=3

1. A B A B Good years: =3 Bad years: =.7 =3 =.7 =3 =.7 Third example: Single population with temporal variability in growth rates. If the probability of a good year = 0.2, what is the probability of a bad year? 1pt: 1-0.2=0.8 What is the long-term growth rate if the probability of a good year = 0.2 ? 2pts: (3)0.2 x (0.7)0.8 = 0.963 if the probability of a good year = 0.5 ? 2pts: (3)0.5 x (0.7)0.5 = 1.449 In the latter example, why is your answer different than your first answer in the second example ? 2pts: geometric mean is sensitive to variance in growth rates. Second example: Even (i.e., 50%) migration between patches. What is the growth rate of the metapopulation? 3pts: (3+0.7)/2=1.85 How much must you reduce the growth rate in patch A to produce a stable metapopulation (i.e., neither growing nor declining) ? 3pts: change by 1.0 to make it 1.3 since (1.3+0.7)/2=1.0 First example: no migration between patches. Which patch is a source and which a sink ? 1pt: Pop A What will be the density of patch A in 4 years (t=4) if it starts out with 50 individuals (t=0) ? 1pt: 4050 or N4= (50)(3)4 What will be the density of patch A after an infinite amount of time? Is this realistic? 2pts: infinity, no What will be the density of patch B after an infinite amount of time? Is this realistic ? 2pts: 0, yes Extra Credit: Calculate the long-term growth rate for the white rhino example we went over in class. 5pts, answer on a separate sheet