Functions to calculate several ecological indices of individual
and population niche width (Araujo's E, clustering and pairwise similarity
among individuals, IS, Petraitis' W, and Roughgarden's WIC/TNW) to assess
individual specialization based on data of resource use. Resource use can
be quantified by counts of categories, measures of mass or length, or
proportions. Monte Carlo resampling procedures are available for hypothesis
testing against multinomial null models.
Details are provided in Zaccarelli et al. (2013)