multipart: Multiplicative Diversity Partitioning

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

Description

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

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multipart(...)
## Default S3 method:
multipart(y, x, index=c("renyi", "tsallis"), scales = 1,
    global = FALSE, relative = FALSE, nsimul=99, ...)
## S3 method for class 'formula'
multipart(formula, data, index=c("renyi", "tsallis"), scales = 1,
    global = FALSE, relative = FALSE, nsimul=99, ...)

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. If x 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, where y is the community data matrix with samples as rows and species as column. Right hand side (x) must be grouping variables 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, at least two levels specified). 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 permutation to use if matr is not of class 'permat'. If nsimul = 0, only the FUN argument is evaluated. It is thus possible to reuse the statistic values without using a null model.

...

Other arguments passed to oecosimu, i.e. method, thin or burnin.

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_i)

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, β_{i} = mean(β_{ij}).

If relative = TRUE, the respective beta diversity values are standardized by their maximum possible values (mean(β_{ij}) / β_{max,ij}) given as β_{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 randomisation of the community data matrix. This is done by the "r2dtable" method in oecosimu by default.

Value

An object of class 'multipart' with same structure as 'oecosimu' objects.

Author(s)

Péter Sólymos, solymos@ualberta.ca

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.

See Also

See adipart for additive diversity partitioning, hiersimu for hierarchical null model testing and oecosimu for permutation settings and calculating p-values.

Examples

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## 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(
    l1=1:nrow(mite),
    l2=cutter(y, cut = seq(0, 10, by = 2.5)),
    l3=cutter(y, cut = seq(0, 10, by = 5)),
    l4=cutter(y, cut = seq(0, 10, by = 10))))
## Multiplicative diversity partitioning
multipart(mite, levsm, index="renyi", scales=1, nsimul=19)
multipart(mite ~ ., levsm, index="renyi", scales=1, nsimul=19)
multipart(mite ~ ., levsm, index="renyi", scales=1, nsimul=19, relative=TRUE)
multipart(mite ~ ., levsm, index="renyi", scales=1, nsimul=19, global=TRUE)

Example output

Loading required package: permute
Loading required package: lattice
This is vegan 2.4-3
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    8.0555  -57.642 12.19732 12.08629 12.21029 12.3135     0.05 *
alpha.2   11.2353  -80.659 14.09259 14.02745 14.09644 14.1556     0.05 *
alpha.3   12.0064 -304.976 14.13633 14.12600 14.13761 14.1489     0.05 *
gamma     14.1603    0.000 14.16027 14.16027 14.16027 14.1603     1.00  
beta.1     1.3568   25.650  1.15877  1.14627  1.15961  1.1703     0.05 *
beta.2     1.0710   27.762  1.00311  0.99855  1.00270  1.0077     0.05 *
beta.3     1.1794  359.115  1.00169  1.00080  1.00160  1.0024     0.05 *
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
multipart object

Call: multipart(formula = mite ~ ., 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  -69.574 12.1712 12.0881 12.1628 12.2884     0.05 *
alpha.2   11.2353  -90.855 14.0714 14.0289 14.0710 14.1307     0.05 *
alpha.3   12.0064 -483.106 14.1347 14.1271 14.1340 14.1416     0.05 *
gamma     14.1603    0.000 14.1603 14.1603 14.1603 14.1603     1.00  
beta.1     1.3568   27.375  1.1604  1.1445  1.1620  1.1689     0.05 *
beta.2     1.0710   32.363  1.0045  1.0004  1.0044  1.0071     0.05 *
beta.3     1.1794  568.722  1.0018  1.0013  1.0019  1.0023     0.05 *
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
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  -66.238 12.178840 12.111465 12.179886 12.2923     0.05 *
alpha.2 11.235261 -107.566 14.081574 14.038939 14.082429 14.1210     0.05 *
alpha.3 12.006443 -293.102 14.135137 14.123732 14.136415 14.1463     0.05 *
gamma   14.160271    0.000 14.160271 14.160271 14.160271 14.1603     1.00  
beta.1   0.078594   23.389  0.068437  0.067709  0.068512  0.0691     0.05 *
beta.2   0.535514   35.425  0.501908  0.500405  0.502146  0.5034     0.05 *
beta.3   0.589695  345.059  0.500889  0.500494  0.500844  0.5013     0.05 *
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
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  -57.118 12.2037 12.0819 12.2163 12.3333     0.05 *
alpha.2   11.2353 -106.017 14.0854 14.0419 14.0797 14.1237     0.05 *
alpha.3   12.0064 -403.394 14.1344 14.1257 14.1348 14.1419     0.05 *
gamma     14.1603    0.000 14.1603 14.1603 14.1603 14.1603     1.00  
beta.1     1.7578   86.542  1.1604  1.1481  1.1591  1.1720     0.05 *
beta.2     1.2603  132.886  1.0053  1.0026  1.0057  1.0084     0.05 *
beta.3     1.1794  474.860  1.0018  1.0013  1.0018  1.0024     0.05 *
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

vegan documentation built on May 2, 2019, 5:51 p.m.