Graduate Take-Home Exam

This exam is open-book, open-notes. Properly attribute words or ideas of other people (published or not). Please do not collaborate on your responses; let me know if you require clarification or additional information. Submit your responses, using an alias, by 17 February 2003 at noon. Type your answers (double-spaced), and adhere strictly to the indicated length limits.

1. Some people have indicated that I have a bleak perspective of the human role in nature (my view was briefly described on 22 January 2003). During class, I proposed several solutions to the dilemma of simultaneously using and conserving the world's natural capital. I would like you to propose others. Specifically, I would like you to identify and describe solutions at the level of an individual vegetation manager and at the broader level of society that can be influenced by a vegetation manager (i.e., sociopolitical solutions). Identify and describe two solutions in each category (individual, society) that are unique from the ones I listed in class. [400 words or fewer; 50 points]

1. Briefly describe a realistic scenario in which two specific objectives of vegetation management would conflict with each other. [6 points]

2. The components or processes of the natural world that we choose to conserve depend to a great extent on human values. These values change over time, at least at the level of societies. Briefly describe one example of a societal value that has changed within the last few decades. [4 points]

3. Do scientists or managers (circle one) have a greater role in deciding what components or processes will be conserved? [2 points] List three factors that influence the decision about what to conserve. [6 points]

4. Briefly describe the goal of science, as viewed by typical members of the following groups of people. [2 points each]

   Scientists
   Policy makers
   Managers

5. Describe one specific method or approach that can be used to strengthen interactions between these three enterprises (science, policy, management). [3 points]

6. Define "hypothesis," as the word is used by contemporary philosophers of science. [4 points]

7. List the four "spikes" altering our world at a global scale. [8 points]

8. Briefly describe how each of the spikes is related to global biodiversity. [12 points]

9. Wildland fires require adequate fuel, a dry season to reduce fuel moisture content, and an ignition source. List threshold values associated with fire spread for fuel amount and fuel moisture content, then list the primary historical source of ignitions for wildland fires in western North America. [6 points]

   Threshold fuel amount:
   Threshold fuel moisture content:
   Primary ignition source:

10. List the four general classes of techniques used to manipulate species composition of terrestrial ecosystems. [4 points]Mesquite has increased in abundance throughout much of southern Arizona, apparently at the expense of diversity and biomass of herbaceous plants. If you faced virtually no economic constraints, how would you reduce density and cover of large mesquite plants in this area? [6 points]

11. Flammability increases with time since fire in some woodlands and shrublands, and decreases in others. Select one system (woodland or shrubland) and describe how and why flammability changes as time passes without a fire. [6 points]

12. Historically, fire frequency of grasslands increased / decreased (circle one) with increased precipitation. [2 points]

13. Most managers who apply prescribed fires to grasslands of southern Arizona do so during what months of the year? [2 points]

14. What are the apparent consequences of this treatment strategy for (1) abundance of Lehmann lovegrass (Eragrostis lehmanniana) and (2) richness of native plants? [6 points]

15. Our experimental research at Fort Huachuca indicates that fires during what month(s) may be more appropriate for reducing Lehmann lovegrass and maintaining richness of native plants? [3 points]

16. Gene proposed a prescribed-fire season that is different from the two described above. What season did he recommend for controlling Lehmann lovegrass? [3 points]

17. Why would prescribed fires during the latter season be potentially detrimental to Lehmann lovegrass? [4 points]

18. The following research approach typically engenders greatest confidence in the results: comparison description experiment model (circle the best single answer) [3 points]

19. Why, then, do we not employ this approach for every question? [6 points]