Homework for Session 6

STUDENTS: Type the answers to the exercises and questions neatly and hand them in or e-mail them to your instructor before the next session.

Exercise

  1. The data below give the densities of small rodents and owls in a 100 km2 study area in western Finland from 1977 to 1987 (Korpimaki and Norrdahl 1989): Rodents: 190000, 60000, 103000, 66000, 58000, 229000, 82000, 98000, 147000, 188000, 63000. Tengmalm's owl: 54, 4, 17, 15, 9, 33, 22, 4, 27, 60, 4. Use the PAS Single-Species Time Series Analysis (P1a) and Two-Species Time Series Analysis (P2a) to analyze and model the data. Use the model to simulate the dynamics of the two-species interaction. Explain your results. Use the Two-Species Modeling and Simulation (P2b) to examine the equilibrium isoclines and discuss the meaning in terms of the biological control of small rodents.
  2. The data below give an index of the densities of jackrabbits and coyotes in Curlew Valley, Utah, from 1963 to 1973 (Wagner and Graetz 1981): Rabbit Index: 60, 38, 30, 24, 17, 63, 138, 180, 160, 60, 10. Coyote Index: 17.4, 15, 14.7, 10, 5.8, 2.3, 6.4, 10.6, 12.5, 25, 8.3. Use the PAS Single-Species Time Series Analysis (P1a) and Two-Species Time Series Analysis (P2a) to analyze and model the data. Use the model to simulate the dynamics of the two-species interaction. Explain your results. Use the Two-Species Modeling and Simulation (P2b) to examine the equilibrium isoclines and discuss the meaning in terms of the biological control of rabbits.

Reading

Berryman, A. A. 1998. The theoretical foundations of biological control. Chapter 1 in Theoretical Approaches to Biological Control, B. A. Hawkins, Ed., Cambridge University Press, Cambridge.

References

Korpimaki, E. and K. Norrdahl. 1989. Predation by Tengmalm's owls: numerical responses, functional responses and dampening impact on population fluctuations of microtines. Oikos 54: 154-164.

Wagner, F. H. and R. D. Graetz. 1981. Animal-animal interactions. Chapter 4 in Arid land ecosystems: structure, functioning and management, Volume 2, International Biological Programme 17, Cambridge University Press, Cambridge.