indicator_moran: Moran's Index at lag of 1

In spatialwarnings: Spatial Early Warning Signals of Ecosystem Degradation

Description

This functions computes the Moran's spatial correlation index (with lag one). It also computes a null value obtained by randomizing the matrix.

Usage

indicator_moran(input, subsize = 1, nreplicates = 999)

Arguments

input	An matrix or a list of matrix object. It should be a square matrix
subsize	logical. Dimension of the submatrix used to coarse-grain the original matrix (set to 1 for no coarse-graining).
nreplicates	Number of replicates to produce to estimate null distribution of index (default: 999).

Value

A list (or a list of those if input is a list of matrix object) of:

• 'value': Spatial autocorrelation of the matrix

If nreplicates is above 2, then the list has the following additional components :

• 'null_mean': Mean autocorrelation of the null distribution

• 'null_sd': SD of autocorrelation in the null distribution

• 'z_score': Z-score of the observed value in the null distribution

• 'pval': p-value based on the rank of the observed autocorrelation in the null distribution.

References

Dakos, V., van Nes, E. H., Donangelo, R., Fort, H., & Scheffer, M. (2010). Spatial correlation as leading indicator of catastrophic shifts. Theoretical Ecology, 3(3), 163-174.

Legendre, P., & Legendre, L. F. J. (2012). Numerical Ecology. Elsevier Science.

Examples

## Not run: 
data(serengeti)

# One matrix
indicator_moran(serengeti[1])

# Several matrices
indicator_moran(serengeti)

## End(Not run)

spatialwarnings documentation built on May 2, 2019, 5:16 p.m.