mirror.barplot - mirrored barplot for comparing positive and negative changes in a variable

The code for this function can be found here.

The arguments to pass to the function are:

To demonstrate this function I will use data comparing the climatic conditions of invasive ranges of species to that of their native ranges (N. Crouch, unpublished data)

# The function
source("mirror.barplot.R")

# The data
dat <- read.csv("analysis_data.csv")

I will first calculate whether the temperature of the invasive ranges exceeds that of the native ranges

# Lower minimum temperature in invasive range
tMin <- dat$Native_Temp_Min - dat$Invasive_Temp_Min
tMin[tMin < 0] <- 0
dat$TempMinIncrease <- tMin

# Higher maximum temperature in invasive range
tMax <- dat$Invasive_Temp_Max - dat$Native_Temp_Max
tMax[tMax < 0] <- 0
dat$TempMaxIncrease <- tMax

Now the plot can be generated:

mirror.barplot(lower.vals = dat$TempMinIncrease, upper.vals = dat$TempMaxIncrease, upper.y.text = "Increase in Maximum Temperature", lower.y.text = "Increase in Minimum Temperature", cols=c("#0072B2", "#D55E00"), margins=c(0.05,0.75,0.05,0.1), y.lab.cex=0.6)

Each column in the plot represents a single species. The orange values below the line show where the minimum temperature in the invasive range exceeds that of the native range. The blue values show where the maximum temperature of the invasive range is greater than that of the native range.