O-statistics, or overlap statistics, measure the degree of community-level trait overlap.
They are estimated by fitting nonparametric kernel density functions to each species’ trait
distribution and calculating their areas of overlap. For instance, the median pairwise overlap
for a community is calculated by first determining the overlap of each species pair
in trait space, and then taking the median overlap of each species pair in a community.
This median overlap value is called the O-statistic (O for overlap).
The Ostats() function calculates separate univariate overlap statistics for each trait,
while the Ostats_multivariate() function calculates a single multivariate overlap statistic for all traits.
O-statistics can be evaluated against null models to obtain standardized effect sizes.
'Ostats' is part of the collaborative Macrosystems Biodiversity Project "Local- to continental-scale
drivers of biodiversity across the National Ecological Observatory Network (NEON)."
For more information on this project, see the Macrosystems Biodiversity Website
(< https://neon-biodiversity.github.io/>). Calculation of O-statistics is described in
Read et al. (2018)