macroBiome (version 0.4.0)

cliHoldridgePoints: Vegetation Classifier Using the HLZ System

Description

Calculates the values of bioclimatic indices used in the Holdridge life zone (HLZ) system (Holdridge 1947, 1967), and designates the HLZ type using these values, by using the monthly time series of temperature and precipitation.

Usage

cliHoldridgePoints(temp, prec, verbose = FALSE)

Value

Depending on the setting, a data frame with one or more columns where the HLZ types are stored in the last (character) column, while the additional columns contain the values of bioclimatic indices used. The abbreviations of HLZ types can be found in the data frame vegClsNumCodes. If

verbose = FALSE, the return object is a one-column data frame with the HLZ types.

Arguments

temp

'numeric' R object with one-year time series of monthly mean air temperature (in °C)

prec

'numeric' R object with one-year time series of monthly precipitation sum (in mm)

verbose

'logical' scalar that indicates whether or not values of the bioclimatic indices used should be added to the output.

Details

To classify vegetation, the HLZ system developed by Holdridge (1947, 1967) uses the values of the following 3 bioclimatic indices:

• abt: Mean Annual Biotemperature (Eq 1 in Szelepcsényi et al. (2014); in °C)

• tap: Total Annual Precipitation (in mm)

• per: Potential Evapotranspiration Ratio (Eq 4 in Szelepcsényi et al. (2014); dimensionless)

For details about calculating bioclimatic indices, see the function cliBioCliIdxPoints.
The HLZ system classifies the vegetation type based on the distance from the ideal (theoretical) point in the 3-dimensional space of bioclimatic indices. Numerous variants of the HLZ system are known (e.g., Henderson-Sellers 1994; Yates et al. 2000). Here, one of its most widely used versions ('version with no altitudinal belts') is implemented, in accordance with works of Szelepcsényi et al. (2014, 2018). In this version, a total of 39 HLZ types are distinguished (see vegClsNumCodes).

References

Henderson-Sellers A (1994) Global terrestrial vegetation ‘prediction’: the use and abuse of climate and application models. Prog Phys Geogr 18(2):209–246. tools:::Rd_expr_doi("10.1177/030913339401800203")

Holdridge LR (1947) Determination of World Plant Formations From Simple Climatic Data. Science 105(2727):367–368. tools:::Rd_expr_doi("10.1126/science.105.2727.367")

Holdridge LR (1967) Life zone ecology. Tropical Science Center, San Jose, Costa Rica

Szelepcsényi Z, Breuer H, Sümegi P (2014) The climate of Carpathian Region in the 20th century based on the original and modified Holdridge life zone system. Cent Eur J Geosci 6(3):293–307. tools:::Rd_expr_doi("10.2478/s13533-012-0189-5")

Szelepcsényi Z, Breuer H, Kis A, Pongrácz R, Sümegi P (2018) Assessment of projected climate change in the Carpathian Region using the Holdridge life zone system. Theor Appl Climatol 131(1–2):593–610. tools:::Rd_expr_doi("10.1007/s00704-016-1987-3")

Yates DN, Kittel TGF, Cannon RF (2000) Comparing the Correlative Holdridge Model to Mechanistic Biogeographical Models for Assessing Vegetation Distribution Response to Climatic Change. Clim Chang 44(1–2):59–87. tools:::Rd_expr_doi("10.1023/A:1005495908758")

Examples

# Loading mandatory data for the Example 'Points'
data(inp_exPoints)
data(vegClsNumCodes)

# Designate the HLZ type (using the related bioclimatic indices),
# at a grid cell near Szeged, Hungary (46.3N, 20.2E) (for the normal period 1981-2010)
with(inp_exPoints, {
HLZ <- cliHoldridgePoints(colMeans(temp), colMeans(prec), verbose = TRUE)
numCode <- which(sapply(vegClsNumCodes$Code.HLZ, identical, HLZ[, "vegCls"]))
cbind(HLZ[,-c(4)], vegClsNumCodes[numCode, c("Name.HLZ", "Code.HLZ")])
})