 Heard Island supports a relatively low number of terrestrial invertebrate species compared to other Southern Ocean islands, in parallel with the low species richness in the flora–that is, the island's isolation and limited ice-free area.Endemism is also generally low and the invertebrate fauna is exceptionally pristine with few, if any, (successful) human-induced introductions of alien species.Two species, including the thrips "Apterothrips apteris" and the mite "Tyrophagus putrescentiae" are thought to be recent, possibly natural, introductions.