Distribution of non-naturalised (yellow) and naturalised (purple) scores based on WRA (left) and likelihood-only scoring (right). Dotted lines represent the lower quartile, median and upper quartile while thick solid red lines represent the scoring threshold used by the Hawai‘i-Pacific WRA for designating species as high risk (> 6) and low risk (< 1). Dots represent scores for “Questionably Naturalised” species; grey = possibly extirpated, black = recently observed.