Model thinking and model building is an inherently iterative process.
In this group activity, you will choose a scenario and work through several iterations of a model-building process together.
Before class, you need to individually complete the following tasks so that you’re ready to work with your group:
NOTE: These scenarios are intentionally broad. I want to see where your group ends up given sparse starting materials.
Cattails, Typha spp., are emergent wetland plants, familiarly known as cattails because of their distinctively shaped infructescence. There are several species of cattail common in North America including T. latifolia, T. domingensis, and T. angustifolia. There are many species of cattails, and some species can produce vigorous, potentially invasive hybrids. T. latifolia and T. domingensis are thought to be native to North America, while T. angustifolia may be native to Eurasia, although determining the native range each species has not been straightforward.
Cattail abundance has recently been increasing, especially in disturbed eutrophic sites. In the Chesapeake Bay region cattails have outcompeted other species in some wetlands, displacing native plants and potentially interfering with animals that use wetland habitats. In other wetlands, cattails are present in smaller stable populations. It is thought that the different patterns may be influenced by human activity and hybridization.
Snowpack accumulates throughout the winter at mid to high elevations in the central Cascades of Oregon. The amount of precipitation varies widely from year to year. On many slopes, snow accumulates under the dense canopy of the native conifer forests, composed mostly of hemlocks (Tsuga spp.), true firs (Abies spp.), and pines (Pinus spp.). The snowpack melts rapidly on exposed slopes, but in areas with tree cover the snow melts more slowly over an extended period. The timing, duration, and rate of the snowmelt affect soil moisture conditions, streams, erosion, and flooding in the region.
Most of the area is sparsely populated, but some areas are popular for outdoor recreation. Timber harvests have been carried out in many of the more accessible forest stands throughout the 20th century.
The upper Midwest region of the US is home to large forests dominated by red and eastern white pines (Pinus resinosa, and P. strobus). The forests are highly valued for their aesthetic, recreational, and timber values. Numerous species of gooseberry (Ribes spp.) occur throughout the region in the understory, and at forest edges.
A fungal pathogen, the white pine blister rust, was accidentally introduced to the area sometime around 1900. Some of the native forest plants are resistant to the rust. Many others, including all of the Ribes spp, are hosts but do not seem to be negatively affected by the rust. Eastern white pine is highly susceptible and often killed by the rust.
Compile your group members’ thoughts into a document that contains answers to these report questions:
Describe the key ecological, economic, aesthetic, or other problems your group identified related to your scenario.
Describe the questions that guided your group’s model building.
Which items in in Epstein’s Sixteen Reasons Other Than Prediction to Build Models helped guide your group’s model building process?
Briefly describe each group member’s contributions to the activity.