railSims {wiqid}

Simulated detection/non-detection data for two species of rails

Description

A data set for single-season two-species occupancy modelling. See occ2sps for details of these kinds of models.

Usage

data("railSims")

Format

A data frame with detection (1) vs non-detection data for 2 species at 160 sites on three occasions.

A1, A2, A3

detection histories for the dominant species on 3 occasions

B1, B2, B3

detection histories for the subordinate species on 3 occasions

logArea

a continuous site covariate, standardised to mean 0, sd 1

reeds

a logical site covariate.

Details

The data come from a simulated scenario with the following parameters:

psiA	= plogis(0 + 2*logArea)	= probability of occupancy of species A
psiBa	= 0.77	= probability of occupancy of B if A is absent
psiBA	= plogis(-1 + 2*reeds)	= probability of occupancy of B if A is present
pA	= 0.75	= probability of detection of species A if B is absent
rA	= pA	= probability of detection of species A if both are present
pB	= 0.80	= probability of detection of species B if A is absent
rBa	= pB	= probability of detection of species B if both are present but A was not detected
rBA	= 0.40	= probability of detection of species B if both are present and A was detected

Source

Simulated data

References

Richmond, O.M.W., Hines, J.E., & Beissinger, S.R. (2010) Two-species occupancy models: a new parameterization applied to co-occurrence of secretive rails. Ecological Applications, 20, 2036-2046.

Examples

data(railSims)
# Separate the two detection histories
DHA <- railSims[, 1:3]
DHB <- railSims[, 4:6]

# Default model (no interaction)
occ2sps(DHA, DHB)


# Model with full interaction
occ2sps(DHA, DHB, list(psiBA ~ 1, rA ~ 1, rBa ~ 1, rBA ~ 1))

# Model corresponding to the data generation model
occ2sps(DHA, DHB, list(psiA ~ logArea, psiBA ~ reeds, rBA ~ 1), data=railSims)