The emphasis in TIEE Issues is use of figures and tables for discussion and other types of student-active teaching and learning. These notes will give you ideas about using the figures in this paper in your ecology class. The Student-Active Teaching table will introduce you to a variety of approaches you can use in your class to actively engage your students. To see an essay on leading good discussions, go to Guided Class Discussions.
You can use the Turner et al (Frontiers, 2003) paper to discuss many ecological topics including disturbance, landscape ecology, patches, adaptations of trees to fire, and succession. Students will also be interested in the more applied aspects and some will likely recall seeing the fire on TV or in the news. For example, George W. Bush used this and other large fires to promote his “healthy forests” initiative. Also, as discussed in the Scientific Teaching section of this issue, the Turner et al. paper is a good opportunity to discuss a misconception that many students have — that disturbances such as fire have irreparable, negative ecological effects.
Points of emphasis for Figure 3: These data show clear effects of fire severity and patch size on plant cover and richness in the 10 years right after the fire. Although these effects are diminishing, smaller patches have more forbs (e.g., wildflowers and other herbaceous plants), grasses, and total cover. In addition, in more severely burned areas, forb, grass, and shrub cover is less. (In this study a small area is one hectare (ha), moderate is 70-200 ha, and large is 500-3600 ha.) Dispersal from surrounding unburned areas has not been an important reestablishment mechanism; most plant cover in the first three years is from re-sprouting survivors. Therefore, community composition (types of plants but not distribution, abundance, etc.) may eventually be similar to what it was before the fire. The three locations in Figure 3 “c” are meant to be replicates although they show considerable variation; therefore the authors state that despite the significant effects of patch size and burn severity, response varied a great deal by geographic location, showing the importance of landscape-scale effects on ecosystems.
For more details, see Turner, M.G., W.H. Romme, R.H. Gardner, and W.W. Hargrove. 1997. Effects of fire size and pattern on early succession in Yellowstone National Park. Ecological Monographs. 67(4): 411-433 (Click here for PDF). Figure 1 from this paper shows the three site locations and Figures 2-5 (figure 2, figure 3, figure 4, figure 5) are data for forbs, grasses, and shrubs separately.
Points of emphasis for Figure 5: The response of this serotinous tree is clearly seen in this figure. Tree seedling density was higher in large patches and areas with severe surface burning. Crown fires appeared to be so hot as to reduce seed viability.
As described below, these are good figures to use for “turn-to-your neighbor” although you can of course just use them for a general class discussion as well. (Approaches like turn-to-your-neighbor usually result in better discussions.)
Note: “Turn-to-Your-Neighbor” is an easy and effective group approach you can use in large classes.
Project or hand out Turner et al.’s Figure 3 and/or 5. With the class as a whole or in small groups (no more than five students per group), ask students to first describe and then interpret the figure. (Ahead of time explain terms such as “% cover” and S.E. and sources of the data). For students working in groups, ask each group to present one question or comment they have about the figure. You can call on one group at random to describe and interpret the figure, and then ask for additional comments/questions.
Additional discussion questions:
Another idea: In a small class use this topic as the focus of a citizen’s argument or role-playing in a town meeting-type setting. Students could be assigned roles and asked to use the resources below and other sources as evidence for their point of view, now that 20 years has passed since the Yellowstone fire. For instance, did the worst-case economic scenarios pan out or, as with the vegetation, was the recovery faster than anticipated?
In their 1998 paper in Ecosystems, "Comparing Large, Infrequent Disturbances: What Have We Learned?" Turner and Dale introduce a series of papers in this issue of Ecosystems on large, infrequent disturbances (LIDs). They cite the Yellowstone 1988 fire as an example along with Hurricane Hugo in 1989, Mount St. Helens in 1980, and the 1993 Midwest floods. They describe LIDs as “much larger in spatial extent (terrestrial systems), or in depth/duration (floods) than the disturbances that ‘typically’ affect the system.” To avoid a circular definition of LIDs they go on to more specifically define them (e.g., by size and frequency of fires). They consider LIDs to be important ecologically because of the large and persistent effect on ecosystems that endure for very long periods of time.
An important point is that despite their scale, LIDs do not uniformly impact the area but instead create “complex heterogeneous patterns across the landscape....and have the potential to generate more heterogeneity than do small or weak disturbances.” (p. 494).
Landscape ecology is a relatively new subdiscipline of ecology. It is the study of landscape structure and processes and the scale is usually larger than that studied by community or ecosystems ecologists. A central tenet is that the patterning of landscape elements (patches) strongly influences ecological processes. The resource list below will direct you to more information.