baycheck {UsingR} | R Documentation

## Population estimate of type of Bay Checkerspot butterfly

### Description

Estimates of the population of a type of Bay Checkerspot butterfly near San Francisco.

### Usage

    data(baycheck)

### Format

A data frame with 27 observations on the following 2 variables.

year
  a numeric vector
Nt
  estimated number

### Source

From chapter 4 of Morris and Doak, Quantitative Conservation Biology: Theory and Practice of Population Viability Analysis, Sinauer Associates, 2003.

### Examples

    data(baycheck)
    plot(Nt ~ year,baycheck)
    ## fit Ricker model N_{t+1} = N_t e^{-rt}W_t
    n = length(baycheck$year)
    yt = with(baycheck,log(Nt[-1]/Nt[-n]))
    nt = with(baycheck,Nt[-n])
    lm(yt ~ nt,baycheck)

[Package UsingR version 0.1-4 Index]