Relative Methods of Population Measurement and the Derivation of Absolute Estimates

Relative sampling methods usually requiring comparatively simple equipment are described. These often concentrate the animals and provide impressive collections. Factors affecting the size of relative samples are reviewed to show that biological interpretation can be difficult. A wide variety of methods for aquatic and terrestrial sampling are reviewed, including pitfall, interception, light, sticky, and flight traps, electric fishing, drift samplers, and gill nets. The use of baited traps, including vertebrate hosts, is discussed. Removal trapping to estimate population density is described, and R software code listed.