Multiplicative Diversity Partitioning
multipart.Rd
In multiplicative diversity partitioning, mean values of alpha diversity at lower levels of a sampling hierarchy are compared to the total diversity in the entire data set or the pooled samples (gamma diversity).
Usage
multipart(...)
# S3 method for default
multipart(y, x, index=c("renyi", "tsallis"), scales = 1,
global = FALSE, relative = FALSE, nsimul=99, method = "r2dtable", ...)
# S3 method for formula
multipart(formula, data, index=c("renyi", "tsallis"), scales = 1,
global = FALSE, relative = FALSE, nsimul=99, method = "r2dtable", ...)
Arguments
- y
A community matrix.
- x
A matrix with same number of rows as in
y
, columns coding the levels of sampling hierarchy. The number of groups within the hierarchy must decrease from left to right. Ifx
is missing, two levels are assumed: each row is a group in the first level, and all rows are in the same group in the second level.- formula
A two sided model formula in the form
y ~ x
, wherey
is the community data matrix with samples as rows and species as column. Right hand side (x
) must be grouping variable(s) referring to levels of sampling hierarchy, terms from right to left will be treated as nested (first column is the lowest, last is the highest level). The formula will add a unique indentifier to rows and constant for the rows to always produce estimates of row-level alpha and overall gamma diversities. You must use non-formula interface to avoid this behaviour. Interaction terms are not allowed.- data
A data frame where to look for variables defined in the right hand side of
formula
. If missing, variables are looked in the global environment.- index
Character, the entropy index to be calculated (see Details).
- relative
Logical, if
TRUE
then beta diversity is standardized by its maximum (see Details).- scales
Numeric, of length 1, the order of the generalized diversity index to be used.
- global
Logical, indicates the calculation of beta diversity values, see Details.
- nsimul
Number of permutations to use. If
nsimul = 0
, only theFUN
argument is evaluated. It is thus possible to reuse the statistic values without a null model.- method
Null model method: either a name (character string) of a method defined in
make.commsim
or acommsim
function. The default"r2dtable"
keeps row sums and column sums fixed. Seeoecosimu
for Details and Examples.- ...
Other arguments passed to
oecosimu
, i.e.method
,thin
orburnin
.
Details
Multiplicative diversity partitioning is based on Whittaker's (1972) ideas, that has recently been generalised to one parametric diversity families (i.e. Rényi and Tsallis) by Jost (2006, 2007). Jost recommends to use the numbers equivalents (Hill numbers), instead of pure diversities, and proofs, that this satisfies the multiplicative partitioning requirements.
The current implementation of multipart
calculates Hill numbers
based on the functions renyi
and tsallis
(provided as index
argument).
If values for more than one scales
are desired,
it should be done in separate runs, because it adds extra dimensionality
to the implementation, which has not been resolved efficiently.
Alpha diversities are then the averages of these Hill numbers for
each hierarchy levels, the global gamma diversity is the alpha value
calculated for the highest hierarchy level.
When global = TRUE
, beta is calculated relative to the global gamma value:
$$\beta_i = \gamma / \alpha_{i}$$
when global = FALSE
, beta is calculated relative to local
gamma values (local gamma means the diversity calculated for a particular
cluster based on the pooled abundance vector):
$$\beta_ij = \alpha_{(i+1)j} / mean(\alpha_{ij})$$
where \(j\) is a particular cluster at hierarchy level \(i\).
Then beta diversity value for level \(i\) is the mean of the beta
values of the clusters at that level, \(\beta_{i} = mean(\beta_{ij})\).
If relative = TRUE
, the respective beta diversity values are
standardized by their maximum possible values (\(mean(\beta_{ij}) / \beta_{max,ij}\))
given as \(\beta_{max,ij} = n_{j}\) (the number of lower level units
in a given cluster \(j\)).
The expected diversity components are calculated nsimul
times by individual based randomization of the community data matrix.
This is done by the "r2dtable"
method in oecosimu
by default.
References
Jost, L. (2006). Entropy and diversity. Oikos, 113, 363--375.
Jost, L. (2007). Partitioning diversity into independent alpha and beta components. Ecology, 88, 2427--2439.
Whittaker, R. (1972). Evolution and measurement of species diversity. Taxon, 21, 213--251.
