The largest of the New Zealand species Dolomedes schauinslandi or Rangatira spider occurs in the Chatham Islands, where it occurs on rodent-free islands where running water is rare.
Rangatira is host to several rare and endemic species of birds and plants and is a sanctuary for endangered invertebrates such as the giant stick insect, Rangatira spider, coxella weevil and the Pitt Island longhorn beetle.