Directional mantel correlation

Share:

Description

Given a two-dimensional vegetation data frame and the x- and y-coordinates of the releves (the rows in the data frame) in geographical space, mantel correlation (function mantel in the vegan package) is evaluated at regular intervals of direction. Direction versus correlation is plotted including 95 percent confidence interval.

Usage

1
2
3
4
5
6
7
dircor(veg, x.axis, y.axis, step,...)
dircor2(veg, x.axis, y.axis, step = 5)

## Default S3 method:
dircor(veg, x.axis, y.axis, step,...)
## S3 method for class 'dircor'
plot(x,...)

Arguments

veg

A data frame of vegetation releves (rows) by species (columns)

x.axis

This is the x-coordinate in geographical space

y.axis

This is the y-coordinate in geographical space

step

The step length in degrees, used to draw the above mentioned function

x

An object of class "dircor"

...

Further variables used for printing

Details

The method presently uses correlation as distance, as.dist((1-cor(t(sveg^2.0)))/2), as distance measure for vegetation releves.

Value

An output list of class "dircor" with at least the following intems:

steps

The explicit steps used in degrees, 0 - 180 degrees

mean.correlation

Mantel correlation at each step

lower.limit

The lower confidence limits

upper.limit

The upper confidence limits

Note

Computation time is fairly long because function mantel() evaluates the confidence limits for each directional step between 0 and 180 degrees.

Author(s)

Otto Wildi

References

Legendre, P. & Fortin, M.-J. 1989. Spatial analysis and ecological modeling. Vegetatio 80: 107–138.

Wildi, O. 2013. Data Analysis in Vegetation Ecology. 2nd ed. Wiley-Blackwell, Chichester.

See Also

The function mantel() in the vegan package.

Examples

1
2
3
4
# vegetation data is taken from sveg
# the x- and y-axes are stored in object ssit
o.dircor<- dircor(sveg,ssit$x.axis,ssit$y.axis,step=40)
plot(o.dircor)

Want to suggest features or report bugs for rdrr.io? Use the GitHub issue tracker.