As usual, the problem set is due
next week at the beginning of lab.Data from: AkepaForest.xls
Year Density
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
1.461805 0.843124 0.809465 0.772998 0.696138 1.178799 0.798981 0.743477 0.734619 2.298882 1.682813 1.328402 0.898546 1.724918 1.539038 1.186112 1.438369 1.555484 0.886994 0.61843 0.942739
All tables and graphs must be in JWM format!! You will be docked points if you do not follow the guidelines. Provide complete captions explaining the figures and tables you hand in.
1a) Estimate relevant parameters (i.e., r(max), b, K) based for each of the 2 density dependent models we discussed (i.e., Ricker and Gompertz). Make a table to report the results. (6 points)
1b) Assuming the initial population density in 1987 = n(0) = 1.46, use the estimated parameters r(max) and b from the Ricker and Gompertz models to plot the predicted population size through 2007 (without adding any effect of stochasticity). (6 points)
1c) On this same graph, plot the actual population sizes from the original time series. (2 points)
1d) Are there any differences between the predictions from the 2 models (Ricker or Gompertz)? Explain. (6 points)
**Bonus** (5 additional points) Using just the parameters from the Ricker model, plot 3 possible time series of abundances with stochasticity starting with the observed density in 1987. You will need the additional parameter sigma = 0.353. Hint: you will need to use the formulas used in Lab 5 to generate random deviates. Add the actual observed densities to this plot. When compared to the predictions from question 2b, does this model seem more realistic when stochasticity is incorporated??
As usual, the problem set is due
next week at the beginning of lab.
Revised: 23 September 2011