Ecology 5th Edition by Manuel Molles

Exercise 16

Concept 10.5 says that we can use the information in life tables and fecundity schedules to estimate some characteristics of populations ( R 0 , T, r ). Why does Concept 10.5 use the word "estimate" rather than "calculate"? In putting together your answer, think about the population of P. drummondii studied by Leverich and Levin (1979). We calculated R 0 for this population by summing the l x m x column. When we did, the number we got was R 0 = 2.4177. Assuming that Leverich and Levin accurately counted seeds and surviving plants, is 2.4177 an estimate of the average reproductive rate of the 996 individual P. drummondii in their study? Right, 2.4177 is not an estimate; it's the actual average number of seeds produced by these 996 individuals. So, what's this estimate business about? If Leverich and Levin had studied a second (or third, fourth, etc.) group of 996 individuals in their P. drummondii population, do you think it's likely that they would have gotten an R 0 exactly equal to 2.4177?