Estimating Population Size Using Lincoln Index - page 2
Keywords: Population Size Lincoln Index
By farahnad on 24/09/2007
Level: A Level (Year 12) / AS Level
Page Number: 2 of 4 pages: 1 2 3 4
N2 = N3 =
= 198 = 230 = 246
=
= 224.667
Discussion:
If a population of animal is large, it will be impossible to count all of them. One way we can obtain an estimate of their number is to use mark-release-recapture method. Mark-release-recapture is a method commonly used in ecology to estimate population size and population vital rates (i.e., survival, movement, and growth). This method is most valuable when a researcher fails to detect all individuals present within a population of interest every time that researcher visits the study area. Other names for this method, or closely related methods, include capture-recapture, capture-mark-recapture, mark-recapture, sight-resight, mark-release-recapture and band recovery.
Another major application for these methods is in epidemiology, where they are used to estimate the completeness of ascertainment of disease registers. Typical applications include estimating the number of people needing particular services, say services for children with learning disabilities, services for frail elderly living in the community, or with particular conditions, say illegal drug addicts, people infected with HIV, etc.
Population size can be estimated from taking at least two samples to estimate the population. Commonly, more than two samples are taken, particularly if estimates of survival or movement are desired. Regardless of the total number of sample taken, it is done by simply records the date of each capture of each individual. The "capture histories" generated are analyzed mathematically to estimate population size, survival, or movement.
Mark-release-recapture method generates an estimate of the population size called the Lincoln Index. This method is particularly suitable for use with small mobile animals living in a fairly well-defined habitat. This might be a population of woodlice under a log or a population of amphipod shrimps amongst some dead seaweed at the top of a beach. In this experiment, beans are used as the sample to show the simulation of population in estimating animal species. This is much simpler as movement of the sample is limited only within the box. The box is shaken so as to mix the marked beans with the unmarked bean. In a real situation, this is the show when the marked species mingle with the rest of the population.
In this experiment, the estimated number of species in the population is 225 which are very near to the actual total number of species in the population which is 211. Therefore, there is only little difference
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