marindicators (version 1.0.0)

heips: Calculates Heip's Evenness Index

Description

This function calculates Heip's Evenness Index (HE) of the community for \(j\) areas and \(i\) years.

Usage

heips(X, groups, species.table = NULL, metric = "ABUNDANCE", years)

Arguments

X

A dataframe of fishery independent data derived from research vessel survey data or model output, with columns YEAR, ID, SPECIES, and ABUNDANCE. YEAR indicates the year the observation was recorded, ID is an area code indicating where the observation was recorded, SPECIES is a numeric code indicating the species sampled, and ABUNDANCE is the corresponding abundance (stratified and corrected for catchability as required).

groups

A vector indicating the species group(s) for which to calculate the indicator. If groups = "ALL", all species will be included; otherwise, each entry must be a character string matching the name of a column in species.table.

species.table

A table where the column names match the entries in groups. Column entries are species codes indicating the species from X included in each group. species.table may also include columns for other species groups; these will be ignored. If groups = "ALL", this table is not required. Default is species.table = NULL.

metric

A character string indicating which column in X to use to calculate the indicator. Default is metric = "ABUNDANCE".

years

A vector of years for which to calculate indicator.

Value

Returns a dataframe with columns ID and YEAR, and a column Heips_group for each entry in groups.

If there is no data for spatial scale \(j\) in year \(i\), indicator value is assigned NA.

Details

Heip's Evenness Index (HE): $$HE = (exp^{H'} - 1)/(S - 1)$$ where \(H'\) is Shannon's index of diversity and \(S\) is species richness. This index ranges from 0 to 1 and measures how equally the species richness contributes to the total abundance or biomass of the community (Heip, 1974).

References

Bundy A, Gomez C, Cook AM. 2017. Guidance framework for the selection and evaluation of ecological indicators. Can. Tech. Rep. Fish. Aquat. Sci. 3232: xii + 212 p.

Heip C. 1974. A new index measuring evenness. J. Mar. Biol. Asso. UK 54: 555-557.

Kenchington T, Kenchington E (2013) Biodiversity Metrics for Use in the Ecosystem Approach to Oceans Management. Can. Tech. Rep. Fish. Aquat. Sci. 3059: vi+188p.

See Also

Other biodiversity indicators: allBiodiversity, hillN1, hillN2, kemptonQ, margalef, pielouEvenness, shannon, speciesRichness

Examples

# NOT RUN {
data(X)
heips(X, groups = "ALL", species.table = NULL, metric = "ABUNDANCE", years = c(2014:2019))
# }