Biological memory of the first pleistocene glaciation in New Zealand

Abstract

Living species retain memories of their evolutionary history in their DNA, and that evolutionary history commonly reflects distinct geological events, such as mountain building and glaciation. We synthesize previously documented genetic data for freshwater fishes and a wide range of upland insect and bird species to document the Pliocene and early Pleistocene topographic and glacial history of the Southern Alps of New Zealand. Genetic data for fish suggest that a long, linear mountain chain was established in the Pliocene. At that time, the mountain chain had a tectonically constructed narrow topographic neck in the middle, with wider uplift zones at either end. Separation of populations of upland insects and birds into faunal zones at the wider ends was caused by a major glacial advance at the narrow tectonic neck at 2 ± 0.5 Ma. The composite biological memory constrains the relative timing of uplift of the Southern Alps as a linear mountain chain, with subsequent imposition of temperate glaciation during Pliocene-Pleistocene cooling in the Southern Hemisphere.