togetherness: Calculates the number of identical co-presences and...
In bipartite: Visualising Bipartite Networks and Calculating Some (Ecological) Indices

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

View source: R/togetherness.r

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.

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

`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`.

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

Carsten F. Dormann

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

C.score for another of Stone & Roberts' indices.

(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)