SIcalc {ecorest}

Computes Suitability Indices

Description

SIcalc computes suitability indices given a set of suitability curves and project-specific inputs. Suitability indices may be computed based on either linear interpolation (for continuous variables) or a lookup method (for categorical variables).

Usage

SIcalc(SI, input.proj)

Arguments

SI

matrix of suitability curves ordered as parameter breakpoints and associated suitability indices for each parameter.

input.proj

numeric or categorical vector of application-specific input parameters associated with the suitability curve data from SI.

Value

A vector of the suitability index values that match given user inputs. Values are returned as equal to the extreme of a range if inputs are outside of model range.

References

US Fish and Wildlife Service. (1980). Habitat as a basis for environmental assessment. Ecological Services Manual, 101.

US Fish and Wildlife Service. (1980). Habitat Evaluation Procedures (HEP). Ecological Services Manual, 102.

US Fish and Wildlife Service. (1981). Standards for the Development of Habitat Suitability Index Models. Ecological Services Manual, 103.

Examples

#Build and define a matrix of the Barred Owl suitability curves
#Allen A.W. 1982. Habitat Suitability Index Models: Barred owl. FWS/OBS 82/10.143.
#U.S. Fish and Wildlife Service. https://pubs.er.usgs.gov/publication/fwsobs82_10_143.
var1 <- cbind(c(0,2,4,NA), c(0.1,1,1,NA)) #Number of trees > 51cm diameter per 0.4 ha plot
var2 <- cbind(c(0,5,20,NA), c(0,0,1,NA)) #Mean diameter of overstory trees
var3 <- cbind(c(0,20,60,100), c(0,0,1,1)) #Percent canopy cover of overstory trees
barredowl <- cbind(var1, var2, var3)
colnames(barredowl)<- c("tree.num", "tree.num.SIV",
  "avg.dbh.in", "avg.dbh.SIV", "can.cov", "can.cov.SIV")

#Set user input variables that should return (1, 0, 0)
input.demo1 <- c(2, 5, 20)
SIcalc(barredowl, input.demo1)

#Set user input variables that should return (1, 1, 1)
input.demo2 <- c(4, 20, 60)
SIcalc(barredowl, input.demo2)

#Set user input variables that should return (1, 1, 0.5)
input.demo3 <- c(4, 20, 40)
SIcalc(barredowl, input.demo3)

#Set user input variables that should return (0.1, 0.5, 0.5)
input.demo4 <- c(0, 12.5, 40)
SIcalc(barredowl, input.demo4)

#Set user input variables that should return (1, 1, 1)
input.demo5 <- c(4, 40, 60)
SIcalc(barredowl, input.demo5)

#Set user input variables that should return (1, NA, 1)
input.demo6 <- c(4, NA, 60)
SIcalc(barredowl, input.demo6)

#Suitability curves may also be drawn from HSImodels (data within ecorest)
#Import Barred Owl suitability curves with HSImodels$barredowl
#The input examples are repeated from above

#Set user input variables that should return (1, 0, 0)
SIcalc(HSImodels$barredowl, input.demo1)

#Set user input variables that should return (1, 1, 1)
SIcalc(HSImodels$barredowl, input.demo2)

#Set user input variables that should return (1, 1, 0.5)
SIcalc(HSImodels$barredowl, input.demo3)

#Set user input variables that should return (0.1, 0.5, 0.5)
SIcalc(HSImodels$barredowl, input.demo4)

#Set user input variables that should return (1, 1, 1)
SIcalc(HSImodels$barredowl, input.demo5)

#Set user input variables that should return (1, NA, 1)
SIcalc(HSImodels$barredowl, input.demo6)