Niche Region and Niche Overlap Metrics for Multidimensional Ecological Niches
Point coordinates for a 2-D ellipse.
Plot for niche parameters.
Plot for 2-d projection of niche regions.
Uniform sampling from an elliptical niche region.
Calculate the size of an elliptical niche region.
(Niche) (R)egion and Niche (Over)lap Metrics for Multidimensional Ecol...
Random draws from the posterior distribution with Normal-Independent-I...
Posterior coefficients of the Normal-Inverse-Wishart distribution with...
Mean and variance of the Normal-Inverse-Wishart distribution.
Random draws from the posterior distribution with Normal-Inverse-Wisha...
Plot the overlap metric.
Monte Carlo calculation of niche region overlap metrics.
Overlap calculation for uniform niche regions.
Random draws from a Normal-Inverse-Wishart distribution.
Random draws from a Wishart (or Inverse-Wishart) distribution.
Implementation of a probabilistic method to calculate 'nicheROVER' (_niche_ _r_egion and niche _over_lap) metrics using multidimensional niche indicator data (e.g., stable isotopes, environmental variables, etc.). The niche region is defined as the joint probability density function of the multidimensional niche indicators at a user-defined probability alpha (e.g., 95%). Uncertainty is accounted for in a Bayesian framework, and the method can be extended to three or more indicator dimensions. It provides directional estimates of niche overlap, accounts for species-specific distributions in multivariate niche space, and produces unique and consistent bivariate projections of the multivariate niche region. The article by Swanson et al. (2015) <doi:10.1890/14-0235.1> provides a detailed description of the methodology. See the package vignette for a worked example using fish stable isotope data.