This Demonstration investigates the effectiveness of simple mark-recapture on a mobile population distributed over a regular grid at random using two popular search techniques. It also illustrates the importance of model assumptions in making reasonable population estimates.
Here the estimated population and estimated variance are based on the modified Lincoln–Petersen method, which can be found at the Wikipedia entry for Mark and recapture. The matrix plot shown illustrates the first round of searches. The lighter spots indicate the presence of an organism and the darker spots indicate a search. The darkest regions occur when an organism is captured. All slider controls are treated as percentages. For example, if we increase our search effort to 1, we effectively search 100% of the forest. The model assumption violation slider allows for a percentage of the original population to disappear. This disappearance can be interpreted as a combination of dropped marks, emigration, and deaths.