Which sampling method involves marking and recapturing animals to estimate population size?

The capture-mark-recapture method is a widely used technique in ecology for estimating an animal population's size. This method involves capturing individuals from a population, marking them in a way that is non-invasive and does not affect their survival or behavior, and then releasing them back into their habitat. After allowing time for the marked individuals to mix back into the population, a second sample of individuals is captured. The proportion of marked to unmarked individuals in the second sample is then used to estimate the overall population size using mathematical formulas.

This method is particularly useful for species that are mobile and difficult to count directly. It provides a systematic approach to population estimation, making it a valuable tool in wildlife management and conservation efforts.

Other methods listed in the options have different applications. For instance, Simpson's Index of Diversity is a measure of biodiversity that takes into account both species richness and evenness, but it does not involve sampling for population size. Light traps are commonly used for capturing insects, but again, they don't provide a method for estimating population size like capture-mark-recapture does. Sweep netting involves collecting organisms from vegetation but is primarily a sampling technique rather than a population estimation method. Thus, capture-mark-recapture stands out as the appropriate method for estimating population size