SEE-U 2000: Biosphere 2 - Module 14:Exercise 14

General Methadology for Instructors and TAs
## Exercise 14: Crazy Ants and Species Extirpation Module 14: Exotic Species Introduction Printer format ### Background Lecture Instructor gives the biological background during the lecture on exotic species, briefly emphasizing the points in the above introduction (exotic introduction, typical introduction methods, population dynamics, reasons for population explosion, effects on biodiversity and ecosystem processes); as well as the following: Give a background as to the crazy ant, how it was introduced, its spread at present, and the basics of its biology Discuss where the ant is found in and around Biosphere 2 Remind students of the community diversity indices that were used in the Community Ecology section, and introduce rarefaction indices (not covered during the community ecology section) Discuss briefly the sampling methods that they should use to collect insects (sweeping, hand collections, ) and survey for the crazy ants ### Student Pre-field Preparation After lecture, before the start of field time, the students will be asked to confer with their labmates and will be required to draw up a plan outlining how their group will answer the question that they have chosen above. This should include the following (this is applicable to all field activities and nearly all digital activities): The question they will answer The hypotheses that they will test The methods that they will use to collect the data The data that they will collect The organisms that they will be focussing on How they will identify the organisms The books that they will need to do the identifications, background, and analyses How they will analyze the data General expected outcome ### Activities in the experiment, Hypotheses to test Possible experimental design (Because this exercise will be performed very late in the class, we will not be providing the students with very much in the way of experimental design. They must create the majority of it themselves) Hypotheses to test using community diversity data Crazy ants have no effect on the biodiversity of the rest of the community Crazy ants generally depress the biodiversity of the rest of the community Crazy ants most strongly depress the biodiversity of community members with which the most directly interact (competitors, predators, prey) Hypotheses to test using ecological correlates data Crazy ants are largely unaffected by ecological conditions and are widespread (therefore, it is possible that crazy ants are so successful in part because they are so adaptable) Crazy ants are strongly affected by ecological conditions and are found in only localized areas (therefore, it is unlikely that crazy ants are so successful because they are so adaptable and their success must be because of other reasons) Independent variables Community Diversity data: presence of crazy ants Ecological Correlates data: ecological components (temp, humidity, slope, etc.) Dependent variables Community Diversity data: diversity of rest of species in the community Ecological Correlates data: number of crazy ant colonies Possible experimental methods Locate appropriate sites Community Diversity data: Sample for insects using an active sampling method - probably either sweeping or searching and hand collecting -- alternatively, the TAs could set up some pitfall traps in probably useful areas, and the responsibilities of the students could then be to collect and sort the results Ecological Correlates data: systematically survey (preferably using a grid and randomly choosing sites) for crazy ant presence in a diversity of sites and thoroughly describe the abiotic and biotic components of each sample site Analyze data (using community diversity indices for the Community Diversity data and using a regression for the Ecological Correlates data) Students should compare their results with each other and a discussion of measurement error should ensue, facilitated by the instructor -- students should be made to realize that the collection of all data involves subjectivity and that it is the responsibility of the scientist to be aware of when subjectivity is present in a research design and to impose standards that will minimize measurement error Exact experimental methods will depend on the question and hypotheses being addressed ### Student Evaluation Students will be evaluated by having each lab group present a 10 minute oral lab report Each student in the group should present a component of the talk, unless a huge number of students are involved in a single project. In the latter instance, only a subset of the students should present.