-forests.htm
Insect Rearing Container Construction
http://entomology.wisc.edu/~dbiggs/
rearing_container.html
MSDS: Isopropyl Alcohol
http://msds.farnam.com/msds/m000673.htm
Oak Savannas in Wisconsin
http://biology.usgs.gov/s+t/noframe/m1106.htm
Savanna Oak Foundation, Inc.
www.savannaoak.org
Use of Cattle in Oak Savanna Restoration
www.prairieoaks.com/images/savannareport.pdf
April/May 2006 41