bipartite: togetherness – R documentation

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togetherness

Calculates the number of identical co-presences and co-absences for species-on-islands

Description

Togetherness, or T-score, describes the level of similarity in the distributional pattern of two species. Originally proposed by Stone & Roberts (1992) for biogeographical situations can it also be applied e.g. to pollinators on different host plants.

Usage

togetherness(web, normalise=TRUE, FUN = mean, ...)

Arguments

`web`	A matrix with binary or counted interactions/links, where the higher trophic level is represented by columns.
`normalise`	Logical; shall index be normalised to a range of 0-1?
`FUN`	The function to summarise species-pair T-scores with; defaults to mean.
`...`	Arguments passed on to `FUN`, especially `na.rm=T` or colours for `hist`.

Value

Returns the average (default) togetherness of all species combinations.

Author(s)

Carsten F. Dormann

References

Stone, L. and Roberts, A. (1992) Competitive exclusion, or species aggregation? An aid in deciding. Oecologia 91, 419–424

Examples

(m <- matrix(c(0,1,0,0,1,1,0,1,1,0), ncol=2, byrow=TRUE))
togetherness(m)
# or, with two togethernesses:
(n <- matrix(c(0,1,1,0,1,1,0,0,1,1,0,1,0,1), ncol=2, byrow=TRUE))
togetherness(n, normalise=FALSE)

data(Safariland)
togetherness(m)

bipartite

Visualising Bipartite Networks and Calculating Some (Ecological) Indices

v2.16

GPL

Authors

Carsten F. Dormann, Jochen Fruend and Bernd Gruber, with additional code from Stephen Beckett, Mariano Devoto, Gabriel Felix, Jose Iriondo, Tove Opsahl, Rafael Pinheiro, Rouven Strauss and Diego Vazquez, also based on C-code developed by Nils Bluethgen, Aaron Clauset/Rouven Strauss and Miguel Rodriguez-Girones

Initial release

2021-02-08