Nassella tussock current and potential distributions in New Zealand

Abstract

Nassella tussock (Nassella trichotoma) occurs most frequently in droughtprone grasslands in several areas of New Zealand where it is the subject of surveillance and/or regional management strategies The potential range of nassella tussock in New Zealand was estimated using a climate model developed from global distribution data (excluding the known distribution for New Zealand) The climate suitability of New Zealand for nassella tussock was estimated using a gridded climate dataset with a spatial resolution of 10 minutes of arc The model projections encompassed all areas of current occupation as determined from the records of ten Local Authorities and revealed vast tracts of land particularly in southern Canterbury and Otago which are currently climatically suitable yet unoccupied by the weed This map will enable regional authorities to recognise sites most at risk of invasion (those with high climatic suitability that are nearby current or historical infestations) and factor this into their management programmes