Change statistics.

getDeclineStats calculates the Proportional Rate of Decline (PRD), Absolute Rate of Decline (ARD) and Annual Rate of Change (ARC), given two areas at two points in time. Also provides the total area difference. Inputs are usually the results from getArea.

Usage

getDeclineStats(A.t1, A.t2, year.t1, year.t2, methods)

Arguments

A.t1: Area at time t1
A.t2: Area at time t2
year.t1: Year of time t1
year.t2: Year of time t2
methods: Method(s) used to calculate rate of decline. Either 'PRD', 'ARD', and/or 'ARC'. See vignette to see a more detailed explanation for each of them.

Value

A dataframe with absolute differences between the two inputs, and a selection of:

Proportional Rate of Decline (PRD)
Absolute Rate of Decline (ARD)
Annual Rate of Change (ARC)

References

IUCN 2024. Guidelines for the application of IUCN Red List of Ecosystems Categories and Criteria, Version 2.0. Keith, D.A., Ferrer-Paris, J.R., Ghoraba, S.M.M., Henriksen, S., Monyeki, M., Murray, N.J., Nicholson, E., Rowland, J., Skowno, A., Slingsby, J.A., Storeng, A.B., Valderrábano, M. & Zager, I. (Eds.) Gland, Switzerland: IUCN. ix + 94pp. https://doi.org/10.2305/CJDF9122 Puyravaud, J.-P. 2003. Standardizing the calculation of the annual rate of deforestation. Forest Ecology and Management, 177, 593-596.

Author

Nicholas Murray murr.nick@gmail.com, Calvin Lee calvinkflee@gmail.com

Examples

a.r1 <- 23.55
a.r2 <- 15.79
decline.stats <- getDeclineStats(a.r1, a.r2, year.t1 = 1990, year.t2 = 2012,
                                 methods = c('ARD', 'ARC'))