Azolla rubra R.Br. (Salviniaceae) on Rēkohu / Wharekauri / Chatham Island

Abstract

Azolla rubra (Salviniaceae) is reported from the Chatham Islands for the first time based on chance finds made in February and April 2023 from two lakes in the north-eastern portion of Rēkohu / Wharekauri / Chatham Island (hereafter Rēkohu). The biostatus of Azolla on the islands is reviewed and it is believed that plants are more likely to have arrived naturally via fragments bought to the islands by waterfowl from Aotearoa / New Zealand than by other means, so should be treated as indigenous. We advise that the impact of Azolla on the most sheltered, shallow, freshwater bodies of the islands should be monitored, as hitherto the islands waterbodies have been mostly devoid of free-floating aquatic plants.