Estimating Sloth Population in Costa Rica using the Lincoln Index Method

Question:

How can we estimate the sloth population in Costa Rica using the Lincoln Index (capture-mark-recapture) Method?

Answer:

Using the mark and recapture method or the Lincoln Index, the estimated sloth population in Costa Rica would be around 21 individuals.

The question pertains to using the Lincoln Index or the mark and recapture method, which is a common technique in ecology for estimating animal populations. This method involves capturing and marking a certain number of individuals, then recapturing and noting the proportion of marked individuals in the second capture.

The estimated abundance of the sloth population in Costa Rica is calculated by the product of the number of individuals captured the first and second times, divided by the number of marked individuals rediscovered on the second capture. In this case, with 15 sloths captured initially and 10 captured on the second visit with 7 being recaptures, the estimated population size would be (15 * 10) / 7, which equals approximately 21 sloths.

It is important to acknowledge that the Lincoln Index makes certain assumptions, such as the assumption that marked individuals mix back into the population, no significant changes in population size occur between captures, and the visibility of marks is consistent. Despite these assumptions, the method is valuable for estimating populations in large ecosystems.