sads-package {sads}R Documentation

Maximum Likelihood Models for Species Abundance Distributions


Maximum likelihood tools to fit and compare models of species abundance distributions and of species rank-abundance distributions.


The distribution of abundances of species is one of the basic patterns of ecological communities. The empirical distributions of abundances (SADs) or their ranks (RADs) are traditionally modelled through probability distributions. Hence, the maximum likelihood method can be used to fit and compare competing models for SADs and RADs. The sads package provides functions, classes and methods to:


Paulo I. Prado, Murilo Dantas Miranda and Andre Chalom

Maintainer: Paulo I. Prado <>


Magurran, A.E. 2004. Measuring Biological Diversity. Blackwell.

Magurran, A.E. and McGill, B.J. 2011. Biological Diversity – Frontiers in measurement and assessment. Oxford University Press.

May, R.M. 1975. Patterns of Species Abundance and Diversity. In M. L. Cody and J. M. Diamond (Eds.), (pp. 81–120). Harvard University Press.

Green,J. and Plotkin, J.B. 2007 A statistical theory for sampling species abundances. Ecology Letters 10:1037–1045.

Saether, B.E., Engen, S. and Grotan, V. 2013. Species diversity and community similarity in fluctuating environments: parametric approaches using species abundance distributions. Journal of Animal Ecology, 82(4): 721–738.

See Also

vignettes of sads; vegan-package and poilog-package


## Rank-abundance plot
plot( rad(moths) )
## Preston's plots
plot (octav(moths) )
## Fit logseries model <-  fitsad(moths, sad = 'ls')
## Diagnostic plots
par(mfrow = c(1,1))
## Model summary
## Confidence interval

[Package sads version 0.4.2 Index]