SIcalc: Computes Suitability Indices

In ecorest: Conducts Analyses Informing Ecosystem Restoration Decisions

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 or dataframe of suitability curves ordered as parameter breakpoints and associated suitability indices for each parameter. Suitability curves that contain both continuous and categorical variables should be formatted as a dataframe rather than a matrix.
input.proj	numeric or categorical vector of application-specific input parameters associated with the suitability curve data from SI. Note that users should enter NA for excluded variables in HSImodels.

Value

A vector of the suitability index values ranging from 0 to 1 that match given user inputs.

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)

#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)


#Import juvenile Alewife suitability curves with HSImodels$alewifeJuv
#Demonstrate how to enter NA for excluded variables in HSImodels
#Pardue, GB. 1983. Habitat suitability index models: alewife and blueback herring. 
#U.S. Dept. Int. Fish Wildl. Serv. FWS/OBS-82/10.58. 22pp.

#Set user variables that should return (NA, NA, 1, 1, 0)
input.demo7 <- c(NA, NA, 125, 5, 5)
SIcalc(HSImodels$alewifeJuv, input.demo7)

ecorest documentation built on March 31, 2026, 1:07 a.m.