[1] Plot sampling through area-based counts can also estimate the relative abundance of mobile organisms, like large mammals observed during aerial surveys.
However, additional information, like detection probability, may be necessary to estimate absolute population sizes for mobile organisms.
The first is design-based methods, which examine the randomness in the plots and relate it to the entire survey region.
The second approach is model-based methods, which uses statistical models to relate the numbers to the survey region.
The ability to quantify species abundance and statistically analyze this has been extremely helpful in studying community and population dynamics.