fitEcm: Fit Equal Capture Model (ECM)

In mwpennell/capwire: Estimates population size from non-invasive sampling

Fit Equal Capture Model (ECM)

Description

Fits the Equal Capture Model (ECM) to count data to obtain the MLE for population size

Usage

fitEcm(data, max.pop)

Arguments

data	A two-column data frame with the first column specifiying the capture class (i.e. individuals in class i were caught i times) and the second column specifying the number of individuals in each class
max.pop	The maximum population size

Details

The ECM model fit by this function assumes that all individuals are equally likely to be "captured".

The value is specified for max.pop is not likely to matter as long as it is much greater than the maximum likelihood estimate for population size.

Note that if the data contains only singletons, the data is not informative and the maximum likelihood estimate for population size will be equal to max.pop

Value

an object of class capfit containing the follow elements:

model

The model specified

likelihood

The likelihood of the model

ml.pop.size

The maximum likelihood estimate for population size

cap.ind

The mean number of captures per individual

sampled.ind

The total number of individuals in the sample

sample.size

Total number of samples in the data set

max.pop

The maximum population size specified by max.pop

Author(s)

Matthew W. Pennell

References

Miller C. R., P. Joyce and L.P. Waits. 2005. A new method for estimating the size of small populations from genetic mark-recapture data. Molecular Ecology 14:1991-2005.

Pennell, M. W., C. R. Stansbury, L. P. Waits and C. R. Miller. 2013. Capwire: a R package for estimating population census size from non-invasive genetic sampling. Molecular Ecology Resources 13:154-157.

See Also

simEcm

Examples

## Simulate data under Equal Capture Model

data <- simEcm(n=40, s=150)

## Fit Equal Capture Model to Data

res <- fitEcm(data=data, max.pop=200)

res

mwpennell/capwire documentation built on Jan. 12, 2023, 11:19 a.m.