Persisting in a glaciated landscape: Pleistocene microrefugia evidenced by the tree wētā Hemideina maori in central South Island, New Zealand

Aim: Repeated cycles of Pleistocene glaciation have influenced phylogeographic structure of taxa on New Zealand’s South Island. Many taxa became restricted to refugia at either end of the island during glaciation, resulting in an area of low endemicity in central South Island. This area of low endemism is typified by the so-called beech (or biotic) gap, where the absence of Nothofagus forest (and many other plant and invertebrate taxa) has been attributed to repeated glaciation. Some taxa, however, appear to have persisted in situ in localized refugia within the biotic gap. We test these alternative hypotheses in a large flightless alpine wētā (grasshopper).

Location: Southern Alps, South Island, New Zealand

Taxon: Hemideina maori Pictet & Saussure, 1891 (Orthoptera: Anostostomatidae)

Methods: We used phylogeographic analysis of mitochondrial cytochrome c oxidase I (cox1) and twenty-five nuclear DNA (nuDNA) markers to test for Pleistocene glacial microrefugia within the cur...