BIOL 122 Lecture Notes - Lecture 18: Santa Barbara City College, Common Starling, Transect
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Censuses: counting all individuals in a population. Surveys: count a subset of the population. A number of techniques can be used to estimate population sizes and densities (stationary organisms) Area or volume-based surveys: count # of individuals within a limited area. Linear transect survey: sampling across a distance, counting the individuals seen as you move across a straight line from point a to b. The mark recapture method is also a reliable way to estimate population size. Better for things that move around a lot (birds) N = # actually in the population. Usually the value trying to be calculated. C = total # captured (time 2) Example: you are trying to estimate the population size of redheads on the. On day 1, you capture and mark 50 of the elusive individuals. On day 2, you capture 200 redheads of which 10 are already marked. For mobile organisms, dispersal can also be predicted by mark and recapture methods.