Author
Péter Sólymos, solymos@ualberta.ca
Examples
## NOTE: 'nsimul' argument usually needs to be >= 99
## here much lower value is used for demonstration
data(mite)
data(mite.xy)
data(mite.env)
## Function to get equal area partitions of the mite data
cutter <- function (x, cut = seq(0, 10, by = 2.5)) {
out <- rep(1, length(x))
for (i in 2:(length(cut) - 1))
out[which(x > cut[i] & x <= cut[(i + 1)])] <- i
return(out)}
## The hierarchy of sample aggregation
levsm <- with(mite.xy, data.frame(
l2=cutter(y, cut = seq(0, 10, by = 2.5)),
l3=cutter(y, cut = seq(0, 10, by = 5))))
## Multiplicative diversity partitioning
multipart(mite, levsm, index="renyi", scales=1, nsimul=19)
#> multipart object
#>
#> Call: multipart(y = mite, x = levsm, index = "renyi", scales = 1,
#> nsimul = 19)
#>
#> nullmodel method ‘r2dtable’ with 19 simulations
#> options: index renyi, scales 1, global FALSE
#> alternative hypothesis: statistic is less or greater than simulated values
#>
#> statistic SES mean 2.5% 50% 97.5% Pr(sim.)
#> alpha.1 11.235 -99.509 14.09048 14.04663 14.09131 14.1474 0.05 *
#> gamma 12.006 -348.038 14.13875 14.12825 14.13803 14.1498 0.05 *
#> beta.1 1.071 33.469 1.00343 0.99973 1.00321 1.0067 0.05 *
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
multipart(mite ~ l2 + l3, levsm, index="renyi", scales=1, nsimul=19)
#> multipart object
#>
#> Call: multipart(formula = mite ~ l2 + l3, data = levsm, index =
#> "renyi", scales = 1, nsimul = 19)
#>
#> nullmodel method ‘r2dtable’ with 19 simulations
#> options: index renyi, scales 1, global FALSE
#> alternative hypothesis: statistic is less or greater than simulated values
#>
#> statistic SES mean 2.5% 50% 97.5% Pr(sim.)
#> alpha.1 8.0555 -47.062 12.2155 12.0911 12.2221 12.3674 0.05 *
#> alpha.2 11.2353 -135.153 14.0817 14.0448 14.0836 14.1160 0.05 *
#> alpha.3 12.0064 -358.454 14.1366 14.1293 14.1363 14.1463 0.05 *
#> gamma 14.1603 0.000 14.1603 14.1603 14.1603 14.1603 1.00
#> beta.1 1.3568 20.543 1.1569 1.1381 1.1593 1.1693 0.05 *
#> beta.2 1.0710 41.656 1.0039 1.0012 1.0040 1.0071 0.05 *
#> beta.3 1.1794 422.087 1.0017 1.0010 1.0017 1.0022 0.05 *
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
multipart(mite ~ ., levsm, index="renyi", scales=1, nsimul=19, relative=TRUE)
#> multipart object
#>
#> Call: multipart(formula = mite ~ ., data = levsm, index = "renyi",
#> scales = 1, relative = TRUE, nsimul = 19)
#>
#> nullmodel method ‘r2dtable’ with 19 simulations
#> options: index renyi, scales 1, global FALSE
#> alternative hypothesis: statistic is less or greater than simulated values
#>
#> statistic SES mean 2.5% 50% 97.5% Pr(sim.)
#> alpha.1 8.055481 -46.057 12.160875 12.017502 12.163440 12.3190 0.05 *
#> alpha.2 11.235261 -84.304 14.090944 14.030323 14.096148 14.1438 0.05 *
#> alpha.3 12.006443 -377.188 14.136991 14.127885 14.138083 14.1454 0.05 *
#> gamma 14.160271 0.000 14.160271 14.160271 14.160271 14.1603 1.00
#> beta.1 0.078594 18.030 0.068586 0.067704 0.068692 0.0695 0.05 *
#> beta.2 0.535514 27.033 0.501641 0.499654 0.501468 0.5040 0.05 *
#> beta.3 0.589695 444.085 0.500823 0.500524 0.500785 0.5011 0.05 *
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
multipart(mite ~ ., levsm, index="renyi", scales=1, nsimul=19, global=TRUE)
#> multipart object
#>
#> Call: multipart(formula = mite ~ ., data = levsm, index = "renyi",
#> scales = 1, global = TRUE, nsimul = 19)
#>
#> nullmodel method ‘r2dtable’ with 19 simulations
#> options: index renyi, scales 1, global TRUE
#> alternative hypothesis: statistic is less or greater than simulated values
#>
#> statistic SES mean 2.5% 50% 97.5% Pr(sim.)
#> alpha.1 8.0555 -61.701 12.2040 12.1199 12.1869 12.3385 0.05 *
#> alpha.2 11.2353 -86.090 14.0830 14.0156 14.0933 14.1336 0.05 *
#> alpha.3 12.0064 -479.841 14.1363 14.1288 14.1361 14.1451 0.05 *
#> gamma 14.1603 0.000 14.1603 14.1603 14.1603 14.1603 1.00
#> beta.1 1.7578 93.927 1.1603 1.1477 1.1619 1.1684 0.05 *
#> beta.2 1.2603 107.736 1.0055 1.0019 1.0048 1.0103 0.05 *
#> beta.3 1.1794 565.007 1.0017 1.0011 1.0017 1.0022 0.05 *
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1