entropart (version 1.1.3)

Simpson: Simpson entropy of a community

Description

Calculates the Simpson entropy of a probability vector.

Usage

Simpson(Ps, CheckArguments = TRUE)
bcSimpson(Ns, Correction = "Lande", CheckArguments = TRUE)

Arguments

Ps

A probability vector, summing to 1.

Ns

A numeric vector containing species abundances.

Correction

A string containing one of the possible corrections accepted by bcTsallis or "Lande", the default value.

CheckArguments

Logical; if TRUE, the function arguments are verified. Should be set to FALSE to save time when the arguments have been checked elsewhere.

Value

• A number equal to the calculated entropy.

Details

Lande's correction has been derived (Lande, 1996; Good, 1953) especially for Simpson entropy, while other corrections are for generalized Tsallis entropy. It is identical to the unbiased estimator proposed by Simpson, although arguments were different. Bias correction requires the number of individuals to estimate sample Coverage. Use bcSimpson and choose the Correction.

References

Good, I. J. (1953). On the Population Frequency of Species and the Estimation of Population Parameters. Biometrika 40(3/4): 237-264. Lande, R. (1996). Statistics and partitioning of species diversity, and similarity among multiple communities. Oikos 76: 5-13. Simpson, E. H. (1949). Measurement of diversity. Nature 163(4148): 688.

See Also

Tsallis, bcSimpson

Examples

# Load Paracou data (number of trees per species in two 1-ha plot of a tropical forest)
  data(Paracou618)
  # Ps is the vector of probabilities
  Ps <- Paracou618.MC$Ps
  # Calculate Simpson entropy
  Simpson(Ps)

  # Ns is the vector of abundances of the metacommunity
  Ns <- Paracou618.MC$Ns
  # Calculate an unbiased estimator of Simpson's index of diversity
  bcSimpson(Ns)