hpie {benthos} | R Documentation |
The probability that two individuals selected at random (without replacement) from a sample will belong to different species is given by (Hurlbert, 1971, p.579, Eq. 3):
Δ1 = ∑_{i=1}^S (N[i]/N)((N-N[i])(N-1)) = (N/(N-1))Δ2
where Δ2 (Hurlbert, 1971, p.579, Eq. 4) is the probability that two individuals selected at random (with replacement) from a sample will belong to different species:
Δ2 = 1 - ∑_{i=1}^S π[i]^2
where N[i] is the number of individuals of the ith
species in the community, N is the total number of individuals in the
community, π[i] = N[i]/N, and S is the number of
species in the community.
Note that Hurlbert's PIE hpie
is the complement of
simpson
.
hpie(.data = NULL, taxon, count) hpie_(.data = NULL, taxon, count)
.data |
data in a |
taxon |
name of column in |
count |
name of column in |
A numeric vector with the probability of interspecific encounter (PIE).
hpie_
: suitable for calling from a function
(see package lazyeval).
Hurlbert, S.H., 1971. The Nonconcept of Species Diversity: A Critique and Alternative Parameters. Ecology 52:577-586.
hpie( taxon = c("Euspira pulchella", "Nephtys cirrosa"), count = c(6, 12) )