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Earthworms & Ecosystems

All earthworms in the Northeast are invasive, a fact that is not common knowledge among people of all ages. Their presence has significant consequences for the health of our forest ecosystems. However, worms are charismatic and easy for students to investigate, making them perfect schoolyard ambassadors.

Cary Institute scientists Alan Berkowitz and Peter Groffman worked with Cindy Hmelo-Silver (a collaborator from Indiana University) to study people's understanding of earthworms and ecosystems, given the fact that all earthworms in the Northeast are invasive.

In 2006, Cary Institute REU student Lina Yamashita (from Oberlin College) conducted semi-structured interviews of 46 gardeners, foresters, vermicomposters, farmers and soil scientists. The interview protocol consisted of written survey questions and verbal open-ended questions. Most farmers and gardeners, and some of the soil scientists interviewed felt that exotic species are "bad" but that earthworms are "good." Many of these people persisted with their idea that worms are "good" even after learning from the interviewer that worms in the northeast are all exotic. Most foresters, on the other hand, felt that earthworms are not necessarily good, consistent with their thinking that exotics are "bad." Vermicomposters also had consistent views, in this case that earthworms are "good" and that exotics are not necessarily "bad."

In addition to these questions, interviewees were asked to sort cards with different components of a forest/soil ecosystem to explore their system-level thinking. The results this activity indicated that farmers and gardeners tended to use physical principles, such as above/below-ground, to sort the cards while the vermicomposters and soil scientists tended to use process-oriented principles, such as energy flow. The reason for this trend may be explained by the number of years of post-secondary education, increasing from gardeners, farmers, foresters, vermicomposters to soil scientists. Not surprisingly, the gardeners and farmers used plant-growth-centered principles when applying either process-oriented or like-object principles. People with process-oriented views of the forest ecosystem were more likely to demonstrate ecological thinking, such as systems, temporal, and spatial thinking. This suggests the importance of directing educational programs to focus on the processes that occur in forest and soil ecosystems.

Galeet Cohen, a high school biology and ecology teacher from Philadelphia, PA, joined the project as a Research Experiences for Teachers (RET) Fellow in the summer of 2008. She built on the preliminary analysis of the interview transcripts done by Ms. Yamashita, and completed a study that embraced the entire collection of responses. The purpose of the study was to better understand how people think about ecosystems, to assess their existing knowledge of the ecology of earthworms in New York State, and to explore the way in which elements of ecosystems thinking are applied to consideration of the role/function of earthworms in local ecosystems. The new analysis is describing each respondent's use of ecological thinking skills—systems, spatial, temporal, evidence-based, contingency—and their overall perspectives as these were manifest in the way they discussed ecosystems in general and earthworms and exotic species in particular.

Worm Worlds

Worm Worlds is activity guide developed by Drs. Berkowitz and Patrick Bohlen (a Cary Institute post doc at the time) for the North American Association for Environmental Education. It was used throughout the country in the Volunteer-Led Investigations of Neighborhood Ecology (VINE) program.