redlistr (version 2.1.0)

getDeclineStats: Change statistics.

Description

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)

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)

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.

Author

Nicholas Murray , Calvin Lee

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. Puyravaud, J.-P. 2003. Standardizing the calculation of the annual rate of deforestation. Forest Ecology and Management, 177, 593-596.

See Also

Other Change functions: declineForecast(), getArea(), getAreaChange(), getAreaTrend()

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'))