MultiTraits (version 0.6.0)

LHS: Calculate LHS (Leaf-Height-Seed) Plant Ecological Strategy Classification

Description

The LHS scheme uses three fundamental plant traits that reflect important trade-offs controlling plant strategies:

• Specific Leaf Area (SLA): Light-capturing area deployed per unit dry mass, reflecting the trade-off between rapid resource acquisition and leaf longevity

• Height: Canopy height at maturity, expressing the amount of growth attempted between disturbances and competitive ability for light

• Seed Mass: Reflecting the trade-off between seed number and individual seed provisioning, affecting dispersal capacity and seedling survival

All three axes are log-scaled as they are approximately lognormally distributed between species. Species are classified into eight strategy types based on whether their log-transformed trait values are above (L = Large) or below (S = Small) the median values.

Usage

LHS(data)

Value

A data frame with the original columns plus:

log_SLA

Natural logarithm of SLA

log_Height

Natural logarithm of Height

log_SeedMass

Natural logarithm of SeedMass

LHS_strategy

Character string indicating the LHS strategy type (e.g., "S-L-S")

Arguments

data

A data frame containing plant trait data with the following required columns:

SLA

Specific leaf area (area per unit dry mass, typically mm2/mg or m2/kg)

Height

Canopy height at maturity (typically in metres)

SeedMass

Seed mass (typically in mg or g)

Row names should represent species names or identifiers.

Details

This function implements the LHS plant ecology strategy scheme proposed by Westoby (1998), which classifies plant species based on three key functional traits: specific leaf area (SLA), canopy height at maturity, and seed mass. The LHS scheme provides a quantitative framework for comparing plant ecological strategies worldwide.

The function performs the following operations:

1. Validates input data for required columns and checks for missing, zero, or negative values

2. Log-transforms all three traits

3. Calculates median values for each log-transformed trait

4. Classifies each species based on whether traits are above (L) or below (S) medians

5. Returns the original data with added log-transformed columns and strategy classification

References

1. Westoby, M. (1998). A leaf-height-seed (LHS) plant ecology strategy scheme. Plant and Soil, 199, 213–227.

2. Yang, J., Wang, Z., Zheng, Y., & Pan, Y. (2022). Shifts in plant ecological strategies in remnant forest patches along urbanization gradients. Forest Ecology and Management, 524, 120540.

Examples

data(PFF)
pff <- PFF[, c("SLA", "Height", "SeedMass")]
rownames(pff) <- PFF$species
head(pff)
result <- LHS(pff)
head(result)