ettersonEq14v1 {carcass}

Equation 14 of Etterson (2013) Ecological Applications 23, 1915-1925, adapted so that persistence probability and searcher efficiency can vary with calender date

Description

Calculates the probability that a carcass that has fallen in the search area during n regular or irregular search intervals is found by a searcher.

Usage

ettersonEq14v1(s, f, J)

Arguments

s

vector of persistence probabilities with N elements, where N is the number of days in the full study period (i.e, N = sum(J)).

f

vector of searcher efficiency values (probabilities that a carcass present in the search area is found during one search) with n elements, where n is the number of searches performed.

J

a vector containing the lengths of the search intervals.

Details

This function assumes that persistence probability and searcher efficiency change over time and that this change depends upon serial date within your study period. In other words, it assumes that all carcasses in the environment on a given date experience the same scavenging probability and detectability, regardless of how old the carcasses is. However it does allow persistence probability and searcher efficiency to change with the calendar date.

Value

the probability that a carcass that has fallen into the search area during the study is found by the searcher.

Author(s)

M. A. Etterson

References

Etterson, M.A. (2013) Hidden Markov models for estimating animal mortality from antropogenic hazards. Ecological Applications, 23, 1915-1925.

See Also

ettersonEq14 ettersonEq14v2 pkorner phuso perickson

Examples

J <- c(2,3,2,4,3,5,3,2,3,4)
s <- plogis(seq(0.2, 2, length=sum(J)))
f <- plogis(seq(1.5, 0.9, length=length(J)))
ettersonEq14v1(s,f,J)