Students determine soil invertebrate diversity in samples they have collected using Berlese-Tullgren funnels to test hypotheses that they have generated. For example, diversity could be compared in a deciduous versus a coniferous forest, or along a chronosequence of forest plots undergoing succession or regeneration after disturbance, such as logging or wind damage. This exercise will extend over two lab periods. Back in lab, students will extract and identify invertebrates, and quantify their abundance in samples. Using a spreadsheet, they will calculate diversity indices and test for differences among samples. Outside of class, they will write a research-style paper.
Department of Biological Sciences, Nunn Drive, Northern Kentucky University, Highland Heights, KY 41099, email@example.com
Two three-hour lab periods (1 for field trip and set-up, 1 for data collection and analysis).
OUTSIDE OF CLASS TIME
4-12 hours for students to finish their research papers.
Students are assessed on their individual research papers that are based on student-collected data. If desired, students could also make oral or poster presentations.
Outdoors: several areas with one or more kinds of different vegetative cover. As long as soil is accessible, there should be no seasonal issues.
Lab: a bench with enough room for a set of Berlese-Tullgren funnels (about 1 meter of bench or table top surface). Also needed are dissecting microscopes to identify soil invertebrates and computers for data analysis.
Undergraduate biology and other science majors (course name: Ecology Laboratory, Bio 306, http://www.nku.edu/%7Eboycer/ecollab.html), 10-14 per lab section.
Regional public, primarily undergraduate comprehensive university.
This activity is highly transferable. It could run in introductory lab courses in ecology, environmental science, or upper division courses in a variety of sub-disciplines, including entomology and zoology. It could also be modified to run in any undergraduate introductory biology lab course for majors at any college or university. It could also be modified for biology lab courses for non-majors and for grades 8-12.
The inspiration for this laboratory came from Buck Sanford at the University of Denver, from whom I received the original version. The invertebrate key and illustrations were adapted from a web page developed as part of the Winter Science Curriculum Project at the State University of New York at Oswego by Peter G. Weber and colleagues. Bruce Grant from Widener University was full of constructive comments that vastly improved the laboratory, especially regarding nail polishes. He also generously donated the data for the examples I use in this lab, and he relayed the insights that eH' is “the equivalent number of equally common species” and the use of the Kolmogorov-Smirnov test to compare H´ between two sites, which originated from unpublished work by John and Robert MacArthur. Both Bruce Grant and Charlene D’Avanzo (Hampshire College) made numerous insightful and constructive suggestions on an earlier draft of this experiment, as did an anonymous reviewer. I also want to thank the students of Bio 306, Ecology Laboratory, at Northern Kentucky University, who served as guinea pigs for the development of this laboratory.
Richard L. Boyce. April 2005, posting date. Life Under Your Feet: Measuring Soil Invertebrate Diversity. Teaching Issues and Experiments in Ecology, Vol. 3: Experiment #1 [online]. http://tiee.ecoed.net/vol/v3/experiments/soil/abstract.html
Courtesy of USDA Natural Resources Conservation Service.
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