# CzekanowskiVariance Niche Overlap Metric

### Description

Takes a niche utilization matrix returns the variance of the Czekanowski niche overlap index

### Usage

1 | ```
czekanowski_var(m = matrix(rpois(80, 1), nrow = 10))
``` |

### Arguments

`m` |
a matrix of resource utilization values. |

### Details

A large value for variance implies that some species pairs show high niche overlap and others show low niche overlap. A low value for variance implies that niche overlap (high or low) is very similar among all species pairs.

### Value

Returns the variance of the average pairwise niche overlap.

### Note

The resource utilization matrix (rows = species, columns = discrete resource categories) may include zeroes, but no negative numbers or missing values. Relative resource within a species is first calculated, so the rows need not sum to 1.0.

### References

Winemiller, K.O. and E.R. Pianka. 1990. Organization in natural assemblages of desert lizards and tropical fishes. Ecological Monographs 60: 27-55.

### See Also

`czekanowski`

niche overlap index.

### Examples

1 | ```
obsVar <- czekanowski_var(m=matrix(rpois(40,0.5),nrow=8))
``` |