ChapmanMR: Chapman Mark/Recapture Abundance Estimator

In KevinSee/SiteAbundances: Template

Description

This is the modified Lincoln-Petersen or Chapman estimator. It estimates abundance based on a single mark event with a single recapture event.

Usage

ChapmanMR(data, rmInvalid = T)

Arguments

data	a dataframe or matrix with 3 columns for the number of marked, captured and recaptured individuals.
rmInvalid	if TRUE, marks any invalid estimates of N.hat and N.hat.SE as NA

Details

The data must consiste of a dataframe or matrix with three columns. The first is the number of individuals marked after the first capture event. The second is the total number of individuals captured during the second capture (recapture) event. The third is the number of those captured during the second capture event that were marked individuals, i.e. the number of recaptures.

The equation used is: N = [(M+1) * (C+1)] / (R+1) - 1

Estimates may be considered invalid when the product of the number of individuals captured on the first and second capture events is smaller than 4 times the estimated abundance. Based on Robson & Regier criteria.

Value

N.hat	estimate of abundance
N.hat.SE	standard error of abundance estimate
p.hat	estimate of the probability of capture

Author(s)

Kevin See, QCI, Seattle, WA

Examples

data(MR.data)
# estimate abundance
ChapmanMR(MR.data[,c('M', 'C', 'R')])

KevinSee/SiteAbundances documentation built on May 7, 2019, 12:30 p.m.