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Tim Crane
Rick Fabian
Ron Schulze
Valerie Sumner
Johanna Vienneau
Introduction
When students think of biodiversity, they think of the rainforest -- a far-off place that they will probably never see. They do not see biodiversity around their school or in their
own backyard. Overlooking the local biodiversity is largely a matter of not knowing where or for what to look. It is also a matter of scale, for much of this diversity exists among small invertebrates, especially
the arthropods. This series of field and laboratory activities allows teachers to demonstrate the incredible amount of diversity that exists in a local area using simple techniques that make observing biodiversity
easy and enjoyable. A goal of this approach is to make the topic of biodiversity real and meaningful for the students, no matter where they live.
The activities that follow do not simply demonstrate biodiversity in a single local area; rather, they demonstrate biodiversity in and around one single tree. The sampling techniques described allow students to
observe arthropod diversity in the lower canopy, on bark, on the ground under the tree, and in the leaf litter around the tree. Students will see diversity not only among the organisms found within one of these
regions, but also among the different regions. Ecological concepts, such as habitat, niche, and predator-prey relationships, are all visible on this small scale.
Another feature of these activities is that they stimulate questions that may lead to further individual or class research and that they provide techniques that make the research easier to do. Students may compare
the number, types, and diversity of organisms on different sides of the tree, in sunny versus shady areas, or in damp versus dry areas. They may also compare samples from around two different trees. There are
limitless possibilities for further study. The activities are useful on their own and as a possible stimulus for more inquiry.
Methodology
Selecting a Tree: Ideally the tree to be studied will have leaf litter under it, will have branches low enough to reach, and will have rough bark. It should be easily accessible for
your class and should not have any poisonous plants or prickly bushes nearby. If you have several trees that fit this description, then look for contrasting factors that may influence diversity, like a moist
side and dry side, a dark side and a sunny side, a windy side and a protected side.
Collecting Vials and Labeling: Small clear plastic vials with snap on lids are the most versatile collecting containers. Clear 35 mm plastic film containers can be used effectively. Vials should be
labeled as soon as specimens are collected. The label should be on paper and written in pencil and placed inside of the vial with the specimens. The pencil will not run in the alcohol, vials can easily be
cleaned and reused, and this prevents a labeled cap from ending up on the wrong vial. The alcohol can be 70-90% denatured ethyl or 70-90% isopropyl (rubbing alcohol). The label should include the
collection date, type of trap and location of trap and/or number of trap, depending on the information you are trying to collect. For example, if you hypothesize that the sunnier side of the tree will have
less arthropods, then making a map of your pitfall traps and keeping the specimens collected from each trap in a separate vial is necessary. But if you simply want to see what crawls and hops about under the
tree, then all the specimens can be stored in the same vial.
Identifying Specimens: Keys that exist for identifying arthropods are often too difficult for students to use. It is preferable to use several different field guides to identify to the level of
order, and then have your students make a key for your local arthropods. See the resource list for available guides and keys.
Activity:Berlese Funnel Arthropod Diversity From Leaf Litter
Activity: Arthropod Collecting Using Tree Belts, Bands, and Wraps
Activity: Pitfall Trapping
References and Acknowledgements
Considerations: Classroom Implementation
This series of activities shows great promise for use in the classroom. It relates to the studies of biodiversity, ecology, arthropods, and local
organisms. It may be used different areas with different types of trees. Students collect much data, which may be used for numerous comparisons and allow for statistical and graphical analyses.
Timetable
We intend to use these activities in our classes this fall. By the end of October, we should have information on the implementation of our work in five different states. This information, along
with feedback from other Woodrow Wilson Biology Institute participants, will allow us to revise and complete our report well in advance of the December 31 deadline. We hope to submit our work to a journal for
publication.
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