Assessment, Feedback & Suggestions
For a follow-up activity, we asked students to relate the direction
of plant–soil feedbacks (positive or negative) to the abundance of
specific plant species and total species richness (using results
from the primary literature: Packer & Clay, 2000; Klironomos,
2002; Bais et al., 2003; Mangan et al., 2010; Bennett et al.,
2017). Students successfully predicted that species with negative
feedbacks would be rarer in communities that could sustain a
greater total number of species, and that species with positive
plant–soil interactions would be more abundant in less diverse
We also asked the following question before and after the
activity: “What do plant–soil feedbacks make you think of?”
Responses that included the words “fungi” or “mycorrhizae”
increased by 75%, and the word “diversity” appeared only in
post-activity responses (7 out of 26 responses) (Figure 2B). This
suggests that students began to recognize how plant–soil relationships relate to biodiversity patterns.
The activity takes ~30 minutes to complete and preceded a
brief lecture and small-group work in an upper-level ecology
course (24 students, 18–25 years old). Depending on student level
and module topic, instructors using this activity could discuss a
range of mechanisms, such as soil nutrient depletion by the plant,
mutualistic benefits from mycorrhizal fungi, or buildup of soil-borne pathogens. Since plant–soil interactions have been explored
in a variety of areas (van der Putten et al., 2013), the activity can
be uniquely paired with different biology topics. For introductory
students, shapes could be used in place of species to focus on the
mechanics of feedback loops in nature.
This activity may be most applicable for small class sizes (20–
40 students). In larger classes, it could be implemented as a demonstration with student volunteers or during discussion/laboratory
sections. We found it best to use paper cutouts and notecards to
drive home the role-playing aspects of the game. We have provided
resources for teachers to print the species used in the current example ( https://github.com/mvannuland/Species_supplies), but the
activity is amenable to any suite of species (four or five plant species is the appropriate number for a small class). With an inexpensive, time-efficient, and engaging activity, we hope to enable
teachers to encourage student understanding of prolific, but overlooked, forms of biological interactions that impact the diversity
and functioning of ecosystems.
AAAS (2011). Vision and Change in Undergraduate Biology Education: A Call to
Action. Washington, DC: American Association for the Advancement of
Bais, H.P., Vepachedu, R., Gilroy, S., Callaway, R.M. & Vivanco, J.M. (2003).
Allelopathy and exotic plant invasion: from molecules and genes to
species interactions. Science, 301, 1377–1380.
Bennett, J.A., Maherali, H., Reinhart, K.O., Lekberg, Y., Hart, M.M. &
Klironomos, J. (2017). Plant–soil feedbacks and mycorrhizal type
influence temperate forest population dynamics. Science, 355, 181–184.
Bever, J.D. (1994). Feedback between plants and their soil communities in
an old field community. Ecology, 75, 1965–1977.
Heisey, R.M. (1990). Evidence for allelopathy by tree-of-heaven (Ailanthus
altissima). Journal of Chemical Ecology, 16, 2039–2055.
Klironomos, J.K. (2002). Feedback with soil biota contributes to plant rarity
and invasiveness in communities. Nature, 417, 67–70.
Link-Pérez, M.A., Dollo, V.H., Weber, K.M. & Schussler, E.E. (2010). What’s in
a name: differential labelling of plant and animal photographs in two
nationally syndicated elementary science textbook series. International
Journal of Science Education, 32, 1227–1242.
Mangan, S.A., Schnitzer, S.A., Herre, E.A., Mack, K.M.L., Valencia, M.C., Sanchez,
E.I. & Bever, J.D. (2010). Negative plant–soil feedback predicts tree-species
relative abundance in a tropical forest. Nature, 466, 752–755.
Packer, A. & Clay, K. (2000). Soil pathogens and spatial patterns of seedling
mortality in a temperate tree. Nature, 404, 278–281.
Schussler, E.E., Link-Pérez, M.A., Weber, K.M. & Dollo, V.H. (2010). Exploring
plant and animal content in elementary science textbooks. Journal of
Biological Education, 44, 123–128.
Uno, G.E. (1994). The state of precollege botanical education. American
Biology Teacher, 56, 263–267.
van der Putten, W.H., Bardgett, R.D., Bever, J.D., Bezemer, T.M., Casper, B.B.,
Fukami, T., et al. (2013). Plant–soil feedbacks: the past, the present and
future challenges. Journal of Ecology, 101, 265–276.
Wandersee, J.H. & Schussler, E.E. (2001). Toward a theory of plant
blindness. Plant Science Bulletin, 47, 2–9.
MICHAEL E. VAN NULAND is a postdoctoral scholar in the Department of
Biology, Stanford University, Stanford, CA 94305; e-mail:
firstname.lastname@example.org. MIRANDA CHEN is a PhD candidate in the
Department of Ecology and Evolutionary Biology, University of Tennessee,
Knoxville, TN 37917; e-mail: email@example.com. BENJAMIN J. ENGLAND
is postdoctoral researcher and lecturer in the Division of Biology,
University of Tennessee, Knoxville, TN 37996; e-mail: firstname.lastname@example.org.