curvature: Compute the values of the curvature of the beta profile...

In BioFTF: Biodiversity Assessment Using Functional Tools

Description

This function provides the values of the curvature of the beta profile for each part of the domain. The curvature reflects the community composition; in particular, if we consider communities with different numbers of species, the curvature is a good indicator of the lack of balance among species. Great levels of curvature highlights high imbalance among different species and vice-versa.

Usage

curvature(x,n)

Arguments

x

A data matrix with the abundance of the species (the rows are the communities and the columns indicate the species living in a community). The user can freely choose to use the absolute or relative frequencies.

n

The number of points of the domain [-1,1] that the user wants to consider in computing the functional tools. It is suggested to choose a number in the interval [3,10000] because a value of less than 3 has little sense; indeed, the major indices of biodiversity are the richness index, the index of Shannon and the index of Simpson (that we get for beta equal to -1, 0, +1, respectively). On the other hand, a value greater than 10000 is not very interesting because with a value of approximately 100 we already have a good approximation. The examples provided in this package always divide the domain into 20 intervals. The default value is n=20.

Author(s)

Fabrizio Maturo, Francesca Fortuna, Tonio Di Battista

Source

ENVIRONMENTAL MONITORING THROUGH FUNCTIONAL BIODIVERSITY TOOLS - T. Di Battista, F. Fortuna, F. Maturo - Ecological Indicators (2016) 60, 237-247 - online (2015). DOI: 10.1016/j.ecolind.2015.05.056.

PARAMETRIC FUNCTIONAL ANALYSIS OF VARIANCE FOR FISH BIODIVERSITY ASSESSMENT - T. Di Battista, F. Fortuna, F. Maturo - Journal of Environmental Informatics. Special issue of Marine and Freshwater Environmental Engineering and Management, Journal of Environmental Informatics. In press.

Examples

x=matrix(c(0.3,0.5,0.1,0.05,0.05,0.25,0.25,0.25,0.25,0,0.35,0.3,0.35,0,0),3,5)
curvature(x,20)

BioFTF documentation built on May 1, 2019, 10:26 p.m.