Increasing undergraduates’ understanding of community assembly and dynamics using inquiry-based exploration of a new NetLogo simulation model
Undergraduate students of ecology are often challenged by the topic of complex systems behavior. The time scales, large populations, and geographic distances in real systems present barriers to student understanding of community dynamics. To overcome these challenges, we created a virtual community using the free programming environment NetLogo. Each cell on a two-dimensional grid has a discrete habitat type, and contains one individual plant. With each time step, a random individual dies and is replaced by a new recruit. The user-friendly NetLogo interface allows students to change variables in the virtual world and observe the resulting community dynamics with a dynamic map of individuals on a grid, and a real-time graph of abundances versus time. In the classroom, after a brief overview of the program, we allowed students to play with the program, choosing number of species, size of habitat patches, degree of fidelity to habitat type, dispersal range, as well as the immigration rate. After this period of free exploration, we asked students to devise hypotheses about community dynamics to test with the program. The model allows students to run repeated tests, to collect data, and to draw conclusions to share with peers.
We tested the model in a classroom setting with two cohorts of upper level students, and then used a pre- and post-test approach for a group of sophomores in a lower level course to gauge the utility of this simulation model approach to teaching concepts in community dynamics. Student engagement in discussions after exploring the NetLogo simulation was very high. For all age-groups, the free-ranging inquiry in a monitored classroom setting enabled students to become more comfortable (self-reported after the exercise) with the role of stochasticity, and the idea of multiple stable states in ecological communities. Students needed very little instruction with the model itself, allowing time for exploration of the model variables and development of sophisticated ecological questions. Post-test assessment showed marked improvement of conceptual understanding compared to pre-test results. Interactive simulations in the classroom are valuable tools for facilitating students’ understanding of ecological dynamics.