Quadrats are a used as a method of random sampling that assesses community diversity and composition (it is mostly used for plants and practically immobile animals).
http://hosho.ees.hokudai.ac.jp/~tsuyu/figs/50_frame.jpg
Radio Tracking is a method of sampling that is used to record the movement and actions of highly mobile species (best used for animals that are mobile).
http://www.planetepassion.eu/amphibians-in-france/Pond-turtle.with.radio.tracking.France.jpg
Point Sampling is good for determining species abundance and community composition; however, species in low abundance can be missed.
Transects determine changes in community composition along an environmental gradient, but can be time consuming to carry out.
http://www.ylmass.edu.hk/~bio/images/transect_line.jpg
