Question 1. Consider a population of perennial plants that breed in the early spring and

suffer high drought-related mortality late in the summer. Field monitoring experiments

suggest that drought leads to a 50% decline in the population during the late summer (d =

0.5). Given this degree of mortality, use the model to calculate how many offspring each

individual would, on average, have to produce during the breeding season to prevent the

population from declining over time. In other words, calculate the minimum value of b that

would be compatible with population growth.

Scoring: Full credit for providing the correct answer and showing how the answer was

obtained (i.e., show your work).

Suppose that you are monitoring island endemic cricket population that has recently become

threatened due to an invasive parasitoid wasp species that is attacking its members. From

observations of birth and death rates, you estimate that the intrinsic growth rate of the cricket

population to be r = -0.05, which has a 95% confidence interval of:

95% C.I. for r = [-0.01, -0.1]

Since the entire confidence interval for your estimate of r is negative, your data imply that the

population will decline over time.