hillN2: Calculates Hill's Species Dominance (N2)

Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/hillN2.R


This function calculates Hill's Species Dominance (N2) for j areas and i years.


hillN2(X, groups, species.table = NULL, metric = "ABUNDANCE", years)



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).


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.


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.


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


A vector of years for which to calculate indicator.


Hill's Species Dominance (HillN2):

HillN2 = 1/Σ p_i^2

p_i is the proportion of the total sample contributed by the i(th) species. HillN2 is the inverse of the Simpson's index. This index is sensitive to the evenness of the distribution of individuals between species (Hill, 1973).


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

If there is no data for spatial scale j in year i, indicator values is assigned NA.


Danielle Dempsey Danielle.Dempsey@dfo-mpo.gc.ca, Adam Cook, Catalina Gomez, Alida Bundy


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.

Greenstreet SP, Rogers SI. 2006. Indicators of the health of the North Sea fish community: identifying reference levels for an ecosystem approach to management. ICES J Mar Sci J du Cons 63:573-593

Hill MO. 1973. Diversity and evenness: a unifying notation and its consequences. Ecology 54: 427-431.

See Also

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


hillN2(X, groups = "ALL", metric = "ABUNDANCE", years = c(2014:2019))

Example output

      ID YEAR HillDominance_ALL
1  AREA1 2014          3.951117
2  AREA1 2015          3.903130
3  AREA1 2016          3.174042
4  AREA1 2017          4.679784
5  AREA1 2018          5.597405
6  AREA1 2019          2.447229
7  AREA2 2014          4.886472
8  AREA2 2015          3.987204
9  AREA2 2016          4.597779
10 AREA2 2017          4.387534
11 AREA2 2018          3.031386
12 AREA2 2019          3.118748

marindicators documentation built on Nov. 12, 2019, 5:07 p.m.