Size ratio model is a data frame where each row is a different species and each column is a different site. In the size overlap analyses, each entry represents the body size of a particular species in a particular site. In phenology analyses, each entry represents the peak flowering time of a particular species in a particular site. EcoSimR comes with an example data set from Brown (1975).
species | Sonoran |
---|---|
Perognathus_flavus | 7.2 |
Reithrodontomys_megalotis | 11.4 |
Perognathus_penicillatus | 17.1 |
Peromyscus_maniculatus | 24.3 |
Dipodomys_merriami | 45.3 |
Dipodomys_spectabilis | 120.0 |
Using the defaults you can run a model with a uniform size algorithm and a variance ratio metric
rodentMod <- size_null_model(dataRodents)
summary(rodentMod)
## Time Stamp: Tue Mar 31 22:24:01 2015
## Reproducible: FALSE
## Number of Replications: 1000
## Elapsed Time: 0.15 secs
## Metric: var_ratio
## Algorithm: size_uniform
## Observed Index: 0.25135
## Mean Of Simulated Index: 3.6846
## Variance Of Simulated Index: 21.524
## Lower 95% (1-tail): 0.31041
## Upper 95% (1-tail): 13.572
## Lower 95% (2-tail): 0.23314
## Upper 95% (2-tail): 17.999
## Lower-tail P = 0.032
## Upper-tail P = 0.968
## Observed metric > 32 simulated metrics
## Observed metric < 968 simulated metrics
## Observed metric = 0 simulated metrics
## Standardized Effect Size (SES): -0.74
Get a standard histogram plot of output.
plot(rodentMod, type="hist")
Plot observed vs simulated body size data.
plot(rodentMod, type="size")
Brown, J. H. 1975. Geographical ecology of desert rodents. Pages 314-341 in M. L. Cody and J. M. Diamond, eds. Ecology And Evolution Of Communities. Harvard University Press, Cambridge.