While these results do not rule out alternative cold limitations, they indicate kudzu can survive winters north of its current distribution. Consistent with acclimation, the cold tolerance threshold of aboveground stems at the coldest time of year was - 26 ☌, while stems insulated from cold extremes survived to - 17 ☌-colder than the survival limits indicated by kudzu's biogeographic distribution. To assess this, we measured relative conductivity of above- and belowground stems, and roots collected throughout the winter at a kudzu population in southern Ontario, Canada. Temperatures causing this damage averaged - 19.6 ☌ for northern and - 14.4 ☌ for southern populations, indicating kudzu acclimates to winter cold. Relative conductivity above 36% was lethal. We evaluated this hypothesis using survival tests and electrolyte leakage to determine relative conductivity, a measure of cell damage, on 14 populations from eastern North America. Here, we used biogeographic evidence to hypothesize that exposure to - 20 ☌ is lethal for kudzu and thus determines its northern distribution limit. lobata) is an important invasive whose northern distribution appears to be limited by winter survival however, kudzu's cold tolerance thresholds are uncertain.
Abstract : The use of species distribution as a climate proxy for ecological forecasting is thought to be acceptable for invasive species.