As part of a study of the effects of timber management strategies (Ecological Applications [2003]: 1110–

1123) investigators used satellite imagery to study abundance of the lichen Lobaria oregano at different elevations.

Abundance of a species was classified as “common” if there were more than 10 individuals in a plot of land. In the table below, approximate proportions of plots in which Lobaria oregano were common are given.

Proportions of Plots Where Lobaria oregano Are Common Elevation (m) 400 600 800 1000 1200 1400 1600 Prop. of plots with lichen common 0.99 0.96 0.75 0.29 0.077 0.035 0.01

a. As elevation increases, does the proportion of plots for which lichen is common become larger or smaller? What aspect(s) of the table support your answer?

b. Using the techniques introduced in this section, cal-
culate yr 5 lna p 1 2 p b for each of the elevations and fit the line yr 5 a 1 b(Elevation). What is the equation of the best-fit line?

c. Using the best-fit line from Part (b), estimate the proportion of plots of land on which Lobaria oregano are classified as “common” at an elevation of 900 m.